TM-55-1680-308-24

TM-55-1680-308-24
TM 55-1680-308-24
TECHNICAL MANUAL
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB80000
This copy is a reprint which includes current
pages from Changes 1 through 10.
TM 55-1680-308-24, dated 13 December
1974, rescinded by DA Pam 310-1, is now
reinstated for active Army and is available
through normal supply channels.
HEADQUARTERS, DEPARTMENT OF THE ARMY 13 DECEMBER 1974
This manual is published for the use of all concerned.
By Order of the Secretary of the Army
Official
VERNE L. BOWERS
Major General, United States Army
The Adjutant General
FRED C. WEYAND
General. United States Army
Chief of Staff
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31 Organizational Maintenance Requirements for OV-1A, B and
C, and OV-1D aircraft.
TM 55-1680-308-24
C 10
URGENT
CHANGE
NO. 10
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 14 May 1991
}
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB80000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical bar in the
margin. An illustration change is indicated by a miniature pointing hand.
2.
Remove pages
Insert pages
i and ii
1-1 and 1-2
3-1 and 3-2
4-47 and 4-48
4-48A/4-48B
i and ii
1-1 and 1-2
3-1 and 3-2
4-47 and 4-48
4-48A/4-48B
Retain this sheet in front of manual for reference purposes.
By Order of the Secretary of the Army:
CARL E. VUONO
General, United States Army
Chief of Staff
Official:
PATRICIA P. HICKERSON
Colonel, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31-E,
requirements for TM 55-1680-308-24.
URGENT
block no.
1102,
AVUM and AVIM maintenance
CHANGE
NO. 9,
TM 55-1680-308-24
C9
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 17 April 1990
}
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB80000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical bar in the
margin. An illustration change is indicated by a miniature pointing hand.
2.
Remove pages
Insert pages
4-47 and 4-48
4-48A/4-48B
4-47 and 4-48
4-48A/4-48B
Retain this sheet in front of manual for reference purposes.
By Order of the Secretary of the Army:
Official:
CARL E. VUONO
General, United States Army
Chief of Staff
WILLIAM J MEEHAN II
Brigadier General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31, AVUM and AVIM Maintenance requirements for OV-1B, OV-1C,
OV-1D, Airplane, Observation and RV-1D, Airplane Reconnaissance.
TM 55-1680-308-24
C8
CHANGE
NO. 8
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 4 October 1988
}
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB8000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical bar in the
margin. An illustration change is indicated by a miniature pointing hand.
2.
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i and ii
1-1 and 1-2
1-15 and 1-16
4-1 and 4-2
4-2A/4-2B
4-16A and 4-16B
4-17 and 4-18
4-37 and 4-38
4-41 and 4-42
4-51 and 4-52
--------4-55 through 4-58
5-31 and 5-32
--------5-49 and 5-50
A-1/A-2
i and ii
1-1 and 1-2
1-15 and 1-16
4-1 and 4-2
4-2A/4-2B
4-16A and 4-16B
4-17 and 4-18
4-37 and 4-38
4-41 and 4-42
4-51 and 4-52
4-52.1/4-52.2
4-55 through 4-58
5-31 and 5-32
5-32.1/5-32.2
5-49 and 5-50
A-1/A-2
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TM 55-1680-308-24
C8
By Order of the Secretary of the Army:
Official:
CARL E. VUONO
General, United States Army
Chief of Staff
WILLIAM J. MEEHAN II
Brigadier General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31, AVUM and AVIM Maintenance requirements for OV-1B, OV-1C,
OV-1D, Airplane, Observation and RV-1D, Airplane, Reconnaissance.
TM 55-1680-308-24
URGENT
CHANGE
NO. 7
C7
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 30 December 1987
}
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB8000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical bar in the
margin. An illustration change is indicated by a miniature pointing hand.
2.
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3-1 and 3-2
4-35 and 4-36
4-55 and 4-56
-----
3-1 and 3-2
4-35 and 4-36
4-55 and 4-56
4-56.1/4-56.2
Retain this sheet in front of manual for reference purposes.
By Order of the Secretary of the Army:
CARL E. VUONO
General, United States Army
Chief of Staff
R. L. DILWORTH
Brigadier General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31, AVUM and AVIM Maintenance requirements for OV-1B, OV-1C,
OV-1D, Airplane, Observation, and RV-1D, Airplane, Reconnaissance.
URGENT
TM 55-1680-308-24
C6
CHANGE
NO. 6
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 24 June 1987
}
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134B80000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical bar in the
margin. An illustration change is indicated by a miniature pointing hand.
2.
Remove pages
Insert pages
1-1 and 1-2
4-37 and 4-38
4-47 and 4-48
4-48A/(4-48B)
4-57 and 4-58
5-45 and 5-46
A-1/(A-2)
C-1 and C-2
1-1 and 1-2
4-37 and 4-38
4-47 and 4-48
4-48A/(4-48B)
4-57 and 4-58
5-45 and 5-46
A-1/(A-2)
C-1 and C-2
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By Order of the Secretary of the Army:
Official:
JOHN A. WICKHAM, JR.
General, United States Army
Chief of Staff
R. L. DILWORTH
Brigadier General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31, AVUM and AVIM Maintenance requirements for OV-1B, OV-1C,
OV-1D, Airplane, Observation, and RV-1D, Airplane, Reconnaissance.
TM 55-1680-308-24
C5
CHANGE
NO. 5
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 30 May 1985
}
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB80000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical bar in the
margin. An illustration change is indicated by a miniature pointing hand.
2.
Remove pages
Insert pages
i and ii
1-1 and 1-2
1-17 and 1-18
3-1 and 3-2
--4-1 and 4-2
--4-31 and 4-32
4-45 and 4-46
--4-47 through 4-48A/4-48B
4-51 and 4-52
4-57 and 4-58
5-9 and 5-10
5-37 and 5-38
i and ii
1-1 and 1-2
1-17 and 1-18
3-1 and 3-2
3-2A/3-2B
4-1 and 4-2
4-2A/4-2B
4-31 and 4-32
4-45 and 4-46
4-46A/4-46B
4-47 through 4-48A/4-48B
4-51 and 4-52
4-57 and 4-58
5-9 and 5-10
5-37 and 5-38
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By Order of the Secretary of the Army:
Official:
JOHN A. WICKHAM, JR.
General, United States Army
Chief of Staff
DONALD J. DELANDRO
Brigadier General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31, Organization,
Maintenance requirements for OV-1B/C and OV-1D/RV-1D aircraft.
Direct Support and General Support
TM 55-1680-308-24
C4
CHANGE
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 9 October 1982
}
NO. 4
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB80000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1.
Remove and insert pages as indicated below.
Table of Contents
Chapter 1
Chapter 3
Chapter 4
Chapter 5
Appendix A
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1 and ii
1-1 and 1-2
3-1 and 3-2
3-5 and 3-6
4-1 and 4-2
4-15 and 4-16
4-23 and 4-24
4-47 and 4-48
4-57 and 4-58
5-5 and 5-6
5-11 and 5-12
A-1/A-2
i and ii
1-1 and 1-2
3-1 and 3-2
3-5 and 3-6
4-1 and 4-2
4-15 thru 4-16B
4-23 and 4-24
4-47 and 4-48
4-57 and 4-58
5-5 and 5-6
5-11 and 5-12
A-1/A-2
2. New or changed text material is indicated by a vertical bar in the margin.
by a miniature pointing hand.
3.
An illustration change is indicated
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By Order of the Secretary of the Army:
Official:
E. C. MEYER
General, United States Army
Chief of Staff
ROBERT M. JOYCE
Major General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31, Organizational Maintenance Requirements for OV-1B/C and
OV-1D/RV-1D Aircraft.
TM 55-1680-308-24
C3
CHANGE
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 18 May 81
}
No. 3
ORGANIZATIONAL, DS AND GS MAINTENANCE MANUAL
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB80000
TM 55-1680-308-24, 13 December 1974 is changed as follows:
1.
Remove and insert pages as indicated below.
Chapter 1
Chapter 3
Chapter 4
Chapter 5
Remove pages
i and ii
1-1 and 1-2
1-5 and 1-6
1-11 and 1-12
1-15 and 1-16
3-1 and 3-2
4-1 and 4-2
4-5 and 4-6
4-15 thru 4-18
4-23 and 4-24
4-27 and 4-28
4-31 and 4-32
4-45 thru 4-48B
4-49 thru 4-52
4-57 and 4-58
5-3 and 5-4
5-39 and 5-40
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i and ii
1-1 and 1-2
1-5 and 1-6
1-11 and 1-12
1-15 and 1-16
3-1 and 3-2
4-1 and 4-2
4-5 and 4-6
4-15 thru 4-18
4-23 and 4-24
4-27 and 4-28
4-31 and 4-32
4-45 thru 4-48A/B
4-49 thru 4-52
4-57 and 4-58
5-3 and 5-4
5-39 and 5-40
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An illustration change is indicated by a miniature pointing hand.
3.
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By Order of the Secretary of the Army:
Official:
E. C. MEYER
General, United States Army
Chief of Staff
J. C. PENNINGTON
Major General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31, Organizational Maintenance Requirements for OV-1B/C and
OV-1D/RV-1D aircraft.
TM 55-1680-308-24
C2
CHANGE
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, DC., 17 January 1980
}
No. 2,
Organizational, DS and GS Maintenance Manual
EJECTION SEAT, MODEL MK-J5D
(MARTIN-BAKER)
PART NUMBER 134AB80000
TM 55-1680-308-24, 13 December 1974, is changed as follows:
1.
Remove and insert pages as indicated below.
Chapter 1
Chapter 3
Chapter 4
Chapter 5
Remove pages
Insert pages
Table of Contents
1-1 and 1-2
1-17 thru 1-19/1-20
3-1 and 3-2
4-1 and 4-2
4-15 and 4-16
4-17 thru 4-24
4-25 and 4-26
4-29 and 4-30
4-33 thru 4-34A/4-34B
4-37 thru 4-44
4-47 and 4-48
4-51 and 4-52
5-3 and 5-4
5-9 thru 5-12
5-33 thru 5-38
Back of Manual
i and ii i and ii
1-1 and 1-2
1-17 thru 1-20
3-1 and 3-2
4-1 and 4-2
4-15 thru 4-16B
4-17 thru 4-24A/4-24B
4-25 thru 4-26A/4-26B
4-29 and 4-30
4-33 and 4-34
4-37 thru 4-44
4-47 thru 4-48B
4-51 and 4-52
5-3 and 5-4
5-9 thru 5-12
5-33 thru 5-38B
DA Forms 2028
2. New or changed text material is indicated by a vertical bar in the margin.
An illustration change is indicated by a miniature pointing hand.
3.
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By Order of the Secretary of the Army:
Official:
E C. MEYER
General, United States Army
Chief of Staff
J. C. PENNINGTON
Major General, United State Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA Form 12-31 Organizational Maintenance Requirements for OV-1B/C and
OV-1D/RV-1D aircraft.
TM 55-1680-308-24
WARNING
PRECAUTIONARY DATA
Personnel performing operations, procedures, and practices which are included or implied in this technical manual shall
observe the following warnings. Disregard of these warnings and precautionary information can cause serious injury,
death, or destruction of material.
MAINTENANCE
Only authorized personnel may perform work on this ejection seat and only in an authorized area. Ensure that TCR
rocket motor locking pin is installed before removing seat from the aircraft.
Ensure that ground lock safety pins are installed unless preparing the aircraft for a mission or performing authorized
maintenance on components of the ejection seat requiring removal of safety pins.
No attempt shall be made by organizational maintenance personnel to service the personnel parachute or drogue
parachute.
CARTRIDGES
Primary cartridge O-ring is a special type and the correct type must be used. There is no serviceable substitute.
Never remove firing pin sear from primary firing mechanism until primary cartridge has been removed from primary
cartridge breech.
When removing or installing firing cables (thick and thin) from firing pin sear of ejection gun primary firing mechanism,
ensure firing pin sear safety pin is installed.
Use extreme caution when removing and handling primary, drogue and guillotine cartridges. These cartridges have a
percussion-type primer cap (See TM 9-1300-206).
The auxiliary cartridges do not contain percussion-type primer caps, but are filled with an explosive powder which can be
accidentally fired by either spark or flame.
DROGUE GUN
Use extreme caution when removing drogue gun barrel to prevent dropping the drogue gun cartridge.
Ensure that drogue firing pin does not protrude above bottom surface of firing body hole.
FACE BLIND
Operational check of the face blind should only be accomplished when the ejection seat has been disarmed.
DROGUE CHUTE
For proper operation, it is essential that drogue chute withdrawal line be routed over all other lines on top of the ejection
seat.
Failure to remove webbing carrying handle will result in improper drogue parachute operation.
HARNESS
Do not dry harness assembly in direct sunlight as sunlight causes harness deterioration.
TM 55-1680-308-24
RELEASE MECHANISM
Keep hands clear of area below time release mechanism plungers. Plungers extend with great force.
Ensure rocket motor locking pin is installed before removing TCR motor.
PRIMARY CARTRIDGE INSTALLATION
The primary cartridge shall be installed in the ejection gun only after the ejection gun and ejection seat are installed in the
aircraft.
Ensure plastic separators provided in the cartridge shipping container are not installed with cartridges.
REPAIR
Only minor sheet metal repair to the seat bucket assembly is authorized. Repair shall not be attempted on other seat
structure.
DROGUE GUN ARMING
Do not attempt to arm the drogue gun until ejection seat is installed in the aircraft.
EJECTION GUN
Ensure ejection gun primary firing pin sear is installed and that firing pin does not protrude beyond bottom surface prior to
installation of cartridge.
GUILLOTINE
Ensure guillotine firing pin sear is installed and that firing pin does not protrude above bottom surface prior to installation
of cartridge.
Remove guillotine cartridge from breech prior to operational check of the manual override system.
UNSERVICEABLE CONDITIONS
If drogue gun or time release mechanism are dropped during installation on seat, the device shall be considered
unserviceable.
The ejection seat, ejection gun and associated parts are considered unserviceable after being subjected to an ejection.
Rocket motor assemblies out of their respective container dropped more than 4 feet will be considered unserviceable.
RECHARGING CYLINDER
Ensure that the recharging cylinder contains only aviator's breathing oxygen. Do not recharge oxygen cylinder with
anything else.
Do not allow any oil or grease to come in contact with compressed oxygen as the slightest trace of oil or grease may
cause fire or explosion.
INSPECTION
To ensure proper shearing characteristics on ejection, use rivet, part No. MS20470A2-6, only. Incorrect rivet may
cause malfunction of emergency oxygen system.
Ensure that the upper firing cable (thick) is routed over link line, under scissor shackle and over the lower (thin) firing
cable.
TM 55-1680-308-24
TABLE OF CONTENTS
Chapter
Page
Chapter
SECTION III INSPECTION AND
SERVICING ................................. 3-1
3-1. General......................................... 3-1
3-2. Inspection Requirements .............. 3-1
3-3 Thirty Day Inspection .................... 3-2
3-4 Servicing....................................... 3-3
LIST OF ILLUSTRATIONS ............................. iii
LIST OF TABLES ........................................... iv
1
INTRODUCTION ................... ................ 1-1
SECTION I GENERAL INFORMATION ..1-1
1-1
Scope ........................................1-1
1-2
General Maintenance ............... 1-1
1-3
Administrative Storage .............. 1-1
1-4
Maintenance Forms and Records1-1
1-5.
Reporting of Errors .................. 1-1
1-5.1 Reporting of Equipment .............1-1
SECTION IV PREVENTIVE
MAINTENANCE............................ 3-3
3-5
3-6.
3-7
3-8.
SECTION II. DESCRIPTION AND
LEADING PARTICULARS ..................... 1-3
1-6.
1-7.
1-8.
3-9
3-10
3-11
3-12
General......................................... 3-4
Operational Checks....................... 3-4
Troubleshooting Data.................... 3-5
Adjustment and Alignment............ 3-6
1-9. Test Equipment and Special
Tools ...................... ............... 1-15
1-10. Consumable Materials .............. 1-15
1-11. Fabrication of Test Equipment,
Special Tools, and Support
Equipment ................................ 1-15
1-12. In-Service Cartridge
Storage ................................. 1-20
SECTION VI REPAIR AND
REPLACEMENT OF AUTHORIZED
PARTS................................................... 3-7
GENERAL SYSTEM DESCRIPTION . ....2-1
3-17
3-18
3-19
3-20
2-1.
2-2.
2-3.
2-4.
2-5.
3
Introduction................................... 3-3
Cleaning ...................................... 3-3
Lubrication ................................... 3-4
Extreme Environmental
Maintenance ................................. 3-4
SECTION V OPERATIONAL
CHECKOUT.................................. 3-4
Description ................................ 1-3
Theory of Operation .................. 1-9
Leading Particulars ................... 1-14
SECTION III. TEST EQUIPMENT,
SPECIAL TOOLS AND MATERIALS .... 1-15
2
Page
3-13
3-14
3-15
3-16
General .....................................2-1
Operating Controls .................... 2-1
Normal Operating Procedures ...2-1
Emergency Operating Procedure 2-3
Use of Oxygen Supply and
Survival Kit ...... ...................... 2-3
3-21
3-22
3-23
3-24
ORGANIZATIONAL MAINTENANCE
INSTRUCTIONS .............................. 3-1
4
SECTION I. PREPARATION FOR
MAINTENANCE, STORAGE AND
RESHIPMENT .......................................3-1
SECTION II. INSTALLATION ................ 3-1
Change 5 i
Introduction .................................. 3-7
Ground Safety Lock ............ ......... 3-7
Face Blind Locking Mechanism .... 3-7
Top Latch Mechanism and
Trip Rod........................................ 3-7
Harness and Lap Belt.................... 3-7
Sticker Clips................................ 3-10
Leg Restraint System ................ 3-10
Seat Actuating Jack
Mechanism........ ......................... 3-12
Emergency Oxygen System....... .3-12
Personnel Parachute Container
and Restraint Straps ................... 3-12
RSSK, Seat Pan, and Cushion. .3-15
Lumbar Support Pan ................. .3-15
DIRECT SUPPORT AND GENERAL
SUPPORT MAINTENANCE
INSTRUCTIONS . ......................... 4-1
TM 55-1680-308-24
Chapter
4-1.
4-2.
4-3.
Page
SECTION I. PREPARATION FOR
MAINTENANCE, STORAGE AND
RESHIPMENT ......................................4-1
5-11
Preparation for Maintenance..................4-1
Storage and Reshipment .......................4-1
Removal Procedures for
Ejection Seat and Telescopic
Ejection Gun from Aircraft .....................4-1
5-13
SECTION II CHECKOUT AND
ANALYSIS...........................................4-14
4-4
4-5
4-6
4-7
4-8
4-8.1
4-9.
4-10
4-11
4-12
4-12.1
4-12.2
4-12.3
4-12.4
4-12.5
Chapter
General ...............................................4-14
Special Inspections..............................4-14
One Hundred Eighty
Day Inspection.....................................4-16
One Year Requirements ......................4-48
Three Year Requirements....................4-48
Deleted ...............................................4-48
Deleted .............................................4-48A
Five Year Requirements ....................4-48A
Six Year Requirements......................4-48A
Seven Year Requirement ..................4-48A
Deleted..............................................4-48A
Deleted .............................................4-48A
Deleted .............................................4-48A
Eleven Year Requirements ... ............4-48A
Fifteen Year Requirements ................4-48A
SECTION III. INSTALLATION OF
EJECTION SEAT ................................4-49
4-13
Seat Installation Procedures ................4-49
5
REPAIR PROCEDURES, AND
PREPARATION FOR STORAGE
AND RESHIPMENT ..............................5-1
5-12
5-14
5-15
5-16
5-17
5-18
5-19
5-20
5-21
5-22
5-23
5-24
5-25
5-26
5-27
5-28
5-29
5-30
5-31
5-32.
Page
Leg Restraint Cords and
Quick Release Garters ........................ 5-12
Dual Leg Restraint Cord
Lock and Snubber Unit ....................... 5-12
Leg Restraint Cord Lock
Release Handle .................................. 5-13
Lower Firing Handle and
Cable Assembly ................................. 5-13
Inertia Reel Manual
Control Linkage .................................. 5-14
Inertia Reel Manual
Control Handle .................................... 5-20
Inertia Reel Mechanism...................... .5-21
Manual Override System..................... 5-23
Manual Override Handle . ................... 5-25
Emergency Oxygen Bottle
Assembly ........................................... 5-25
Emergency Oxygen System
Linkage ............................................... 5-31
Scale Actuating Jack
Mechanism ....................................... ..5-32
Time Release Mechanism ................. .5-34
Guillotine System ............................... 5-38
Tip-Off Compensating Rocket
(TCR) Motor and Mounting
Brackets.............................................. 5-39
Tip-Off Compensating Rocket
Cable Dispenser.................................. 5-42
Tip-Off Compensating Rocket
Initiator Cable...................................... 5-42
Sticker Clips........................................ 5-44
Ejection Seat Slippers ......................... 5-44
Thigh Supports ................................... 5-44
Backplate Roller ................................. 5-45
Ejection Seat and Ejection
Gun Identification Number ................. 5-45
SECTION II. PREPARATION FOR
STORAGE AND RESHIPMENT ........ 5-48
SECTION I REPAIR PROCEDURES....5-1
5-33
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
General .................................................5-1
Telescopic Ejection Gun .......................5-1
Primary Firing Mechanism .....................5-3
Drogue Parachute System .....................5-5
Face Blind Locking Mechanism .............5-5
Face Blind Assembly .............................5-9
Top Latch Mechanism .........................5-10
Drogue Gun.........................................5-11
Personnel Parachute Pack...................5-11
RSSK .. ...............................................5-12
5-34
Uncrating, Unpacking,
Storage, and Reshipment
Instructions.......................................... 5-48
Repair Parts and Special Tools ........... 5-50
6
DIFFERENCE DATA SHEETS.............. 6-1
APPENDIX
A
B
C
REFERENCES ....................................A-1
BASIC ISSUE ITEMS LIST ...................B-1
PRELIMINARY MAINTENANCE
ALLOCATION CHART ..........................C-1
INDEX...........................................INDEX-1
Change 10 ii
TM 55-1680-308-24
LIST OF ILLUSTRATIONS
Number
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
1-10
1-11
1-12
2-1
3-1
3-2
3-3
3-4
3-5
3-6
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
Title
Number
Page
4-19
4-20
4-21
MK-J5D Ejection Seat.................................1-2
Ejection Seat Component Location .............1-4
Main Beam Assembly Component Location 1-6
Seat Actuating Jack Mechanism .................1-7
Ejection Gun Operating Sequence..............1-8
Tip-Off Compensating Rocket (M 119)........1-9
Harness Assembly ....................................1-10
Leg Restraint Mechanism ........................1-11
Emergency Oxygen System .....................1-12
Low Level Ejection Sequence ...................1-13
Top Latch Plunger Retaining Tool.............1-18
Cartridge Block.........................................1-19
Operating Controls .....................................2-2
Ground Safety Lock Location View .............3-8
Inspection of Top Latch Mechanism............3-9
Trip Rod Indicating Collar Installation .......3-10
Seat Pan Component Location .................3-11
Lubrication Chart ......................................3-13
Seat Actuation Jack Mechanism ...............3-14
Air Release for Escape Hatch Actuator
Bottle .........................................................4-1
Removal of Escape Hatch ..........................4-2
Drogue Gun Component Location...............4-4
Ejection Gun Firing Mechanism
Components ...............................................4-5
Primary Cartridge Removal ........................4-6
Top Latch Mechanism ...............................4-6
Disconnecting Time Release Mechanism
Trip Rod .....................................................4-6
Ejection Seat Hoisting Points......................4-7
Hoisting Ejection Seat With Hoisting
Sling ..........................................................4-7
Alignment Tool Installed on Ejection
Gun (Broken Position) ...............................4-9
Alignment Tool Installed on Ejection
Gun (Extended Position) ..........................4-10
Installation of Transportation Cradle
Mounting Rail on Ejection Seat
Shippers ..................................................4-10
Mounting Rail and Ejection Seat on
Seat Cradle .............................................4-11
Removal of Manual Override Handle
Link Rod ...................................................4-12
Location View of Ejection Gun Mounting
Points .......................................................4-13
Removal of Lower Auxiliary Cartridge.......4-14
Sticker Strap Spring Clip Check................4-16
Drogue Gun Firing Pin Protrusion
Check .....................................................4-18
4-22
4-23
4-24
4-25
4-26
4-27
4-28
4-29
4-30
4-31
4-32
4-33
4-34
4-35
4-36
4-37
4-38
4-39
4-40
4-41
4-42
4-43
4-44
4-45
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
iii
Title
Page
Installing Cocking Tool in Drogue Gun ...... 4-19
Firing Pin Spring Compression Test .......... 4-20
Drogue Gun Time Delay Check Test
Setup ....................................................... 4-21
Time Release Mechanism Time Delay Test
Setup ...................................................... 4-22
Time Release Mechanism Barostat Test
Setup ........................................................ 4-24
Removing Firing Pin Sear From Primary
Firing Mechanism .................................... 4-26
Checking Firing Pin Protrusion .................. 4-27
Ejection Gun-Exploded View ..................... 4-28
Correct Positioning of Mounting Blocks ..... 4-29
Guillotine System...................................... 4-30
Guillotine Initiator Exploded View............. 4-31
TCR Motor and Cable Dispenser
Inspection ............................................... 4-32
Checking Slipper Alignment ...................... 4-33
Measuring Tension of Scissor Mechanism. 4-35
Snubber Contacting Stop .......................... 4-37
Face Blind Installation ............................. 4-39
Cocking Time Release Mechanism ........... 4-42
Rigid Seat Survival Kit (RSSK) ................. 4-44
Survival Equipment Pack .......................... 4-45
Personnel Parachute and Restraint
Strap-Location View ................................ 4-46
Attachment of Ejection Gun Top Attachment
Sleeve ..................................................... 4-51
Electrical Lead and Emergency Oxygen
Quick-Release Pins ................................. 4-53
Removal of Top Latch Plungers-Correct
and Incorrect Methods............................... 4-54
Primary Cartridge Location ....................... 4-56
Firing Cables Installation ........................... 4-56
Crowfoot Wrench Part No AN8506-11
(Modified) ................................................. 4-57
Installation of Escape Hatch ..................... 4-58
Telescopic Ejection Gun-Exploded
View............................................................ 5-2
Face Blind Locking Mechanism................... 5-6
Face Blind Locking Mechanism Plunger
Assembly-Exploded View ............................ 5-8
Face Blind Assembly .................................. 5-9
Top Latch Mechanism Installation ............. 5-10
Removal of Roller Bracket ....................... 5-14
Removal of Seat Bucket Cover Plate ........ 5-14
Manual Override and Locking Mechanism 5-15
Lower Firing Handle and Cable Assembly 5-16
Inertia Reel Manual Control Linkage ......... 5-17
TM 55-1680-308-24
Number
5-11
5-12
5-13
5-14
5-15
5-16
5-17
5-18
Title
Number
Page
5-19
5-20
5-21
Inertia Reel Mechanism Disassembly .....5-18
Emergency Oxygen Bottle Assembly
-Exploded View ......................................5-26
Recharging Setup for Emergency Oxygen
Bottle (Typical) .......................................5-27
Locating of Seat Actuating Jack .............5-33
Seat Actuating Jack Mechanism-Exploded
View ......................................................5-35
Guillotine System ..................................5-38
TCR Motor and Mounting Brackets .........5-40
TCR Cable Dispenser Removal ..............5-43
5-22
5-23
5-24
5-25
5-26
TitlePage
Thigh Support Removal .............................5-45
Backplate Roller .........................................5-46
Ejection Seat and Ejection Gun
Identification Number Location....................5-47
Ejection Seat In Shipping Container ............5-48
Wedge at Head of Seat (In Position) ...........5-49
Ejection Seat With Outer Wrapping
Removed ...................................................5-50
Ejection Seat Cradle, Part No 105GT1040 5-52
Shipping Pallet for MK-J5D Ejection Seat ...5-52
LIST OF TABLES
Number
1-1
1-2
1-3
2-1
3-1
Title
Number
Page
3-2
Special Tools and Test Equipment................ 1-15
Consumable Materials .................................. 1-17
Test Equipment, Special Tools and
Support Equipment Fabrication Data ............ 1-18
Operating Controls..........................................2-1
Thirty Day Inspection Requirements ...............3-2
4-1
5-1
5-2
iv
Title
Page
Troubleshooting, Organizational
Maintenance ................................................. 3-6
Nut Torque Values for UNF and UNC Bolts .. 4-40
Troubleshooting, DS and GS Maintenance.. 5-20
Items Included with Seat Shipment .............. 5-51
TM 55-1680-308-24
CHAPTER 1
INTRODUCTION
1-1.
Scope.
Section I. GENERAL INFORMATION
1-4.
Maintenance Forms and Records.
The Model MK-JS5D Ejection Seat (figure 1-1) is
designed to provide safe escape from an aircraft at a
minimum of 60 knots at ground level (straight and level)
through the maximum capability of the aircraft. After
ejection,
a personnel parachute is automatically
extracted, opened, and the occupant separated from the
ejection seat in preparation for a safe landing.
1-2.
General Maintenance.
Prescribed maintenance on the ejection seat should
be accomplished in a clean work area free of grease, oil
and blowing dirt. All prescribed maintenance performed
on this ejection seat shall be accomplished by qualified
ejection seat personnel in accordance with instructions
contained in this manual. Lubrication shall be limited to
that specified in figure 3-5. Excessive lubrication should
be guarded against since grease or oil combined with dirt
is a source of abrasive reaction.
Use of locally
manufactured dust covers of waterproof material is
recommended whenever the ejection seat is not installed
in the aircraft.
1-3.
Administrative Storage.
For storage information on Model MK-J5D Ejection
Seat, refer to TM 55-1500-204-25/1 and Chapter 5.
Maintenance forms, records, and reports which are to be
used by maintenance personnel at all maintenance levels
are listed in and prescribed by DA PAM 738-751.
1-5.
REPORTING ERRORS AND RECOMMENDING
IMPROVEMENTS.
You can help improve this manual. If you find any
mistakes or if you know of a way to improve the
procedures, please let us know. Mail your letter, DA
Form 2028 (Recommended Changes to Publications and
Blank Forms), direct to Commander, US Army Aviation
Systems Command,
ATTN AMSAV-MC,
4300
Goodfellow Boulevard, St. Louis, MO 63120-1798. A
reply will be furnished directly to you.
1-5.1. REPORTING EQUIPMENT
RECOMMENDATIONS (EIR).
IMPROVEMENTS
You can help improve this manual. If you find any
mistake or if you know of a way to improve the procedure,
please let us know. EIR's will be prepared using SF 368,
Quality Deficiency Report Instructions for preparing EIRs
are provided in DA PAM 738-751,
The Army
Maintenance Management System (TAMMS).
EIRs
should be mailed directly to Commander, US Army
Aviation Systems Command, ATTN AMSAV-MMD, 4300
Goodfellow, St. Louis, MO 63120-1798. A reply will be
furnished directly to you.
Change 10 1-1
TM 55-1680-308-24
Figure 1-1. MK-J5D ejection seat
TM 55-1680-308-24
Section II. DESCRIPTION AND LEADING PARTICULARS
1-6.
cartridges. See figure 1-5 for details of the ejection gun
firing.
Description.
The Model MK-J5D Ejection Seat (figure 1-2) is a
fully automatic personnel ejection seat.
This seat
provides for safe personnel ejection from the OV-1
aircraft at 60 knots ground level, during takeoff, and at
all operational flight altitudes. Seat systems provide for
automatic parachute deployment and separation of
seat from occupant after ejection. The ejection seat
assembly is composed of subassemblies and systems
described in the following subparagraphs.
c. Tip-Off Compensating Rocket (TCR). A TCR
(M1119), attached to the bottom of the ejection seat, is
fired 9 inches before ejection gun tube separation (see
figure 1-6). The thrust of the TCR positions the seat in
the correct attitude for safe deployment of the drogue
chute and optimal seat position for main canopy
withdrawal. The TCR initiator is attached to a cable
approximately 64 inches long. One end of the cable is
attached to the stationary seat rails causing the cable
dispenser (28, figure 1-2) to pay out the cable as the seat
rises. When the cable has been completely paid out, the
initiator ignites the TCR.
a. Basic Seat Assembly. The basic seat assembly
(figure 1-1) consists of the following:
(1) A basic seat structure consists of a light
frame and two side beams bridged by three crossmembers and a lumbar contour support backplate which
provides for the occupant's comfort and protection.
d. Harness. (See Figure 1-7.). The harness
assembly, worn by the occupant is sized to fit his body.
The parachute release fittings (6), located at the top of
the harness assembly are connected to the parachute
riser release fitting (5).
(2) The seat assembly also consists of the seat
bucket, seat and back cushions, and thigh supports. The
personnel lowering devices are stored in the thigh
support cushions.
Storage space for the survival
equipment is in the survival kit container located under
the seat cushion.
e. Leg Restraint Mechanism. (See Figure 1-8 ). A
leg restraint mechanism is provided to prevent injury to
the occupant's legs. As the seat leaves the flight
compartment, the dual leg restraint cords (2) tighten,
pulling the occupant's legs aft and together against the
thigh supports (38, figure 1-2). As the ejection seat
moves farther upward, rivets in the leg restraint roller
brackets (11, figure 1-8) shear off, freeing the lower end
of the leg restraint cords from the deck of the aircraft.
The occupant's legs continue to be held securely against
the ejection seat by the upper cord lock and a snubber
mechanism.
(3) The main beam assembly is the framework
to which all the major components of the ejection seat are
mounted. See figure 1-3 for main beam assembly details.
(4) The seat rail mounting is attached to the
ejection gun by two guide tracks. The tracks mate with
three sets of slippers on the main beam assembly. A
plunger, engaging in the locking groove of the ejection
gun primary cartridge breech, locks the seat in position.
f.
Drogue Gun,
Drogue Parachute,
Personnel Parachute. (See Figure 1-2.)
(5) The seat bucket (29, figure 1-2) can be
raised and lowered by an electrical seat actuating
jack mechanism (see figure 1-4). A momentary toggle
switch (13, figure 1-2) on the right side of the seat raises
or lowers the seat bucket. When the toggle switch is
pushed forward, the seat is lowered. When the toggle
switch is pulled aft, the seat is raised. When the toggle
switch is released, it returns to the middle (neutral)
position.
and
(1) Drogue gun. One-half second after the
drogue gun trip rod (27) pulls the sear from the drogue
gun (26), the drogue gun fires. This propels a piston
from the drogue gun which extracts the drogue parachute
by means of a drogue line.
(2) Drogue parachute A five-foot drogue
parachute is housed in a rigid container at the top of the
ejection seat. The drogue parachute is shackled to a
restraining scissor attached to the top of the ejection seat
main beam assembly. The jaws of the restraining scissor
remain closed until allowed to open by the time release.
b. Ejection Gun. A medium velocity, long stroke
cartridge actuated gun provides initial thrust for the
ejection seat and occupant. The pressure resulting from
the explosion of the primary cartridge causes the seat to
rise and, in turn, fire the lower and upper auxiliary
1-3
TM 55-1680-308-24
Figure 1-2. Ejection seat component location (Sheet 1 of 2)
TM 55-1680-308-24
1.
2.
3.
Link line
Drogue line
Face blind locking
mechanism
4. Face blind handle
5. Personnel parachute
riser
6. Personnel parachute
container
7. Backplate with lumbar
support contour
8. Occupant retention
assembly
9. Rigid seat survival kit
cushion
10. Leg restraint quick-release
garter
11. Guillotine initiator
12. Manual override handle
KEY to Figure 1-2.
13. Seat height adjustment
switch
14. Electrical disconnect
15. Emergency oxygen quickrelease pin
16. Oxygen quick-disconnect
fitting
17. Emergency oxygen manual
control
18. Oxygen cylinder
19. Tune release mechanism
trip rod
20. Time release mechanism
21. Parachute restraint strap
(long)
22. Parachute restraint strap
(short)
23. Guillotine head assembly
24. Link line
25. Top latch plunger (with
handwheel installed)
26. Drogue gun
27 Drogue gun trip rod
28. TCR cable dispenser
29. Seat bucket
30 Leg restraint roller bracket
31. Leg restraint quick-release
pin
32. Inertia reel manual control
handle
33. Leg restraint cord lock
release handle
34. Leg restraint cords
35. Tip-off compensating
rocket motor
36. Snubber finger rings
37. Lower firing handle
38. Thigh supports
Figure 1-2. Ejection seat component location (Sheet 2 of 2)
mechanism (20). So long as the scissor is closed, the
shackle and the drogue parachute remain securely
attached to the ejection seat. When the jaws of the
scissor open,
the pull of the drogue parachute is
transmitted,
through a link line to the personnel
parachute,
extracting it from the container (6) for
deployment.
(3) Personnel parachute. A 28-foot inflation aided
personnel parachute is housed in a fiberglass container
(6) near the top of the ejection seat The personnel
parachute provides a safe descent for the occupant at
approximately 18 feet per second.
g.
Time Release Mechanism. The time release
mechanism (20, figure 1-2) is mounted on the upper right
side of the ejection seat Its function is to provide a time
delay of approximately 1-3/4 seconds after the ejection
seat has started to rise before allowing the drogue to
extract the personnel parachute. A barostat, mounted on
the time release mechanism, prohibits action above a
present altitude of 14, 000 to 15, 000 feet. The time
release mechanism accomplishes the following actions
simultaneously by, mechanical linkages:
(1) Allows the restraining scissor on the, ejection
seat to open. This releases the drogue parachute from its
attachment to the seat structure enabling it to extract the
personnel parachute for deployment.
(2) Releases occupant restraint points, freeing the
occupant from the ejection seat for subsequent safe
parachute descent.
h.
(1) A manual override system is provided in case
the automatic system malfunctions. The manual override
system can be used in the following conditions
(a)
Bailout becomes necessary and ejection
(b)
Ejection gun fires, but drogue gun fails.
gun fails.
(c) Ejection gun and drogue gun fire,
time release mechanism fails.
but
(d) Ejection gun and drogue gun fire, time
release mechanism functions, but scissor jaws fail to
open.
(e) The manual override handle is also used
for crash rescue or emergency egress
(2) When the manual override handle (12) is
pulled, the following actions take place:
(a) The guillotine cartridge is fired causing
the guillotine cutter to sever the link line.
(b) The leg restraint cords are released from
the leg restraint cord locks.
(c) The rigid seat survival kit restraint lugs
are released from the seat bucket.
(d) The loop strap lug is released from the
harness lock mechanism.
Manual Override System.
(e)
are locked.
Change 3 1-5
The face blind and lower firing handles
TM 55-1680-308-24
Figure 1-3. Main beam assembly component location
1-6
TM 55-1680-308-24
Figure 1-4. Seat actuating jack mechanism
1-7
TM 55-1680-308-24
Figure 1-5. Ejection gun operating sequence
1-8
TM 55-1680-308-24
containing a survival kit.
The case is opened by
squeezing either of two release grips mounted in the
sides. Three different survival kits are designed to fit into
the survival kit case. The particular survival kit in use
will depend on the nature of the mission. The three
survival kits are cold climate survival kit, hot climate
survival kit, and overwater survival kit.
k. Ground Safety Lock Assembly. The ground
safety lock assembly (flag) consists of six safety pins
plus one positioning (bucket pin) clip. This assembly
protects against inadvertent firing of the ejection seat.
WARNING
Never remove the safety pins of the ground safety lock
assembly unless preparing the aircraft for a mission or
performing authorized maintenance on components of the
ejection seat requiring removal of safety pins.
Figure 1-6. Tip-off compensating rocket (M119)
i.
Automatic Emergency Oxygen System. The
emergency oxygen system (figure 1-9) consists of a 22 5
cubic inch oxygen cylinder (13), filled with 1, 800 to 2,
000 psi of aviator's breathing oxygen, and a manual
actuating knob (2) located on the upper right side of the
seat bucket. An oxygen hose (6) from the oxygen
cylinder is routed to the upper right side of the seat bucket
and is held in place by an oxygen quick-disconnect
bridle and lanyard (5). An additional oxygen hose (4) is
routed from the quick-disconnect clamp to the occupant's
face mask.
The emergency oxygen system is
automatically actuated upon ejection. As the ejection
seat rises during ejection, a trip lever (30) is deflected
downward and transmits the deflection to the bellcrank
(24), pulling on the oxygen cylinder cable, fracturing a
breakoff nipple within the oxygen cylinder, and releasing
the oxygen supply. Since only a 1/4-inch pull on the
cable is required to actuate the oxygen cylinder, and the
deflection is not enough to allow the bellcrank and trip
lever to clear the striker pin, the 1/16-inch aluminum rivet
securing the two links is sheared. This permits the trip
lever and bellcrank to be deflected farther downward,
unrestricted by the limitations of the oxygen cylinder
cable. The emergency oxygen can also be actuated
manually. The manual actuating knob (2) provides for
manual actuation of the oxygen cylinder in case of a
malfunction in the normal oxygen system. Pulling the
manual actuating knob deflects the bellcrank (24)
downward, pulls the oxygen cylinder actuating cable,
fracturing a breakoff nipple within the oxygen cylinder,
and releasing the emergency oxygen supply.
1-7.
Theory of Operation
Operation of the ejection seat is divided into four
phases clearing the aircraft, stabilization and deceleration
of seat and occupant,
deployment of personnel
parachute, and separation of occupant from ejection scat
for safe parachute descent. These four phases are
described in detail in the following subparagraphs In
addition, operation of the manual override system is
explained.
a. Clearing the Aircraft. Clearing the aircraft
is depicted m figure 1-10. Ejection is initiated when the
occupant pulls either the face blind handle (4, figure 1-2)
or the lower firing handle (37). This action withdraws the
primary firing pin sear from the firing mechanism in the
ejection gun. Withdrawal of the sear allows firing pin to
strike the primary cartridge. The heat and pressure from
the primary cartridge ignites the lower and upper auxiliary
cartridges, electing the seat and occupant. As the
ejection seat moves upward, five separate events are
initiated.
(1) The drogue gun sear is pulled from the
drogue gun (26, figure 1-2) by the drogue gun trip rod
(27) attached to the ejection gun crossbeam.
(2) The time release mechanism sear is
pulled from the time release mechanism (20) by the time
release mechanism trip rod (19) attached to the ejection
gun crossbeam.
j.
Survival Kit Assembly. The rigid seat survival
kit (RSSK) assembly consists of a rigid fiberglass case
1-9
TM 55-1680-308-24
1. SHORT RESTRAINT STRAPS
2. PARACHUTE RIPCORD
"D" RING
3. INERTIA REEL LOOP
STRAP
4. ROLLER YOKES
5. RISER RELEASE FITTING
6. PARACHUTE RELEASE
FITTINGS
7. HARNESS
8. LUMBAR BACK REST
Figure 1-7. Harness assembly
1-10
9.
PARACHUTE
RISER
10. PERSONNEL
PARACHUTE
11. LONG RESTRAINT
STRAPS
TM 55-1680-308-24
Figure 1-8. Leg restraint mechanism
(3) Dual leg restraint cords (34) tighten,
pulling the occupant's legs aft and together against the
seat bucket (29) to prevent injury as the ejection seat
leaves the flight compartment.
(4) The automatic emergency oxygen system
is activated whether needed or not
(5) The TCR initiator cable, attached to the
ejection gun crossbeam, is deployed from its dispenser
as the seat rises from the aircraft. When the ejection gun
is approximately rune inches from full extension, the
TCR initiator cable is fully extended. As the ejection seat
continues to rise, the firing pin sear of the rocket motor
initiator is withdrawn which activates the rocket motor.
Thrust from the TCR positions the ejection seat in the
correct attitude for rapid unrestricted deployment of the
drogue parachute, and increases seat trajectory height.
b. Stabilization and Deceleration of Seat and
Occupant. The seat is now clear of the aircraft with the
occupant held securely in place by the loop straps and
parachute harness assembly (figure 1-7), the lap belt and
survival kit assembly, and leg restraint cords (2, figure 18). The TCR has positioned the ejection seat in the
proper attitude for drogue parachute deployment. The
drogue gun fires,
forcibly extracting the drogue
parachute. The drogue parachute inflates, stabilizing and
decelerating the seat and occupant.
c. Deployment of Personnel Parachute. if the
ejection took place above 15,000 feet, the barostat on
the time release mechanism prohibits any further action
until seat and occupant are below a pre-set altitude (14,
000 to 15,000 feet) if the ejection occurred below the preset altitude, the automatic series of events continues.
Approximately 1-3/4 seconds after the sear has been
pulled from the time release mechanism (20, figure 1-2),
the following events are initiated by mechanical linkage
The scissor, holding the drogue shackle to the ejection
seat, opens, releasing the drogue parachute. The pull of
the drogue parachute is then transmitted, through the link
line, to the personnel parachute (6), extracting it from its
pack for deployment. The long and short parachute
restraint straps (21 and 22), holding the personnel
parachute to the ejection seat, have also been released,
enabling the personnel parachute to be extracted.
Change 3 1-11
TM 55-1680-308-24
Figure 1-9. Emergency oxygen system
1-12
TM 55-1680-308-24
Figure 1-10. Low level ejection sequence
1-13
TM 55-1680-308-24
d. Separation of Occupant From Seal, and
Descent. Simultaneously with the release of the drogue
shackle, the link line pins are withdrawn from the pin
retainers. This releases the face blind, which the
occupant has been holding over his face for protection
during ejection The leg restraint cords (34, figure 1-2),
the retention assembly (8), and the loop straps, are
released,
freeing occupant from ejection seat.
Temporary restraint of the occupant in the ejection seat is
maintained by two spring-loaded sticker clips. The
sticker clips prevent collision of occupant with ejection
seat during the separation process. This is accomplished
by providing enough restraint to effect a positive
separation of occupant from ejection seat in response to
the opening shock of the personnel parachute. This
opening shock overcomes the spring tension established
for the sticker clips thus causing the seat and occupant to
separate.
The separation action automatically
disconnects the emergency oxygen
hose from the
occupant at the oxygen quick-disconnect fitting (16).
The occupant, suspended in the parachute harness
assembly, executes a normal parachute descent. The
ejection seat, having been separated from the occupant,
falls free.
e. Operation of Manual Override. A manual
override system is provided in the event of failure of the
automatic system. The occupant initiates the manual
override system by squeezing and pulling the manual
override handle (12, figure 1-2) up and aft. This action
frees the occupant by releasing the leg restraint cords,
seat survival kit retention system, and loop straps. At the
same time the guillotine cartridge is fired actuating the
guillotine. The guillotine severs the drogue parachute link
line from the personnel parachute withdrawal line. Now
the occupant can separate himself from the ejection seat
by grasping the lefthand personnel parachute riser, near
the parachute pack, with his left hand, and thrusting his
left shoulder forward, with a twisting motion from the
waist. Simultaneously with the thrusting and twisting
motion, the occupant pulls the parachute "D" ring,
located at the top left corner of the parachute container,
with his right hand.
1-8.
Leading Particulars
Leading particulars for the Ejection Seat,
MK-J5D, are as follows:
a.
Lower auxiliary cartridge
After 14 inches of travel of inner
and intermediate tubes.
Upper auxiliary cartridge
After 31 inches (total) travel of
Inner and intermediate tubes.
M119 rocket
When ejection gun is 9 inches
short of maximum extension.
b.
Thrust.
Ejection gun velocity
62 feet per second
M119 rocket
Approximately 2, 000 pounds thrust
c.
Parachute Dimensions.
Drogue parachute
5 feet diameter
Personnel parachute
28 feet diameter
d.
Time Release Mechanism.
Barostatic function
Approximately 14, 000 feet
Time delay
1-3/4 seconds
e.
Drogue Gun Mechanism.
Time delay
1/2 second
f.
Seat Raising Mechanism.
Voltage
28 volts dc
Model
Travel
4.7 inches
Firing Time.
Primary cartridge
When either face blind or lower firing
handle is pulled.
1-14
TM 55-1680-308-24
Section III. TEST EQUIPMENT, SPECIAL TOOLS, AND MATERIALS
1-9
1-11. Fabrication of Test Equipment,
and Support Equipment
Test Equipment and Special Tools.
Table 1-1 provides a list of test equipment and special
tool used to maintain the MK-J5D Ejection Seat.
1-10.
Special Tools,
Table 1-3 provides tabular data for fabrication of test
equipment, special tools, and other support equipment
Consumable Materials.
Table 1-2 lists consumable materials required for
maintenance of the MK-J5D Ejection Seat.
Table 1-1 Special Tools and Test Equipment
Figure and
Index No.
Nomenclature
Part No.
Alignment tool
105GT1024-59
Function
Align ejection seat during
removal and installation.
**
Barostat adapter assembly
105GT1030-23
Vacuum-test barostat on time
release mechanism.
*
Belt insertion tool
105GT1043
Install harness loop strap lock
fitting in inertial reel mechanism
loop strap lock.
*
Cartridge extractor
GR506
Remove primary and auxiliary
cartridges
from ejection gun.
*
Cocking tool
MBEU/1 1038
Cocking tool for time release
mechanism
*
Cocking tool
MBEU/4341
Cock
drogue
mechanism.
Cradle, transportation, maintenance
105GT1040
Maintenance
preparation,
storage, and transporting seat.
Crow foot wrench
AN8506-11
Tighten drogue gun barrel to
specified (modified) torque.
Cutter, back spot
134XM15499
(or)
TDO/742
Spotface slipper attachment
holes.
Ejection gun clamp mounting blocks
MBEU/8463
Protect ejection
supported in vise.
*
Extractor
105GT1046
Remove cartridge from drogue
gun barrel.
*
Firing pin cocking tool
MBEU/1321
Cock ejection gun and guillotine
firing mechanisms.
Change 3 1-15
gun
gun
firing
when
TM 55-1680-308-24
Table 1-1 Special Tools and Test Equipment - Continued
Figure and
Index No.
*
Part No.
Function
Firing pin protrusion tool
105GT1029
Measure firing pin protrusion of
drogue gun and ejection gun
firing mechanism.
Handwheel
MBEU/26568
Withdraw
plunger.
Hoisting sling
105GT1024-33
Install and remove ejection seat
from aircraft.
Holding tool
105GT1027
Hold drogue gun and time release
mechanism during maintenance.
Leak test cap
212A31
Leak-test
cylinder.
Oxygen filling fixture
214A38
Service oxygen cylinder.
Plunger retaining tool
4920-OV-020
Retain top
plunger.
Pressure altimeter
MS28044LlA
Indicate altitude at which barostat
initiates time release mechanism.
Screwdriver
105GT1044
Remove and install special slotted
nuts m ejection seat.
Spanner wrench
MBEU/5787
Assemble
bushing.
Spanner wrench
105GT1039
Remove and install barostat on
time release mechanism.
Spanner wrench
128GT10155
Remove and install ejection gun
firing mechanism and auxiliary
cartridge breech caps.
Special tool kit
134GT1048-T3
Maintain and service ejection seat.
**
Start switch assembly (drogue gun)
105GT1030-101
Perform operational check of
drogue gun in conjunction with
timing clock assembly.
**
Stop switch assembly (drogue gun)
105GT1030-11
Perform operational check of
drogue gun in conjunction with
timing clock assembly.
Streamer assembly
134SEME10035
Safety pin locking device for seat.
Test unit
134GT1041-T5
Check
mechanical
timing
mechanism of drogue gun and time
release mechanism.
Timing clock assembly
134GT1041-35
Check timing mechanism of drogue
gun and time release mechanism.
***
*
*
**
Nomenclature
Change 8 1-16
indicating
top
emergency
latch
piston
latch
oxygen
mechanism
top
guide
TM 55-1680-308-24
Table 1-1 Special Tools and Test Equipment - Continued
Figure and
Index No.
Nomenclature
Part No.
Function
Switch assembly
105GT1030-21
Check time release mechanism
running time
Safety lock pin
134SEME10053
Guillotine
sear
maintenance
Safety lock pin
1345EME10054
TCR rocket Initiator ground
maintenance.
Firing pin protrusion gage
J9126
Measure firing pin protrusion of
guillotine firing mechanism
Vacuum pump
4310-900-8136
Operationally check barostat on
time release mechanism.
Vacuum Test Box
TDO 1153
Operationally check and adjust
barostat on time release
mechanism.
*
Wrench
WS1516
Remove drogue gun barrel from
drogue gun.
*
Wrench
105GT1036
Remove and install harness
strap retraction reel nut
*
Wrench
105GT1037
Remove and install leg restraint
lever retaining nuts.
*Included in Special Tool Kit, Part No. 134GT1048-T3
**Included in Test Unit, Part No. 134GT1041-T6
***Used on 51C3804 Filler Valve only
Table 1-2 Consumable Materials
Item No.
1
2
3
4
5
6
7
8
Nomenclature
Military
Specification
Used For
Lockwire
Lubricating oil, general purpose
MS20995C20
MIL-L-7870
Safety wiring
General lubrication
Tetrachloroethylene, technical
Grease, aircraft and instrument
Drycleaning solvent
Oxygen, aviators', breathing,
grade 1
Grease, molybdenum disulfide
O-T-236
MIL-G-23827
P-D-680
MIL-0-27210
Cleaning
Lubrication
Cleaning
Oxygen servicing
MIL-G-21164
Change 5 1-17
Lubrication
ground
TM 55-1680-308-24
Table 1-2. Consumable Materials-Continued
Item No.
Military
Specification
Nomenclature
Used For
10
Lubricant, solid, film
MIL-L-23398
Lubrication
11
Nylon thread (No 6 ticket)
FED V-T-295
Safe tie
12
Lubricating oil
MIL-L-83767
Vacuum pump
13
Leak test compound
MIL-L-265567
Leak-testing oxygen system
14
Locktight
MIL-S-22473
Dowel screw, safety
Table 1-3. Test Equipment, Special Tools and Support Equipment Fabrication Data
Figure and
Index No.
Nomenclature
Function
1-11
Top latch plunger retaining tool
Retain top latch plunger during disassembly
1-12
Cartridge block
Store and ship spare cartridges.
Figure 1-11. Top latch plunger retaining tool
Change 2 1-18
TM 55-1680-308-24
Figure 1-12. Cartridge block
Change 2 1-19
TM 55-1680-308-24
1-12.
In-Service Cartridge Storage.
Ejection seat cartridges may be stored in a
designated area of the hangar or maintenance area
approved by the local safety officer. The designated area
must be free of battery charging fuses, large electric
motors, flammables and/or open flame. The following
provisions shall also apply:
a. A maximum of six ejection seats worth of
cartridges may be stored at any one time.
b. Ejection seat cartridge sets shall be packaged
in the cartridge block depicted in figure 1-12. A 50 caliber
ammunition container similarly configured may also be
used.
d. The container should measure 29 inches long,
18 inches wide and 10 inches deep. These minimum
measurements will accommodate the cartridge blocks and
one rocket motor shipping container.
e. The storage container shall be painted insignia
red
(MIL-E-7729)
with
the
words
"CAUTION
EXPLOSIVES CONTAINED INSIDE" painted in white
insignia enamel (MIL-E-7729). It shall be secured to the
floor in an area free of traffic.
f.
A key lock with two sets of keys, one retained
by the ejection seat lead man (NCOIC) and the other by
the Maintenance Officer, shall be utilized for controlled
access to the explosives.
NOTE
c. A metal container constructed of 1/8 inch thick
mild steel sheet, with welded joints, hinged lid and hasp
for locking is an approved storage container. Six each
1/4 inch vent holes shall be drilled through each end to
facilitate ventilation.
M119 rocket motors are not normally removed from the ejection seat except for
replacement actions. Therefore, not more
than two motors packed in original crate,
shall be stored in this locker during
unscheduled maintenance periods.
Change 2 1-20
TM 55-1680-308-24
CHAPTER 2
GENERAL SYSTEM DESCRIPTION
figure 2-1), or the lower firing handle (4) when pulled, will
General.
begin a normal ejection and automatic separation from
This chapter provides a description of the operating
the ejection seat. Pulling down on the face blind handle
controls, their use, and location. Both normal and
with both hands will provide a face cover and, at the
emergency operating procedures are described Data is
same time, fire the ejection gun. The lower firming
provided describing the use of the emergency oxygen
handle is used for ejection in event the face blind handle
supply and the use of components of the survival kit.
is inaccessible because of abnormal flight conditions or
for any other reason.
2-2.
Operating Controls.
2-1.
b.
Table 2-1 provides a list of operating controls and
their functions Figure 2-1 depicts the locations of the
operating controls.
2-3.
Normal Procedures Not Involving Ejection.
(1) Inertia reel manual control handle. The
inertia reel manual control handle (5, figure 2-1) is a
three-position lever which is connected to and
controls the operation of the inertia reel
mechanism The mechanism consists of a springloaded strap retention reel, loop straps, snubbers,
and a harness lock. When the three-position handle
is m the forward or locked position,
forward
movement is prevented by snubbers, and any slack
is taken up by the reel, keeping the harness loop
strap taut When the handle is cycled through the aft
position, the snubbers unlock and the handle is
Normal Operating Procedures.
Normal operating procedures for the ejection seat
can be divided into two categories ejection procedures,
and procedures not involving ejection.
a. Normal Ejection Procedures. Either one of two
pull handles, the face blind (or upper firing handle) (1,
Table 2-1. Operating Controls
Figure 2-1
Index No.
Nomenclature
Function
1
Face blind handle
Initiate ejection sequence
2
D-Ring
Release personnel parachute for deployment.
3
Survival kit grips
Open survival kit rigid container
4
Lower firing handle
Initiate ejection sequence.
5
Inertia reel manual control handle
Release or locks inertia reel system loop
strap
6
Leg restraint cord lock release handle
Release leg restraint cords
7
Manual override handle
Emergency release from ejection system.
8
Seat height adjustment switch
Raise and lowers seat bucket
9
Emergency oxygen manual control knob
Manually actuate the oxygen cylinder
2-1
TM 55-1680-308-24
Figure 2-1. Operating controls
2-2
TM 55-1680-308-24
spring-loaded to the auto lock position. In the auto lock
position, the loop straps may be extended, allowing the
occupant to move forward and will lock when subjected to
2 to 3 g.
(2) Leg restraint cord lock release handle (6,
figure 2-1). The leg restraint cord lock release handle is a
two-position lever, spring-loaded to the aft position.
Placing the handle m the forward position releases the
upper end of the leg restraint cords.
(3) Leg restraint cord snubber finger rings (7,
figure 1-8). The leg restraint cord snubber finger rings,
when pulled, allow the occupant to pull the leg restraint
cords forward to provide sufficient comfortable leg
movement.
(4)
Seat height adjustment switch (8, figure
a. Manual Override Handle (7, Figure 2-1). The
manual override handle is used to bypass the automatic
ejection functions of the drogue gun,
the drogue
parachute, or the time release mechanism. To use the
manual override handle, the trigger and handgrip must
be squeezed and the handle pulled up and aft. This
results in the following actions.
(1) The face blind handle and the lower firing
handle are locked in position to prevent accidental firing
of the ejection gun if it had not been fired.
(2) The leg restraint cords and seat retention
system are released, freeing occupant from ejection seat.
(3) A cartridge is fired, causing the guillotine
to sever the drogue parachute from the personnel
parachute.
2-1).
b. D-Ring (2, Figure 2-1). After the occupant is
free of the ejection seat, he pulls the D-ring which
deploys the personnel parachute.
Do not operate the seat raising actuator more
than 1 minute (maximum) during any 8-minute
period of time. Extended operation will shorten
the seat raising actuator service life.
When the seat height adjustment switch is pushed
forward, it lowers the election seat by activating the seat
actuating jack mechanism. When the seat height
adjustment switch is pulled aft, the ejection seat is raised.
The switch is spring-loaded and will return to the center
(neutral) position when released. The total vertical travel
capability of the MK-J5D Ejection Seat is 4 7 inches A
white EYE LEVEL line is painted on the side of the
ejection seat to guide the occupant while correcting seat
height adjustment.
2-4.
Emergency Operating Procedure.
If the automatic ejection system of the MK-J5D
Ejection Seat fails, there are provisions for bypassing the
automatic functions These provisions involve the use of
two controls, the manual override handle (7, figure 2-1),
and the D-ring (2).
2-5.
Use of Oxygen Supply and Survival Kit
Operation of the oxygen supply system and the
survival kit involves use of the emergency oxygen manual
control (9, figure 2-1) and the survival kit grips (3).
a. Emergency Oxygen Manual Control. The
emergency oxygen manual control provides for manual
actuation of the emergency oxygen system in case of
malfunction in the aircraft (normal) oxygen system.
When the emergency control (ball) is pulled outward, it
pulls the oxygen cylinder actuating cable, fractures a
breakoff nipple within the oxygen cylinder, and releases
the oxygen.
b. Rigid Seat Survival Kit A successful ejection
ends with the occupant performing a normal parachute
descent supported by his 28-foot personnel parachute
Attached to the parachute harness and providing a seat
for the occupant during his parachute descent, is a
fiberglass case containing a survival kit To open the
fiberglass case and release the survival kit, occupant
must squeeze and pull either survival kit grip (3, figure 21) For contents of survival kit container, refer to TM 558645-206-23.
2-3/(2-4 blank)
TM 55-1680-308-24
CHAPTER 3
ORGANIZATIONAL MAINTENANCE INSTRUCTIONS
Section I. PREPARATION FOR MAINTENANCE, STORAGE, AND RESHIPMENT.
(Not applicable)
Section II. INSTALLATION.
(Not applicable)
Section III. INSPECTION AND SERVICING.
3-1. General.
The following paragraphs provide inspection,
servicing and maintenance procedures authorized for
organizational maintenance by the Maintenance
Allocation Chart for the MK-J5D Ejection Seat.
(2) One-hundred eighty day Inspection The
one- hundred eighty day inspection shall be accomplished
at direct support or general support maintenance level.
(Refer to paragraph 4-6 ).
WARNING
3-2. Inspection Requirements.
The types of
follows:
inspection to be performed are as
a Daily Inspection. Perform daily inspection to
verify serviceability of the ejection seat in accordance
with PMD.
b
Intermediate
Inspection.
Accomplish
scheduled intermediate inspection of the ejection seat in
accordance with TM 55-1510-217-PM.
c. Periodic Inspection. The scheduled periodic
inspection of the ejection seat shall be accomplished in
accordance with TM 55-1510-217-PM.
Personnel parachute pack utilizing plastic
suspension time stowage tray shall require
ejection seat to be inspected at 90 day interval.
(3) One year requirements
The one year
requirements shall be accomplished at direct support or
general support maintenance level (Refer to paragraph 47 ).
(4) Three year requirements. The three year
requirements shall be accomplished at direct support or
general support maintenance level (Refer to paragraph 48).
(5) Deleted.
d
Special Inspections The special inspections
listed as follows shall be performed in accordance with
the applicable specified time interval and in accordance
with the procedures contained in this technical manual.
(6) Five year requirements.
The five year
requirements shall be accomplished at direct support or
general support maintenance level (Refer to paragraph 410).
e. Thirty day inspection. The thirty day inspection
will be performed by organizational maintenance as
outlined in paragraph 3-3.
(7) Six year requirements
The six year
requirements shall be accomplished at direct support or
general support maintenance level (Refer to paragraph 411).
Change 10 3-1
TM 55-1680-308-24
(8) Seven year requirements
The seven
year requirements shall be accomplished at AVIM
maintenance level (Refer to paragraph 4-12).
3-3. Thirty Day Inspection.
This inspection shall be performed by qualified
personnel as outlined in table 3-1.
(9) Eleven year requirements The eleven
year requirements shall be accomplished at AVIM
maintenance level (Refer to paragraph 4-13).
NOTE
(10) Fifteen year requirements
The fifteen
year requirements shall be accomplished at AVIM
maintenance level (Refer to Paragraph 4-14).
Upon completion of the following inspection, the
date, inspector's name, and unit will be entered
on DA Form 3912 located on the right- hand side
of the personnel parachute pack and the flap on
top of the drogue pack.
(11) Deleted.
Table 3-1. Thirty Day Inspection Requirements
Item
Major Assembly, Item, or Area
Requirement
Lines
Drogue line and link line
Inspect for condition and security of installation.
Safety tie
Drogue shackle safety tie and drogue
flap securing pin safety tie
Inspect for security of installation and proper
attachment
Restraint
Personnel parachute pack
Unbuckle personnel parachute restraint strap
on each side of head box.
Locking pins and cones
Personnel parachute pack
First remove parachute withdrawal line from
guillotine and then pull top of personnel
parachute forward approximately 3 inches.
Open top outer and inner flaps exposing
locking pins and cones Check for proper
engagement, corrosion and damage to
locking pins and condition of parachute
withdrawal line
Safety tie
Personnel parachute pack
Ensure that safety tie is intact
Flaps and covers
Personnel parachute pack
Check condition of covers and secure top
inner and outer flaps
Restraint straps
Personnel parachute pack
Move parachute aft on support, flush with
seat back. Inspect parachute restraint straps
for condition and security. If restraint straps
are free of defects, reinstall strap on each side
of head box. Install parachute withdrawal line
into guillotine with the excess line positioned
to the rear of the guillotine.
Change 10 3-2
TM 55-1680-308-24
Table 3-1. Thirty Day Inspection Requirements (Cont)
Item
Major Assembly, Item, or Area
Requirement
Risers
Personnel parachute
Inspect personnel parachute risers for cuts,
frayed stitching, and discoloration from
exposure to sunlight.
D-ring
Personnel parachute
Check parachute ripcord handle (D-ring)
for retention to clip on left side of
parachute pack.
Release fittings
Personnel parachute
Check riser release fittings for ease of
operation and positive locking There shall
be no binding or hangup during opening
and closing.
NOTE
If any doubt of the serviceability
of the items listed in this table
exists,
a qualified parachute
rigger should be consulted.
Change 5 3-2.A/(3-2.B blank)
TM 55-1680-30824
3-4.
Servicing.
The application of recommended lubricants to their
relevant bearing surfaces, together with the observance
of absolute cleanliness, will ensure the maximum
efficiency and utmost service of the ejection seat and
the components thereof
a. Lubrication
Frequencies.
Lubrication
frequencies are limited to the intervals specified herein,
except where conditions warrant their change
b. Lubrication Precautions and Procedures.
Lubrication precautions and procedures outlined in this
technical manual will be strictly complied with at all
tunes No alternate lubricant shall be applied to the
ejection seat unless specifically outlined herein.
c. Lubrication Requirements. Each part of the
ejection seat or any component thereof, as depicted in
figure 3-5, is indicated by a frequency symbol which shows
the time interval between lubrications. Application symbols
within the frequency symbol show how the lubricant is
applied A parts nomenclature key, referred to by a number
adjacent to the frequency symbol, identifies the part to be
lubricated A code of either one, two, or three letters within
the frequency symbol identifies the type of lubricant. Parts
or areas to be lubricated on both sides of the ejection seat
are indicated by broken leader lines. If a part Is to be
lubricated in more than one place, the number of places is
indicated In parentheses along the leader line All symbols
and codes are explained in figure 3-5
Section IV. PREVENTIVE MAINTENANCE
3-5.
Introduction.
Periodic performance of the preventive maintenance
detailed herein will ensure maximum efficiency and
reliability of the MK-J5D Ejection
Seat and its
components
3-6.
lightly with a soft-bristled brush.
(2) Rinse harness assembly by applying clear
water, as sparingly as possible, to remove detergent
solution.
Cleaning.
(3) Allow harness assembly to dry thoroughly
Cleaning of the ejection seat and the ejection seat
components by organization maintenance is to be
accomplished as such conditions warrant Only the
components outlined in following subparagraphs a
through d should be cleaned, using the prescribed
materials and procedures. Never attempt to perform
cleaning on any unauthorized area or component.
WARNING
Do not dry harness assembly in direct sunlight, as
sunlight causes harness deterioration which may
result In separation of occupant from personnel
parachute after ejection.
b. Loop Strap.
WARNING
Before attempting to service the ejection seat or
ejection seat components with ejection seat
installed In the aircraft, ensure that ground
safety locks are installed.
a. Harness Assembly.
(1) Clean harness assembly using a solution of
warm water and a synthetic detergent (handdishwashing compound). Dissolve one to four ounces of
detergent m one gallon of water and scrub harness
(1) Position inertia reel manual control handle to
unlock (aft) position and pull loop strap out to the fully
extended position and hold loop strap.
(2) Spot-clean soiled areas with a soft-bristled
brush or clean cloth dampened with tetrachloroethylene
(item 4, table 1-2).
(3) Rinse
spot-cleaned
tetrachloroethylene (item 4, table 1-2).
3-3
area
with
TM 55-1680-308-24
c. Seat Cushion, Back Rest Cushion and Floating
Lap Belt.
(1) Clean soiled seat cushions and lap belts
with a solution of warm water and a synthetic detergent
(hand-dishwashing compound). Dissolve one to four
ounces of detergent In one gallon of water and scrub
cushions lightly, using a soft-bristled brush or a clean
cloth.
(1) Hold snubber finger rings out and pull leg
restraint cord out as far as possible Remove quick-release
garters from leg restraint cords
(2) Clean leg restraint cords quick-release garters
in same manner as prescribed for harness assembly (Refer
to preceding subparagraph a )
(3) Install quick-release garters on leg restraint
(2) Remove detergent solution with a clean
cloth dampened in clear water
cords
3-7.
Lubrication.
NOTE
For lubrication instructions, refer to paragraph 34.
Seat and back rest cushions may be lifted out
for improved accessibility.
d. Leg Restraint Cords and Quick-Release Garters.
3-8.
Extreme Environmental Maintenance.
No special instructions or special maintenance is required
for extreme environmental conditions.
Section V. OPERATIONAL CHECKOUT
3-9.
General.
WARNING
Operational requirements and procedures for verifying
serviceability of the operating controls and linkages, as
applicable to organizational maintenance, shall be
performed on the ejection seat and components as
conditions warrant These components include the face
blind locking mechanism, dual leg restraint mechanism,
inertia reel manual control, and the seat actuating jack
mechanism.
310.
Operational Checks
The following operational checks are authorized for
organizational maintenance
Do not pull face blind.
(4) Install safety pin of ground safety lock In the
face blind locking mechanism.
b. Leg Restraint Mechanism.
(1) Ensure leg restraint cord lock release handle
(33, figure 1-2) Is m forward (locked) position.
(2) Pull on lower end (under seat bucket) of leg
restraint cord (2, figure 1-8) and ensure it passes through
snubber freely
a. Face Blind Locking Mechanism.
(1) Remove safety pin of ground safety lock
from face blind locking mechanism (3, figure 1-2).
(2) With the safety lock of face blind locking
mechanism m up (locked) position, the locking plunger
must engage the face blind handle body (visual).
(3) Pull forward on leg restraint cord and ensure
that line Is held by snubber.
(4) Pull forward on leg restraint cord and pull on
snubber finger ring (7). Ensure leg restraint cord will pull
out freely while snubber finger ring is held out
NOTE
(3) With the safety lock of the face blind locking
mechanism in the down (unlocked) position, the locking
plunger must be clear of the face blind handle body
(visual).
The snubber finger ring is spring-loaded and will
return to the locked position when released.
3-4
TM 55-1680-308-24
(5) Insert cord lock fitting (6) on upper end of
leg restraint cord (2) into leg restraint cord lock (5) in
front of seat bucket. Ensure cord lock fitting is secure.
completely retract.
(6) Move leg restraint cord lock release handle
(33, figure 1-2) to its aft (unlocked) position and ensure
that upper end of leg restraint cord (2, figure 1-8) is
released Leg restraint cord lock release handle should
move freely without binding.
(1) Ensure all switches are off.
(2) Connect
external
power to aircraft in
accordance with TM 55-1510-204-23 or TM 55-1510-21323.
(7) Ensure leg restraint cord lock release
handle (33, figure 1-2) returns to its forward (locked)
position.
d. Seat Actuating Jack Mechanism.
(3) Check that ejection seat moves up when seat
height adjustment switch (2, figure 3-6) is pushed aft, and
stops when switch is released.
CAUTION
(8) Perform preceding steps (1) through (7) on
opposite leg restraint cord (2, figure 1-8) and cord lock
fitting (6).
c.
Do not operate the seat raising actuator more than I
minute (maximum) during any 8-minute period of
time Extended operation will shorten the seat
raising actuator service life.
Inertia Reel Manual Control.
(1) Place inertia reel manual control handle (32,
figure 1-2) in center (autolock) position
(4) Check that ejection seat moves down when
seat height adjustment switch is pushed forward, and stops
when switch is released.
(2) Pull loop strap out to extreme position
(3) Move inertia reel manual control handle to
forward (locked) position.
(4) Slowly allow loop strap to retract a few
inches at a time; then pull forward on loop strap to see if
loop strap locks.
(5) Check that ejection seat actuating jack stops
when full down position Is reached.
(6) Remove external power from aircraft m
accordance with TM 55-1510-204-23 or TM 55-1510-21323.
3-11.
(5) Repeat procedure m
until loop strap is fully retracted.
Troubleshooting Data.
preceding step (4)
(6) Move inertia reel manual control handle to
center (autolock) position and pull on loop strap. Loop
strap should be locked.
(7) Move inertia reel manual control handle to
aft (unlocked) position and release handle. Handle
should move to center (autolock) position.
NOTE
The inertia reel manual control handle is springloaded to the center (autolock) position.
(8) Pull loop strap out to the fully extended
position and slowly release loop strap Loop strap should
Troubleshooting is the systematic isolation of
defective or inoperative components or systems by means
of analysis of trouble symptoms, checking to determine the
component(s) or system at fault, and the application of the
corrective action. Troubles which may be encountered
during operation or checkout of the ejection seat are listed
in table 3-2. Probable causes and corrective actions are
listed opposite each medication of trouble Careful study of
this table will give a general knowledge of difficulties which
may be encountered at organizational maintenance level, a
quick, easy method to analyze the probable cause, and the
corrective action to be taken Before condemning a
component or system, a thorough check should be made to
determine if failure is due to another component or system
operating in conjunction with the component or system
assumed to be faulty.
Change 4
3-5
TM 55-1680-308-24
Table 3-2. Troubleshooting, Organizational Maintenance
Malfunction
1. Seat height adjustment
switch
Probable Cause
Corrective Action
a. Monitored dc bus not energized.
a. Apply external power. (Refer
to inoperative. TM 55-1510-20423 or TM55-1510-213-23)
b. Low or no power supply.
b. Check for proper source of
supply (minimum 20 amperes).
c.
Foreign object
movement of seat.
blocking
normal
c. Remove foreign object
d. Electrical lead to seat height adjustment d
Notify
Direct
mechanism defective
maintenance.
2. Leg restraint cords do not
lock when pulled in restrainmg position.
a. Leg restraint cords twisted.
b.
Snubber
defective.
mechanism
a Straighten leg restraint cords.
jammed
or
3. Leg restraint cords will not a. Locking mechanism jammed in locked
unlock when leg restraint
position
cord lock release handle is
positioned to aft (unlocked)
position.
b. Snubber jammed in locked position.
b.
Notify
maintenance.
a.
Notify
maintenance
b.
Notify
maintenance.
4. Harness loop strap will not a. Dirt or obstruction in snubber mechanism. a
Notify
lock.
maintenance
b. Maladjusted linkage
312.
Adjustment and Alignment
Adjustment and alignment procedures are not
applicable to organizational level of maintenance.
3-6
Support
Change 4
Direct
Direct
Direct
Support
Support
Support
Direct
Support
b
Notify
Direct
maintenance.
Support
TM 55-1680-308-24
Section VI. REPAIR AND REPLACEMENT OF AUTHORIZED PARTS
3-13.
bucket seat pin at locations shown in figure 3-1 in reverse
order of removal.
Introduction.
Prescribed Inspections detailed herein will ensure
maximum efficiency of the MK-J5D Ejection Seat.
314.
Ground Safety Lock.
Ground safety lock inspection. The ground safety
lock (figure 3-1) consists of safety pins and one
positioning (bucket pin) clip. The safety pins provide
protection against the inadvertent firing of any charges
in the ejection seat.
3-15.
Face Blind Locking Mechanism.
Face blind locking mechanism Inspection. The face behind
locking mechanism (3, figure 1-2) is located on top of the
headbox. It prevents accidental extraction of the face blind
by locking the face blind handle (4) in its proper, position.
The face blind locking mechanism is in the unlocked
position when the safety lock is down and is in the locked
position when the safety lock is up.
WARNING
a. Ensure safety lock will lock and unlock easily
without binding
Never remove the safety pins of the ground
safety lock assembly unless preparing the
aircraft for a mission or performing authorized
maintenance on components of the ejection
seat requiring removal of safety pins.
b. Ensure safety pin lock is not malformed and will
accept the safety pin of ground safety lock when in locked
position.
3-16.
a. Removal. Remove quick-release type safety
pins and bucket pin from ejection seat as follows:
(1) Lower firing handle (Detail E)
(2) Manual override handle (Detail F)
Top Latch Mechanism and Trip Rods.
Top latch mechanism and trip rod Inspection. The top latch
mechanism locks the seat structure to the ejection gun so
that the ejection seat is held firmly in the aircraft until
ejection occurs. The top latch mechanism Is installed m
the top of the left vertical main beam. Inspect the top latch
mechanism as follows:
(3) Bucket pin (Detail G)
(4) TCR cable dispenser (Detail D)
a. Ensure indicating dowel pin is flush with plunger
face (See figure 3-2 ).
b. Ensure plunger face is flush with edge of plunger
housing.
(5) Drogue gun (Detail C)
(6) Face bind locking mechanism (Detail B)
(7) Ejection gun firing pin sear (Detail A)
b. Inspection.
(1) Inspect quick-release type safety pins for
security of attachment to ground safety lock (flag).
(2) Inspect safety pins for corrosion and for
ease of operation.
c.
d. If the top latch mechanism and indicating trip rod
collars do not meet the above requirements. Indicating an
improperly installed ejection seat, notify Direct Support
level of maintenance.
3-17.
Installation.
Harness and Lap Belt
Harness assembly and floating lap belt inspection. The
harness assembly (figure 1-7) and the floating lap belt
provide a means of attaching the occupant to the ejection
seat.
type safety pins and
3-7
(1) Remove ground safety lock from storage
area in aircraft.
(2) Install quick-release
c. Visually check to ensure drogue gun/TCR initiator
cable assembly and time release mechanism trip rod
(figure 3-3) indicating collars are flush with, or not more
than 1/2-inch maximum away from, edge of trip rod outer
barrel when connected to crossbeam
TM 55-1680-308-24
Figure 3-1. Ground safety lock location view
3-8
TM 55-1680-308-24
Figure 3-2. Inspection of top latch mechanism
3-9
TM 55-1680-308-24
(2) Check for quick-release action
during
installation of the adapters to the fittings for smoothness of
operation.
c.
Removal.
(1) Check quick-release action of fittings during
removal.
(2) Remove harness and lap belt from seat and
store in appropriate area if assembly meets the installation
and removal check requirements. If repair is required,
dispatch harness or belt to parachute riggers or replace with
a serviceable harness assembly or floating lap belt.
3-18.
Sticker Clips.
Sticker clips inspection. A sticker clip Is located on each of
the outer sides of the seat bucket. These clips provide a
receptacle for the sticker strap lugs (figure 3-4). The sticker
clips restrain the occupant in the ejection seat until the
personnel parachute is deployed.
a. Inspect sticker clips on both sides of seat bucket for
security of installation.
Figure 3-3. Trip rod Indicating collar installation
b. Ensure that each sticker strap lug is securely
inserted into its respective sticker clip.
Quick-release
type
fittings
are
provided
for
attachment to adapters located on the parachute risers
and the rigid seat survival kit (RSSK).
c. If defects are found, inform Direct or General
Support level of maintenance.
3-19.
a. Inspection.
(1) Inspect harness and floating lap belt for
cleanliness, fraying, discoloration and loose stitching.
(2) Inspect metal fittings and quick-release
adapters for corrosion and damage.
NOTE
If any doubt of the serviceability of this system
exists, a qualified parachute rigger should be
consulted or the personnel harness assembly
should be forwarded to a parachute
maintenance shop for rework.
b. Installation.
(1) Attach harness to the parachute riser
adapters and the floating lap belt to the RSSK retention
adapter fittings.
Leg Restraint System
a. Leg restraint cords and quick-release garters. The
leg restraint cords (2, figure 1-8), attached to the quickrelease garters (1), pull the occupant's legs against the
ejection seat thigh supports during ejection by the initial
movement of the seat.
(1) Cleaning. Clean the leg restraint cords and
quick-release garters in accordance with paragraph 3-6d
(2) Inspection.
(a) Inspect leg restraint cords for fraying, loose
stitching, and for cleanliness.
(b) Inspect quick-release garters for fraying,
loose stitching, and cleanliness.
(c) Inspect hardware of leg restraint cords and
quick-release garters for corrosion and for ease of
operation.
3-10
TM 55-1680-308-24
30VJ5M-4
Figure 3-4. Seat pan component location
3-11
TM 561680-30824
(d) Replace leg garters if found defective
during inspection.
(e) Inform Direct or General Support level
of maintenance if leg restraint cords are found defective
during inspection.
b. Dual leg restraint cord lock and snubber unit.
The dual leg restraint cord lock and snubber unit
secures the lock fitting of the leg restraint cord (2, figure
1-8) to the ejection seat.
(1) Servicing. Service the dual leg restraint
cord lock and snubber unit in accordance with figure 3-5.
(5) An additional oxygen hose (4) is routed from the quickdisconnect clamp to the occupant's face mask. The
emergency oxygen system is automatically actuated upon
ejection. As the ejection seat rises during ejection, a trip
lever (30) is deflected downward and transmits the
deflection to the bellcrank (24), pulling on the oxygen
cylinder cable, fracturing a breakoff nipple within the
oxygen cylinder, and releasing the oxygen supply. Since
only a 1/4-inch pull on the cable is required to actuate the
oxygen cylinder, and the deflection is not enough to allow
the bellcrank and trip lever to clear the striker pin, the 1/16inch aluminum rivet securing the two links is sheared. This
permits the trip lever and bellcrank to be deflected further
downward, unrestricted by the limitations of the oxygen
cylinder cable.
(2) Inspection.
a. Inspect oxygen hose for cracks and deterioration.
(a) Refer to paragraph 3-10b for operational
procedures to check out the dual leg restraint cord and
snubber unit
(b) If defects are found during inspection,
inform Direct or General Support level of maintenance.
b. Inspect oxygen hose fittings for serviceability.
c. Inspect oxygen quick disconnect bridle and lanyard
for fraying, loose stitching, and for proper installation.
d. Inspect oxygen cylinder for security of mounting.
3-20.
Seat Actuating Jack Mechanism.
Seat actuating jack mechanism inspection. The seat
actuating jack is located in back of the seat bucket,
between the main beams The shaft end of the actuating
jack is bolted to the 40 g crossmember, and the motor
end is attached to the seat bucket. The seat actuating
jack motor operates off the aircraft 28-volt dc system
and Ls actuated by a seat height adjustment switch (2,
figure 3-6) located on the forward right side of the seat
bucket. The seat height adjustment switch has three
positions up (switch aft), down (switch forward), and
neutral. The height of the seat bucket may be adjusted
through a distance of 4.7 inches.
a. Inspection of the seat actuating jack mechanism
consists of the proper operation of the switch and seat
travel. Refer to paragraph 3-10d for operational
procedures.
e. Visually check oxygen cylinder quantity indicator
for proper capacity.
f.
g. Inspect green knob for security.
h. If defects are found during inspection, refer to
Direct Support or General Support level of maintenance.
3-22. Personnel Parachute Container and Restraint
Straps.
Personnel parachute container and restraint strap
inspection. The personnel parachute container (6, figure 12), which packs a 28-foot diameter inflation aided
parachute, is held in position on the ejection seat by a long
restraint strap (21) and a short restraint strap (22).
b. If defects are found during inspection, inform
Direct or General Support level of maintenance.
3-21.
Emergency Oxygen System.
Emergency oxygen system inspection.
The
emergency oxygen system consists of a 22.5 cubic inch
oxygen cylinder (13, figure 1-9) filled with 1,800 to 2,000
psi of breathing oxygen, and a manual actuating knob
(2) located on the upper right side of the seat bucket.
An oxygen hose (6) from the oxygen cylinder is routed
to the upper right side of the seat bucket and is held In
place by an oxygen quick-disconnect bridle and lanyard
Ensure quick-release pin is installed.
a. Inspect for cleanliness
b. Inspect personnel parachute container covering for
loose stitching, wear, deterioration, and security of cover to
velcro fasteners.
c. Ensure ripcord D-ring is fully inserted in its proper
position and secured by retainer clip.
d. Inspect personnel parachute (fiberglass) container
for fractures.
3-12
TM 55-1680-308-24
Figure 3-5. Lubrication chart
3-13
TM 55-1680-308-24
Figure 3-6. Seat actuation jack mechanism
3-14
TM 55-1680-308-24
e. Inspect personnel parachute restraint straps for
loose stitching, fraying, and cleanliness.
attachment by pulling up hard on the floating lap belt
attachment fittings.
f. Inspect to ensure that long and short restraint
straps properly secure the container to the seat.
f. Replace cushions by aligning velcro strips and
pressing firmly toward seat.
g. If discrepancies are found during Inspection,
inform parachute riggers or Direct or General Support
level of maintenance.
g. If discrepancies are found during inspection, inform
Direct or General Support level of maintenance.
3-24
3-23.
Lumbar Support Pan
RSSK, Seat Pan, and Cushion.
RSSK, seat pan, and cushion Inspection. The seat pan
(figure 34) provides proper support for the lower portion
of the torso and is covered with a seat cushion Attached
to the seat cushion are padded thigh supports which
contain the personnel lowering device The seat, thigh,
and back cushions are secured with self-adhering velcro
material.
Lumbar support pan and cushion inspection . The
lumbar support pan is contoured and cushioned (7, figure 12) The pan is hinged on the lower end and is pre-positioned
to accommodate the occupant's back position during seat
bucket height adjustment.
a. Remove and inspect back cushion for cleanliness,
tears, and loose stitching
a. Remove cushions by pulling them away from
seat and inspect RSSK seat pan for nicks, dents,
fractures, and distortion.
NOTE
Pad is secured to pan by velcro material.
b. Inspect velcro for adhesion to pan and thigh
supports.
c. Inspect cushions for cleanliness, tears, and
loose stitching.
d. Inspect the dual quick-release grip device for
corrosion of components and fraying of cables and
flexible conduit.
e. Inspect
RSSK
assembly
for
security
of
b. Inspect velcro material for adhesion to lumbar
support pan.
c. Inspect
security.
lumbar
support pan
for damage
and
d. Inspect roller and bracket for damage and security.
e. If discrepancies are found during inspection, inform
Direct or General Support levels of maintenance.
3-15/(3-16 blank)
TM 55-1680-308-24
CHAPTER 4
DIRECT SUPPORT AND GENERAL SUPPORT
MAINTENANCE INSTRUCTIONS
Section I. PREPARATION FOR MAINTENANCE, STORAGE, AND RESHIPMENT
4-1.
wood approximately 3/8 inch thick and 1/2 inch square.
Preparation for Maintenance.
The MK-J5D Ejection Seat received from supply will
require a 180-day special inspection prior to installation.
(Refer to paragraph 4-6 )
4-2.
Storage and Reshipment.
For storage and reshipment, uncrating, and
unpacking of the MK-J5D Ejection Seat, refer to
paragraph 5-33.
4-3.
Removal Procedures for Ejection Seat and
Telescopic Ejection Gun From Aircraft.
Removal procedures apply to all Model OV-1 and
RV-1 (Mohawk) aircraft with MK-J5D ejection seats
installed.
a. Removal of Escape Hatch To remove escape
hatch, proceed as follows.
(1) Remove nosewheel splash shield to gain
access to torque tube mechanism (3, Figure 4-2).
(2) Open right and left side cockpit entrance.
To avoid personnel injury or equipment
damage, loosen filler valve locking nut only
enough to allow a slow rate of air escape (figure
4-1).
(3) Evacuate pressure in escape hatch
pneumatic bottle by removing cap from filler valve and
turning filler valve nut counterclockwise.
(4) Install two spacer blocks on top of fuselage
at aft pivot pin covers to prevent damage top hinge
covers during removal and installation of escape hatch.
The spacer blocks may be fabricated from micarta or
Figure 4-1. Air release for escape hatch actuator bottle
Change 5
4-1
TM 551680-308-24
(5) From aft side of torque tube mechanism,
insert 3/8 inch diameter pin (4, Figure 4-2) in hole on
right end of torque tube. (Note: a cut-off screwdriver with
a 3 inch shank is ideal for this procedure). Do not insert
pin more than 1 inch thru torque tube. This is to avoid
damage to airframe structure.
(6) Rotate torque tube mechanism with pin by
pulling downward on pin This will slide the escape hatch
aft
(7) Disconnect the H/F wire antenna from the
antenna fitting at the top of fuselage.
Note: A spring loaded quick disconnect is attached to
the antenna wire.
(8) Lift the escape hatch leading edge to an
angle of not more than 45 degrees to the top of the
aircraft. Move the escape hatch forward until cantilever
arms (10) clear the aft pins and remove the escape
hatch. A minimum of two personnel are required. One
in the cockpit and one on top of the aircraft fuselage.
(9) Connect auxiliary power to aircraft. Raise
pilots and co-pilots seat buckets to center of travel. This
is to accommodate installation of the seat hoisting sling.
(10) Disconnect auxiliary power from the
aircraft.
(11) Disconnect the seat height electrical
connectors from the right side of the Pilots and co-pilots
seat buckets.
4-2 Change 8
TM 55-1680-308-24
Figure 4-2. Removal of escape hatch. 40VJM-2
Change 8
4.2A/(4.2 B blank)
TM 55-1680-308-24
CAUTION
WARNING
Ensure that all aircraft electrical power is turned
off after positioning seat bucket to center of
travel.
Never remove firing pin sear from primary firing
mechanism until primary cartridge has been
removed from primary cartridge breech. Any
attempt to do so will cause the cartridge to be fired
Ensure that the firing pin sear is secured by the
safety pin when installing or removing the firing
cables. Failure to do so will result in serious
injury or death to maintenance personnel.
b. Disarming of Seat Prior to Removal.
the ejection seat as follows:
Disarm
(1) Ensure ground safety locks are installed.
(2) Disconnect drogue line from top of drogue
gun piston (3, figure 4-3) by removing bolt and nut (2)
from special shackle (1).
(7) With safety pin installed in firing pin sear (4,
figure 4-4) of ejection gun primary firing mechanism, push
sear forward as far as possible and remove firing cables
(3) Remove lockwire securing drogue gun
barrel (5) to firing body (8) and remove lockwire and
lead seal.
(8) Remove lockwire securing primary firing
mechanism (6) to primary cartridge breech (9). Remove
lockwire and lead seal
WARNING
WARNING
Use extreme caution when removing drogue
gun barrel to prevent dropping the drogue gun
cartridge.
When removing safety pin from firing pin sear of
ejection gun primary firing mechanism, ensure
firing pin sear does not become dislodged. Never
remove safety pin from inside the flight
compartment, or while leaning over the ejection
seat or the ejection gun Removal of firing pin sear
from under firing pin will cause the ejection gun to
fire.
(4) Remove drogue gun barrel (5) from firing
body (8) using wrench, Part No WS1516
WARNING
Use extreme caution when removing drogue
gun cartridge, as cartridge has a percussiontype primer cap.
(5) Remove drogue gun cartridge, Part No
MBEU/7536, from drogue gun barrel (5) using extractor,
Part No 105GT1046
(9) Carefully remove safety pin (5) from firing pin
sear (4) on ejection gun primary firing mechanism.
(10) Unscrew primary firing mechanism (6) from
primary cartridge breech (9) with spanner wrench, Part No
128GT10155.
(11) Remove primary firing mechanism and inner
tube retainer collar (10, figure 44).
NOTE
WARNING
For handling of cartridge, refer to TM 9-1300206.
Use extreme caution when removing and handling
primary cartridge, as cartridge has a percussiontype primer cap.
(Refer to TM 9-1300-206).
(6) Reinstall drogue gun barrel (5) handtight in
firing body (8) to prevent foreign matter from entering
barrel.
4-3
TM 55-1680-308-24
Figure 4-3. Drogue gun component location
4-4
TM 55-1680-308-24
(13) Reinstall primary firing mechanism (6, figure
44) handtight in primary cartridge breech (9).
c.
Preparation for Seat Removal.
(1) Withdraw top latch plunger by installing
handwheel, Part No. MBEU/26568, and turning clockwise
until handwheel bottoms. (See figure 46.)
NOTE
Do not remove handwheel unless ejection gun or
plunger retaining tool, Part No. 4920-OV1-020, is
placed in position. The top latch plunger is held in
the plunger housing by the holding action of the
handwheel and/or ejection gun primary cartridge
breech or plunger retaining tool.
(2) Disconnect drogue gun/TCR initiator cable
assembly trip rod (11, figure 4-3) by disconnecting quickrelease pin (13) from ejection gun trip rod crossbeam (14).
Install quick-release pin (13) in drogue gun safety pin hole.
(3) Remove screw, washer, and nut securing
aircraft oxygen system hose clamp to ejection seat.
Disconnect oxygen hose from ejection seat.
(4) Disconnect leg restraint cords by removing two
quick-release pins (9, figure 1-8) from floor fittings in
aircraft.
CAUTION
Figure 4-4. Ejection gun firing mechanism
components
Do not reinstall time release mechanism quickrelease pin in ejection gun trip rod crossbeam until
ejection seat is completely removed from aircraft.
Failure to observe this procedure will result in
discharging of the oxygen cylinder.
(12) Remove primary cartridge, Part
No.
MBEU/26434, from primary cartridge breech using
cartridge extractor, Part No GR506. (See figure 4-5 )
(5) Disconnect time release mechanism trip rod (2,
figure 4-7) by removing quick-release pin (3) from ejection
gun trip rod crossbeam (4)
NOTE
CAUTION
Do not install inner tube retainer collar at this
time.
Change 3
On aircraft equipped with APX-72, ensure APX-72
plug is disconnected prior to ejection seat removal.
4-5
TM 55-1680-308-24
Figure 4-5. Primary cartridge removal
Figure 4-7. Disconnecting time release mechanism trip
rod
d. Removal of Seat From Aircraft.
(1) Attach hoisting sling, Part No. 105GT1024-33,
to ejection seat at four hoisting points (See figure 4-8.)
CAUTION
Ensure inner tube retainer and firing pin sear safety
pin are removed prior to ejection seat removal.
Figure 4-6. Top latch mechanism
4-6
TM 55-1680-308-24
CAUTION
When removing ejection seat, do not exceed 200
pounds on spring scale If ejection seat does not
move, ensure top latch plunger is completely
withdrawn If 200 pounds spring scale reading Is
exceeded, perform special inspection. (Refer to
paragraph 4-5a ).
(3) Take up tension until spring scale reads
approximately 150 pounds (white line on spring scale) and
shake ejection seat with hands to break It free from its
mounting. (See figure 4-9 ).
(4) Grasp top of ejection seat and pull up sharply
Raise ejection seat approximately 12 inches.
Figure 4-8. Ejection seat hoisting points
(2) Position overhead hoist directly over
ejection seat and mate hoist hook to hoisting sling eye
on spring scale.
Change 1
Figure 4-9. Hoisting ejection seat with hoisting sling
4-7
TM 66-1680-308-24
(5) Disconnect electrical lead to seat height
adjustment actuating jack at quick-disconnect on right
side of seat bucket (14, figure 1-2).
remove manual override handle connecting link rod (2)
(2) Remove lockwire securing breech to tab
washer. Remove lead seal.
(6) Remove quick-release pin from emergency
oxygen system (15).
WARNING
(7) Raise ejection seat with overhead hoist until
the alignment tool can be extended. Extend alignment
tool and insert quick-release pin in alignment tool (figure
4-11).
(8) Install rocket safety pin 134SEME10054 in
hole of TCR motor initiator located under the seat
bucket.
Use extreme caution when removing breech to
prevent dropping the guillotine cartridge.
(3) With safety pin (7) still in sear (3), remove
breech (5) using tool, Part No. VSB2022.
WARNING
Use extreme caution when removing and handling
guillotine cartridge, as cartridge has a percussiontype primer cap. (Refer to TM 9-1 300-206.)
(9) Pull quick-release pin in rear of alignment
tool, Part No 105GT1024-59, and break alignment tool.
Install alignment tool on top of ejection gun (figure 410).
(4) Remove guillotine cartridge from breech (5)
using extractor, Part No. 105GT1046.
(10) Install guillotine safety pin 134SEME10053
in hole In the sear.
(5) Reinstall breech (5) handtight into guillotine
initiator housing (6)
(11) Raise ejection seat until bottom of ejection
seat clears top of ejection gun. Disengage alignment
tool from ejection gun by lifting upward on release lever
of alignment tool and remove alignment tool from
ejection seat.
(12) Install ejection seat on seat cradle, Part No.
105GT1040, as follows:
(a) Install transportation cradle mounting
rail on section seat slippers (figure 4-14).
(b) Install mounting rail and ejection seat on
seat cradle (figure 4-13).
(13) Remove hoisting sling from ejection seat.
e. Disarming of Guillotine After Seat Removal.
f.
Removal of Telescopic Election Gun From Aircraft.
(1) Remove ejection gun upper clamp fittings on
aircraft sloping bulkhead by removing locknut (1, figure 415), washer (2), and bolt (3).
(2) Remove locknut (4) and bolt (5) securing
ejection gun (6) to lower pivot and remove ejection gun
from aircraft.
(3) Transport ejection gun and seat to authorized
work area.
g. Removal Of Auxiliary Cartridges From Telescopic
Election Gun.
(1) Remove auxiliary
cartridges,
MBEU/2923 1, from ejection gun as follows.
WARNING
Part
No.
Never remove firing pin sear from guillotine
initiator firing mechanism until guillotine
cartridge has been removed from guillotine
initiator breech Any attempt to do so will cause
the cartridge to be fired. Ensure that firing pin
sear is secured by the safety pin when installing
or removing the manual override handle link
rod.
(a) Remove lockwire from lower auxiliary
cartridge chamber cap.
(1) With safety pin, Part No 134SEME10053 (7,
figure 4-14), installed in sear (3) of guillotine firing
mechanism (4), push sear up as far as possible, and
(b) Carefully unscrew lower auxiliary cartridge
chamber cap with spanner wrench, Pay No. 128GT101SS.
(See figure 4-16.).
4-8
CAUTION
Do not attempt to break or pull lockwire from
auxiliary cartridge chamber cap or lockwire holes
may break out.
Change 1
TM 55-1680-30824
Figure 4-10. Alignment tool installed on ejection gun (extended position)
4-9
TM 55-1680-308-24
Figure 4-11. Alignment tool installed on ejection
gun (extended position)
WARNING
Although the auxiliary cartridges do not contain
percussion-type primer caps, they are filled with
an explosive powder which, if accidentally fired
by either spark or flame, could cause death or
serious injury.
Figure 4-12. Installation of transportation cradle
mounting rail on ejection seat slippers
(c) Remove auxiliary cartridge using cartridge
extractor, Part No GR506.
NOTE
Handle auxiliary cartridges In accordance with
TM 9-1300-206.
(d) Remove
cartridge chamber.
auxiliary
cartridge
seal
from
(e) Repeat preceding subsets (a) through (d)
for removal of upper auxiliary cartridge.
4-10
TM 55-1680-308-24
Figure 4-13. Mounting rail and ejection seat on seat cradle
4-11
TM 55-1680-308-24
Figure 4-14. Removal of manual override handle link rod
4-12
TM 55-1680-308-24
Figure 4-15. Location view of ejection gun mounting points
4-13
TM 55-1680-308-24
Figure 4-16. Removal of lower auxiliary cartridge
Section II. CHECKOUT AND ANALYSIS
4-4.General.
The following inspections shall be performed by
Direct Support and General Support maintenance
(2) Inspect top latch plunger indicating dowel pin
for scoring.
(3) Check ejection seat slippers
alignment. (Refer to paragraph 4-6r.)
for
proper
4-5.Special Inspections.
Special inspections consist of visual Inspection and
specified checkout procedures to verify serviceability
when an abnormal condition exists on the ejection seat
or the components of the ejection seat
(4) Verify proper clearances between the ejection
gun guide rails and slippers (Refer to paragraph 5-29 )
(5) Inspect seat lift points and lower portion of
ejection seat bucket for damage and deformation
(6) Verify freedom of' movement of seat bucket
a. Spring Scale Reading Exceeding 200 Pounds.
When 200-pound spring scale reading occurs during
ejection seat removal, proceed as follows
NOTE
Disconnect seat raising actuator and manually
elevate and lower seat bucket.
(1) Inspect top latch plunger for damage (Refer
to paragraph 5-7c )
4-14
TM 55-1680-308-24
(7) Verify proper operation of the manual
override system. (Refer to paragraph 4-6b.)
(e) Inspect M119 rocket motor initiator cable
and conduit for damage. Replace if conduit is crushed.
NOTE
Release of attachment points must be in proper
sequence.
(f) Lift lowering line thigh pads and inspect
fiberglass supports for damage. Replace thigh supports if
damaged.
(g) Remove main parachute pack and inspect
for exterior damage. Return to parachute repack area if
damage is observed.
(8) Upon receiving new or overhauled drogue
guns or time release mechanisms, perform time delay
checks in accordance with paragraph 4-6k or 4-61, as
applicable.
b. Inspection requirement after guillotine has been
inadvertently fired: Replace activated guillotine
components.
CAUTION
The guillotine components are not repairable
after firing.
Burnt powder and gaseous
contaminants will cause severe corrosion.
c. Inspection requirement after ejection seat has
been fired: Replace ejection seat with serviceable
assembly. The ejection seat is a "one-time" use item
and not recoverable after ejection.
d. Inspection requirement after M119 (TCR) rocket
motor has been fired: Replace ejection seat with
serviceable assembly if ejected or severally damaged
as a result of inadvertent rocket motor firing. Locally
dispose of expended explosives and ejection seat
catapult assembly.
(h) Remove time release mechanism and
functionally test barostat. Replace barostat if altitude
differs by 2,000 feet or more from previous reading.
(i) Verify freedom of motion (opening) of
scissor shackle with time release mechanism removed.
(j) Using four (4) foot straight edge, verify
main beam structure alignment by placing straight edge
against main beam inner surface. Surface to surface
contact should occur. Replace seat if main beams fail this
inspection.
(2) Dropped more than four (4) feet but less than
eight (8) feet.
(a) Accomplish all checks of paragraph 4-5e(1)
above.
(b) Replace M119 rocket motor.
(c) Accomplish time release
functional tests.
mechanism
(d) Accomplish drogue gun functional tests.
c. Inspection requirement after ejection seat has
been accidentally dropped onto a concrete, asphalt or
equivalent surface:
(e) Remove and inspect RSSK contents for
damage.
(f) Operationally test all linkage for proper
(1) Dropped four (4) feet or less:
operation.
(a) Visually inspect structure for damage.
(b) Operationally test seat elevation
mechanism through full seat travel. Replace motor if
binding or erratic.
(c) Remove M-119 rocket motor and
visually inspect seat attachment brackets for damage. If
deformed or damaged, replace the ejection seat with a
serviceable assembly.
CAUTION
If rocket motor brackets are damaged or deformed
the seat must be replaced.
(g) Remove withdrawal line from guillotine and
inspect line for cut-damage from guillotine blade. Replace
withdrawal line if protective sleeve has been cut through.
(3) Dropped from a height In excess of eight (8)
feet.
NOTE
M119
rocket
motor
is
not
rendered
unserviceable by a four (4) foot drop.
(a) Forward
ordnance disposal.
M119
rocket
for
explosive
(b) Remove drogue parachute assembly
excluding the Hardshell container, and forward to repack
facility
for
inspection
and
reuse.
Change 3 4-15
(d) Inspect guillotine rigid tube for crushing
at seat bottom. Replace if damaged.
TM 55-1680-308-24
(c) Remove main parachute pack assembly
and forward to repack facility for Inspection and re-use.
(3) Ensure loop straps lugs are inserted in harness
lock of the inertia reel mechanism.
(d) Remove survival kit contents from
RSSK and inspect for subsequent use in replacement
ejection seat.
NOTE
The RSSK (complete with contents bag), drop
line and fry pan are to remain with the ejection
seat as an assembly.
(4) Ensure that the rigid seat survival kit restraint
lugs are locked to the seat bucket.
(5) Ensure leg restraint cords (2, figure 1-8) are
retained by cord lock fittings (6).
(6) Ensure that the face blind locking mechanism
latch is in the down or unlocked position.
(e) Replace with a serviceable assembly.
NOTE
Place unserviceable ejection seat in the crate
received and tag the unserviceable "dropped in
excess of eight (8) feet."
(7) Ensure that the lower firing handle safety is in
the down or unlocked position.
(8) Install manual override link rod in guillotine
initiator sear.
(f) Package ejection seat records with
damaged seat.
(9) Slowly move manual override handle (7, figure
2-1) to up-(unlocked) position.
4-6.
NOTE
The following events should occur in the order listed or
adjustment of the initiator link rod lower adjustment rod
tube will be required.
One-Hundred Eighty Day Inspection.
NOTE
A 10-day maximum free period may be utilized
before deducting from the next scheduled
ejection seat inspection cycle in the event
aircraft maintenance actions prevent timely
installation. If held in an area away from normal
seat maintenance, a suitable covering and all
safety pins shall be utilized. Perform 180-day
inspection as follows:
a. Cartridge and Rocket Motor Expiration Date
Inspection. Check all cartridges and rocket motor for
expiration date If new cartridges or rocket motors are to
be installed, mark each item with expiration date and
ejection seat serial number in black permanent marking
ink Enter expiration and installation dates on applicable
DA Form 2408-18. Cartridges and rocket motors with
less than 180 days service life remaining must be
replaced with serviceable items, or the next scheduled
seat inspection must be adjusted to correspond with the
remaining life of installed explosives.
(a) Guillotine initiator sear should be withdrawn
from its firing mechanism.
(b) Leg restraint cords should release from leg
restraint cord locks.
(c) Survival kit rigid seat restraint lugs should
be released from the seat bucket.
(d) Loop straps lugs should release from
harness lock mechanism.
(e) Upper and lower firing handles should lock.
NOTE
The upper and lower firing handles do not have to
lock in any given sequence.
b. Functional Check of Manual Override System.
This function is satisfactory if the two handles are locked
when the manual override handle is in the full up (unlocked)
position.
WARNING
Ensure that guillotine cartridge has
removed from guillotine breech initiator.
(10) If retention points do not release in sequence,
refer to paragraphs 4-15b and 5-18
been
(1) Position manual override handle (7, figure
2-1) in its down (locked) position.
c.
Function Check of Sticker Strap Spring Clip.
(1) Push sticker strap lugs into their respective
spring clips on each side of the ejection seat.
(2) Ensure that spring-loaded leg restraint cord
lock release handle (6) is in its forward position.
4-16 Change 4
TM 55-1680-308-24
(2) Attach a spring scale into strap end of
sticker strap lugs and pull on spring scale, noting spring
scale reading, until each sticker strap lug releases from
spring clips. Release tension shall be 35±15 pounds.
(See figure 4-17.)
(2) Disconnect bungee
mechanism trip rod (2, figure 4-7).
(1) Ensure that time release mechanism is
time
release
(3) Carefully support time release mechanism and
remove three nuts and three washers from mounting studs.
(3) If release tension is not within tolerance,
refer to paragraph 5-28c for corrective action.
d. Removal of Time Release Mechanisms.
from
CAUTION
Use caution when removing time release
mechanism to prevent bending the upper plunger
rod in the scissor release plunger housing.
cocked.
(4) Slide time release mechanism down while
turning it outward, only as much as necessary, until upper
plunger rod is clear of guard and guide tubes.
Keep hands clear of area below time release
mechanism plungers. Plungers extend with
great force.
Change 4
4-16A
TM 55-1680-308-24
7). Disconnect parachute roller yokes (4).
(2) Remove the personnel parachute withdrawal
line from the shackle at the scissor on top of the seat.
(3) Pull the withdrawal line retaining pins from both
sides of the head box releasing the personnel parachute
restraint straps.
(4) Remove the withdrawal line from the guillotine
cutter head assembly by pulling the yellow guard outboard
from the seat.
(5) Remove restraint straps from spreaders at
central support bracket.
CAUTION
Figure 4-17. Sticker strap spring clip check
e. Removal of Drogue Gun.
(1) Remove bungee (16, figure 4-3) from
drogue gun/TCR cable trip rod (11).
(2) Ensure that special shackle has been
removed from drogue projectile.
(3) Remove drogue gun barrel (5) from body (8)
which was left handtight and ensure cartridge has been
removed. Reinstall barrel handtight.
NOTE
Caution should be taken when transporting
parachutes between maintenance activities to
insure damage does not occur. Consult TM 101670-201-23,
Chapter
4,
for
shipment
requirements.
(6) Lift personnel parachute container (6, figure 12) from ejection seat; forward personnel parachute pack to
parachute support facility.
NOTE
When cross-servicing the personnel parachute and
drogue parachute systems, ensure inspection,
maintenance, and repack procedures are
performed in accordance with TM 10-1670-250-20.
g. Removal of Rigid Seat Survival Kit (RSSK).
If drogue gun barrel is not handtight, refer to
paragraph 4-3b.
(4) Disconnect TCR cable (15) from lower end
of drogue gun/TCR cable trip rod (11) by removing
cotter pin, flathead pin (12).
(5) Remove nuts and washers (7) from studs
(6) in seat securing drogue gun and pull drogue gun
outboard to remove from studs (6) and seat.
f.
Remove of Personnel Parachute Container.
(1) Position manual override handle to up
(unlocked) position and pull out loop strap (3, figure 1-
4-16B
NOTE
Ensure that guillotine has been disarmed.
(1) Remove
cushions.
seat,
(2) Position
(unlocked) position.
manual
back,
and
override
thigh
handle
support
to
up
(3) Pull up on retention strap (8, figure 1-2) and
forward portion of seat pan to remove RSSK from seat
bucket.
Change 8
TM 55-1680-308-24
h. Remove
Container.
of
Drogue
Parachute
Hardshell
receptacle.
(1) Withdraw upper (thick) cable through pocket
on flap of drogue parachute Hardshell container.
(5) Check firing cable extension for freedom from
binding and retention of face blind restraint strap by link line
quick-release pins.
(2) Ensure that special shackle nut and bolt are
fingertight.
(6) While holding face blind handle at full
extension, check that each locking plunger retracts fully.
(3) Remove screw, spacer washer, washer, lock
washer and nut from each side of drogue parachute
container and lift Hardshell container from ejection seat,
using lift loops on outer edges of Hardshell container.
(4) Dispatch drogue parachute and Hardshell
container assembly to parachute support facility for
topriate action.
(5) Loosely install hardware removed from
Hardshell container installation into ejection seat head
box holes to preclude loss.
i.
Remove of Emergency Oxygen Cylinder.
(1) Disconnect oxygen cylinder (13, figure 1-9)
from oxygen linkage by removing quick-release pin (25)
that secure cable link (29) to bellcrank (24)
(2) Disconnect oxygen hose (6) from oxygen
quick disconnect bridle and lanyard (5) by pulling on the
bridle.
(3) Loosen adjusting nut (14), open clamp (1),
and lift oxygen assembly out of oxygen cylinder support
backet (11).
Functional Check of Face Blind and Locking
(7) Deleted.
(8) Check for general condition, signs of wear,
fraying, or corrosion of metallic parts.
(9) With face blind fully extended, the upper firing
cable must withdraw the primary firing mechanism sear.
(10) Inspect firing cable for kinks, broken wires, and
corrosion.
(11) Ensure upper firing (truck) cable is securely
attached to face blind.
(12) Face blinds and locking mechanisms which do
not meet this criteria must be replaced.
(Refer to
paragraph 5-6.)
k.
Drogue Gun Inspection.
NOTE
If one year requirements defined in paragraph 4-7
are due, accomplish at this time.
(1) Remove drogue gun barrel.
(2) Perform a firing pin protrusion check on the
drogue gun as follows:
WARNING
The operational check of the face bind should only be
accomplished when the ejection seat has been
disarmed.
(1) Remove face blind locking mechanism
safety pin.
(2) Check that face blind cannot be pulled from
its receptacle with locking mechanism m up (locked)
position.
(3) Position face blind locking mechanism in
down unlocked position. Grasp face blind handle and
pull face ad to its full extension.
(a) Pull trip rod (11, figure 4-3) to unlock
drogue gun.
(b) Install drogue gun body on holding tool,
Part No. 10SGT1027.
(c) Check firing pin protrusion using firing pin
protrusion tool, Part No. 105GT1029. Firing pin must
protrude 0.109 (+0.031, -0.015) inch. (See figure 4-18.)
(3) Perform a firing spring compression check on
the drogue gun as follows:
(a) Install drogue gun on holding tool, Part No.
105GT1027, and mount holding tool securely in a vise.
(4) Check that spring-loaded locking plungers
figure
of face blind handle release smoothly from their
Change 8 4-17
(b) Remove access bolt from end plug (6,
4-19).
TM 55-1680-308-24
Figure 4-18. Drogue gun firing pin protrusion check.
4-18
TM 55-1680-308-24
No. MBEU/4341, into end plug hole in base of firing body
(1).
(d) Carefully locate tapped hole in firing pin (2)
with threaded end of cocking tool (6) by oscillating cocking
tool until it can be screwed into tapped hole.
(e) Attach a spring scale to shank of cocking
tool with lockwire. (See figure 4-20).
(f) With spring scale In line with cocking tool,
pull back on spring scale. The firing pin must not start to
move until spring scale reads approximately 8 to 15
pounds.
NOTE
Initial firing pin movement may be detected by
inserting finger in opening of drogue gun body and
lightly resting finger on firing pin.
(4) Replace drogue gun if spring compression does
not fall within allowable limits.
(5) Cock the drogue gun as follows:
(a) Place sear in firing body (8, figure 4-3)
Lock sear in place by pushing In on locking plunger
assembly (4, figure 4-19).
NOTE
The ground lock pin or tool, Part No. 105GT1044,
may be used for this purpose.
(b) Ensure that locking plunger assembly.
(4) is properly positioned by inserting ground lock
pin (9, figure 4-3) in safety pin hole.
NOTE
If ground lock pin will not enter safety pin hole, the
locking plunger assembly is not in its proper
position.
(c) After properly positioning locking plunger
assembly (4, figure 4-19), remove ground lock pin (9, figure
4-3) from safety pin hole.
(d) Holding firing body (1, figure 4-19) firmly,
pull cocking tool (5) against firing spring tension as far as
possible.
(e) Release tension on cocking tool and, after
a very slight return motion (approximately 1/8 inch), firing
pin will lock In the cocked position.
Figure 4-19. Installing cocking tool in drogue gun
(c) Insert drogue gun cocking tool (5), Part
Change 2
4-19
TM 55-1680-308-24
Figure 4-20. Firing pin spring compression test
NOTE
During cocking the firing mechanism must move freely (except for the spring tension), and the locking plunger
assembly will raise and then lower to the locked position, holding the sear firmly in position. The escapement
mechanism operation will be audible during the cocking action.
(f) Ensure firing pin does not protrude. Unscrew cocking tool and remove from tapped hole in firing body
(1).
(6) Perform a drogue gun time delay check using test umt, Part No. 134GT1041-T5; holding tool, Part No.
105GT1027; and a 110-volt ac, 60 Hz power source as follows:
NOTE
Test unit, Part No. 134GT1041-T5, consists of a timing clock assembly, Part No. 134GTI041-35, a start switch
assembly, Part No. 105GT1030-13; a stop switch assembly, Part No. 1OSGT1030-11; and a barostat adapter
assembly, Part No. 105GT1030-23.
(a) Ensure drogue gun is cocked and that firing pin does not protrude.
(b) Install drogue gun on holding tool and mount holding tool securely in vise.
(c) Attach start switch assembly over locking plunger assembly. (See figure 4-21.)
4-20
TM 55-1680-308-24
Figure 4-21. Drogue gum time delay check test setup
(d) Install stop switch assembly In firing pin
end of firing body (1, figure 4-19).
(i) Pull sear from drogue gun firing body.
Timing clock assembly will start and stop.
(e) Insert plugs of start and stop switch
assemblies into proper jacks in relay control section of
timing clock assembly.
(f) Connect timing clock assembly to a
110-volt ac, 60 Hz power source.
(j) Check clock for time delay of 0 40 to 0.60
seconds on drogue gun
(g) Apply power to timing clock assembly
by setting toggle switch to ON. Indicator light next to
toggle switch will illuminate.
NOTE
If timing clock assembly starts when toggle
switch is positioned to ON, the start and stop
switch assembly has been incorrectly installed
or is out of adjustment.
(7) If drogue gun falls to meet the time delay
specified In preceding substep (j), replace drogue gun.
(h) Ensure that timing clock assembly is set
to zero. If necessary, depress reset lever on timing
clock assembly to reset clock.
(k) Repeat time delay check two additional
times.
NOTE
Prior to installing a new or newly over-hauled
drogue gun assembly accomplish all tests within
paragraphs 4-6k(1) through 4-6k(7)(c) herein.
(a) If test was satisfactory, remove test unit
and holding tool from drogue gun.
Change 2
(b) Recock the drogue gun.
4-21
TM 55-1680-308-24
result if this procedure is not followed.
CAUTION
(b) Uncock the time release mechanism.
Ensure that the cocking tool is pulled full back
as noted by the 1/8 over travel and audible gear
movement
(c) Install access bolt into end plug (6,
figure 4-19 )
(c) Using test umt, Part No 134GT1041-T5,
install time release start and stop switch assembly on time
release mechanism and secure with knurled knob (See
figure 4-22.)
NOTE
I.
Time Release Mechanism Inspection.
(1) Time
operational test.
release
mechanism
time
delay
(a) Mount time release mechanism on
holding tool, Part No 105GT1027, and secure holding
tool in a vise with the time release mechanism in a
horizontal position.
CAUTION
Do not allow harness release plunger to extend
during timing tests, only the rack plunger need
extend Damage to the timing mechanism can
Test unit, Part No. 134C;T1041-T5, consists of a
timing clock assembly, Part No 134GT1041-35,
and a start and stop switch assembly, Part No
IOSGT1031-21.
(d) Connect plugs of start and stop switch
assembly to their respective jacks on relay control section
of timing clock assembly.
(e) Connect timing clock assembly to a 110volt ac, 60 Hz power source, and position toggle switch to
ON position Indicator light next to toggle switch will
Illuminate.
Figure 4-22 Time release mechanism time delay test setup
4-22
TM 55-1680-308-24
NOTE
If timing clock assembly starts when toggle
switch is positioned to ON, the start and stop
switch assembly has been incorrectly installed
or is out of adjustment.
(f) Ensure timing clock indicates zero. If
necessary, depress reset lever on timing clock assembly
to reset clock.
(g) Accomplish the following procedures to
make a coarse adjustment on the start and stop switch
assembly.
1. Manually depress start switch and adjust
stop switch until timing clock stops.
NOTE
Cock only the rack plunger.
2. Insert sear and
mechanism using cocking tool.
cock
time
release
3. Adjust start switch by loosening thumbscrew
and move start switch in until timing clock assembly
runs.
4. Move start switch out until timing clock
assembly stops. Tighten thumbscrew.
5. Depress reset lever
assembly to reset clock to zero.
on
timing
clock
(h) Accomplish the following procedure to
make a fine adjustment on the start switch assembly:
1. Screw out adjusting screw until timing clock
assembly runs.
2. Screw in adjusting screw until timing clock
assembly stops.
3. Depress reset lever
assembly to reset clock to zero.
on
timing
clock
(2) Time release mechanism test procedure.
(a) Grasp trip rod of time release
mechanism and pull sear Rack plunger will extend and
timing clock assembly should start and stop.
(b) Check clock for time delay of 1.65 to
1.85 seconds.
(c) Recock time release mechanism, recheck
installation of start and stop switch assembly, and repeat
preceding subsets (a) and (b) two more times. Replace any
time release mechanism that does not meet the specified
time requirements.
NOTE
Prior to installing a new or newly overhauled time
release mechanism accomplish all tests within
paragraphs 4-61(1) through 4-61(3) (k) herein.
(d) Position toggle switch of timing clock
assembly OFF. Cock both plungers of the time release
mechanism and remove start and stop switch assembly
from time release mechanism.
NOTE
Do not remove time release mechanism from
holding tool as it is required during the barostat
operational check.
(e) With both plungers cocked, check freedom
of movement of the plungers by pressing inward. The rack
plunger should retract and return to the locked position with
an audible gear movement (whirring) sound The harness
release plunger.
being spring-loaded, should retract and extend without
binding.
NOTE
There should be approximately 1/4-inch of travel of
the rack plunger, and 1/2-inch travel on the harness
release plunger.
(3) Barostat check procedures.
Barostat
operational check of time release mechanisms
incorporating a standard barostat assembly (MBEU690J5).
NOTE
These procedures apply to use of the barostat
adapter assembly (P/N 105GT1030-23) with
separate vacuum source and altimeter.
(a) Ensure time release mechanism is cocked.
(b) Remove lockwire and lead seal from
barostat assembly.
(c) Install barostat adapter assembly, Part No.
105GT1030-23, over time release mechanism barostat
assembly. (See figure 4-23.)
NOTE
Ensure barostat adapter assembly is securely held
to
barostat
assembly
by
retainer
clips.
Change 3 4-23
TM 55-1680-308-24
(d) Connect vacuum adapter tee fitting on
barostat adapter assembly to vacuum pump, FSN4310671-4481, and to pressure altimeter, Part No.
MS28044L1A.
CAUTION
Ensure pressure altimeter is set to 29.92 inches
(standard sea level) before beginning tests.
4-24 Change 4
TM 55-1680-308-24
Figure 4-23. Time release mechanism barostat test setup.
(e) Ensure bleeder valve on barostat adapter
assembly is closed. Set pressure altimeter hands to field
elevation.
(f) Slowly open bleeder valve until pressure
altimeter indicates 19,000 to 20,000 feet. Hold vacuum
at this altitude for approximately one minute.
CAUTION
Do not allow harness release plunger to extend
during test; only the rack plunger need extend.
Damage to the timing mechanism can result if
this procedure is not followed.
NOTE
Restrain harness release plunger with cocking
tool to preclude rapid extension
(h) Watching the pressure altimeter closely, slowly
release vacuum from barostat assembly, using bleeder
valve, and note the altitude on the pressure altimeter
when rack plunger starts to move. The rack plunger
should start its extension at an altitude range of 15,500
to 14,000 feet.
NOTE
Record altimeter reading for time release
mechanism by serial number for subsequent test
reviews.
(g) Grasp trip rod and pull sear from time release
mechanism. Plunger must not extend.
Change 2 4-24A/(4-24B blank)
TM 55-1680-308-24
WARNING
A barostat which exhibits a 2,000 feet or
more change (decrease in altitude) from
that previously recorded shall be replaced
with a serviceable barostat Refer to
paragraph 5-23.
(f) Lower the vacuum box lid down onto the mating
surface making sure the seal uniform makes contact.
(g) Adjust altimeter to read standard "sea level"
(29.92 INCHES OR 1013 MILLIBARS) to assure all test
results are independent of elevations and/or field
elevations.
(i) Recock time release mechanism and repeat
preceding substeps (e) through (h) two more times.
CAUTION
Do not use force when closing the air
admittance valve to preclude damaging
the seal.
NOTE
Do not cock harness release plunger.
(h) Move the ON/OFF switch to ON and verify the
red indicator light illuminates and the vacuum motor
starts.
NOTE
A barostat that does not operate at
the prescribed altitude may be
adjusted
In
accordance
with
paragraph 5-23(h).
(j) Remove barostat adapter assembly from barostat
assembly. Recock both plungers on time release
mechanism
(k) Secure serviceable barostat assembly with
lockwire and lead seal (items 1 and 3, table 12)
(4) Barostat check procedures utilizing vacuum test
box (TD01153). Barostat operational check of time
release mechanisms incorporating a standard barostat
assembly (MBEU690J5).
(a) Lift cover of test box and check inner area for
dirt and contamination, clean as required
(b) Check lid seal for damage and wipe with a clean
lint free cloth to remove
(c) Remove trip rod and sear from time release
mechanism to be tested.
(i) Apply a moderate hand pressure to top of lid and
carefully close air admittance valve Observe that
altimeter begins recording an increase in altitude.
(j) Allow vacuum motor to run until an altitude
reading of 25,000 to 30,000 feet is attained, and then
turn switch OFF.
NOTE
When vacuum motor is turned OFF the
altimeter may fluctuate momentarily If altitude
continues to decrease, the lid seal is most likely
upset, or a test box control seal may be worn.
(k) Hold at this altitude for approximately one
minute and remove time release mechanism gear by
depressing the firing control knob. At this point the time
release must not operate.
(I) Slowly open the air admittance valve by rotating
counter clockwise until the altimeter shows a steady fall
of 200 feet per second (MAXIMUM), and note the
altitude at which the time release mechanism begins to
operate.
CAUTION
Before
installing
time
release
mechanism, ensure barostat adjustment
screw driver mechanism and test box
firing control are fully withdrawn.
(d) Insert time release mechanism into vacuum test
box, locating it on the two mounting pins, and secure in
position with clamp. Tighten clamp nut securely using
spanner wrench provided.
CAUTION
Only the time release RACK plunger
(SHORT) shall be cocked to perform this
test
NOTE
Time release mechanism operation is
noted by an audible operation of the
gearing and visible movement of the
RACK PLUNGER.
(m) Record the altitude at which time release
mechanism operation began. The altitude reading at the
first motion shall be 14,500 feet plus or minus 500 feet.
(e) Fully insert the special firing pin attached to the
firing cable and cock the RACK PLUNGER only using
the cocking tool.
Change 2 4-25
WARNING
A barostat which exhibits a 2,000
feet or more change (decrease in
altitude)
from
that
previously
recorded shall be replaced with a
serviceable barostat
Refer to
paragraph 5-23.
TM 55-1680-308-24
NOTE
If the firing pin sear is bent or
cracked, replacement is required.
(n) Evacuate the vacuum chamber by opening the
air admittance valve and repeat this test two more
times.
(5) Check Initial compression of primary firing
mechanism spring using a spring scale attached to firing
pin cocking tool. Firing pin must not move until a load of
at least 8 pounds is applied..
CAUTION
When evacuating the vacuum changer, do not
exceed 1,000 feet per second decrease In
altitude to prevent damage to altimeter.
CAUTION
Do not attempt to alter spring tension by adding or
removing washers.
(o) A barostat that does not operate at the
prescribed altitude may be adjusted in accordance with
paragraph 5-23(h).
(p) Remove serviceable time release mechanism
from vacuum test chamber and cock both plungers for
installation on ejection seat.
NOTE
Record altitude reading for time release
mechanism by serial number for subsequent test
reviews.
m. Primary Firing Mechanism Inspection.
(1) Remove
ejection gun.
primary
firing
mechanism
(6) Check firing pin protrusion with firing pin
protrusion tool, Part No 105GT1029. The pin protrusion
should be 0.109 (-+0 030, -0.015) inch. (See figure 425.) If firing pin does not protrude to the above
dimensions, refer to paragraph 5-3.
(a) Deleted.
(b) Deleted.
(c) Deleted.
(e) Deleted.
(f) Deleted.
n. Ejection Gun Inspection.
from
(2) Using firing pin cocking tool, Part No.
MBEU/1321, remove firing pin sear. (See figure 424.)
CAUTION
No lubricant should be present or be applied
to guide rails. Guide rails should always be
kept clean and dry.
(3) Ensure that firing pin sear moves freely in firing
pin slot.
(1) Inspect ejection gun guide rails (6, figure 4-26)
for scoring, gouges, and cleanliness.
(4) Place firing pin sear on a flat surface and
inspect for deformation.
4-26
Change 2
TM 55-1680-308-24
Figure 4-24. Removing firing pin sear from primary firing mechanism
Mounting blocks must be placed around the
thick end of the cylinder barrel to prevent
possible damage to the ejection gun.
(2) Mount ejection gun in vise using ejection gun
clamp mounting blocks, Part No. MBEU/8463. (See
figure 427.)
Do not attempt to separate the inner tube
from the intermediate tube. They are
restricted from separating by the inner tube
guide bushing, which Is riveted to the top of
the intermediate tube. Use extreme care to
prevent shearing of these rivets during
servicing If a rivet is sheared, replace the
entire ejection gun assembly.
(3) Extend election gun inner and intermediate tubes
to their full extension.
Change 2 4-26A/(4-26B blank)
TM 55-1680-308-24
(6)
Lubricate the ejection gun as follows
WARNING
Excessive lubrication of the ejection gun inner and
intermediate tubes can dampen the effect of the
primary charge.
(a) Lubricate inner and intermediate tubes with
lubricating oil (item 2, table 1-2).
(b) Lubricate primary cartridge breech O-ring with
grease (item 5, table 1-2).
(7) Compress (retract) ejection gun inner and
intermediate tubes Into cylinder barrel and install ejection
gun auxiliary cartridges as follows.
WARNING
Do not use plastic separators (provided m the
cartridge shipping container) as gas sealers. Use of
plastic separators will result in ejection gun
malfunction.
Figure 4-25. Checking firing pin protrusion
(4) Clean ejection gun inner and intermediate tubes
with clean, lint-free cloth moistened with lubricating oil
(item 2, table 1-2).
NOTE
Drycleaning solvent (Item 6, table 1-2) IS not a
suitable or authorized cleaning agent and shall not
be used.
(5)
Inspect the ejection gun as follows.
(a) Inspect entire ejection gun for visible damage and
for corrosion
(b) Inspect primary cartridge breech O-ring for
damage and deterioration.
(c) Inspect ejection gun interior for oil and moisture
accumulations
(a) Inspect auxiliary cartridges for damage around
flange edges and for corrosion.
(b) Insert new seal in lower auxiliary cartridge chamber
and insert auxiliary cartridge, Part No. MBEU/29231, flat
side inboard.
NOTE
Check all cartridges for expiration date. If new
cartridges are installed, mark cartridge with
expiration date and ejection seat serial number
in black permanent marking ink. Enter cartridge
expiration and installation dates on applicable
DA Form 2408-18. Cartridges with less than 180
days service life remaining shall be replaced.
(c) Screw on auxiliary cartridge chamber cap and
tighten to a torque of 300 to 550 inch-pounds using
spanner wrench, Part No. 128GT10155.
(d) Secure auxiliary chamber cap to lower auxiliary
cartridge chamber with lockwire and lead seal.
(e) Repeat preceding substeps (b) through (d) for
installation of the upper auxiliary cartridge.
NOTE
If contamination is present, clean ejection gun (Refer
to paragraph 5-2c.)
Change 3
4-27
TM 55-1680-308-24
Figure 4-26. Ejection gun - exploded view (Sheet 1 of 2)
TM 55-1680-308-24
(h) The tab to be bent flat on the guillotine cartridge
(10) Ensure that guillotine initiator (8) is secured to
seat bucket.
breech should be opposite tab engaged in retaining collar
slot
p. Guillotine Initiator Firing Pin Inspection.
(i) Repeat preceding substeps (a) through(h) If the
(1) Ensure that guillotine initiator was disarmed when pin does not extend the required amount, replace the firing
mechanism
seat was removed from aircraft. Refer to paragraph 43e.
(j) Install right thigh support with screws and replace
(2) Remove link rod (6, figure 4-28) by using firing pin
cocking tool, Part No. MBEU/1321, and remove firing pin padding by pressing down firmly
sear (12).
q. TCR Motor (MI 19) and Cable Dispenser
NOTE
Inspection.
The firing pin sear must move freely firing pin slot.
(1) Inspect TCR cable dispenser (2, figure 4-30) for
(3) Place firing pin sear on flat surface and inspect for secure installation on seat.
deformation.
(2) Inspect visible dispenser cable (3) for kinks, nicks,
NOTE
or fraying
Replace firing pin sear if it is bent or cracked.
(3) Inspect TCR motor cable conduit (1) for sufficient
(4) Check initial compression of guillotine initiator firing slack, kinks, gouges, and security to seat.
mechanism (13) spring by securing mechanism into
padded vice jaws and using a spring scale attached to
firing pin cocking tool. Firing pin must not move until a load
of at least 8 pounds is applied.
NOTE
Plunger should be flush or slightly protruded.
The TCR cable conduit must have a generous
loop coming out of dispenser and a loop
approximately 7 to 7-1/2 inches at the motor to
assure free cable travel
(5) Check firing pin protrusion with firing pin protrusion
tool J9126 by inserting tool into guillotine cartridge breech
(6, figure 4-29). If firing pin does not cause gage plunger to
(4) Inspect TCR initiator cable small con- nector for
be flush or protrude slightly, proceed as follows:
security of lockwire at TCR dispenser housing and large
connector for security of lockwire at TCR motor Initiator
(a) Remove firing pin assembly by bending down
tabs of tab washer (2) that secures retaining collar (3).
(b) Remove retaining collar (3), tab washer (2),
firing pin spring (4), and firing pin (5).
(c) Inspect firing pin for burrs and bending.
(d) Clean cartridge breech with dry, filtered,
compressed air to remove possible foreign matter.
(e) Lubricate firing pin with a light coat of
lubricating oil (item 2, table 1-2).
(f) Screw retaining
cartridge breech (6).
collar (3) into guillotine
(g) Bend tab to make contact with flat surface of
guillotine cartridge breech (6).
Figure 4-29 Guillotine initiator - exploded view
Change 5
4-31
TM 55-1680-308-24
Figure 4-30. TCR motor and cable dispenser inspection
4-32
TM 55-1680-308-24
(5) Inspect TCR motor (7) for security of installation
TCR motor nozzle must be seen through bracket (6)
hole, and be free of obstruction.
(6) Ensure safety lock streamer (134SEME10054)
is installed.
(7) Inspect TCR motor (Ml 119) for expiration of
installed life.
r. Slipper Alignment and Calibration Check.
readings, and adjust as necessary, using either of the
following methods
Maximum allowable spot face of main beam
material for middle and top slippers is 0 050 inch
each beam maximum allowable spot face of
main beam material for lower slippers is 0010
Inch each beam. The left and right beams must
be spot-faced an equal amount
1.
Insufficient clearance. Remove top slippers
from main beam. Remove necessary shuns (if any) and
use spot-facing tool, Part No 134XM15499 or TD0/742,
to spot-face slipper attachment holes on inside of main
beam until a micrometer reading of 0001 to 0006 inch is
established between ejection gun and slippers.
NOTE
Although the ejection gun and ejection seat
are individually replaceable, the calibration
check should be accomplished. on mated
ejection guns and ejection seats to preclude
unnecessary removal of main beam material
If replacement of ejection gun and election
seat is necessary, reidentification to mated
assemblies (by identification number) should
be accomplished in accordance with
paragraph 5-32 before installation
2. Excessive clearance. If the clearance exceeds
0006 inch, install shims between slippers and inside
face of each beam
NOTE
(1) Remove election seat from seat cradle and
support ejection seat using hoisting sling, Part No
105GT1024-33, and a suitable hoist
Install equal thickness of shims between
each slipper and inside face of each main
beam
(d) Repeat preceding substeps (a) through (c) for
the center and bottom set of slippers The clearance
must be as follows:
Do not attempt to remove slipper material.
Removal of material could result m ejection
seat failure during ejection or crash landing.
NOTE
The outside diameter of the ejection gun
must be measured where the slippers mate
with the ejection gun.
(2) Inspect slippers for evidence of corrosion or
metal bum. Replace defective slippers.
(3)
Perform slipper calibration check as follows:
(a) Using an outside micrometer, measure the
distance across inserts (I, figure 4-26) at top of ejection
gun. Record this reading.
(b) Tighten top slippers In main beam to
proper torque (50 to 60 Inch-pounds) Using an inside
micrometer, measure the distance between top slippers
at point of minimum dimension.
(c) Compare ejection gun and slipper
Change 1
1. Middle slippers 0.010 to 0.012 inch
2. Bottom slippers 0 000 to 0.005 inch.
Ensure that locating pin slot of the ejection gun inner
barrel aligns with the main beam locating pin.
4-33
TM 55-1680-30824
(e)
seat.
Install ejection gun onto slippers of the ejection
(3) Pull on spring scale, noting force required to
rotate scissor to a parallel position with the main beams.
Spring scale must be maintained at 90 degrees to the
scissors during this test. (See figure 432.)
NOTE
When the preceding substeps have been
accomplished, it should be possible to remove
ejection gun by hand If seat still binds,
reposition upper or lower slipper shims to the
side opposite the binding Under this condition,
equal number of shims per side cannot be
maintained.
(4)
NOTE
Spring scale reading shall be between 5 to 25
pounds. If spring scale reading is above or
below these limits, adjustment of the scissor
rotational force is required.
(4)
Perform slipper alignment as follows.
(a) Check slipper alignment on main beams by
placing an accurate 4 foot straightedge against the sides
of the top and lower slippers. Both slippers must contact
the straightedge completely. (Refer to fig. 4-31 )
(b)
Adjust scissor rotational force as follows:
(a) Remove scissor retaining bolts, washers,
and nuts securing scissor to main beam. (See figure 432.)
(b) Add or subtract number of washers to
increase or decrease scissor rotational force, as
required.
Align misaligned slippers as follows'
1. Loosen slipper locking nut slightly and tap
misaligned slipper in proper direction with a soft fiber or
plastic mallet until slipper is in alignment
2. Tighten all slipper attaching nuts to a
torque of 50 to 60 inch-pounds.
NOTE
Misaligned slippers will cause difficulty in
aligning ejection seat on ejection gun guide
rails.
(c) Install scissor retaining bolts, washers, and
nuts securing to main beam.
(5) Verify freedom of opening of the scissor arm
when the locking plunger is retracted and the scissor is
rotated throughout its range of movement
WARNING
The scissor arm must not make contact with
the locking plunger when plunger is fully
retracted.
s. Scissor Rotational Force Check.
(1) Ensure scissor is resting on scissor shackle
buffer stop.
(6) Verify freedom of motion of the locking plunger
and clean of any contaminants and/or corrosion.
(2) Connect a suitable spring scale to scissor
shackle.
Figure 4-31. Checking slipper alignment
Change 2 4-34
TM 55-1680-30824
Figure 4-32 Measuring Tension of Scissor Mechanism
center (autolock) position
NOTE
(2) Pull loop strap out to the farthest position
Inspect loop strap for cuts, fraying, and cleanliness.
Washers shall always be installed behind the
bolt head and not behind the nut
NOTE
(d) Recheck scissor rotational force as outlined in
preceding step (3).
Frayed loop strap edges 1/8 inch maximum
both sides are considered serviceable
t. Functional Check of Inertia Reel Mechanism.
(1) Position inertia reel manual control handle in
Change 7
4-35
TM 55-1680-308-24
(3) Position inertia reel manual control handle to
forward (locked) position.
(5) Insert cord lock fitting (6) on upper end of leg
restraint cord (2) into leg restraint cord lock (5) in front
of seat bucket. Ensure cord lock fitting is secure
(4) Slowly allow loop straps to retract a few inches
at d time, then pull on loop straps to ensure that they
lock. Repeat this procedure until loop straps are fully
retracted
(6) Move leg restraint cord lock release handle (6,
figure 2.1) to its aft (unlocked) position and ensure that
upper end of leg restraint cord (2, figure 1-8) is released
from cord locks
(5) Move Inertia reel manual control handle to
center (autolock) position and pull on loop straps Loop
straps should be locked.
(7) Return leg restraint cord lock release handle (6,
figure 2.1) to its forward (locked) position
(6) Position inertia reel manual control handle to
(unlocked) position and release handle Handle should
move to center (autolock) position.
(8) Perform preceding steps (1) through (7) on
opposite leg restraint cord and cord lock fitting.
(9) Pull snubber finger ring (7, figure 1-8) out and
pull forward on leg restraint cord (2) until it is extended
to Its farthest position.
(10) Inspect leg restraint cords (2) for cuts,
deterioration, and fraying, and end fittings for damage
(11) Inspect garters for cuts, deterioration and
proper operation of the quick release fittings
NOTE
Inertia reel manual control handle is spring-loaded to
the center (autolock) position
(7) Position inertia reel manual control handle to aft
(unlocked) position and pull loop straps out
approximately 2 feet Ensure the snubber contacts
snubber stop (See figure 4-33 ) Release loop straps and
inertia reel manual control handle
v. Functional Check of Lower Firing Mechanism.
WARNING
(8) Pull loop straps out to their farthest position and
allow loop straps to retract slowly Loop straps should
fully retract
The operational check of the lower firing
mechanism should only be accomplished
when the ejection seat has been disarmed.
u. Functional Check of Dual Leg Restraint
Mechanism.
(1) Ensure leg restraint cord lock release handle is
in forward (locked) position
(1) Position lower firing handle safety guard (4,
figure 1-8) In up (locked) position and pull upward on the
lower firing handle (3) Lower firing handle should be
locked
(2) Pull on lower (aft) end (under seat bucket) of leg
restraint cord (2, figure 1-8) and ensure it passes
through snubber freely
(2) Position lower firing handle safety guard (4) In
down (unlocked) position and pull upward on the lower
firing handle (3) Handle should pull freely
(3) With lower (thin) cable extended, inspect cable
for kinks, broken wires, and corrosion
(3) Pull forward on leg restraint coral (2) and
ensure that Lord IS held by snubber
(4) Pull forward on leg restraint cord (2) and pull on
snubber finger ring Ensure leg restraint cord will pull out
freely while snubber finger ring is held out
To prevent damage to the lower firing (thin)
cable, pull on ring end of lower firing cable,
located at the top of the seat, to take up slack
as lower firing handle is installed In its original
position
NOTE
The snubber finger ring is spring-locked and
will return to the locked position, when
released.
4-36
TM 55-1680-308-24
Figure 4-33. Snubber contacting stop
4-37
TM 55-1680.308-24
(4) Install lower firing handle (3) 180 degrees from its
original position and repeat preceding steps (1) and (2).
w. Maintenance Operational Check of Lower Firing
Mechanism.
WARNING
Ensure that leg restraint cord lock fittings are
installed in leg restraint locks, and that slack
from the leg restraint cord lock release handle,
when held back, does not lock the lower firing
handle with the lower firing handle safety guard
down, which would give an incorrect indication.
and cleanliness.
NOTE
The exterior seat surfaces and interior seat
bucket area should be thoroughly cleaned
during this inspection. The overall appearance
of the ejection has an effect on the user's
confidence in the escape system
(2) Check all accessible cotter pins for security and
condition.
(1) Insert restraint cord lock fittings (6, figure 1-8) in
their respective leg restraint cord locks (5).
(2) Position lower firing handle guard (4) in up
(locked) position and pull upward on lower firing handle
(3). Lower firing handle should not move.
WARNING
Slack in the restraint cord release handle must
be removed to ensure proper operation of the
lower firing handle locking mechanism.
(3) Position lower firing handle safety guard (4) in
down (unlock) position. Move leg restraint cord lock
release handle (6, figure 2-1) aft until all slack is
removed. Holding back on this slack, pull upward on the
lower firing handle (3, figure 1-8). Handle should pull
freely.
(4) Install lower firing handle (3) 180 degrees from its
original position and repeat preceding steps (1), (2), (3).
x. Functional Check of Emergency Oxygen System.
(1) Disconnect oxygen cylinder (13, figure 1-9)
from oxygen linkage by removing quick-release pin
(25)
securing cable link (29) to bellcrank (24).
(2) Assure positive engagement of trip lever (30) to
the shaft (23) by depressing lever while restricting
movement of bellcrank (24).
(3) Pull manual actuating knob (2) and note
movement of bellcrank (24). Bellcrank should move
downward as manual actuating knob is pulled.
(4) Return manual acutating knob (2) to its original
position in actuating knob support bracket (3).
WARNING
Only minor sheet metal repair to the seat bucket
assembly is authorized Repair shall not be
attempted on the other seat structure. (3)
Inspect seat structure for damage. Coverage will
include cracks, loose or missing rivets, buckling
and corrosion.
z. Installation of Drogue Parachute Hardshell
Container.
WARNING
Failure to remove webbing carrying handle will
result in improper drogue parachute operation.
(1) Remove webbing carrying handle from hard shell
container. Verify that next scheduled repack date is due
concurrently with or after next scheduled ejection seat
inspection. Ensure service life remaining on the drogue
parachute withdraw line is at least equal to the number
of days remaining until next scheduled ejection seat
inspection (Refer to TM 10-1670-250-20).
WARNING
Drogue connector line must be located in the
left-hand rear corner (drogue gun side) of the
container. Return to parachute pack facility if
not properly located.
(2) Install hardshell container on ejection seat
utilizing prior removed hardware. The large flat washer
is placed between the drogue container and the ejection
seat, and the solid washer is placed against the ejection
seat with the lock washer and nut last
NOTE
The head of the screw should be inside with nut
outboard.
(3) Scissor should remain vertical on top of drogue
container until personnel parachute pack is installed on
seat.
Insert upper firing cable through pocket on forward
sunlight cover flap of hardshell container.
y. Inspection of Ejection Seat Structure.
(1) Inspect seat structure for evidence of corrosion
4-38
Change 8
TM 55-1680.308-24
Figure 4-34. Face blind installation
TM 55-1680-308-24
(5) Position upper firing cable off to side of container
for subsequent installation of drogue hardshell container
aa. Repack of Face Blind.
(1) Push face blind restraint strap connector links
through guide tubes on each side of drogue parachute
container and secure in fitting (attached to container)
with link line quick-release pins.
NOTE
The face blind must be repacked after installing
the drogue parachute system.
(2) Push upper firing (thick) cable through rear of
face blind container until end ring contacts back of
container
NOTE
Ensure that straps are not twisted and that face
blind is installed with rubber stops on handle
pointing down.
(3) Fold under sides of face blind curtain to width
of drogue parachute container mouth. Fold under
stitched aft end of face blind curtain and insert In drogue
parachute container mouth (See figure 4-34 )
(4) Stow excess upper firing cable (loop to left)
between first and second folds of the face blind. (See
figure 4-34.)
(5) Pack face blind curtain (accordian fold) into
container, using thumbs to press it back and down into
container.
(6) Place face blind handle body In mouth of
container, placing the palm of one hand against body,
and push Inward. With the other hand, grasp face blind
handle and pull outward to retract spring-loaded locking
plungers while pushing body into mouth of container
(See figure 4-34.)
NOTE
Check that plungers are fully engaged in their
receptacle when face blind handle is
released.
(7)
to lock face blind handle in place, and insert face blind
safety pin through locking mechanism.
NOTE
Face blind locking mechanism should lock
without binding.
ab. Drogue Gun Installation. Install drogue gun on
ejection seat, In the unloaded but cocked condition, as
follows:
NOTE
Verify drogue gun is not overage (refer to para 4-8).
WARNING
Do not attempt to arm the drogue gun until
ejection seat is installed in the aircraft.
(1) Ensure engagement of locking plunger by
hitting drogue gun body with palm of hand.
(2) Install drogue gun on main beam mounting
studs (6, figure 4-3) and secure with nuts and washers
(7). Tighten nuts to torque specified in table 4-1.
(3) Check trip rod for binding and corrosion.
(4) Install bungee (16) on drogue gun/TCR
cable trip rod (11).
Table 4-1. Nut Torque Values
for UNF and UNC Bolts
Bolt Size
6 UNC
8 UNC
10 UNF
1/4 inch
5/16 inch
3/8 inch
7/16 inch
1/2 inch
9/16 inch
5/8 inch
3/4 inch
7/8 inch
1 inch
(Inch-Pounds)
10-12
14-18
36-45
77-96
145-180
290-360
420-520
620-770
920-1,150
1,250-1,560
2,525-3,125
3,680-4,600
5,200-6,500
(5) Connect TCR dispenser cable (15) to lower end
of drogue gun/TCR cable trip rod (11) with flathead pin,
cotter pin (12).
Raise face blind locking mechanism bellcrank
Change 2
Torque Value
4-40
TM 55-1680-308-24
(5) Position face blind locking mechanism and lower
firing handle in down (unlocked) position.
ac. Installation of Time Release Mechanism.
NOTE
Verify time release mechanism is not overage
(refer to para 4-8).
(1) Ensure time release mechanism is cocked.
WARNING
Keep hands clear of area below time release
mechanism plungers. Plungers extend with great
force.
WARNING
Keep hands clear of area below time release
mechanism plungers. Plungers extend with
great force.
(6) Position cocking tool, Part No. MBEU/ 6945, on
top of time release mechanism and insert pin on end of
cocking tool cable into hole in lower end of harness
release plunger (inboard plunger).
(2) Remove slack from harness release plunger rod
by carefully depressing rod until it bottoms out.
(3) Insert harness release plunger rod into guard
and guide tubes on ejection seat. Slide time release
mechanism upward, being careful not to bend the
harness release plunger rod.
(7) With cocking tool in place, restrain harness
release plunger. Grasp cocking tool handle and apply a
firm downward hold, then grasp trip rod and pull sear
from time release mechanism.
CAUTION
The time release mechanism shall never be
actuated on the ejection seat, allowing the
harness release plunger to strike down on the
harness release lever. Restrict movement of the
harness release plunger with the cocking tool.
Lower release plunger slowly until the ejection
seat harness release arm has been depressed.
(See figure 4-35.)
(4) Carefully support time release mechanism and
install three washers and three nuts on mounting studs.
(5) Check trip rod for binding and corrosion.
(6) Connect bungee to time release mechanism trip
rod.
ad. Functional Check of Time Release Mechanism
(1) Ensure manual override handle on the right side
of seat bucket is in the down and locked position.
(2) Ensure restraining scissor is locked at the top of
the ejection seat main beam.
(3) Engage dual leg restraint cord upper lock fittings
into their leg restraint cord locks at front of seat bucket.
Leg restraint cord lock release handle must be in the
forward (locked) position.
(4) By visual inspection, check that the following
harness lock fitting locking pins are in the extended
(locked) position:
(a) Harness loop straps release lock (located in
the center of central support bracket).
(b) Two rigid seat survival kit restraint lug locks
(located on the aft, right, and left inside corners of seat
bucket).
Change 8
(8) When rack plunger is fully extended and
harness release plunger escapement mechanism is
unlocked, slowly release pressure on cocking tool
handle and allow harness release plunger to extend
slowly and actuate harness release lever.
(9) Check that face blind and lower firing handles
lock and that the following have released:
(a) Harness loop strap release lock (visually
check that locking pin has withdrawn).
(b) Scissor release plunger at the top of release
plunger housing (scissor must be free to open).
(c) Rigid seat survival kit restraint lugs (visually
check that locking pins have withdrawn).
(d) Leg restraint cords (upper lock fitting
released from leg restraint cord lock).
(10)
Cock time release mechanism as follows:
(a) Check that scissor restrained shackle is
within jaws of scissor at top of the ejection seat main
beam.
4-41
TM 55-1680-308-24
Figure 4-35. Cocking time release mechanism
4-42
Change 2
TM 55-1680-308-24
(b) Insert sear fully into its hole In time release
mechanism.
cocked position. The time release mechanism is now
cocked.
(1) Remove cocking tool from time release
mechanism
NOTE
Due to a double detent in the sear receptacle,
a slight tap may be necessary to seat the sear.
(m) Connect trip rod bungee
ae. Inspection of Oxygen System.
(c) Place cocking tool, Part No MBEU/6945, on
top of tune release mechanism with hand lever forward.
(See A, figure 4-35 ).
(1) Inspect oxygen hose for cracks and
deterioration.
(2) Inspect oxygen hose fittings for serviceability
(d) Insert small pin at end of chain on cocking
tool into vertical hole in scissor release plunger housing.
Insertion of this pin will prevent plunger from releasing
restraining scissor movable arm
(3) Inspect oxygen quick-disconnect bridle and
lanyard for fraying, loose stitching, and for proper
installation
(4) Inspect oxygen cylinder for visible damage and
corrosion.
(e) Insert pin on end of cocking tool cable in hole
in lower end of mechanism rack plunger (outboard
plunger with short stroke)
(5) Visually check oxygen cylinder quantity
indicator for proper capacity
(f) Cock rack plunger by pushing cocking tool
handle down until plunger retracts into body of time
release mechanism as far as it will go (B, figure 4-35).
af. Installation of Oxygen System.
(1) Position oxygen cylinder (13, figure 1-9) on
oxygen cylinder support bracket (11), routing oxygen
hose (6) through bracket
(g) Slowly release cocking tool handle. After a
short return motion, rack plunger should lock m
retracted position.
NOTE
NOTE
The escapement mechanism operation
will be audible during the rack plunger
cocking.
(h)
Ensure that oxygen quantity gage faces
right side of seat.
(2) Secure oxygen cylinder to seat bucket with
clamp (1), then tighten adjusting nut (14), and secure
oxygen hose (6) to oxygen quick-disconnect bridle and
lanyard (5).
Remove cocking tool pin from rack plunger
(I) Insert cocking tool pin at end of cable into
hole in harness release plunger (inboard plunger with
the long stroke (C, figure 4-35))
(3) Position cable link (29) on bellcrank (24) and
secure with quick-release pin (25)
When cocking time release harness release
plunger with trip rod indicator is installed, care
should be exercised to prevent damage to the
trip rod indicator
ag. Rigid Seat Survival Kit (RSSK).
(1) Inspect occupant's retention straps (1, figure
436) for fraying and loose stitching
(j) Cock harness release plunger by pushing
handle of cocking lever down as far as it will go Plunger
must be retracted as far as it will go into mechanism. At
same time, the small pin which was inserted at top of
scissor release plunger housing will be expelled (D,
figure 435).
(2) Inspect metal and fiberglass parts of survival
kit container (6) for signs of wear, fractures, and soft
spots (discoloration)
(3) Inspect velcro strips (4) for proper adhesion to
seat pan (5).
(k) Slowly release cocking tool handle After a
short return motion, release plunger should lock m the
4-43
TM 55-1680-308-24
Figure 4-36. Rigid seat survival kit (RSSK)
(4) Inspect release cable (3) for nicks, gouges, and
security.
(5) Inspect dual quick-release grip device (2) for
overall security.
(6) Apply approximately 15 pounds of hand pull
force on quick-release grip device (2) to unlock seat pan
(5) from survival kit container (6).
(7) Inspect survival kit equipment for contents and
condition of each component in accordance with TM 551680-317-23&P.
(8) Inspect inside of RSSK for cleanliness, security
of attachment fittings (1, figure 4-37) and condition of
nylon lines (2).
(9) Repack survival equipment in accordance with
TM 55-1680-317-23&P and secure equipment bag (3)
with straps (4, fig 4-37).
container (6) and engage latches to locking mechanism
and press down to lock .
(11) Ensure that seat pan is securely locked to
survival kit container.
ah. Installation of RSSK.
(1) Ensure that guillotine initiator is disarmed.
(2) Position manual override handle to up
(unlocked) position.
(3) Place RSSK into ejection seat bucket. Position
RSSK so that retention lugs (7, figure 4-36) fall into slots
In rear of seat bucket.
(4) Firmly push aft on RSSK to engage retention
lugs into slots.
(10) Attach seat pan (5, figure 4-36) to survival kit
4-44
Change 2
TM 55-1680-308-24
Figure 4-37. Survival Equipment Pack
Change 5 4-45
TM 55-1680-308-24
(5) Position manual override handle to down
(locked) position and pull up hard on occupant retention
straps (1) to ensure that RSSK has been latched to seat
bucket.
(6) Install sticker strap lugs into their respective
sticker clips.
NOTE
Loose stitching on cushion velcro strips and
cushion edge folds may be repaired by
parachute repair facilities.
(5) Install back cushion by firmly pressing against
the lumbar support pad.
al. Inspection of Lumbar Support and Cushion.
aj. Installation of Personnel Parachute Pack.
(1) Inspect cushion for cleanliness, tears and loose
stitching.
NOTE
If cleaning of cushion is to be accomplished.
(Refer to paragraph 3-6c.)
(1)
Prior to Installation.
(a) Verify that parachute has been repacked and
next repack date will be m phase with ejection seat
inspection. (Refer to DA form 1042).
(2) Inspect velcro material for adhesion to lumbar
support.
Personnel parachute pack with plastic
suspension line storage tray will require seat
to be removed and inspected at 90-day
interval.
(3) Inspect lumbar support for damage and
security.
(4) Inspect roller and bracket for cracks and
security.
(b) Ensure that both parachute rip cords under
inspection flap are engaged with locking cones and
safety-tied.
4-46
Change 5
TM 55-1680-308-24
Figure 4-38. Personnel Parachute and Restraint Strap - Location View
Change 5 4-46.A/(4-46.B blank)
TM 55-1680-308-24
(c) Check general condition of parachute container
for cracks and distortion Check riser ex- tension for rips,
tears, soil, etc. Check security of pack opening velcro
bands .
(d)
Ensure proper installation of ripcord handle.
(e) Ensure serviceability of roller yoke assemblies
and riser release fittings
NOTE
When deficiencies exist in any of the above
items, return parachute to repack facility.
the scissor shackle jaws and drogue shackle by
observing free movement of the drogue shackle jaws
after the nut has been tightened.
(f.1) Position scissor mechanism down over the
drogue chute container and install a safe tie nylon
thread (item 11, table 1-2) between drogue shackle and
drogue sunlight cover flap securing pin
Assure link line is not pinched between scissor
and stops.
(2) installation procedure.
(a) Place personnel parachute on ejection meat
central support bracket
(b) On left side of ejection seat, place short restraint
strap (4, figure 4-38) under face blind restraint strap
(c) Pass link line quick-release pin (3) on left side of
ejection seat through face blind restraint strap and short
restraint strap (4) fitting
(d) Pass the link line under the scissor mechanism
and secure the face blind restraint strap and short
restraint strap fittings to the seat with the link line quickrelease pin on the right side of the seat.
Special shouldered scissor shackle bolt only shall
be used to secure the drogue shackle to the
scissor shackle.
(g) Pass nylon thread under flap securing pin and
under front flap securing tie.
The drogue scissor shackle must point slightly
toward left side of seat (drogue gun side) or full
forward when safety tied. If shackle faces right
side of seat, the drogue parachute must be
returned to the parachute pack facility for proper
packing.
(h) Route the nylon thread through the drogue
shackle and tie ends with a surgeon's knot and locking
knot. Cut loose ends approximately one inch from knot.
NOTE
When tying knot, slack should be taken out of
looped thread without pulling tight Loose ends
should be seared and welded together.
(i) Place link line behind guillotine gate located on
the left side of the seat.
(e) Attach the link line white loop. along with the
dorgue line green loop, onto the dorgue shackle Install
the special bolt through drogue shackle and scissor
enclosing both lines between scissor and dorgue shackle
with the bolt head nearest to the face blind handle
(j) Attach both long restraint straps (5) to personnel
parachute restraint spreaders at central support bracket
The scissor shackle nut must be face up when scissor is
in stowed (forward) posi- tion. Tighten nut until contact is
made with the drogue shackle. Do not torque. Verify that
clearance exists between the dorgue shackle and the
scissor assembly, and that the shackle can be freely
rotated on the scissor assembly
(k) Extend parachute risers and hold them straight
out Attach roller yokes so there is no twist in the
parachute riser harness between the para- chute roller
yokes and the parachute risers
NOTE
Manual override lever must be forward (locked)
and time release mechanism must be cocked
before attaching loop strap to loop strap lock.
(I) Pass loop strap down and through, roller yoke
(top to bottom)
(f) Install scissor shackle nut and wrench tighten
but do not torque Verify that clearance exists between
Change 6 4-47
TM 55-1680-308-24
(m) Attach strap lug installation tool, Part No
105GT1043, to loop strap lug. Push loop strap into the
loop strap lock. Pull vigorously to assure loop strap is
locked.
NOTE
Pull on both long restraint straps to assure the
restraint straps are locked into position (verify
visually).
CAUTION
Do not remove the lowering line from the
stow loops.
(4) Inspect lowering device friction brake for
obvious damage and corrosion.
(5) Inspect zipper for corrosion, damage and loose
stitching
(n) Pass long restraint strap (5, figure 4-38) through
buckle of short restraint strap (4).
NOTE
Loose stitching on cover, velcro and
zippers may be repaired by parachute
repair facilities.
(o) Pass right restraint strap through buckle of short
restraint strap and tighten both restraint straps.
(p) Store excess end of long restraint straps by
folding under long restraint strap
NOTE
The personnel lowering device and line
are "on-condition items". If serviceability
is m doubt replace with serviceable
assembly
(q) Store parachute risers (8) on velcro pads on the
restraint straps.
ak Inspection and Installation of Seat Cushion and
Personnel Lowering Line
(1)
Inspect cushion for cleanliness, tears and loose
stitching.
NOTE
Refer to paragraph 3-6c for cleaning procedures.
(2)
Inspect velcro strips on cushion for loose
stitching
(6) Install scat cushion by pressing firmly against
RSSK cover assembly
(7) Install thigh cushion and lowering line by pressing against the thigh extensions on the forward edges of
the seat bucket
4-7. One Year Requirements.
Accomplish the following every twelve months:
a Remove drogue gun piston and inspect piston
and barrel for corrosion
NOTE
Loose stitching on seat cushion edge folds only
and velcro strips may be repaired by parachute
repair facilities.
b. Lightly lubricate barrel and piston
lubricating oil (2, table 1-2) prior to assembly
with
c. Replace O-ring and shear pin during assembly.
(3) Inspect personnel lowering line for oil and liquid
stains by lifting the velcro attached cover
4-48
d. Accomplish functional test of barostat test
altimeter per TM 55-151()0-204-25/1 Record test date
on gummed label and affix to altimeter mounting plate
Change 10
TM 55-1680-308-24
NOTE
4.8. Three Year Requirements.
Accomplish the following every three years.
a. Replace time release mechanism three years
after installation on the Ejection Seat. (Refer to para 46d).
b. Replace drogue gun three years after
Installation on the Ejection Scat (Refer to para 4-6c)
4-8.1
Deleted.
4-9.
Deleted
The expiration date of the guillotine
cartridge is defined as 6 years from the date
of opening the sealed container, but under
no circumstance can this calculated date
exceed the stated year of manufacture
(shelf life)
4-12. Seven Year Requirements.
Replace parachute harness assembly providing It is
seven years of age from date of installation
4-12.1 Deleted
4-10. Five Year Requirements.
following every five years
Accomplish the
4-12.2 Deleted
a. Replace ejection gun primary cartridge (Refer to
paragraph 4-3b)
4-12.3 Deleted
4-12.4 Eleven Year Requirements.
b. Replace ejection gun auxiliary cartridge (Refer
to paragraph 4-6n (7).
c. Replace
paragraph 4-3b)
drogue
gun
cartridge
(Refer
to
a Replace ejection gun primary cartridge
regardless of installed date (Refer to paragraph 43b)
b Replace election gun auxiliary cartridges
regardless of installed date (Refer to paragraph 46N(7).
NOTE
The expiration date is defined as (5) years
from date of opening the sealed container
but under no circumstances can this
calculated date exceed the stated year of
manufacture (shelf life)
NOTE
Refer to TB 9-1300-385 for the most
current (manufacture) life limits for
compliance
4-11. Six Year Requirements.
4-12.5 Fifteen year requirements.
a. Replace ejection seat Ml 119 rocket rotor 6
years from the date of manufacture regardless of
installation date (Refer to paragraph 5-25 a)
a
Replace the drogue gun cartridge (Refer to
paragraph 4-3b)
b.
4-3c)
b. Replace the guillotine cartridge (Refer to
paragraph 4-3c)
Replace guillotine cartridge. (Refer to paragraph
NOTE
Refer to TB 9-1800-385 for the most current
manufacture (shelf) life limits for compliance
Change 10 4-48A/(4-48B blank)
TM 56-1680-30824
Section III. INSTALLATION OF EJECTION SEAT
with a serviceable cartridge set.
4-13. Seat Installation Procedure
Installation of the ejection seat in the Model OV-l
(Mohawk) aircraft will require a minimum of two men.
Direct Support and General Support maintenance
personnel should thoroughly familiarize themselves with
the installation and arming procedures outlined herein
before attempting to install the ejection seat.
(a) If auxiliary cartridge cap is installed, remove
with spanner wrench, Part No. 128GT10155. (See figure
416.)
a. Preinstallation Arming Procedure & The following
arming procedures apply to the' ejection gun auxiliary
cartridges and the guillotine cartridge.
(c) Secure auxiliary cartridge chamber cap and
tighten to a torque of 300 to 550 inch-pounds using
spanner wrench, Part No. 128GT10155. (See figure 416.)
(b) Insert new seal in lower auxiliary cartridge
chamber and insert auxiliary cartridge flat side inboard.
WARNING
Use extreme caution when removing
and handling guillotine cartridge as
cartridge has a percussion-type primer
cap. Ensure safety lock streamer
assembly, Part No. 134SEME10053,
safety pin is installed in guillotine sear.
The auxiliary cartridges do not contain
percussion-type primmer caps but are
filled with an explosive powder which can
be accidentally fired by either spark or
flame.
(d) Secure auxiliary chamber cap to lower
auxiliary cartridge chamber with lockwire and lead seal
lockwire (items I and 3, table 1-2).
(e) Repeat steps (a) through (c) for installation of
upper auxiliary cartridge.
(2) Installation of guillotine initiator cartridge, Part
No. MBEU/16650.
(a) To remove breech from guillotine initiator
assembly, refer to paragraph 4-p.
(1)
Installation of auxiliary cartridges, Part No.
MBEU/29231.
Ensure that the firing pin does not protrude
above the bottom surface of the body hole.
Do not use plastic separators (provided in
the cartridge shipping container) as gas
sealers. Use of plastic separators will
result in ejection gun malfunction.
NOTE
Check all cartridges for expiration date. If
new cartridges are to be installed, mark
cartridge with expiration date and ejection
seat serial number in black permanent
marking ink. Enter cartridge expiration and
installation dates on applicable DA Form
240&18. Cartridges with less than 180 days
service life remaining shall be replaced
(b) Insert guillotine initiator cartridge into barrel of
breech, being careful not to drop cartridge, and carefully
screw breech into initiator body.
(c) Tighten breech on initiator assembly to a
torque of 140 to 160 inch-pounds and secure to tab with
lockwire and lead seal (items I and 3, table 1-2).
(d) Ensure the manual override handle is down
and locked securely.
(e) Wit the safety Iockpin 134SEME10053
installed In the firing pin sear, push the sear upward and
install manual override handle link rod
Change 3 4-49
TM 5-1680-308-24
b. Preinstallation Inspection. Accomplish Inspection
of the ejection seat and ejection gun m accordance with
the following instructions.
(1) Ensure that
ground
lock
safety pins
134SEME10035 are Installed in all locations except
primary firing sear and drogue gun
(2) Ensure ejection seat is mated to the proper
ejection gun (by ejection seat identification number).
(17) Verify proper installation of loop strap by
vigorously tugging on strap.
(18) Inspect overall condition of seat cushion and
ensure personnel lowering device is installed in thigh
supports.
(19) Verify proper installation of rigid seat survival
kit (RSSK) by vigorously tugging on the occupant
retention assembly.
NOTE
Ejection seats and ejection guns may be
interchanged when operational requirements
dictate. However, when an interchange is
required, a slipper calibration check must be
performed and the ejection gun must be
reidentified (stenciled) to the ejection seat
(by the ejection seat identification number).
(20) Inspect leg restraint cords for cuts, fraying,
and obvious damage.
(21) Inspect leg restraint brackets (on
compartment floor) for damage and corrosion.
(3) Visually inspect primary firing pin sear on
ejection gun for bending Ensure that firing pin does not
extend beyond body .
(4) Visually inspect ejection gun guide rails for
damage.
(5) Ensure auxiliary cartridge chamber caps are
properly secured with lockwire to auxiliary cartridge
chamber .
(6) Visually check installation of sticker clips.
(7) Check ejection seat slippers for proper
alignment
(8) Ensure that drogue gun Is cocked and firing
pin does not extend beyond body.
(9)
(16) Inspect drogue pack for visible damage and
security.
(22) Ensure
foreign material.
flight compartment
flight
area is free of
(23) Inspect lower firing cable housing for damage
and routing to prevent damage during installation
(24) Ensure guillotine breech is lockwired.
(25) Inspect TCR firing cable housing for damage
and routing to prevent damage during seat installation.
(26) Ensure TCR firing cable is lockwired to M119
rocket motor initiator.
(27) Ensure TCR safety lock pin 134SEME10054
is installed.
(28) Ensure TCR nozzle is not obstructed and
diaphragm is not punctured.
Ensure top latch mechanism is fully retracted.
(10) Ensure
exposed.
guillotine
cutting
blade
is
not
(11) Ensure parachute withdrawal line passes
through guillotine and is secured by guillotine gate.
(12) Inspect guillotine rigid tubing for damage.
(29) Ensure that TCR initiator cable forms a 7 to
7.5 inch diameter loop about the TCR initiator.
(30) Ensure freedom of movement of the time
release mechanism rack plunger and harness release
plunger by using special tool, Part No. MBEU/6945, and
pulling upward toward housing base The rack plunger
and harness release plunger should retract and return to
the locked position unassisted.
(13) Ensure small connector of TCR initiator cable
conduit is lockwired to TCR cable dispenser housing and
large connector is lockwired to the TCR motor initiator.
If either or both plungers fail to extend
unassisted, replace the unit.
(14) Ensure that TCR dispenser cable is connected
to drogue gun trip rod.
(15) Inspect parachute pack for visible damage, and
security.
(31) Ensure barostat assembly on time release
mechanism is secured with lockwire.
4-50 Change 3
(32) Ensure appropriate ejection seat records have
been annotated and that aircraft log book contains proper
ejection seat records.
NOTE
Ejection seat historical records are required to
be included in the aircraft log book by ejection
seat identification number.
c. Ejection Gun Installation (See figure 415). Install
ejection gun in aircraft as follows:
NOTE
The ejection gun at time of installation should
have the auxiliary cartridges installed and
lockwired.
(1) Install the primary firing mechanism loosely
without the inner tube retainer.
(2) Position ejection gun in aircraft and attach to
lower floor pivot with bolt(5) and locknut (4), and torque nut
from 160 to 190 inch pounds.
(3) Attach EJECTION gun upper clamp to fitting on
bulkhead with bolt (3), washer (2), and locknut (1).
NOTE
Upper clamp link fitting must be 90 degrees to
sloping bulkhead of aircraft. If 90 degrees is not
attained, insufficient clearance between sloping
bulkhead and main beam will result.
(4) Adjust upper clamp, if necessary, to obtain proper
clearance between sloping bulkhead as follows:
(a) Loosen nuts securing top attachment sleeve (2,
figure 4-39) to ejection gun cylinder body.
(b) Gently tap top attachment sleeve up or down to
obtain the proper clearance.
Failure to observe proper torque outlined in
the following step will result in damage to
the cylinder body of the ejection gun.
(c) Tighten attachment bolts to a torque of 26 inchpounds.
NOTE
The transponder (APX-72) should be tested
in conjunction with the 180 day seat
inspection and prior to seat installation.
Figure 4-39. Attachment of ejection gun
top attachment sleeve
Change 8 4-51
TM 55-1680-308-24
(1) Avionics repairman and ejection seat personnel
will assist one another, using test set AN/APM-378, to
test AN /APX-72 transponder
(2) Connect APM-387 to aircraft according to
Instructions, connect pilots APX-72 connector plug to
the bulkhead connector.
(3) Using the APM-378 as a monitor, depress and
release actuating switch to ensure emergency signal is
transmitted. (Check both seats).
4-52 Change 8
TM 55-1680-308-24
d. Ejection Seat Installation. To install ejection seat in
aircraft, proceed as follows:
(1) Ensure that safety pins of the ground safety lock
assembly are installed in the face blind locking
mechanism, drogue gun, TCR cable dispenser, manual
override handle, lower firing handle, and seat bucket
locking plunger.
(2) Install hoisting sling, Part No 105GT1024-33, on
ejection seat (See figure 4-8.)
(3) Remove ejection seat from seat cradle, Part No.
10SGT1040, as follows:
(a) Pull locking pin and lift ejection seat clear of
seat cradle using lifting hoist.
(b) Remove transportation cradle mounting rail
from ejection seat.
(4) With the ejection seat supported by a lifting
hoist, check slipper alignment on main beam.
NOTE
Slipper misalignment will cause difficulty in
installing ejection seat on gun guide rails.
(a) If misaligned, loosen slipper locking nut
slightly and lightly tap misaligned slipper in proper
direction with a soft mallet until slipper is properly
aligned.
(b) Tighten all slipper locking nuts to a torque of
50 to 60 Inch-pounds.
NOTE
Usually the lower slippers are misaligned.
This is due to improper removal and
installation techniques which can be
avoided by proper use of the alignment
tool.
(5) Install alignment tool, Part No. 105GT1024-59,
on ejection seat in the extended position.
NOTE
Ensure quick-release pin on alignment tool
is to the rear. Quick-release pin cannot be
removed during ejection seat installation if
it is in the forward position between the
ejection seat and the ejection gun.
(6) Lift ejection seat with a suitable overhead hoist
and align bottom of alignment tool with top of ejection
gun.
ejection gun are in the correct (left and
right) position to accept the locating pin on
the top crossbeam of the ejection seat.
(7) Mate ejection seat with alignment tool and
slowly lower ejection seat onto ejection gun until center
set of slippers engage bottom half of alignment tool.
NOTE
If ejection seat tends to bind in track,
remove ejection seat from its position and
recheck slipper alignment If ejection seat
continues to lower with the same hoisting
sling scale reading, the slippers are in
alignment.
(8) Remove quick-release pin In alignment tool,
break alignment tool, and lower ejection seat until center
slippers engage the ejection gun guide rails. Remove
alignment tool from top of the ejection gun.
(9) Lower ejection seat to approximately 12 inches
from bottom of its travel. Connect the emergency
oxygen cable link to the bellcrank by inserting the quickrelease pin on right side of the seat bucket (See figure
4-40.)
(10)
Remove TCR motor initiator safety pin
134SEME10054, and guillotine seal safety pin
134SEME10053.
(11) Connect the seat height adjustment electrical
lead to its plug on right side of seat bucket.
(12) Connect leg restraint cords to floor fittings by
installing two quick-release pins (9, figure 1-8).
Ensure that leg restraint cords are not
caught between the seat main beam
assembly and cockpit floor, and they are
not twisted.
(13) Lower ejection seat to bottom of its travel.
Press ejection seat firmly down on ejection gun.
NOTE
As the ejection seat nears the bottom of its
travel, a binding action caused by the
jamming of the lower slippers on the
ejection gun guide rails will commence.
(14) Remove handwheel, Part No MBEU/26568, by
turning in a counterclockwise direction (See figure 4-6 ).
This action will allow the top latch plunger to extend into
the ejection gun inner tube groove. (See figure 4-41.)
Ensure that the locating slots on top of the
Change 8
4-52.1/(4-52.2 blank)
TM 55-1680-308-24
Figure 4-40. Electrical lead and emergency oxygen quick-release pins.
4-53
TM 55-1680-308-24
Figure 4-41. Removal of top latch plungers - correct and incorrect methods
4-54
TM 55-1680-308-24
NOTE
If the indicating dowel and top latch plunger
are not flush with plunger housing, ensure
ejection gun inner tube is fully down (if
plunger indicates top latch mechanism is
not aligned with the groove or the ejection
gun, it will not fully lock), that beam locating
pin is m proper alignment (pin must not bind
in slot in ejection gun), and that ejection
seat structure is fully down on ejection gun.
(15) Remove lifting hoist from the ejection seat.
NOTE
On aircraft equipped with the APX-72
modification, the actuating switch on the
section gun shall be adjusted to provide 1/8mch overtravel from the point of NO
CONTACT.
Overtravel is to be
accomplished by adjusting the jamnuts on
the switch.
(16) Connect drogue gun/TCR cable trip rod (11,
figure 4-3) to ejection gun trip rod crossbeam using
quick-release pin (13) stowed in drogue gun safety pin
hole and insert safety pin of ground safety lock, Part No
134SEME10035, in drogue gun safety pin hole.
(a) Remove the primary firing mechanism (6,
figure 44) that was installed loosely in the primary
cartridge breech (9).
(b) Ensure that the primary cartridge breech (9) is clear
to receive the primary cartridge (7).
WARNING
Primary cartridge O-ring is a special type
and the correct type must be used. There is
no serviceable substitute. Failure to install
correct type may result in O-ring rolling over
primer cap of primary cartridge, preventing
firing pin from striking primer cap causing
ejection gun to misfire.
(c) Install a new primary cartridge O-ring (8) on primary
cartridge (7), Part No MBEU/26434, of valid service life.
WARNING
Extreme care should be taken when
handling primary cartridge as cartridge has
a percussion-type primer cap.
NOTE
Handle primary cartridge in accordance with
TM 9-1300-206.
NOTE
Ensure that the distance between the trip
rod indicator and the outer housing of the
trip rod is not more than 1/2 inch. Any more
than 1/2 inch indicates that the ejection seat
is not properly locked to the ejection gun.
(17) Install aircraft oxygen hose and clamp to seat
bucket with screw, washer, and nut.
Leave sufficient slack in oxygen hose to
allow seat bucket to be raised to the
maximum position. Failure to comply will
result in damage to the oxygen hose or
connection to the aircraft.
(18) Connect time release mechanism trip rod (2,
figure 4-7) to ejection gun trip rod bracket by installing
quick-release pin (3) stowed in bracket.
(d) Using cartridge extractor tool, Part No GR506,
gently insert primary cartridge (7, figure 4-4) into
primary cartridge breech (9).
(e) Ensure that primary firing mechanism (6) is
cocked and firing pin does not protrude.
(f) Install primary firing mechanism (6) with inner
tube retainer collar (10) into primary cartridge breech
(9). Tighten primary firing mechanism to a torque of
200 to 275 inch-pounds, using spanner wrench, Part No
128GT10155. (See figure 4-42.)
Open end of inner tube retainer collar must
be facing aft.
(6) Install safety pin (5, figure 44) of the ground
safety lock into firing pin sear (4).
(h)
Iockwire.
(19) Arm the ejection gun as follows:
Change 1
4-55
Secure primary firing mechanism with
TM 55-1680-308-24
(i) With safety pin (5, figure 4-4) installed in firing pin
sear (4), push sear forward and install lower firing cable
eye (thin) first and then upper firing cable eye (thick)
onto hooked end of sear (See figure 4-43.)
(20) Arm the drogue gun as follows:
WARNING
Ensure that firing pin does not protrude
above bottom surface of firing body hole.
A physical check is required Drogue gun
cartridge should be handled with extreme
care as it has a percussion-type cap.
(a) Unscrew barrel (5, figure 4-3) from firing body
(8).
(b) Ensure that sear (10) is in place, and that
ground lock pin (9) is properly inserted into safety pin
hole.
(c) Insert a cartridge of unexpired service life into
barrel (5), being careful not to drop cartridge, and
carefully screw barrel into primary firing body (8).
The crowfoot wrench and torque wrench
must be at 90-degree angle to each
other. Failure to comply will result in
improper torque.
Figure 4-42. Primary cartridge location
NOTE
The lockwire is routed from the primary
firing mechanism to the top of the
primary cartridge.
breech
Do not exceed 160 inch-pounds torque.
Excessive torque will result in damage to
drogue gun cartridge and barrel.
WARNING
Install safety pin in primary sear before
attempting to install firing cables, failure
to do so can cause sear to dislodge and
fire cartridge.
WARNING
Ensure upper firing cable is routed over
link line segment which passes across
the head box, but under the link line
segment which is connected to the
scissor shackle The upper firing cable is
then routed directly to the sear, ensuring
the upper cable (thick) is placed over the
lower (thin) firing cable.
Change 8
4-56
TM 55-1680-308-24
Figure 4-43. Firing cables installation
Change 7
4-56.1/(4-56.2 blank)
TM 55-1680-308-24
(d) Tighten barrel (5) on firing body (8) using
crowfoot wrench, Part No. AN8506-11 (modified) (figure
4-44), and tighten barrel to a torque of 140 to 160 inchpounds.
edge of trip rod outer barrel when connected to the
ejection gun crossbeam.
(e) Secure barrel (5, figure 4-3) to firing body (8)
with lockwire.
Ejection seat out of tolerance with the
above inspection requirements should be
considered improperly installed.
NOTE
WARNING
(3) Check for proper operation of the ejection seat
height adjustment mechanism.
It is essential for safe operation of ejection
seat that drogue line (line attached to
special shackle) is passed over all other
lines on top of the ejection seat. The
drogue line must be free to extract the
drogue parachute without entanglement.
(4) Verify proper installation of the leg restraint lines
to the floor brackets m flight compartment.
(5) Check for lockwire on primary firing mechanism,
drogue gun, and guillotine breech.
(f) Secure special shackle (1) to fork end fitting (3)
on piston with bolt and nut (2), ensuring that the drogue
line is passed over all other lines on top of the ejector
seat and that special shackle and fork end fitting face
near forward.
(6)
Ensure TCR motor initiator safety pin
134SEME10054 and guillotine seal safety pin
134SME10053 have been removed.
(7) Ensure emergency oxygen link pin is connected.
NOTE
Due to manufacturing tolerance of barrel
and cartridge casing, a maximum 20
degree variance to the right or left of
forward is acceptable.
(8) Perform daily Inspection In accordance with TM
55-1510-217-PMD.
f. Installation of Escape Hatch.
CAUTION
(21) Ensure that safety pin of ground safety lock is
installed in drogue gun.
Ensure right and left side cockpit
entranceways are in full open position.
Damage to the escape hatch can occur if
cockpit entranceways are not in the full
open position.
e. Inspection After Seat Installation. After the ejection
seat is installed in the aircraft, perform the following
inspection:
(1) Ensure proper engagement of the top latch
mechanism. (See figure 4-41.)
(2) Visually inspect to ensure drogue gun and time
release mechanism trip rod indicating collars are flush
with or not more than 1/2-inch (maximum) away from
NOTE:
MODIFY CROW FOOT WRENCH,
PART NO. AN8506-11, TO
INCREASE OPENING FROM
1.062 IN. TO 1.105 IN.
(1) Insure two spacer blocks are installed on top of
fuselage at aft pivot pin covers to prevent damage to
hinge cover during installation of escape hatch.
(2) Insert 3/8 inch diameter pin (4, Figure 4-2) in
hole on right end of torque tube mechanism (Note: A
cut-off screwdriver with a 3 inch shank is Ideal for this
procedure). Do not insert pin more than 1 inch thru
torque tube. This is to avoid damage to air frame
structure. Rotate torque tube mechanism with pin by
pushing up and aft so that outboard cams (5) are In the
up position.
40VJ5M-5
Figure 44. Crowfoot wrench part no. AN80506-11
(modified)
Change 8
4-57
TM 55-1680-308-24
(6) Recharge escape hatch pneumatic actuator
bottle. (Reference TM 55-1510-204-23-1 or TM 551510-213-23-1 as applicable.)
CAUTION
When lowering escape hatch, take care to
avoid damaging the defogging disconnect
seal. Also ensure the 2 moveable fairing
tabs attached to the aircraft structure on
the aft side of the cantilever arms (10,
Figure 402) are positioned and held in the
down position prior to and during lowering
of the escape hatch over the cockpit.
(7)
Perform inspection
installation (paragraph 4-13g).
after
escape
hatch
(8) Install nosewheel well splash shield.
g. Inspection After Escape Hatch Installation
(3) Position and lower escape hatch over cockpit.
Engage aft pins in cantilever arms on escape hatch.
Engage outboard cams (5) of torque tube mechanism
(3) with escape hatch fittings. Align forward edge of
escape hatch to insure the insertion of the five forward
pins in their receptacles.
(4)
Connect bungee cord to hold pneumatic
actuator (6) forward, and rotate torque tube mechanism
(3) with rigging pin (4) to lower outboard cams (5), slide
the escape hatch forward and engage all five pins on
the forward edge. Check that center bellcrank of torque
tube mechanism (3) rests on roller of pneumatic
actuator (6). Escape hatch should be m closed position.
(Reference TM 55-1510-204-23-1 or TM 55-1510-21323-1 as applicable.) Proceed as follows:
(1) Inspect defogging disconnect seal for damage.
(2) Inspect that outboard cams (5) of torque tube
mechanism (3) bottom of track fittings of escape hatch.
(3) Ensure that center bellcrank of torque tube
mechanism (3) rests on the roller of the pneumatic
actuator (6).
(4) Ensure that escape hatch is secured by all
eleven pins (five on forward and two on rear and each
side of escape hatch) being engaged in receptacles.
(5) Remove rigging pin (4) and spacer blocks.
(5) Inspect escape hatch pneumatic air pressure
gage (figure 4-1) for proper pressure.
Figure 4-45. - Deleted
Change 8
4-58
TM 55-1680-308-24
CHAPTER V. REPAIR PROCEDURES, AND PREPARATION FOR
STORAGE AND SHIPMENT
SECTION I. REPAIR PROCEDURES
stopped by the action of the 12 shock absorbing
compression rings at the top of the cylinder barrel,
remains with the aircraft after ejection. The inner tube is
This section contains repair procedures for Direct
open at the bottom and closed at the top by the primary
Support and General Support maintenance
The
firing mechanism and the primary cartridge. The lower
instructions and procedures outlined herein will be
end of the inner tube forms a piston, containing one
accomplished as conditions warrant.
group of six piston rings which bear on the inside of the
intermediate tube. The inner tube carries the ejection
5-2. Telescopic Ejection Gun.
seat from the aircraft. It bears against the upper
crossmember of the ejection seat main beam assembly
The cylinder barrel outer tube (the first of three
to transmit the thrust of the telescopic ejection gun The
sections) of the ejection gun is that part which is
alignment of the inner tube is maintained at the top by
attached to the aircraft The top is attached to the sloping
the inner tube guide bushing (riveted to the inside of the
bulkhead by one bolt which passes through an upper
top of the intermediate tube) and at the bottom by the
clamp, bolted to the barrel, and two links, bolted to the
inner tube piston. The inner tube is held to the seat by
sloping bulkhead. The clamp may be adjusted for
the inner tube retaining ring. The inner tube retaining
height by loosening four bolts, sliding fitting into proper
ring is located near the firing mechanism body and
position, then tightening bolts. The bottom is attached
prevents the inner tube from falling free of the seat
to the flight compartment floor by one bolt which passes
when the momentum of the ejection has been spent The
through a block which swivels fore and aft to
stroke of the inner tube is 33 inches.
compensate for possible misalignment.
The
construction of this attachment point allows the ejection
a. Removal.
gun to be tipped forward for maintenance, after the
upper attachment is disconnected, without removing the
(1) Remove ejection seat (Refer to paragraph 4-3.)
ejection gun from the aircraft The upper end of the
cylinder barrel has a locking window through which the
(2) Remove ejection gun upper clamp fitting from
top latch plunger passes Inside the cylinder, between
aircraft
sloping bulkhead by removing locknut (1, figure
the intermediate tube and the cylinder barrel, there are
415), washer (2), and bolt (3).
12 gas-filled, shock absorbing compression rings.
These rings are retained by a bushing and a carrier ring.
(3) Remove locknut (4) and bolt (5) securing
The bushing is threaded into the cylinder and locked by
ejection gun (6) to lower pivot and remove ejection gun
a special staked screw. During the ejection process,
from aircraft.
these 12 rings provide a shock absorbing stop for the
intermediate tube when it reaches its full extension. The
b. Disassembly.
intermediate tube is open at both ends and merely
provides an extension of the ejection gun stroke. The
(1) Mount telescopic ejection gun (21, figure 5-1) m
lower portion of the intermediate tube forms a piston
a smooth jaw vise, using ejection gun clamp mounting
which contains two groups of piston rings (six rings in
blocks, Part No MBEU/8463. (See figure 4-27.)
each group), which bear on the inside of the cylinder
barrel. During ejection, the intermediate tube alignment
(2) Remove dowel screw (13, figure 5-1) from top
is maintained by the intermediate tube guide bushing on
of cylinder body (18).
the top and by the piston on the bottom. The inner tube
guide bushing, riveted to the inside of the top of the
(3) Extend inner tube (19) and intermediate tube
intermediate tube, prevents complete withdrawal of the
(20) approximately 9 inches.
inner tube. The two flush rivets are sheared during
ejection and the inner tube guide bushing is carried
(4) Remove intermediate tube guide bushing (16)
away on the inner tube. The intermediate tube, having
using spanner wrench, Part No. MBEU/5787.
been extended to its full 39-inch stroke and then
5-1. General.
5-1
TM 55-1680-308-24
Figure 5-1. Telescopic ejection gun - exploded view
5-2
TM 55-1680-308-24
CAUTION
Do not attempt to separate the inner tube
from the intermediate tube.
They are
restricted from separating by the inner tube
guide bushing, which is riveted to the top of
the intermediate tube. Use extreme care to
prevent shearing of these rivets during
servicing. If they are sheared, replace the
entire ejection gun assembly.
(5) Withdraw intermediate tube guide bushing (16),
inner tube (19), and intermediate tube (20) as an
assembly.
f. Reassembly.
(1) Install intermediate tube (20, figure 5-1), inner
tube (19), and intermediate tube guide bushing (16) in
ejection gun housing as an assembly.
(2) Install intermediate tube guide bushing (16)
using spanner wrench, Part No MBEU/5787.
(3) Install dowel screw (13) In top of intermediate
tube guide bushing (16) Secure screw using
LOCKTIGHT (Table 1-2).
(4) Compress (retract) ejection gun inner and
intermediate tubes into cylinder barrel.
c. Cleaning.
(1) Remove water, debris, and excess oil from
bottom of ejection gun.
g. Installation.
NOTE
The telescopic ejection gun, at time of
installation, should have the auxiliary
cartridges installed and secured with
lockwire. The primary firing mechanism
should be installed loosely without the
inner tube retainer
(2)
Clean outer barrel of ejection gun with
lubricating oil (item 2, table 1-2).
CAUTION
Drycleaning solvent (item 6, table 1-2) is
not a suitable or authorized cleaning
agent, and shall not be used.
(3) Clean ejection gun guide rails using a clean, dry
cloth.
(1) Position telescopic ejection gun (6, figure 4-15)
in aircraft and attach telescopic ejection gun to lower
pivot with bolt (5) and locknut (4). Torque nut from 160
to 190 inch pounds.
d. Inspection
(1) Inspect entire telescopic ejection gun for visible
damage and for corrosion.
(2) Inspect primary cartridge breech and guide
bushing O-rings for damage and deterioration.
(2) Inspect ejection gun auxiliary chamber cap to
ensure it is properly lockwired to auxiliary cartridge
chamber.
(3) Attach telescopic ejection gun upper clamp to
fitting on bulkhead with bolt (3), washer (2), and locknut
(1). Torque nut from 80 to 100 inch pounds.
(3) Inspect breech on top of outer barrel for stripped
or malformed threads.
NOTE
(4) Inspect ejection gun guide rails for scoring,
gouges, cracks, and cleanliness.
Upper clamp link fitting must be 90
degrees to sloping bulkhead of aircraft If
90 degrees is not attained, insufficient
clearance between sloping bulkhead and
main beam will result.
e. Lubrication.
WARNING
5-3. Primary Firing Mechanism.
Excessive lubrication of the ejection gun
inner and intermediate tubes can dampen
the effect of the primary charge.
(1) Lubricate inner and intermediate tubes with a
light coating of lubricating oil (item 2, table 1-2).
(2) Lubricate primary cartridge breech and guide
bushing O-rings with grease (item 5, table 1-2).
Change 3
The telescopic ejection gun primary firing mechanism,
which is threaded into the top of the Inner tube, consists
of a primary firing mechanism (6, figure 4-4), firing pin
sear (4), firing pin (3), and a compression spring. A slot
in the top of the firing pin retains the wedge-shaped
sear. When the firing pin sear is pulled by the occupant
pulling the face
5-3
TM 55-1680-308-24
blind handle or the lower firing handle, the firing pin will
strike the primary cartridge initiating the ejection
process.
firing mechanism and inner tube retainer collar (10,
figure 44).
WARNING
a. Removal
Use extreme caution when removing and
handling primary cartridge, as cartridge has
a percussion-type primer cap
WARNING
Never remove firing pin sear from primary
firing mechanism until primary cartridge
has been removed from primary cartridge
breech. Any attempt to do so will cause the
cartridge to be fired Make certain that the
firing pin sear is secured by the safety pin
when installing or removing the firing
cables. Failure to do so will result In serious
Injury or death to maintenance personnel.
NOTE
The following procedures are for use with
the ejection seat installed in the aircraft.
(1) With safety pin installed in firing pin sear (4,
figure 4-4) of telescopic ejection gun primary firing
mechanism, push sear forward as far as necessary and
remove upper primary firing cable (thick) (2) and lower
firing cable (thin) (I) from sear.
(5)
Remove primary cartridge (7), Part No.
MBEU/26434, primary cartridge breech (9) using
extractor, Part No. GR506 (See figure 4-5.)
b. Disassembly Disassemble the primary firing
mechanism as follows:
(1) Remove firing pin assembly by bending down
tabs of tab washer (30, figure 4-26) that bears against
flat surface of retaining collar (11). Unscrew retaining
collar from firing mechanism body (15).
(2) Remove tab washer (30), firing pin spring (12),
and firing pin (14).
c. Cleaning. Clean primary firing mechanism body
(15) with dry, filtered compressed air to remove possible
foreign matter.
d. Inspection.
(2)
Remove lockwire securing primary firing
mechanism (6) to primary cartridge breech (9).
WARNING
(1) Inspect firing pin for burrs and bending.
(2) Place firing pin sear on a flat surface and check
for deformation.
When removing safety pin from firing pin
sear of telescopic ejection gun primary firing
mechanism, ensure firing pin sear does not
become dislodged. Never remove safety
pin from inside the flight compartment, or
while leaning over the ejection seat or the
telescopic ejection gun Removal of sear
from under firing pin will cause the ejection
gun to fire.
(3) Carefully remove safety pin (5) from firing pin
sear (4) on telescopic ejection gun primary firing
mechanism.
(4) Unscrew primary firing mechanism (6) from
primary cartridge breech (9) with spanner wrench, Part
No 128GT10155 (See figure 4-5 ) Remove primary
Change 1
NOTE
Replace firing pin sear if it is bent or
cracked.
(3) Inspect primary firing mechanism for malformed
threads.
e. Repair or Replacement. Replacement of the
election gun primary firing mechanism is required If the
firing pin Is bent or pin end is flattened.
f. Lubrication. Lubricate firing pin with a light coating
of lubricating oil (item 2, table 1-2)'
5-4
TM 55-1680-308-24
g. Reassembly. Assemble primary firing mechanism
as follows:
(1) Install firing pin (14) and firing pin spring (12).
(2) Install new tab washer (30) by bending one tab
and, placing bent tab in firing mechanism body(15) slot.
NOTE
If a new tab washer cannot be obtained,
straighten and mark previously bent tabs
Select previously unbent tab for insertion
in slot and bend for subsequent locking.
(3) Screw retaining collar (11) into firing mechanism
body (15).
(4) Bend up tab of tab washer until It makes contact
with retaining collar.
NOTE
The tab to be bent upward should be
opposite
tab
engaged
In
firing
mechanism body slot.
h.
Test.
Test primary firing mechanism in
accordance with paragraph 4-6m.
i. Installation
(1) Remove primary firing mechanism that was
installed loosely in primary cartridge breech.
(2) Ensure that primary cartridge breech (9, figure
4-4) is clear to receive primary cartridge (7).
Change 1
5-4A(5-4B blank)
TM 55-1680-308-24
NOTE
The lockwire is routed from the primary
firing mechanism to the top of the primary
cartridge breech.
WARNING
Primary cartridge O-ring is a special type
and the correct type must be used. There is
no serviceable substitute. Failure to install
correct type may result in O-ring rolling over
primary cap of primary cartridge and
preventing firing pin from striking primer cap
causing ejection gun to misfire.
5-4. Drogue Parachute System.
NOTE
If the cartridge life has less than 90 days
remaining, replace with a serviceable set.
The drogue parachute system consists of a 5-footdameter canopy, a drogue line, and a shackle. The
drogue chute is packed in a hardshell container which is
housed in the head box at the top of the ejection seat.
The hardshell container has four flaps and secured by a
flap securing pin which is a component of the drogue
line.
(3) Install a new primary cartridge O-ring (8) on a
primary cartridge (7) of valid service life.
a. Removal. Remove the drogue parachute system
in accordance with paragraph 4-6h.
b. Inspection.
WARNING
Extreme care should be taken when
handling primary cartridge as cartridge has
a percussion-type primer cap.
(1) Check canvas material of drogue container flaps
and protective sleeve for tears, deterioration, and loose
stitching. Check hardshell container for fractures.
(4) Using cartridge extractor tool, Part No GR506,
gently insert primary cartridge into primary cartridge.
breech.
(2) Inspect closing flap grommets to ensure they
are firmly placed m the closing flaps Inspect flap
securing loop to ensure that it is not damaged.
(5) Ensure primary firing mechanism (6) is cocked
and firing pin does not protrude.
CAUTION
Caution
should
be
taken
when
transporting
parachutes
between
maintenance activities to insure damage
does not occur. Consult TM 10-1670201-23, Chapter 4, for shipment
requirements.
(6) Install primary firing mechanism (6) with inner
tube retainer (10) into primary cartridge breech (9) and
tighten to a torque of 200 to 275 inch-pounds using
spanner wrench, Part No 128GT10155.
NOTE
If any doubt exists concerning the
serviceability of the drogue parachute,
forward to parachute maintenance for
determination.
NOTE
Open end of inner tube retainer must be
facing aft.
(7) Install safety pin of ground safety lock into
primary firing mechanism sear.
(8) Ensure that the primary firing cable is not
twisted or kinked and is routed down the right side of
drogue container, over the link line and under the
restraining scissor
(9) With safety pin installed in firing pin sear, push
sear forward and install firing cables onto hooked end of
sear. Install lower firing cable (thin) first, then install
primary firing cable (thick).
(10) Secure primary firing mechanism with lockwire
(Item 1, table 1-2).
Change 4
c. Installation. Install the drogue parachute system in
accordance with paragraph 4-6aa.
5-5. Face Blind Locking Mechanism.
The face blind locking mechanism (figure 5-2) is
located on the top of the ejection seat head box. The
locking mechanism is locked when the bellcrank (34) is
In the up position and unlocked when in the down
position. The face blind locking mechanism is safetied
by a plunger pin (30) of the ground safety lock when the
aircraft is on the ground. The face blind locking plunger
slides up and down through the face blind locking body
(29) and a drilled hole in the top of the head box. The
face blind locking plunger pin (30) engages in a hole in
the face blind handle which
5-5
TM 55-1680-308-24
Figure 5-2. Face blind locking mechanism
5-6
TM 55-1680-308-24
prevents the face blind from being pulled out of its
housing in the head box A bellcrank (34), attached to
the face blind locking body (29), which is riveted at the
upper forward edge of the drogue container, provides
the means to raise or lower the locking plunger. A
plunger assembly, which acts as a spring lock, is springloaded and secured at one end to the face blind locking
body (29), and at the other end to bellcrank (34). These
units ensure locking and unlocking of the face blind
handle. A second feature of the face blind locking
mechanism is a plunger (33) which slides within face
blind locking body (29), providing means to house a
curved portion of bellcrank (34). This is accomplished
when the bellcrank is depressed to the unlock position.
The ball end of cable assembly (32) passes through
spring (31) and is secured in a slot in plunger (33). The
spring Is retained by a fitting brazed to the cable
assembly. The cable assembly link end (14) is secured
to eyebolt of plunger assembly (13). The plunger
assembly consists of a housing, an eyebolt which is
inserted through an externally threaded plug, and spring,
which is placed over the eyebolt and retained by nut and
washer. The housing is linked to the plunger bellcrank
and fork end of the manual override bellcrank. These
units act as a lock override when the locking mechanism
Is unlocked and the manual override handle is pulled
back.
NOTE
It is not necessary to separate staked
pin (24) from plunger (20) and the
bellcrank (34) unless signs of wear are
present. Do not remove staked pin
from plunger pin (30).
(6) Remove cotter pin (9), washer (8), and clevis
pin (15) that secure cable assembly link end (14) of
cable assembly to eyebolt of plunger assembly (13).
(7) Remove lower adjusting nut (7) and pull cable
assembly (17) through bracket (6) riveted to head box.
(8) Remove upper adjusting nut (16) and nut (3),
washers (2), screw (1), and clamp (5) that secure cable
assembly (17) to head box.
(9) Carefully unscrew and remove cable assembly
(32) from face blind locking body (29). Pull out and
separate plunger (33) and spring (31) from cable.
(10) Remove cotter pin (10), washer (11), and
clevis pin (12) that secure plunger assembly (13) to
plunger bellcrank and fork end of inertia reel
mechanism.
a. Removal.
NOTE
Upon removal of plunger assembly (13),
temporarily replace clevis pin (12) and
cotter pin (10) This is to ensure that
proper positioning of plunger bellcrank
and fork end until the Installation of the
lock override plunger assembly.
(1)
Press bellcrank (34, figure 5-2) to down
(unlocked) position.
(2) Unscrew lower and upper adjusting nuts (7 and
16) from bracket (6), mounted on head box, to relieve
tension on cable assembly (17).
b. Disassembly (Plunger Assembly).
(3) Carefully remove nut (18), washers (19 and 25),
screw (26) and spacers (23) that secure plunger (22) to
face blind locking body (29) Remove spring (21) housed
within plungers (20 and 22).
(1) Remove lockwire that secures plug (1, figure 53) to housing (6) Unscrew assembled plug and pull
eyebolt (2) from housing (6).
NOTE
Use care when removing attaching
hardware.
The spring (21) housed
within plungers (20 and 22) will tend to
pop out.
(2) Carefully remove nut (3) and washer (4).
Remove spring (5) and plug (I) from shaft of eyebolt (2).
NOTE
Use care when removing attaching
hardware from the eyebolt The spring
will tend to pop off the shaft of the
eyebolt.
(4) Remove screw (27), washers (35 and 28), and
nut (36) which act as the bellcrank (34) pivot.
(5) Carefully lift bellcrank (34) out of position.
Plunger (20), which in pinned and staked to a lever on
bellcrank, and plunger pin (30), which Is not secured but
rests in slotted lever of bellcrank, will come out with
bellcrank.
c. Cleaning.
(1) Clean all parts in drycleaning solvent (item 6,
table 1-2).
5-7
TM 55-1680-308-24
(2) Dry each part carefully to remove solvent with a
clean, lint-free cloth.
g. Installation.
(1) Slip spring (31, figure 5-2) over cable assembly
(32) and insert ball end of cable in slot of plunger (33).
d. Inspection.
(1) Inspect threaded areas for crossed, stripped, or
worn threads.
(2) Properly position plunger (33) in face blind
locking body (29). Secure by screwing fitting (brazed to
cable conduit) to face blind locking body.
(2) Check that all parts are free of nicks, burrs, and
corrosion.
(3)
Slide upper adjusting nut (16) on cable
assembly and pass end of cable through bracket (6)
mounted on side of head box.
(3) Inspect welded area of face blind locking body
for cracks.
(4) Position clamp (5) on cable assembly (17) and
secure loosely to bead box with screw (1), washers (2),
and nut (3).
(4) Inspect brazed fittings of cable assembly for
cracks.
e. Repair or Replacement. Repair of the face blind
locking mechanism consists of replacing defective
components
(5) Position plunger pin (30) In slotted lever of
bellcrank (34) Place bellcrank, plunger (20), and safety
pin on face blind locking body (29). Secure bellcrank to
face blind locking body with screw (27), washers (28 and
35), and nut (36).
f. Reassembly (Plunger Assembly).
(6) Insert spring (21) in plunger (20) and slide
plunger (22) over spring and plunger. Secure plunger
(22) to face blind locking body (29) with screw (26),
spacers (23), washers (25 and 19), and nut (18).
(1) Install plug (1, figure 5-3) and spring (5) on
eyebolt (2) and place eyebolt into housing (6).
(2) Secure plug (I) to housing (6) and install washer
(4) and nut (3) on eyebolt (2) Lockwire plug (I) to
housing (6).
NOTE
Use care when sliding plunger (22) over
spring (21) and plunger (20). The spring
will have a slight tendency to resist
compression.
(7) Remove clevis pin (12) and cotter pin (10) that
were used to temporarily secure inertia reel plunger
bellcrank and fork end.
(8) Position plunger bellcrank (4, figure 5-11) in fork
end (42) and place fork end of plunger assembly (13,
figure 5-2) over fork end of inertia reel mechanism.
Insert clevis pin (12) (head of clevis pin aft) and secure
with washers (11) and new cotter pin (10).
(9) Slide lower adjusting nut (7) over cable and
secure cable assembly link end (14) to eyebolt (2, figure
5-3) of plunger assembly (13, figure 5-2) using clevis pin
(15) (head of pin aft) and secure with washer (8) and
cotter pin (9).
h. Adjustment. Adjust the face blind mechanism as
follows:
Figure 5-3. Face blind locking mechanism plunger
assembly - exploded view
5-8
TM 55-1680-308-24
mechanism in accordance with paragraph 4-6j.
WARNING
Ensure guillotine initiator has
disarmed Refer to paragraph 4-3e.
5-6. Face Blind Assembly.
been
The face blind is one method by which the occupant
of the ejection seat initiates the ejection sequence. The
face blind consists of a face blind handle (figure 54)
containing two spring-loaded plungers and a fabric face
curtain to which the upper firing cable (thick) and two
restraint strap connecting links are attached. The face
blind is located in the forward compartment of the head
box and retained by the spring-loaded plungers of the
face blind handle. The two restraint strap connecting
links, attached to the face curtain, are secured to the
head box by the link line quick-release pins. A locking
mechanism, located on the head box, prevents
accidental extraction of the face blind by locking the
face blind handle in place.
(1) Press down on bellcrank (34, figure 5-2) to
unlock face blind. The tune release mechanism must
be in the cocked position and manual override handle
must be in forward (locked) position Bring upper
adjusting nut (16) down and tighten until slack In cable is
removed.
(2) With bellcrank (34) still in the unlocked position,
bring lower adjusting nut (7) up and tighten against
bracket (6) Tighten clamp (5) securely to head box.
NOTE
After adjustment, ensure bellcrank (34) flap
bottoms on face blind locking body (29)
when in the unlock position Failure to
accomplish may cause interference with
adjustment of the loop strap lug release
plunger.
a. Removal.
(1) With ejection seat removed from aircraft and
face blind locking mechanism in down position, pull face
blind handle.
NOTE
(3) Functionally check manual override system to
ensure related linkage has not been affected by the face
blind locking adjustment.
Ensure face blind handle pulls freely
from its position in the head box.
i.
Maintenance Operational Check.
Perform a
maintenance operation check on the face blind locking
Figure 5-4. Face blind assembly
5-9
TM 55-1680-308-24
(2) Remove link line quick-release pins (3, figure 438) on each side of head box and remove restraint strap
connecting link (See figure 5-4.)
b. Cleaning.
(1) Clean all metallic parts of the face blind
assembly with drycleaning solvent (Item 6, table 1-2).
(2) Dry each part carefully with a clean, dry, lintfree cloth.
c. Inspection.
inner and intermediate tubes to be driven upward to
eject the ejection seat. The top latch requires a
handwheel, Part No. MBEU/26568, for installation and
removal. The top latch provides a continuous visual
indication that the ejection seat is locked to the ejection
gun after it is installed. This is accomplished by an
indicator plunger. When the latch plunger is seated
against the inner tube locking V-groove, the other end of
the locking plunger will be flush with the top latch
housing. (See figury 3-2.) Also, the indicating plunger
will be flush with the locking plunger. As a cross-check
for the top latch, two trip rod indicators are installed on
the ejection seat.
(1) Inspect face curtain for fraying, loose stitching,
and deterioration.
Do not remove handwheel, Part No
MBEU/26568 (figure 5-5), unless ejection
gun or plunger retaining tool Is placed In
position. The top latch plunger is held in
the plunger housing by the holding action
of the handwheel and ejection gun
primary cartridge breech or plunger
retaining tool.
(2) Inspect sear :oiler and roller pins for elongated
holes and distortion.
d. Repair or Replacement.
(1) Replace all parts of the face blind assembly that
do not meet inspection requirements.
(2) Replace sear rollers and roller pins during
reassembly.
e. Lubrication. Lubricate components of the body
(figure 54) prior to reassembly with a light coat of grease
(item 5, table 1-2).
f. Installation.
a. Removal.
(1) Install handwheel, Part No MBEU/26568 (See
figure 5-5.)
(2) Remove four bolts, four washers, and four nuts
securing top latch mechanism to left vertical side beam
and remove mechanism and spring.
(1) Install restraint strap connecting link (figure 5-4)
on side of head box and secure with link line quickrelease pins (3, figure 4-38).
(2) Repack the face blind in accordance with
paragraph 4-6z(1).
5-7. Top Latch Mechanism.
The top latch mechanism locks the ejection seat
structure to the ejection gun so that the ejection seat is
held firmly in the aircraft until ejection occurs. The top
latch mechanism is installed in the top of the left side of
main beam and consists of a spring-loaded, wedgeshaped plunger When locked, this plunger is forced
into a wedge-shaped groove in the ejection gun inner
tube by spring tension. The latch plunger passes
through a rectangular shaped hole m the top lip of the
cylinder barrel with ample clearance to prevent binding.
During ejection, the action of the ejection gun thrusts the
plunger out of the wedge-shaped groove and allows the
Change 5
Figure 5-5. Top latch mechanism installation
5-10
TM 55-1680-308-24
when cocking the drogue gun.
A bungee (16),
connected at one end to the backrest plate and attached
at the other end to the drogue gun/TCR cable trip rod
(11), pulls the trip rod out of the way when the ejection
seat is removed from the flight compartment for
servicing. On ejection, since the drogue gun/TCR cable
trip rod (11) remains with the aircraft, the bungee (16)
will break by the action of the ejection seat moving
upward. The ground lock pin (9) must always be
installed in drogue gun safety pin hole when the aircraft
is on the ground. The drogue gun trip rod quick-release
pin, which normally holds the drogue gun/TCR cable trip
rod (11) to the crossbeam member, is removed from the
crossbeam member and used as the safety in the safety
pin hole when the drogue gun is to be removed for
servicing. Either pin prevents the sear (10) from being
pulled.
b. Cleaning.
(1) Clean top latch mechanism with drycleaning
solvent (item 6, table 1-2).
(2) Wipe each part dry with a clean, dry, lint-free
cloth.
c. Inspection.
(1) Inspect plunger for malformed threads.
(2) Inspect top latch mechanism body for cracks
and burrs.
d. Repair or Replacement. Repair is limited to the
replacement of the top latch mechanism.
a. Removal. Remove drogue gun in accordance with
paragraph 4-6e.
e. Installation
(1) Apply a light coating of grease (item 8, table 12) on plunger, spring, and in the cavity of the top latch
mechanism housing.
b. Cleaning.
(1) Clean the drogue gun with a clean cloth slightly
moistened in drycleaning solvent (item 6, table 1-2).
(2) Position spring on flange end of top latch
mechanism.
(2) Remove all traces of solvent with a clean, dry,
lint-free cloth.
(3) Position latch mechanism on left side of main
beam and secure with four bolts, four washers, and four
nuts. (See figure 5-5.)
c. Inspection.
(1) Inspect threaded area of barrel and firing body
for crossed or malformed threads.
5-8. Drogue Gun.
The cartridge operated drogue gun (figure 4-3)
extracts the drogue parachute from its container during
the ejection process The drogue gun is mounted on the
left vertical side beam by two studs. The cartridge is
contained in the base of the drogue gun barrel (5), which
is threaded into the firing body (8). The barrel contains
a piston (3) which is attached to the drogue line by
means of a bolt and nut (2) and a special shackle (1).
The piston is held In the barrel by means of a special
shear pin (4) which is sheared when the drogue fires.
The drogue gun sear (10) is attached to a drogue
gun/TCR cable trip rod (11). The other end of the trip
rod is attached to the ejection gun crossbeam (14) by
means of a trip rod quick-release pin. As the ejection
seat moves upward on ejection, the trip rod pulls the
sear from the drogue gun and, after approximately a
1/2-second time delay, the firing pin strikes the
cartridge, firing the drogue gun. The drogue gun
contains an escapement which provides a 0.40 to 0.60
second time delay from the time that the sear Is pulled
until thy firing pin strikes the cartridge, firing the drogue
gun. The trip rod sear (10) fits into a slot in the locking
plunger assembly.
This locking plunger assembly
retains the firing pin in the cocked position. Pulling the
sear (10) releases the locking plunger assembly. This
locking plunger assembly must be pushed in manually
(2) Inspect firing body mounting holes for burrs and
cracks.
(3) Ensure quick-release pin slides in and out of
hole in firing body easily and is not bent or malformed.
(4)
Inspect
deterioration.
bungee
for
fraying,
cuts,
and
d. Repair or Replacement. No repair is authorized for
the drogue gun. Replacement is required if drogue gun
fails to pass any test outlined in paragraph 4-6k.
e. Testing. Test drogue gun in accordance with
paragraph 4-6k(6).
f. Installation. Install drogue gun in accordance with
paragraph 4-6ab.
5-9. Personnel Parachute Pack.
a. Removal. Remove personnel parachute pack in
accordance with paragraph 4-6f.
5-11
TM 55-1680-308-24
b. Inspection Dispatch personnel parachute assembly
to parachute personnel for inspection/repack
Caution should be taken when transporting
parachutes between maintenance activities
to insure damage does not occur Consult
TM 10-1670-201-23, Chapter 4, for
shipment requirements
c. Installation. Install personnel parachute pack in
accordance with paragraph 4-6ai.
5-10. Rigid Seat Survival Kit (RSSK).
The RSSK container is rigid fiberglass construction
which includes a retention assembly for the seat
occupant The survival kit assembly fits in the seat pan
and is secured by two lower attachment lugs, which are
released only when the time release mechanism or the
manual override handle is actuated. An occupant
retention assembly is attached to both sides of the
survival container and clips to a floating lap belt which is
part of the personnel harness. To gain access to an
equipment bag containing the survival gear there are
grip handles which, when squeezed, release a locking
assembly separating the container bottom and the lid
assembly. To remove the survival kit assembly from
the seat bucket, release the retention lugs by moving
the manual override lever to the up (unlock) position,
and lift survival kit assembly from seat bucket.
a. Removal.
paragraph 4-6g.
Remove RSSK in accordance with
b. Disassembly. Squeeze grip handles releasing lock
and case will separate.
c. Inspection.
paragraph 4-6ag.
Inspect RSSK in accordance with
d Repair or Replacement. Replace the survival kit
assembly if found to be defective.
e. Reassembly. Position case in place, squeeze
either grip handle, lock will open. Align case and
release grip handles so lock fastens case.
f. Installation
paragraph 4-6ah.
Install RSSK in accordance with
5-11.
Leg Restraint Cords and Quick-Release
Garters.
The two leg restraint cords (2, figure 1-8) and the two
quick-release garters (1) are designed to pull the
occupant's legs in tightly against the ejection seat thigh
supports during ejection The lower end of each leg
Change 4
restraint cord is attached to a separate roller bracket
(11) on the flight compartment floor Each cord is routed
through a snubber unit, through a metal ring on each
quick-release garter (1), and is secured In a leg restraint
cord lock (5) located on the front face of the seat bucket
just under the secondary firing handle (3).
a. Removal.
(1) Remove TCR motor and brackets.
paragraph 4-26a.
Refer to
(2) Remove quick-release garter from leg restraint
cord.
(3) Tie a strong string to leg restraint cord (1, figure
5-6).
(4) Remove bolt (5) and nut (3) securing roller
bracket (4) immediately below snubber (2) and remove
roller bracket.
(5) Pull snubber finger ring (7, figure 1-8) and pull
leg restraint cord form front to rear on underside of
ejection seat, threading string along route of leg restraint
cord.
b. Inspection. Inspect leg restraint cords and quickrelease garters for fraying and cuts.
c. Installation
(1) Remove string from old leg restraint cord (2,
figure 1-8) and tie it to a serviceable leg restraint cord.
(2) Pull snubber finger ring.
(3) Pull string, threading leg restraint cord in its
proper track, through leg restraint cord lock (5), from
rear to front Ensure restraint cord does not twist.
(4) Release snubber finger ring (7).
(5) Install roller bracket (4, figure 56) and secure
with bolt (5) and nut (3).
(6) Install TCR motor and brackets.
paragraph 4-25c.
Refer to
5-12. Dual Leg Restraint Cord Lock and Snubber
Unit.
The leg restraint cord locks (5, figure 1-8) secure the
cord lock fittings (6) of each leg restraint cord (2) to the
front face of the seat bucket, just under thy lower firing
handle. Each leg restraint cord passes through a
snubber unit located on the bottom of the seat bucket.
The snubber units are designed to release the leg
restraint cords when the snubber finger rings (7) are
pulled, thereby allowing the occupant to control the
amount of slack in the leg restraint cords.
5-12
TM 55-1680-308-24
(2) Inspect for cracked or sheared flathead pin.
a. Removal.
(3) Inspect taper pin for burrs or damaged threads.
(1) Remove RSSK (Refer to paragraph 4-6f.)
c. Repair or Replacement. Repair of the leg restraint
cord lock release handle and the related linkage is
limited to the replacement of defective components.
(2) Remove screws, washers, and nuts (1, figure 57) securing cover plate (2) to forward portion of seat
bucket (3).
d. Installation.
(3) Remove screws, washers, and nuts securing leg
restraint cord lock to seat bucket and remove lock.
(1) Position leg restraint cord lock release handle
(25, figure 5-8) on torque tube and secure with taper pin.
b. Inspection.
(2) Secure connecting link (29) to lever link.
(1) Inspect leg restraint cord locks for cracks around
mounting holes and for corrosion.
5-14. Lower Firing Handle and Cable Assembly.
(2) Inspect leg restraint cord lock spring for proper
return of lock when snubber finger ring is released.
The lower firing handle (11, figure 5-9) Is located at the
center of the seat bucket front panel at the top edge.
The lower firing handle is connected to the ejection gun
firing pin sear by lower firing cable (thin) (9) to provide
an alternate means of firing the ejection gun. A safety
guard is mounted on the front panel of the seat bucket.
This guard, when in the up position, prevents the lower
firing handle from being extracted. The guard must be
In the up position at all times except during flight.
Rotating the guard to the right and down will unlock the
lower firing handle. A spring-loaded locking plunger
housed in the front of the seat bucket, and a lever and
plunger secured to a torque tube of the manual override
mechanism, provide a means of locking the lower firing
handle. The lower firing handle will be locked when the
manual override handle is pulled up (unlocked), or dual
leg restraint lock release handle is placed in the aft
(unlocked) position.
c. Installation.
(1) Secure leg restraint cord locks to front face of
seat bucket (white lock on the left side and black lock on
the right side) with screws, washers, and nuts.
(2) Secure cover plate (2, figure 5-7) to forward
portion of seat bucket (3) with screws, washers, and nuts
(1).
(3) Install RSSK seat pan (Refer to paragraph 46ah.)
5-13. Leg Restraint Cord Lock Release Handle.
The leg restraint cord lock release handle (25, figure 58) is located on the forward left side of the seat bucket.
When the handle is in the forward (locked) position, the
cord lock fitting (6, figure 1-8) on the upper end of the
leg restraint cord (2) may be inserted and locked in the
leg restraint cord lock (5) When the handle is in the aft
(unlocked) position, the upper end of the leg restraint
cord is freed.
a. Removal.
(1) Remove firing handle guard by removing nut,
washer, spacer, and bolt securing plunger to attachment
clamp and seat bucket, then remove nut, washers, and
bolt securing firing handle guide to seat bucket.
(2) Pull lower firing handle (11 figure 5-9) out until a
2-inch length of cable is exposed.
a. Removal.
(1) Remove cotter pin and flathead pin and extract
clevis pin from leg restraint cord lock release handle
connecting link.
(3) Remove special washer (12) and nut (13) which
fasten firing handle to cable connector (10).
(2) Remove taper pin and remove leg restraint cord
lock release handle from torque tube.
(4) Pull lower firing cable (thin) (9) and cable
connector (10) from lower firing handle (11) and remove
cable connector (10).
b. Inspection.
(5) Remove remaining special screw (14), washer
(6), and nut (7) which secure attachment clamp (8) to
seat bucket, and pull outer conduit assembly (5) and
lower.
(1) Inspect leg restraint cord lock release handle for
corrosion and damage.
5-13
TM 55-1680-308-24
firing cable (thin), located at the top of the
right main beam, to take up slack as lower
firing handle is installed.
(1) Secure bracket (15, figure 5-9) to main beam
using special screws (1) and nut (3).
(2) Position clamps (4) and guard channel on
conduit and secure to right main beam.
(3) Guide outer conduit assembly (5) and lower
firing cable (thin) (9) through bottom of seat bucket and
position attachment clamp (8).
(4) Place cable connector (10) in lower firing handle
(11) and secure with special washer (12) and nut (13).
(5) Install firing handle guard, securing guard to
seat bucket with bolt, washers, and nut, and securing
plunger to attachment clamp and seat bucket using bolt,
washer, spacer, and nut.
Figure 5-6. Removal of roller bracket
(6) Install remaining special screw (14), washer (6),
and nut (7) securing attachment clamp (8) to seat
bucket.
firing cable (thin) (9) from clamp and through bottom of
ejection seat.
5-15. Inertia Reel Manual Control Linkage.
(6)
Remove special screws (1) and nuts (3)
securing bracket (15) to main beam.
The inertia reel manual control linkage (figure 5-10)
releases the snubbers in the inertia reel mechanism,
enabling the loop straps to extend or retract. The
linkage is spring-loaded to return to the center (autolock)
position from the aft (unlocked) position The forward
(locked).
(7) Remove clamps (4) and guard channel from
right main beam and remove outer conduit assembly
(5).
b. Inspection.
(1) Inspect lower firing cable for broken wires,
kinks, and corrosion.
(2) Inspect outer conduit assembly for dents,
cracks, and corrosion.
(3)
Inspect attachment clamps for elongated
mounting holes and for cracks.
c. Repair or Replacement. Repair of the lower firing
handle and cable assembly consists of replacing
defective components.
1. SCREW, WASHER, NUT,
2. COVER PLATE:
3. SEAT BUCKET
d. Installation.
40VJ5M44
Figure 5-7. Removal of seat bucket cover plate
To prevent damage to the lower firing
cable, pull on cable loop on end of lower
5-14
TM 55-1680-308-24
Figure 5-8. Manual override and locking mechanism
5-15
TM 55-1680-308-24
The following adjustments are compatible only with
serviceable loop straps. If loop straps are frayed or
distorted in cross sectional thickness, they must be
replaced before linkage adjustment. After installation of
new straps, a functional check of the inertia reel
mechanism should be carried out to determine if linkage
adjustment is necessary. Under no circumstances
should linkage adjustment be attempted with
unserviceable loop straps.
(1) Ensure that inertia reel manual control handle
(21, figure 5-10) bottoms out against forward and rear
stops when operated through full range of movement.
(2) Place the control handle (21) in the aft unlocked
position and release handle to center (autolock) position.
(3) Pull out the loop strap 18 inches and push (by
hand) the snubbers (19, figure 5-11) onto the loop strap
(23).
(4) With the snubbers in the locked position pull
hard on the 18-inch length of the loop strap.
(5) Maintain tension on loop straps and check the
rear clearance between faces of torque dogs (detail A,
figure 5-10).
(1)
Inspect all hardware for security and for
corrosion.
NOTE
If the inertia reel manual control handle (21) fails
to bottom out correctly, the length of connecting
rod (18) must be adjusted by rotating the eye end
(14). The gap (detail A, figure 5-10) must be
measured only after linkage slack has been
removed by pushing forward on inertia reel control
fork (31). The seat bucket must be in the up
position in order to obtain access to the jamnut
(8). If the gap (detail A) is less than 0 005 inch,
the linkage relationship between connecting rod
(18) and push-pull rod (25) is too long.
Conversely, if the gap is excessive (e g, 0.040
inch), the linkage is too short.
(2) Inspect inertia reel manual control handle for
ease of operation.
(6)
Remove flathead pin and cotter pin (13)
securing connecting rod (18) to bellcrank lever (12).
(3) Ensure inertia reel manual control handle hits
forward and aft stops when moved through its full range
of travel.
(7) Pull connecting rod (18) out of engagement with
bellcrank lever (12) to give access to flathead pin and
cotter pin (9).
b. Adjustment. If the inertia reel manual control
linkage is out of adjustment (Indicated by a failure of the
snubbers to lock or unlock the loop straps), proceed as
follows:
(8) Remove flathead pin and cotter pin (9) securing
push-pull rod (25) to bellcrank lever (12).
Figure 5-9. Lower firing handle and cable assembly
position prevents the loop straps from extracting and
allows retraction of the loop straps when the occupant
leans back against the ejection seat.
a. Inspection.
5-16
TM 55-1680-308-24
Figure 5-10. Inertia reel manual control linkage
5-17
TM 55-1680-308-24
Figure 5-11. Inertia reel mechanism disassembly (Sheet 1 of 2)
5-18
TM 55-1680-308-24
KEY to figure 5-11
1.
2.
3.
4.
5.
6.
7.
8.
Bearing
Locknut, washer
Support bracket
Plunger bellcrank
Bolt, washer, locknut
Roller
Pivot pin
Locking plunger subassembly
9. Plunger housing
10. Mounting bracket
11. Bolt, washer, locknut
12. Cotter pin
13. Locking sleeve
14. Locking piston
15. Pivot pin
16. Taper pin
17. Locking lever
18. Harness beam assembly
19. Snubber
20. Locknut and taper pin
21. Operating lever
22. Taper pin
23. Loop strap
24. Parachute restraint strap
spreader assembly
25. Inertia reel flange
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
Loop strap drum
Screw, washer
Bearing
Mounting bracket
Bolt, washer, locknut
Taper pin
Lever
Flathead pin, cotter pin
Link
Screw, washer, locknut
Eye end
Flathead pin, cotter pin
Locknut
Torsion bar
Bolt, washer, locknut
Lever
Fork end
Flathead pin, cotter pin
Plunger
Spring
Roller
Cotter pin, pin
Insert
Roller
Cotter pin, pin
Shaft
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
Harness beam subassembly
Bolt, washer, locknut
Mounting bracket
Bolt, washer, locknut
Plunger housing
Support bracket
Screw, washer, locknut
Flathead pin, cotter pin
Locknut, washer
Bearing
Bolt, washer, locknut
Lever
Torsion bar
Eye end
Locknut
Fork end
Flathead pin, cotter pin
Taper pin
Lever
Shaft
Bearing
Screw, washer, locknut
Spring
Strap retainer
Screw, washer
Bearing
Figure 5-11. Inertia reel mechanism disassembly (Sheet 2 of 2)
(9) Back off jamnut (8) of push-pull rod (25).
(11) Tighten up jamnut (8) of push-pull rod (25).
(10) Adjust (half a turn at a time) on push-pull rod
(25) until the correct clearance on the torque dogs is
achieved (detail A).
(12) Using new cotter pins, assemble linkage as
follows:
(a) Install flathead pin and cotter pin (9) securing
push-pull rod (25) to bellcrank lever (12).
NOTE
(b) Engage connecting rod (18) into bellcrank
lever (12).
With each half-turn adjustment it will be
necessary to connect the push-pull rod
(25) and connecting rod (18) to the
bellcrank lever (12) with the flathead pins
only (no cotter pins required during the
adjustment phase) in addition the
procedures In (2), (3), (4) and (5) must be
repeated with each progressive half turn
adjustment. This step-by-step method
must be carried out until a final
adjustment gives the smallest gap within
the tolerance of not less than 0.005 inch.
(c) Install flathead pin and cotter pin (13) securing
connecting rod (18) to bellcrank lever (12).
(13) Carry out a functional check of inertia reel
mechanism in accordance with paragraph 4-6t.
(14) For troubleshooting procedures, refer to table
5-1.
5-19
TM 55-1680-308-24
Table 5-1. Troubleshooting, DS and GS Maintenance
Malfunction
Probable Cause
Corrective Action
Loop straps do not release until
manual override handle engages
aft strap.
Lower adjustment rod tubes too long
Shorten lower adjustment rod tubes on
bottom of ejection seat (Refer to
paragraph 5-18 )
Leg restraint cords release
before or at the same time
as seat restraint system
releases.
Lower adjustment rod tubes too short
Lengthen lower adjustment rod tubes
on bottom of ejection seat. (Refer
to paragraph 5-18.)
Rigid seat restraint lugs
do not release at the same
time.
Adjustment link on left-hand side
of main beam and below drogue
gun, out of adjustment
If left lug releases first, shorten
adjustment link on left side of main
beam. If right lug releases first,
lengthen adjustment link on left
side of main beam (Refer to paragraph
5-18.)
Leg restraint cord will not
lock Into leg restraint locks
Broken spring or worn plunger
In leg restraint cord lock
Replace dual leg restraint cord lock.
(Refer to paragraph 5-12.)
Inertia reel manual control
handle falls to unlock loop
straps
Inertial reel linkage too long
Adjust inertia reel manual control
linkage (Refer to paragraph 5-15b.)
No manual lock or autolock for
inertia reel manual control
Inertia reel linkage too short
Adjust inertia reel manual control
linkage. (Refer to paragraph 5-15b )
Loop strap snubber counterweight
does not contact counterweight
strap
Inertia reel linkage too short.
Lengthen inertia reel manual control
linkage (Refer to paragraph 5-15b )
5-16. Inertia Reel Manual Control Handle.
(1) Inspect inertia reel manual control handle for
damage, corrosion, and excessive wear.
The inertia reel manual control handle is a threeposition control located aft of the leg restraint cord lock
release handle on the left side of the seat bucket. When
placed in the spring-loaded autolock position, the inertia
reel manual control handle allows the harness loop
straps to extend and retract The forward lock position
allows retraction only.
(2) Inspect all attaching parts for burrs, damaged
threads, split washers, and cracked or sheared flathead
pin.
c. Repair or Replacement. Repair of the inertia reel
manual control handle consists of replacing defective
components.
a. Removal.
d. Installation.
(1) Remove bolt, washer, spacer, and nut (20,
figure 5-10) and remove cover plate (22) from seat
bucket.
(1) Place inertia reel manual control handle (21,
figure 5-10) on end of connecting rod (18) and secure
handle with flathead pin and cotter pin (19) and bolt,
washer, nut (17).
(2) Remove flathead pin and cotter pin (19) and
bolt, washer, nut (17) attaching inertia reel manual
control handle (21) to connecting rod (18) and remove
handle.
(2)
Install bolt, washer, spacer, and nut (20)
securing coverplate (22) to seat bucket.
b. Inspection.
5-20
TM 55-1680-308-24
5-17. Inertia Reel Mechanism.
locknut and washer (2), and remove bearing (1), bolt,
washer, and locknut (40), and lever (41).
The inertia reel mechanism (figure 5-11), located
underneath and behind the central support bracket,
consists of four major parts: a harness, loop strap (23), a
snubber (19), and a dual spring4oaded loop strap
retraction reel. The inertia reel mechanism provides a
means of retention for the upper portion of the
occupant's harness. The loop strap, which Is rolled onto
a retraction reel, passes through the snubber and
through the parachute roller yoke on the personnel
parachute. The free end of the loop strap, which
contains a lug, is then inserted into the harness lock.
The snubber prevents forward movements of the
occupant when the occupant exceeds 2 to 3 g's force
parallel to the main beam, or when the inertia reel
manual control handle is in the forward (locked) position.
The retraction reel takes up slack in the loop strap when
the occupant sits back. The occupant cannot lean
forward until he places the inertial reel manual control
handle to the aft (unlocked) position.
(7) Remove bolt, washer, and locknut (5), screw,
washer, and locknut (35), support bracket (3), and
mounting bracket (10).
(8) Remove lever (32), which is secured to shaft
(71) by taper pins (31).
(9) Remove bolts, washers, and locknuts (11) and
mounting bracket (29).
Remove locking plunger
subassembly (8), plunger housing (9), spring (45),
plunger (44), and parachute restraint strap spreader
assembly (24). Drift out pivot pin (7) and remove roller
(6).
(10) Remove loop strap (23) by removing screws
and washers (76); loosen inertia reel flange (25), rotate
snubber (19) aft and remove flange retaining screw from
flange (25).
(11) Pull loop strap off drum and remove loop strap
(23) from loop strap retainer (75) and pull loop strap
past snubber (19) Slide inertia reel flange (25) outboard
away from loop strap (23).
a. Removal.
(1) Remove bolt, washer, and nut that secure back
plate to head box.
(2) Remove flathead pins and cotter pins (68 and
59, figure 5-1 1) that secure fork end (67) and eye end
(65) to levers (63 and 70). Separate fork end and eye
end and remove locknut (66).
(12) Remove loop strap retainer (75) and pull loop
strap (23) past snubber (19).
(13) Remove taper pin (22) and operating lever (21)
Remove locknut and taper pin (20) securing snubber
(19) to shaft (51). Remove taper pin (16) securing
locking lever (17) to shaft (51) and remove shaft and
snubber.
(3) Remove torsion bar (64) which Is secured by
locknut and washer (60), and remove bearing (61), bolt,
washer, and locknut (62), and lever (63).
(4) Remove bolt, washer, and locknut (53), screw,
washer and locknut (58), support bracket (57), and
mounting bracket (54).
(14) Remove locking lever (17) and locking piston
(14) from locking sleeve (13) Remove spring which is
housed in locking sleeve (13), and separate locking
piston (14) from locking lever (17) by removing pivot pin
(15). Remove locking sleeve (13) by removing cotter
pin (12).
b. Disassembly.
(1) Drift out taper pin (69, figure 5-11) and remove
lever (70).
(15) Remove rollers (46 and 49), which are secured
by cotter pins and pins (47 and 50), and remove insert
(48).
(2) Remove bolts, washers, and locknuts (55), and
remove plunger housing (56).
(16) Remove screw, washer, and locknut (73),
screw and washer (27), inertia reel flange (25) bearings
(28 and 72), spring (74), and loop strap drum (26).
(3) Remove flathead pins and cotter pins (43 and
37) that secure fork end (42) to plunger bellcrank (4) and
eye end (36) to lever (32). Separate fork end from eye
end and remove locknut (38).
c. Cleaning.
(4) Remove bolt, washer, and locknut (30), bearing
(77), and plunger bellcrank (4).
(1) Clean all removed components, except the loop
strap, in drycleaning solvent (item 6, table 1-2).
(5) Remove link (34) which is secured by flathead
pins and cotter pins (33).
(2)
Dry component parts with clean, filtered,
compressed air.
(6) Remove torsion bar (39) which is secured by
5-21
TM 55-1680-308-24
install shaft (51), then secure snubber to shaft with
locknut and taper pin (20) Install locking sleeve (13) and
secure with cotter pin (12), then insert spring in locking
piston (14) and insert locking piston In locking sleeve
(13). Position locking lever (17) on shaft (51), then
secure to shaft with taper pin (16), and to locking piston
(14) with pivot pin (15).
d. Inspection.
(1) Inspect all hardware for stripped threads.
(2) Inspect all mounting brackets and components
for elongated mounting holes, cracks, and for bright
areas, indicating binding.
(5) Insert loop strap (23) under roller (46) and
snubber (19), and over roller (49). Insert strap retainer
(75) in end of loop strap (23). Install inertia reel flange
(25) and loop strap (23) on strap retainer (75) and slide
inertia reel flange (25) out on loop strap drum (26) so
that drum screw hole is visible.
(3) Inspect harness release roller for evidence of
wear.
(4) Inspect shafts for defects and evidence of wear.
(5) Inspect loop strap for fraying, broken stitches,
and cuts.
NOTE
Frayed loop strap edges 1/8-inch
maximum both sides are considered
serviceable.
(6) Rotate loop strap drum (26) clockwise (as
viewed from the right side) until fully tight, back off onehalf turn Holding loop strap drum firmly, insert loop strap
(23) with strap retainer (75) In slot in loop strap drum.
Release loop strap drum slowly until loop strap is wound
on drum.
(6) Inspect plunger spring and torsion spring to see
if they are broken, stretched, or bent.
e. Repair or Replacement.
Holes must align, otherwise, screws
securing flanges to drum will be sheared.
(1)
Replace all taper pins removed during
disassembly.
(7) Slide inertia reel flange (25) m on loop strap
drum (26) until holes align, and secure flange to drum
with screw and washer (76) Secure spring (74) to drum
with screw and washer (27). Install flange retaining
screw.
(2) Replace any worn, mutilated, or loose fitting
bearings.
(3) Replace any springs found to be damaged.
(4)
frayed.
(8) Insert roller (6) in slot of locking plunger
subassembly (8) and secure with pivot pin (7). Insert
spring (45), plunger housing (56 and 9), and mounting
bracket (29), and secure to harness beam assembly (18)
with bolts, washers, and locknuts (55 and 11) Install
plunger (44).
Replace loop strap if cut or if excessively
f. Lubrication. Apply a light coating of lubricating oil
(Item 2, table 1-2) to all moving parts prior to
reassembly
(9) Install lever (32) on shaft (71) with taper pins
(31).
g. Reassembly.
(1) Position loop strap drum (26, figure 5-11) and
slide spring (74) over shaft (71), then install shaft, and
secure spring on shaft with screw, washer, and locknut
(73).
(10) Install support and mounting brackets (3 and
10), and secure with screw, washer, and locknut (35).
(11) Position plunger bellcrank (4), insert bearing
(77), and secure with bolt, washer, and locknut (30).
(2) Install bearings (28 and 72) and inertia reel
flange (25) on shaft (71).
(12) Screw locknut (38) on eye end (36) and screw
eye end into fork end (42). Position fork end on plunger
bellcrank (4) and secure with flathead pin and cotter pin
(43). Position eye end on lever (32) and secure with
flathead pin and cotter pin (37).
NOTE
Do not secure inertia reel flange (25) to
loop strap drum (26) at this time.
(3) Install rollers (46 and 49) and secure with pins
and cotter pins (47 and 50) Install insert (48).
(13) Position lever (41) and insert torsion bar (39)
through lever and support bracket (3), then Insert
bearing
(4) Install operating lever (21) on shaft (51) and
secure with taper pin (22) Position snubber (19) and
5-22
TM 55-1680-308-24
(8) Pull loop strap out to its fully extended position
and release loop strap slowly. Loop strap should
completely retract.
(1) and secure torsion bar with washer and locknut (2)
and bolt, washer, and locknut (40).
(14) Position link (34) and secure to levers (41 and
32) with flathead pins and cotter pins (33).
(9) Move inertia reel manual control handle to
forward (locked) position and check to see that snubber
contacts loop strap across the entire surface of loop
strap.
(15) Install lever (70) on shaft (71) and secure with
taper pin (69).
(10) Move inertia reel manual control handle to aft
(unlocked) position and allow handle to return to center
(autolock) position. Ensure snubber hits stop on main
beam assembly.
h. Installation.
(1)
Install mounting bracket (54) and support
bracket (57) and secure with bolt, washer, and locknut
(53) and screw, washer, and locknut (58).
(11) Place inertia reel manual control handle to aft
(unlocked) position, and withdraw loop strap
approximately 2 feet.
(2) Position lever (63) and insert torsion bar (64)
through lever and support bracket (57), then insert
bearing (61) and secure torsion bar with washer and
locknut (60) and bolt, washer, and locknut (62).
(12) Release Inertia reel manual control handle.
(13) With loop strap partially extended, manually
press snubber against the loop strap.
(3) Screw locknut (66) on eye end (65) and screw
eye end in fork end (67). Secure fork end to lever (70)
and eye end to lever (63) with flathead pins and cotter
pins (68 and 59).
(14)
Holding tension on loop strap, measure
distance between lever and end stop (See detail A,
figure 5-11.) Clearance must be 0.005 inch minimum.
(4) Install bolt, washer, and nut securing backplate
to head box.
NOTE
i. Maintenance Operational Check
Reference paragraph 5-16 for corrective
action.
(1) Place inertia reel manual control handle (21,
figure 5-10) in center (autolock) position.
5-18 Manual Override System.
(2) Pull loop strap out to its extreme position.
The manual override system consists of interlinked
push rods and torsion rods which actuate the following
controls.
(3) Move inertial reel manual control handle to
forward (locked) position.
(4) Slowly allow loop strap to retract a few inches at
a time, then pull forward on loop strap to see if the loop
strap locks.
a. Control Actuation.
(1) Breech link (4, figure 5-8) withdraws guillotine
initiator sear (5).
(5) Repeat procedure in preceding step (4) until
loop strap is fully retracted.
(2) Locking plungers (46) lock and unlock the cord
fittings (6, figure 1-8).
(6) Move inertia reel manual control handle to
center (autolock) position and pull on loop strap. Loop
strap should be locked.
(3) Locking plunger (38, figure 5-8) locks and
unlocks the lower firing handle (36).
(7) Move inertia reel manual control handle to aft
(unlocked) position and release handle. Handle should
move to center (autolock) position.
(4)
Plungers (18) lock and unlock rigid seat
retention lugs (7, figure 4-36).
(5) Plunger (44, figure 5-11) locks and unlocks the
loop strap lug.
NOTE
The inertial reel manual control handle is
spring-loaded to the center (autolock)
position.
(6) Plunger pin (30, figure 5-2) locks and unlocks
the body of the face blind.
5-23
TM 55-1680-308-24
b. Operational Sequence When the manual override
handle is moved up and aft, the following actions should
occur in sequence:
(unlocked) position. Check that end of plunger bottoms
out on housing body when manual override handle is in
forward (locked) position.
(1) The guillotine initiator sear should withdraw from
its firing mechanism.
NOTE
The fork end (42) must be adjusted 1/2 a
turn at a time After each 1/2 turn
adjustment, the clevis pin (12, figure 5 2)
must connect the fork end (42, figure 511) to plunger bellcrank (4).
After
connecting the fork end to plunger
bellcrank, the adjustment related to the
locked and unlocked position of the
manual override handle can be checked
on each turn of fork end.
(2) The leg restraint cords should be released at the
cord lock fittings first.
(3)
The rigid seat lugs should next release
simultaneously.
(4) The loop strap lug is released last.
(5) Locking of the face blind and lower firing handle
may occur anytime between steps (1) and (4) above.
(4) When correct adjustment has been achieved,
tighten locknut (38) and assemble In reverse order.
c. Rigging Standard. With the manual override
handle (1, figure 5-8) In the forward and down (locked)
position, the plungers (18) and plunger (44, figure 5-11)
should bottom out against their housings. The end of
the plungers should touch the housing and there should
be no clearance. With the manual override handle in
the up and aft (unlocked) position, the plunger (44)
should be withdrawn so that the end of the plunger is
recessed in the housing by at least 1/16 inch Plungers
(18, figure 5-8) should recess at least 1-32 inch. When
moving the handle from down (locked) to up and aft
(unlocked) position, both plungers (18) must withdraw
within their housings simultaneously.
(5) Verify that face blind locking mechanism linkage
has not affected the plunger (44) adjustment when
plunger assembly (13, figure 5-2) is connected to fork
end (42, figure 5-11) and plunger bellcrank (4).
e. Rigid Seat Restraint Lug Adjustment. If the
plungers (18, figure 5-8) are out of adjustment or fall to
release the side lugs simultaneously, proceed as
follows:
(1) Place the manual override handle in the down
(locked) position.
NOTE
(2) Disconnect lower adjustment rod tubes (24)
from torsion tube levers (21).
Adjustment to the loop strap lug locking
plunger or side plate locking plungers
requires the personnel parachute, RSSK
assembly, and parachute back plate be
removed. In addition, the seat must be
mounted horizontally on the seat
maintenance cradle.
(3) Remove flathead pin and cotter pin (68, figure
5-I1l).
(4) Back off locknut (66).
(5) Adjust fork end (67) by 1/2 turn at a time until
the plunger (18, figure 5-8) meets the rigging standard
established above.
d. Loop Strap Locking Plunger Adjustment. If plunger
(44, figure 5-11) is out of adjustment or fails to release
the loop strap lugs properly, proceed as follows:
NOTE
(1) Place the manual override handle in the forward
(locked) position.
After each 1/2 turn adjustment of fork end
(67, figure 5-1 1), It will be necessary to
engage lever (70) to fork end (67) via
flathead pin, cotter pin (68) By this stepby-step method, a check is made on
every 1/2 turn adjustment until the rigging
standard is achieved.
(2) Remove cotter pin (10, figure 5-2), washer (11)
and clevis pin (12) from plunger assembly (13).
Disconnect plunger assembly from plunger bellcrank (4,
figure 5-11).
(3) Back off locknut (38) and push down on
bellcrank lever in order to adjust fork end (42) until
plunger (44) recesses not less than 1/16 inch in its
housing when manual override handle is moved to aft
(6) Connect lower adjustment rod tubes (24, figure
5-8) to torsion tube levers (21).
5-24
TM 55-1680-308-24
NOTE
b. Cleaning. Clean all parts with drycleainig solvent
(item 6, table 1-2) and dry with a clean cloth or filtered
compressed air.
The lower adjustment rod tubes (24) must
be adjusted to conform to the final
adjustment achieved by fork end rod (67,
figure 5-11). Any incorrect adjustment of
lower tubes (24, figure 5-8) will prevent the
plungers (18) from meeting the rigging
standard. Normally, the first indication of
maladjustment occurs when the plungers
(18) fall to move simultaneously.
c. Inspection.
(1) Inspect manual override handle for corrosion,
cracks and wear.
(2) Inspect trigger and handgrip for spring tension
and locking operation, free from binding.
(7) When correct adjustment has been achieved,
tighten locknut (66, figure 5-11) and assemble in reverse
order.
(3) Inspect threaded parts for stripped threads.
d. Repair or Replacement Repair of the manual
override handle consists of replacement of detective
components.
f. Face Blind Locking Mechanism Adjustment. Refer
to paragraph 5-5h.
e. Installation.
NOTE
(1) Position manual override handle (1, figure 5-8)
on mounting bracket and secure handle to bracket with
bolt (2), bushing (15), washer (14), and nut (13).
The face blind and lower firing handles do
not have to lock in any given sequence.
This function is satisfactory if the two
handles are locked when the manual
override handle is in the aft (unlocked)
position.
(2) Align breech link (4) with manual override
handle (1) and secure breech link to handle with
flathead pin (3) and cotter pin (16).
If retention points do not release in
sequence, refer to preceding subparagraph
b. If both lap belt halves do not release
simultaneously, refer to subparagraph d for
corrective action.
(3) Align operating rod (10) with manual override
handle (1) and secure rod to handle with flathead pin (9)
and cotter pin (8).
5-20. Emergency Oxygen Bottle Assembly.
5-19. Manual Override Handle.
The oxygen cylinder (12, figure 5-12) is mounted on
the right side of the seat bucket. The oxygen cylinder is
equipped with a valve body assembly and pressure
gage (11) and is filled to 1,800 to 2,000 psi with oxygen
(Item 7, table 1-2). During high altitude ejection, the
occupant obtains oxygen from the cylinder, enabling him
to descend to a safe altitude without the danger of loss
of consciousness due to lack of oxygen. Oxygen from
the emergency oxygen bottle assembly can also be
used by the occupant if the aircraft's normal oxygen
system fails during fight. The emergency oxygen bottle
assembly consists primarily of an oxygen cylinder, a
valve and body assembly and pressure gage, and a
hose and connector assembly. The steel, shatterproof,
high pressure oxygen cylinder (12) has an internal
volume of 22 5 cubic inches. The oxygen cylinder is
attached to the valve body assembly by a threaded
connection. The valve body assembly consists of an
oxygen pull cable housing, a pressure gage (II11), and a
valve. The pressure gage (11), which shows the oxygen
pressure of the oxygen cylinder, has no scale
calibration.
The manual override handle (1, figure 5-8), located on
the forward right side of the seat bucket, is a twoposition handle, locked forward and down, unlocked up
and aft. A trigger-type handle grip incorporates a
spring-loaded locking mechanism.
To actuate the
manual override handle, the trigger and handgrip must
be squeezed and pulled up and aft.
a. Removal.
(1) Remove cotter pin (8, figure 5-8) and flathead
pin (9) securing operating rod (10) to manual override
handle (1) and separate rod from handle.
(2) Remove cotter pin (16) and flathead pin (3)
securing breech link (4) to manual override handle (1)
and separate rod from handle
(3) Remove nut (13), washer (14), bushing (15),
and bolt (2) securing manual override handle (1) to
mounting bracket, and remove handle.
5-25
TM 55-1680-308-24
except a mark to denote pressure of 1,800 and 2,500
psi, and a scale divided into two segments, red and
black. The gage pointer, when positioned in the black
segment of the arc, indicates that the oxygen cylinder is
charged to at least 1,800 psi If the pointer is in the red
segment, however, the oxygen cylinder content is too
low for safe operation and the cylinder shall be
recharged. The pressure gage is attached to the valve
body (10) by a threaded connection. The oxygen pull
cable housing (2), attached to the valve by four
cadmium-plated screws and washers (14), is composed
of a housing base, pull cable, and a cable link. The
valve body assembly consists of a valve body (10),
which encases a flow restrictor (8), a breakoff nipple (6),
a bushing (5), and filling nipple. The flow restrictor (8),
consisting of a tubular body into which is secured a
ceramic plug and a filter, controls the flow of oxygen
from the oxygen cylinder to the mask. It is calibrated to
discharge the cylinder pressure of 1,800 psi sit a
predetermined flow rate of from 10 to 12 liters at77°F
(25°C) during the first minute, and approximately 1 liter
during the tenth minute of flow. Ten minutes is
considered the maximum flow period for a cylinder
charged to 1,800 psi. The brass breakoff nipple (6),
consisting of a seat, a flange, and a hollow tip, provides
a leaktight seal until thy tip is broken The bushing (5),
when tightened, forces the breakoff nipple (6) and the
flow restrictor (8) into operating position. When the
emergency oxygen system is activated, the ring
encircling the rubber hose and nipple is pulled over in its
housing and the end of the nipple Is fractured at the
machined undercut, allowing oxygen to flow at full
operating pressure from the cylinder through the flow
restrictor Oxygen leakage is prevented by the metalto-metal seat between the flow restrictor and the valve
body.
The hose and connector assembly (1) is
composed of a rubber hose and bayonet connector.
Do not activate cylinder by pulling the pull cable
a. Service Upon Receipt of Oxygen Cylinder. The
oxygen cylinder may be issued with only enough oxygen
pressure to prevent atmospheric air from entering the
cylinder and causing condensation, corrosion, or rust.
The fact that an oxygen cylinder is received empty or
with only a small amount of pressure does not
necessarily mean that the oxygen cylinder is leaking.
Before the cylinder can be filled with oxygen, any
oxygen already present in the cylinder must be
discharged and the cylinder purged of all air and
moisture. Purge, service, and leak-test cylinder as soon
as oxygen has been discharged from cylinder.
Figure 5-12. Emergency oxygen bottle assemblyexploded view
5-26
TM 55-1680-308-24
b.
Purging Oxygen Cylinder.
cylinder (12, figure 5-12) as follows
(1)
Purge the
Do not allow oxygen pressure to fall below 15 psi in the
oxygen cylinder during purging
Cylinder with 15 to 20 psi remaining.
(f)
Loosen nut at either end of
filling fixture (2, figure 5-13) to permit oxygen to escape
slowly
WARNING
(g) Tighten filling fixture (2) nut and
repeat operation twice more to assure proper purging
Do not allow any oil or grease to come in
contact with compressed oxygen, as the
slightest trace of oil or grease may cause an
explosion. Clean hands, clothes, and tools of all
foreign matter to ensure against contamination
(h) After purging, slowly open valve
on recharging cylinder (1) and allow pressure in cylinder
(3) to reach 2,000 psi, then close recharging cylinder (1)
valve.
(a) Remove four screws and
washers (14) that secure oxygen pull cable housing (2),
slide housing along hose and connector assembly (1)
well out of the way
(b)
NOTE
Cylinder (3) will become warm during filling
operation and lose pressure after it cools to
room temperature
Remove dust cap (13) from
filling nipple
(I)
Allow cylinder (3) to cool to
room temperature, then check pressure gage (11, figure
5-12). Pressure must not be less than 1,800 psi.
WARNING
Ensure that the recharging cylinder contains
only oxygen (item 7, table 1-2) Do not charge
emergency oxygen bottle with anything else
NOTE
Pressure in cylinder must be between 1,800 and
2,000 psi at a temperature of 77°F (250C).
Release or add oxygen to stay within this range
A change m temperature will cause a change in
pressure at a rate of 3.5 psi for each degree
Fahrenheit.
(c) Connect filling fixture (2, figure
5-13) to recharging cylinder (1) first, and then connect
other end to cylinder filling nipple
NOTE
If filling fixture (2) is connected to a partially
filled oxygen cylinder, the oxygen may flow out.
(d) Unscrew bushing (5, figure
5-12) one-fourth turn.
Loosening more than one-fourth turn will allow
oxygen in the cylinder to escape past the
bushing during the charging operation.
(e) Open recharging cylinder valve
slightly to allow oxygen to flow into cylinder (12) When
pressure reading on gage shows approximately 400 to
600 psi, close recharging cylinder valve
Figure 5-13.
Recharging setup for emergency
oxygen bottle (typical)
5-27
TM 55-1680-308-24
(j)
of 180 inch-pounds.
(f)
Remove four screws and four
washers (14, figure 5-12) and washers that secure
oxygen pull cable housing (2), slide housing along hose
and connector assembly (1) well out of the way
Tighten bushing (5) to a torque
(k)
Unscrew filling fixture (2, figure
5-13) from cylinder and replace with leak-test cap (4),
Part No
212A31
(l)
Leak-test
cylinder
(Refer
(g)
Remove dust cap (13) from
filling nipple
NOTE
to
subparagraph d)
(2)
Cylinder
with
less
than
15
If filling fixture (2) is connected to a partially
filled cylinder, the oxygen may flow out.
psi
remaining.
(h) Connect filling fixture (2, figure
5-13) to recharging cylinder (1) first and then connect
other end to cylinder filling nipple.
WARNING
Do not allow any oil or grease to come m
contact with compressed oxygen, as the
slightest trace of oil or grease may cause an
explosion Clean hands, clothes, and tools of all
foreign matter to ensure against contamination.
NOTE
Loosening bushing more than one-fourth turn
will allow oxygen in the cylinder to escape past
the bushing during the recharging operation.
(a) Loosen cylinder valve body
assembly and allow any trapped oxygen to escape.
(i)
12) one-fourth turn.
Unscrew bushing (5, figure 5-
(j)
Open recharging cylinder valve
slightly to allow oxygen to flow Into cylinder (3, figure 513) When pressure reading on pressure gage shows
approximately 400 to 600 psi, close recharging cylinder
valve.
Do not place cylinder in a vise unless protected
by wooden blocks or equivalent. Damage to the
cylinder walls Is cause for rejection.
(b) Remove valve body assembly
from cylinder (12, figure 5-12).
(c) Inspect inside of cylinder (12)
for moisture accumulation and rust.
Do not allow oxygen pressure to fall below 15
psi in the cylinder during purging.
NOTE
(k) Loosen nut at either end of
filling fixture (2) to permit oxygen to escape slowly.
Any evidence of rust Is cause for rejection of
cylinder (12).
(1) Tighten recharging cylinder nut and
repeat operation twice more to assure proper purging.
(d) Connect filling fixture (2, figure
5-13) to recharging cylinder (1) and blow out inside of
oxygen cylinder.
(m) After purging, slowly open
recharging cylinder and allow pressure in cylinder to
reach 2,000 psi; then close recharging cylinder valve.
WARNING
NOTE
Cylinder will become warm during filling operation and
will lose pressure after it cools to room temperature.
Ensure that the recharging cylinder contains only
oxygen (item 7, table 1-2) Do not recharge oxygen
cylinder with anything else.
(e)
(n) Allow cylinder (3) to cool to
room temperature, then check pressure gage (11, figure
5-12). Pressure must not be less than 1,800 psi.
Install valve body assembly into
cylinder.
5-28
TM 55-1680-308-24
to recharging cylinder (1) first, and then connect other
end to cylinder breakoff nipple (6, figure 5-12).
NOTE
Pressure in cylinder must be between 1,800 and
2,000 psi at the temperature of 77°F (250C)
Release or add oxygen to stay within this range
A change in temperature will cause a change in
pressure at a rate of 3.5 psi for each degree
Fahrenheit.
(o)
of 180 Inch-pounds.
Loosening bushing more than one-fourth turn
will allow oxygen in the cylinder to escape past
the bushing during the charging operation.
Tighten bushing (5) to a torque
(4)
(p) Unscrew filling fixture (2, figure
5-13) from cylinder and replace with leak-test cap (4),
Part No. 212A31.
(q)
Unscrew bushing (5) one-fourth turn.
(5) Slowly, open valve on recharging
cylinder (1, figure 5-13) and allow pressure in oxygen
cylinder to reach 2,000 psi, then close recharging
cylinder valve.
Leak-test cylinder (Refer to
subparagraph d).
NOTE
c.
Servicing. If the pressure gage (11, figure
5-12) shows an oxygen pressure of more than 20 psi but
less than 1,800 psi, proceed as follows.
Oxygen cylinder will become warm during filling
operation and will lose pressure after it cools to
room temperature.
NOTE
(6) Allow cylinder, (3) to cool to room
temperature, then check pressure gage (11, figure 512). Pressure must not be less than 1,800 psi.
The cylinder must be purged If oxygen pressure
is 20 psi or less.
NOTE
(1) Remove screws and washer (14) from
valve body (10), and slide pull cable housing (2) and
attached parts along hose and connector assembly (1)
well out of the way.
Pressure m cylinder must be between 1,800 and
2,000 psi at a temperature of 77°F (250C)
Release or add oxygen to stay within this range
A change m temperature will cause a change in
pressure at a rate of 3 5 psi for each degree
Fahrenheit.
WARNING
Do not allow any oil or grease to come in
contact with compressed oxygen, as the
slightest trace of oil or grease may cause an
explosion Clean hands, clothes, and tools of all
foreign matter to ensure against contamination.
(7) Tighten bushing (5, figure 5-12) to a
torque of 180 inch-pounds.
(8) Unscrew filling fixture (2, figure 5-13)
from cylinder and replace with leak-test cap (4), Part No.
212A31.
(2) Remove dust cap (13) from filling
nipple on valve body (10).
(9) Leak-test the oxygen cylinder (Refer
to following subparagraph d).
WARNING
d.
Ensure that the recharging cylinder contains
only oxygen (item 7, table 1-2). Do not charge
emergency oxygen cylinder with anything else.
(1) Using a mild, water mixed solution of
detergent (hand-dlshwashing compound), check for
leaks between valve body (10, figure 5-12) and cylinder
(12), valve body (10) and pressure gage (11) and at
leak-test cap (4, figure 5-13) bleed hole.
NOTE
If filling fixture is connected to a partially filled
cylinder, the oxygen may flow out.
(3)
Leak-Testing Cylinder.
(2) Carefully
tighten
components
suspected of contributing to observed leakage, and
repeat preceding step (1).
Connect filling fixture (2, figure 5-13)
5-29
TM 55-1680-308-24
NOTE
WARNING
If leaks cannot be eliminated by tightening or
replacing parts, replace with a serviceable
emergency oxygen bottle assembly.
To ensure proper shearing characteristics on
ejection, use rivet, Part No MS20470A2-6, only.
Incorrect rivet may cause malfunction of
emergency oxygen system.
(3) If leakage is still detected, replace
suspected defective parts and repeat preceding step (1).
e.
(b) Align lower link in upper link
and position spacer In lower link. Insert shear rivet
through link and spacer, assuring that rivet head faces
right side of aircraft .
Inspection.
(1) Check that pressure gage (11, figure
5-12) reads at least 1,800 psi at an ambient temperature
of 77°F (25°C) A change In. temperature will cause a
change in pressure at a rate of 3.5 psi for each degree
Fahrenheit.
Avoid using unnecessary force on links when
bucking to prevent distorting links and rivet.
NOTE
(c)
Buck rivet using a small, thick
bucking bar.
If the pressure gage reads zero psi, this Is an
indication that a leak exists or that the breakoff
nipple (6) is ruptured.
(3) If oxygen cylinder is partially filled
(less than 1800 psi), proceed as follows.
(2) Inspect pressure gage (11) for
cracked or broken cover glass, dents, or other visible
defects.
(a)
to subparagraph c ).
(b) Leak-test
(Refer to subparagraph d ).
(3) Inspect pull cable housing (2) for
deformity and interference with or binding on pull cable.
oxygen
cylinder
(4) If hose and connector assembly (1,
figure 5-12) requires replacement, proceed as follows.
(4) Inspect shear rivet in cable link for
signs of shearing.
(a) Remove screws and washers
(14) from valve body (10), and slide pull cable assembly
(3) and attached parts along hose and connector
assembly (1) well out of the way.
(5) Inspect hose for cuts, breaks, or
deterioration, and for proper connection to bayonet
connector
(6) Inspect oxygen hose quick-disconnect
bridle and lanyard for cracks and deformation.
(b) Loosen bushing (5) enough to
permit oxygen to start escaping As cylinder pressure is
gradually reduced, bushing may need to be loosened
approximately one and one-half turns to allow all oxygen
to escape from cylinder.
f.
Repair or Replacement. Replace all items
found defective during inspection.
(1) Replace pull cable housing (2, figure
5-12) if pull cable, or pull cable housing rivets show
signs of damage.
(c) Remove breakoff nipple (6)
from hose and connector assembly (1).
(d)
(2) If cable link shear rivet shows signs of
shearing or has been sheared, replace rivet as follows:
Replace O-ring (7).
(e) Insert breakoff nipple (6) into
new hose and connector assembly (1) and work it in
until flanged face seats firmly against hose end.
(f)
Holding hose and connector
assembly (1), work bushing (5) down until it seats firmly
against face of breakoff nipple (6).
Use exterior caution when removing an
unserviceable rivet to avoid enlarging the hole.
(a) Clear holes in cable link
contain unserviceable rivet parts.
Service oxygen cylinder (Refer
that
5-30
TM 55-1680-308-24
Ensure that parts do not fall on floor or come
in contact with any foreign matter when
inverting cylinder.
(g) Invert cylinder (12) so that flow
restrictor (8) and spring (9) drop out of valve body (10).
Use only oxygen (item 7, table 1-2) to blow out
valve body Do not use compressed air.
(h) Inspect interior of valve body
(10) for foreign matter If necessary, blow clean, using
oxygen (item 7, table 1-2).
(i)
Insert spring
restrictor (8) into valve body (10).
(9)
and
flow
(j)
Check that flange of breakoff
nipple (6) is properly seated against bushing (5) Screw
bushing Into valve body (10) only enough to snug up
parts Do not tighten beyond a snug fit.
(k)
to subparagraph b).
Purge oxygen cylinder. (Refer
a.
Removal.
(1) Disconnect oxygen linkage from
oxygen cylinder by removing quick-release pin (25,
figure 1-9) that secures cable link (29) to bellcrank (24).
(2) Separate fork end of cable (9) from
bellcrank (24) by removing cotter pin (27) and flathead
pin (26).
(3) Separate manual actuating knob (2)
from cable (9) by removing nut and washer.
cylinder
(4) Remove screws and nuts securing
cable clamps (8) to seat bucket Remove cable clamps
from cable conduit (7).
Tighten bushing (5) to a torque
(5) Remove nuts securing actuating knob
support bracket (3) to seat bucket and remove cable (9).
(l)
Service
(Refer to subparagraph c ).
(m)
of 180 inch-pounds.
only a 1/4-inch pull on the cable is required to actuate
the oxygen cylinder, and the cable deflection is not
enough to allow the bellcrank and trip lever to clear the
striker pin, the 1/16inch aluminum rivet securing the two
links shears ) This permits the trip lever and bellcrank to
be deflected further downward, unrestricted by the
limitations of the oxygen cylinder cable A manually
actuated knob, located on the upper right side of the
seat bucket, is connected by a cable to the bellcrank
The knob provides for manual actuation of the oxygen
cylinder in case of malfunction in the normal oxygen
system Pulling the manual actuating knob deflects the
bellcrank downward, pulls the oxygen actuating cable,
fracturing a breakoff nipple within the oxygen cylinder,
and releasing the emergency oxygen supply.
(n) Leak-test
(Refer to subparagraph d.)
oxygen
oxygen
cylinder
(o) Slide pull cable housing (2)
down hose and connector assembly (1), over top of
valve body, and secure with screws and washer (14).
5-21. Emergency Oxygen System Linkage.
An actuating cable from the oxygen cylinder is
attached by three links, a 1/16-inch aluminum shear
rivet, flathead pin, washer and cotter pm, and a quickrelease pin to a bellcrank mounted below the oxygen
cylinder The ejection gun trip rod crossbeam mounted
on the ejection gun barrel holds a quick-release type
striker pin (the same quick-release pin that secures the
time release mechanism trip rod to the ejection gun trip
rod crossbeam} As the seat rises during ejection, a trip
lever is deflected downward when it comes in contact
with the quick release sticker pin and transmits the
deflection to the bellcrank, pulling on the oxygen
cylinder cable, fracturing a breakoff nipple within the
oxygen cylinder, and releasing the oxygen supply (Since
Change 8
(6) Remove upper slotted nut and washer
(21), using screwdriver, Part No 105GT1044 Remove
chain of quick-release pin (25) from bellcrank support
bracket (22).
(7) Using
screwdriver,
Part
No
105GT1044, remove remaining slotted nuts securing
bellcrank support bracket (22) to seat bucket and
carefully slide bracket off shaft (23).
(8) Remove shaft (23) by carefully pulling
out on bellcrank (24) As the shaft slides out of trip lever
guard (18), the trip lever (30) will fall out.
(9) Remove spring (19) from shaft (23)
Separate bellcrank (24) from shaft (23) by drifting out
taper pin (20).
b.
Inspection.
(1) Inspect threaded areas for crossed,
stripped, or worn threads.
5-31
TM 55-1680-30824
(2)
Inspect all metal parts for general
(3)
Inspect cable for fraying, corrosion,
condition.
and kinks.
c.
Repair or Replacement. Replace all parts
found to be defective during inspection.
d.
Installation.
(1) Position bellcrank (24, figure 1-9) on
shaft (23) and secure bellcrank to shaft with taper pin
(20).
5-22. Seat Actuating Jack Mechanism.
The seat actuating jack mechanism provides for
height adjustment of the seat bucket The seat actuating
jack (figure 5-14) is located in back of the seat bucket,
between the vertical beams The shaft end of the
actuating jack is bolted to the 40 g crossmember and
the motor end is attached to the seat bucket A
momentary, three-position toggle switch, located on the
right side of the seat bucket, sends 28 volts dc from the
aircraft electrical system to the actuating jack motor
Depending on the position of the toggle switch, the seat
bucket will raise or lower to the desired position, through
a distance of 4.7 inches of travel.
a.
(2)
Removal.
Place spring (19) over shaft (23).
(3) Position trip lever (30) In a horizontal
position in trip lever guard (18) Slide shaft (23) into trip
lever guard and through trip lever so that trip lever will
be In a horizontal position and rest on the flats of the
shaft The bellcrank (24) must also be in a horizontal
position relative to the trip lever (See detail A, figure 19).
(4) Slide bellcrank support bracket (22)
on shaft (23) Position bracket on studs and secure
bellcrank to lower stud with washer and slotted nut Use
screwdriver, Part No 105GT1044, to Install slotted nut.
(5) Position chain of quick-release pin
(25) on upper stud and secure chain and bracket with
slotted nut and washer (21) Use screwdriver, Part No
105GT1044, to install slotted nut.
(6) Install cable (9) and secure by
positioning actuating knob support bracket (3) on seat
bucket and securing with nuts.
(7) Position manual actuating knob (2) on
cable (9) and secure with washer and nut.
(8) Secure cable conduit (7) to seat
bucket with cable clamps (8), screws, and nuts.
(9) Secure terminal end of cable (9) to
bellcrank (24) with flathead pin (26) and cotter pin (27).
(10) Secure cable link (29) to bellcrank
(24) with quick-release pin (25).
e.
Functional Check. Perform a functional
check on the emergency oxygen system as described in
paragraph 4-6x.
The quick release type striker pin has a knurled
head The quick release pin is longer than other
pins so it will strike the trip lever.
Change 8
(1) Remove connector (8, figure 3-6)
from seat raising actuator (7).
(2) Remove bolts, washers, and locknuts
(1 and 6) and remove seat actuating jack from ejection
seat.
(3) Remove bolt, washer, and nut
securing clamp (4) to seat bucket Remove clamp from
electrical clamp (11).
(4) Remove seat height adjustment
switch (2), insulating plate, and spacer plate from seat
bucket by removing bolts, washers, and locknuts (3).
(5) Disconnect cable leads from seat
height adjustment switch and remove electrical cable
(11).
b.
Disassembly.
(1) Remove nuts (1, figure 5-15) washers
(2), and bolts (3) and separate assembled plate (4), gear
housing (11), and motor (12) as an assembly from
bearing housing.
(2) Remove bearing (5), plate (4), gear
(6), bearings (7 and 8), gear (9), bearing (10), and gear
housing (II) from motor (12).
(3) Remove nuts (13), washers(14), and
bolts(15) and separate bearing housing (22), bearings
(16 and 18), and ring gear (17) as an assembly from
jack housing (25) Remove bearing (16), ring gear (17),
and bearing(18) from bearing housing (22).
(4)
Remove bearing (19), Jackscrew
(20), bearing (21), and plug assembly (26) from Jack
housing (25).
(5) Remove screws (23) and connector
(24) from jack housing (25).
5-32.
TM 55-1680-308-24
c.
Cleaning. Clean all parts with dry cleaning
solvent (item 6, table 1-2) and dry with a clean cloth or
filtered, compressed air.
d.
Inspection.
(1) Inspect gears for cracks and
excessive wear.
Change 8
5-32.1/(5-32.2 blank)
TM 55-1680-308-24
Figure 5-14. Location of seat actuating jack
5-33
TM 55-1680-308-24
(2) Inspect bearings for galling, excessive
wear, and for looseness with mating parts.
(1) Apply 28 volts dc power (20 amperes
minimum) to seat actuating jack mechanism.
CAUTION
(3)
Inspect housings for cracks.
(4)
Inspect all threaded parts for stripped
Do not operate the seat raising actuator more
than 1 minute (maximum) during any 8-minute
period of time Extended operation will shorten
the seat raising actuator service life.
threads.
e.
Repair or Replacement. Repair of the seat
actuating jack mechanism is limited to the replacement
of defective components.
f.
Reassembly.
(1) Secure connector (24, figure 5-15) to
jack housing (25) with screws (23).
(2) Install plug assembly (22), bearing
(19), jackscrew (20), and bearing (21) in jack housing
(25).
(3) Install bearing (18), ring gear (17),
and bearing (16) in bearing housing (22). Secure bearing housing to jack housing (25) with bolts (15), washers
(14), and nuts (13).
(4) Install gear housing (11), bearing (10),
gear (9), bearings (8 and 7), gear (6), bearing (5), and
plate (4) on motor (12).
(5) Secure motor (12), gear housing (11),
and plate (4) to bearing housing (22) with bolts (3),
washers (2), and nuts (1).
g.
(2) Check that seat bucket moves up
when seat height adjustment switch is pushed aft, and
stops when switch is released.
Installation.
(1) Connect leads of electrical cable (11,
figure 3-6) to seat height adjustment switch (2).
(2) Secure spacer plate, insulating plate,
and seat height adjustment switch (2) to seat bucket with
bolts, washers, and locknuts (3).
(3) Check that seat jack motor stops
when seat bucket reaches full up position.
(4) Check that seat bucket moves down
when seat height adjustment switch is pushed forward,
and stops when switch is released.
(5) Check that seat jack motor stops
when seat bucket reaches full down position.
5-23. Time Release Mechanism.
The time release mechanism, mounted on the
upper portion of the right main beam, provides a means
whereby the occupant will be automatically released
from the ejection seat between ground level and 15,500
feet maximum.
The time release mechanism is
actuated by a trip rod attached to the ejection gun trip
rod crossbeam by a quick-release pin which pulls the
time release mechanism sear when the ejection seat is
ejected When 1 65 to 1 85 seconds have elapsed after
the sear is pulled, the following items will be
automatically released harness loop strap attachment,
personnel parachute restraint straps, two rigid seat
survival kit restraint lugs attached to the seat bucket, leg
restraint cord attachment, and the scissor-restrained
drogue shackle A barostatic control incorporated in the
time release mechanism prevents the timing
mechanism from operating until the ejection seat has
descended to a pre set altitude of 15,500 to 14,000 feet
optimum
(3) Install clamp (4) on electrical cable
(11) and secure clamp to seat bucket with bolt, washer,
and nut.
a.
Removal.
(1)
(4) Secure seat actuating jack to ejection
seat with bolts, washers, and locknuts (1 and 6).
Ensure the time release mechanism is
cocked.
WARNING
(5)
actuator (7).
h.
Install connector (8) to seat raising
Keep hands clear of area below time release
mechanism plungers. Plungers extend with
great force.
Maintenance Operational Check.
.
Change 2
5-34
TM 55-1680-308-24
Figure 5-15. Seat actuating jack mechanism - exploded view
5-35
TM 55-1680-308-24
(2) Disconnect bungee from time release
mechanism trip rod (2, figure 4-7).
(3) Carefully support time
mechanism and remove three mounting bolts.
release
(4) Slide time release mechanism down
while turning it outward, or: 1y as much as necessary,
until upper plunger rod is clear of guard and guide tubes.
CAUTION
Use caution when removing time release mechanism to
prevent bending the upper plunger rod In the scissor
release plunger housing.
b.
Cleaning. Clean time release mechanism
using :. clean cloth slightly moistened with drycleaning,
solvent (item 6, table 1-2). Remove all traces of dry
solvent using a clean, dry cloth.
c.
CAUTION
Do not allow foreign materials to contaminate
internal time release mechanism gears. Do not
add lubricant to internal mechanisms.
(2)
Remove barostat assembly.
(3)
Install
new
barostat
assembly
handtight.
(4) Perform barostat operational check in
accordance with paragraphs 4-6l(3) or 4-6l(4), as
applicable.
(5)
f.
Lockwire serviceable barostat.
Installation. (See figure 4-35.)
(1) Ensure serviceable time
mechanism is being installed on ejection seat.
Inspection.
release
NOTE
Do not install If overage (refer to para 4- 8).
(1) Inspect time release mechanism for
loose or missing hardware.
(2) Inspect time release mechanism for
cracks and corrosion.
(2) If a replacement time release
mechanism is to be installed, check that lockwire on
barostat assembly is in proper condition before
installation.
(3) Ensure cotter pin properly retains
coverplate on side of time release mechanism.
cocked.
(4) Ensure serrated capsule housing cap
is properly secured with lockwire.
(3)
Ensure time release mechanism is
(4) Remove slack from harness release
plunger rod by carefully depressing rod until it bottoms
out.
d. Test.
(1) Perform a time delay operational
check in accordance with paragraph 4-6l(1).
(5) Insert harness release plunger rod
into guard and guide tube on ejection seat. Slide time
release mechanism upward, being careful not to bend
the harness release plunger rod.
(2) Test time release mechanism m
accordance with paragraph 4-6l(2).
WARNING
(3) Perform
a
standard
barostat
operational check in accordance with paragraphs 4-6l(3)
or 4-6 l (4), as applicable
Keep hands clear of area below time release
mechanism plungers. Plungers extend with
great force.
(6) Carefully support time
mechanism and install three mounting bolts.
e. Barostat Replacement.
(1)
Cut lockwire securing barostat to time
release housing
(7) Connect bungee to time release
mechanism trip rod (2, figure 4-7).
g.
Maintenance Operational Check.
(1)
accordance
Change 2
release
5-36
Cock time release mechanism in
with
paragraph
4-6ad(10).
TM 55-1680-308-24
(2) Functionally check time release
mechanism in accordance with paragraph 4-6ad.
h.
Standard Barostat Adjustment.
(1) The following applies when using the
Vacuum Test Box (TDO 1153).
(a)
barostat assembly.
Remove
barostat
cap
from
NOTE
The lock wire securing the barostat to the time
release mechanism body should not be
removed.
(b) Loosen nut which secures the
clamp to the capsule stack adjustment screw.
NOTE
Loosen the nut sufficiently to enable the capsule
stack to be turned with a well fitting screwdriver.
If too loose, large test variations will occur as a
result of subsequent lock nut tightening after
altitude adjustment.
(c) With lock nut loosened, insert
time release mechanism into vacuum test box with
barostat cap removed.
(g) Accomplish
altitude
tests
and
continue adjustment as necessary until desired release
altitude is attained.
NOTE
Tightening the barostat adjustment screw
clamping nut after testing will decrease the
altitude approximately 500 feet Therefore this
after-test change should be considered when
adjustments are being made.
(h) Repeat altitude test two additional
times to confirm release altitude.
(i)
Remove time release mechanism
from vacuum chamber and tighten adjustment screw
lock nut and install cap finger tight.
(j)
Repeat altitude test three additional
times after tightening lock nut to confirm final
adjustment.
(k)
Remove time release mechanism
from vacuum chamber, tighten barostat cap and safety
wire.
(2) The following applies when using the
barostat adapter assembly (105GT1030) with external
vacuum motor.
Exercise care whenever the barostat cap is
removed to preclude liquid contamination of
exposed surfaces.
Do not remove lock wire securing barostat to
time release mechanism body until after
barostat cap has been loosened.
(d) Evacuate the vacuum chamber
to the prescribed altitude. Refer to paragraph 4-6l(4).
(a) Remove lock wire from barostat
cap and loosen cap. Remove lock wire securing
barostat to time release mechanism body.
NOTE
If a new barostat is being adjusted, accomplish
three altitude checks to establish initial setting
before attempting adjustment.
(e) While viewing through the
chamber lid, carefully insert adjustment screwdriver into
the slot in the barostat adjustment screw.
(f)
If initial test altitude readings
were too high (15,000 to 15,500 feet), turn the
adjustment knob clockwise to DECREASE altitude
release point; turn counter clockwise to retract or
INCREASE altitude release point.
NOTE
Safety wire must be removed from barostat and
time release mechanism body to assure good fit
of vacuum test cup to body face.
(b) Remove barostat cap and
loosen nut which secures clamp to the capsule stack
adjustment screw.
NOTE
Loosen the nut sufficiently to enable the capsule
stack to be turned with a well fitting screwdriver.
If too loose, large variations will occur as a
result of subsequent lock nut tightening after
altitude adjustment.
NOTE
A one-eighth turn of the adjustment screw will
alter release altitude approximately 700 feet.
Change 2 5-37
TM 55-1680-308-24
withdrawal line. The guillotine system consists of the
following components interconnecting link- age and
operating levers to the manual override system, breech
assembly, flex lines and piping, and the guillotine blade
assembly.
NOTE
If a new barostat is being adjusted, accomplish
three altitude checks to establish initial setting
before attempting adjustment.
(c)
If initial test altitude readings were too
high (15,000 to 15,500 feet), insert well-fitting
screwdriver into adjusting screw slot and turn clockwise
to DECREASE altitude release point; turn counter
clockwise to retract or INCREASE altitude release point.
NOTE
A one-eighth turn of the adjustment screw will
alter release altitude approximately 700 feet.
(d) Install barostat adapter cup over
barostat and begin vacuum testing Refer to paragraph
4-61(3).
Exercise care whenever the barostat cap is
removed to preclude liquid contamination of
exposed surfaces.
Before attempting to disarm the guillotine
breech assembly, install ground safety lock
streamer assembly, Part No. 134SEME10053,
into firing pin sear. With safety pin installed in
firing pin sear of the guillotine firing mechanism,
push the sear upward as far as possible and
remove manual override link rod. Remove
lockwire from breech assembly and tab washer
on seat bucket Carefully unscrew the breech
housing Use extreme caution when removing
and handling cartridge, since cartridge has a
percussion-type pressure cap.
Remove
guillotine cartridge from breech assembly.
NOTE
For handling of cartridge, refer to TM 9-1300206.
(e) Accomplish altitude tests and
continue adjustment as necessary until desired release
altitude is attained.
NOTE
Tightening the barostat adjustment screw clamp
nut after testing will decrease the altitude
approximately 500 feet. Therefore this after-test
change should be considered when adjustments
are being made.
(f)
Repeat
altitude
additional times to confirm release altitude.
test
two
(g)
Remove barostat adapter cup,
tighten adjustment screw clamp nut and install barostat
cap finger tight.
(h) Repeat altitude test three
additional times after tightening lock nut to confirm the
final adjustment.
(i)
Lock wire barostat cap and
barostat.
5-24. Guillotine System.
The guillotine system provides a method of
cutting the withdrawal line and separating the personnel
parachute from the drogue system. Operation of the
manual override handle causes a cartridge to be fired
Gas pressure produced by the exploding cartridge
actuates the guillotine blade which severs the
a.
Removal.
(1) Remove thigh supports from leading
edge of ejection seat (Refer to paragraph 5-30a).
(2) Disconnect link assembly (19, figure
5-16) from manual override handle (17) by removing
cotter pin (16) and flathead pin (18).
(3) Disconnect lower pipe assembly (6)
from initiator housing (20) at nut fitting (22).
(4) Remove nuts (24), washers (23), and
bolts (21) securing initiator housing (20) and remove
initiator housing.
(5) Remove nuts (25), washers (26), and
bolts (28) from clamps (27) securing lower pipe
assembly (6). Remove clamps.
(6) Remove nuts (5) and washers (4)
from plate (3) over lower pipe assembly (6) and remove
plate.
(7) Disconnect lower pipe assembly (6)
from hose assembly (1) at nut fitting (2) and remove
lower pipe assembly (6).
(8) Disconnect hose assembly (1) from
guillotine assembly (10) at nut fitting (11).
Change 5 5-38
TM 55-1680-308-24
(9) Remove nuts (9), washers (8), and
bolts (7) securing guillotine assembly (10) to seat and
remove guillotine.
(10) Remove nuts (15), washers (14), and
bolts (13) securing clamps (12) and hose assembly (1).
Remove clamps and hose assembly.
b.
threads.
(2) Inspect interconnecting linkage and
operating levers for cracks, corrosion, distortion,
elongated holes, and for bright areas indicating binding.
(3) Inspect linkage rod ends and all cotter
pins for security.
Cleaning.
(1) Clean all removed components in dry
cleaning solvent (item 6, table 1-2).
(2) Dry components with clean, filtered,
compressed air.
(4) Inspect cartridge breech assembly for
damage or deterioration.
(5) Inspect guillotine blade assembly for
scoring, gouges, cracks, and cleanliness.
d.
c.
Repair or Replacement.
Inspection.
(1)
Inspect all hardware for stripped
Change 2
(1) Replace all tapered pins removed
during disassembly.
5-38A
TM 55-1680-308-24
Figure 5-16. Guillotine system
Change 2
5-38B
TM 55-1680-308-24
(2) Replace any worn, distorted, or
mutilated operating levers and interconnecting linkage.
(3) Replace any
defective during inspection.
e.
component
(5) Secure lower pipe assembly (6) with
clamps (27), bolts (28), washers (26), and nuts (25).
found
Lubrication.
(6) Install and connect hose assembly (1)
to guillotine assembly (10) at nut fitting (11). Torque to
280 to 300 inch pounds.
(1) Apply lubricating grease (item 5, table
1-2) to all working parts of the guillotine system during
assembly.
(7) Connect lower pipe assembly (6) to
hose assembly (1) at nut fitting (2). Torque to 280 to
300 inch pounds.
(2) Apply a light coat of lubricating oil
(item 2, table 1-2) to interconnecting linkage and
operating levers.
(8) Install plate (3) on studs and over
lower pipe assembly (6) and secure with washers (4)
and nuts (5) Tighten hand tight.
f.
(9) Secure hose assembly (1) with
clamps (12), bolts (13), washers (14), and nuts (15).
Installation
WARNING
Use extreme caution when handling and
installing guillotine cartridge into breech
housing, as cartridge has a percussion-type
pressure cap Ensure that firing pin does not
protrude above bottom surface of firing body
hole. A physical check is required.
Install ground safety lock streamer assembly,
Part No 134SEME10053, into firing pin sear
With safety pin installed in firing pin sear of the
guillotine firing mechanism, push the sear
upward as far as possible and install manual
override Ink rod.
Carefully screw In the breech assembly Safetywire breech assembly to tab washer on seat
bucket.
(10) Install thigh supports on leading edge
of ejection seat (Refer to paragraph 5-30c.)
5-25. Tip-Off Compensating Rocket
(M119) and Mounting Brackets
(TCR) Motor
A M119 attached to the bottom of the ejection
seat is fired Immediately after ejection The thrust of the
rocket positions the seat in the correct attitude for safe
firing of the drogue chute The TCR initiator is attached
to a cable approximately 64 inches long One end of the
cable is attached to the stationary catapult crossbeam
causing the cable dispenser to feed out the cable as the
seat rises. When the cable has been completely fed out,
the initiator Is triggered and ignites the M119.
a.
Removal.
WARNING
NOTE
Check spring balance on safety guard. A
disturbing load of 6 to 8 pounds must be
obtained.
Ensure
rocket safety lock
streamer
134SEME10054 is installed before removing
rocket motor.
(1)
Install and secure guillotine assembly
(10, figure 5-16) with bolts (7), washers (8), and nuts (9).
(1) Disconnect connector (27, figure 517) at top of TCR motor (25) by turning
counterclockwise.
(2) Install initiator housing (20) and
secure with bolts (21), washers (23), and nuts (24).
(2)
bumper (19).
(3) Swing link assembly (19) up to
manual override handle (17) and secure to handle with
flathead pin (18) and cotter pin (16).
(3) Remove nut (20), lockwasher (21)
and bolt (23) securing clamp (24) with initiator cable (22)
to bumper (19).
(4) Install and connect lower pipe
assembly (6) to intiator housing (20) at nut fitting (22)
and tighten nut fitting on lower pipe assembly to torque
of 400 inch-pounds.
Change 3
(4) Remove bolts (16) and lockwashers
(17) and remove front support strap (18).
5-39
Remove
screws
(10)
securing
TM 55-1680-308-24
Figure 5 - 17 TCR motor and mounting brackets (Sheets 1 of 2)
5-40
TM 55-1680-308-24
KEY to Figure 5-17
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Right mounting bracket
Bolt
Lockwasher
Nut
Left mounting bracket
Lockwasher
Bolt
Nut
Lockwasher
Screw
11. Bolt
12. Lockwasher
13. Front support angle
bracket
14. Bolt
15. Front support block
16. Bolt
17. Lockwasher
18. Front support strap
19. Bumper
20.
21.
22.
23.
24.
25.
26.
Nut
Lockwasher
Initiator cable
Bolt
Clamp
TCR motor (M119)
Rocket safety lock streamer
locking pin
27. Connector
Figure 5-17 TCR motor and mounting brackets (Sheet 2 of 2)
(5) Support TCR motor (25) and remove
bolts (7) and lockwashers (6) Remove TCR motor.
container dropped more than 4 feet will be
considered unserviceable.
(6) Remove bolts (11) and lockwashers
(12) and remove front support block (15).
(5)
Install bolts (7) and lockwashers (6)
through brackets (I and 5) and secure rocket motor (25)
Tighten to a torque of 95 110 Inch-pounds.
(7) Remove nuts (8), lockwashers (9) and
bolts (14) and remove front support angle brackets (13).
(6) Install front support strap (18) on
rocket motor (25) and against front support block (15),
align holes and secure with bolts (16) and lockwashers
(17).
(8) Remove nuts (4), lockwashers (3) and
bolts (2) and remove left and right mounting brackets (5
and 1).
NOTE
If necessary, adjust front support block (15) by
loosening bolts (11) Secure after positioning.
b.
Repair or Replacement Repair of the tip-off
compensating rocket motor and mounting brackets is
limited to replacing defective components.
(7) Secure initiator cable (22) with clamp
(24) on bumper (19) with bolt (23), lockwashers (21),
and nut (20).
c.
Installation.
(1) Position right and left mounting
bracket (1 and 5, figure 5-17) In place, align holes and
secure with bolts (2), lockwashers (3), and nuts (4).
(8) Place bumper (19) over rocket motor
(25) and inside right and left mounting brackets (1 and
5), align holes and secure with screws (10).
(2) Align front support angle brackets (13)
and secure with bolts (14), lockwashers (9), and nuts (8).
WARNING
(3) Install front support block (15)
between front support angle brackets (13) and secure
with bolts (11) and lockwashers (12).
Prior to connecting the initiator cable connector,
assure that a 7 to 7 5 inch diameter loop is
formed by the initiator cable and that initiator
cable is not loosely routed along the main
beams.
WARNING
Ensure rocket safety lock streamer locking pin is
installed before installing TCR motor.
(9) Connect initiator cable connector (27)
to TCR motor (25) by turning clockwise.
(4)
Position TCR motor (25) against
front support block (15) and align with holes In right and
left mounting brackets (1 and 5).
Ensure cable ball-end makes positive contact
with the rocket initiator ball socket.
WARNING
Rocket motor assemblies out of their respective
5-41
TM 55-1680-308-24
5-26. Tip-Off Compensating Rocket Cable
Dispenser.
(4) Connect initiator cable assembly (3)
to TCR cable dispenser (2) by turning clockwise.
WARNING
(5) Lockwire initiator cable receptacle to
TCR cable dispenser housing.
Install safety lock streamer 134SEME10054 into
TCR initiator before attempting any replacement
actions of TCR cable dispenser.
5-27 Tip-Off Compensating Rocket Initiator Cable.
The TCR initiator cable is connected to the TCR
cable dispenser by a ball socket and receptacle
dispenser and to the M119 rocket initiator by means of a
ball socket and receptacle dispenser The pull force of
the dispenser cable is transmitted by the initiator cable
to the TCR initiator After approximately one-half inch of
pull travel, the initiator cable mechanically disconnects
from the receptacle dispenser cable at the dispenser
housing.
The TCR cable dispenser, mounted on the
ejection seat, leeds out a cable connected to the drogue
gun trip rod. Another mechanical cable (Initiator cable)
is connected from the dispenser to the TCR motor
When the seat rises, the drogue gun trip rod causes the
TCR cable to be completely fed out (approximately 64
inches). The TCR cable pulls the initiator cable
assembly, which is connected to the TCR motor initiator
When the initiator is triggered (pulled), the TCR is
ignited.
WARNING
a.
Reinstall.
Install safety lock streamer pin 134SEME10054
Into initiator before attempting any work on the
initiator cable assembly. Accidental triggering
of initiator will ignite the M119 rocket
(1) Disconnect initiator cable assembly (3
figure 5-18) from TCR cable dispenser (2) BY turning
counter clockwise.
a. Removal.
(2) Remove TCR cable (6) from drogue
gun trip rod (8) by removing Lotter pill (7) and flathead
pin (5).
(1) Disconnect initiator cable assembly
(3, figure 5-18) from the cable dispenser by turning
connector counterclockwise and removing cable.
(3) Remove
lamp (10) from cable
assembly (3) by removing nut (9) and screw (14).
(4) Support TCR cable dispenser (2),
remove nut (4) and screw (I) and remove dispenser.
(2) Remove clamps (10 and 12) from
cable housing by removing nuts (9 and 13) and screws
(11 and 14).
b.
Repair or Replacement. Repair of the tipoff compensating rocket cable dispenser is limited to
replacing defective components.
(3) Disconnect Initiator cable from rocket
initiator by turning connector counterclockwise and
removing cable.
c.
b.
Repair or Replacement Repair of TCR
initiator cable is limited to replacement of the cable
assembly.
Installation.
(1) Position TCR cable dispenser (2,
figure 5-18) on seat, align holes and secure with screw
(1) and nut (4).
c.
Installation.
(2) Place clamp (10) on Initiator cable
assembly (3) and secure lamp (10) and TCR cable
dispenser with screw (14) and nut (9).
( 1) Position Initiator cable ball end into
the dispenser disconnect ball socket and tighten
receptacle dispenser by turning clockwise.
(3) Connect TCR cable (6) to drogue gun
trip rod (8) with flathead pin (5) and cotter pin (7).
(2)
Form a 3 to 4 inch diameter arc with
cable and install clamp (10).
WARNING
(3) Install clamp (12) on initiator cable
assuring the cable assembly Is snugly routed along the
main beam to the seat bucket.
Assure a 3 to 4 inch diameter arc is formed by
the initiator cable assembly between the
dispenser and clamp (10).
5-42
TM 55-1680-308-24
Figure 5-18. TCR cable dispenser removal
5-43
TM 55-1680-30824
ejection, the slippers maintain vertical alignment of the
ejection seat to the ejection gun until the ejection seat
and occupant have cleared the aircraft.
WARNING
Provide a 7 to 7 5 inch diameter loop in the
initiator cable assembly between the seat bucket
clamp and TCR Initiator to assure positive pull
force transmission to the rocket initiator.
a.
Removal. Remove top slippers (5), middle
slippers (12), and bottom slippers (10) from left and right
main beams (7 and 11) by removing nuts and washers
(4) Form a generous loop with excess
cable and position ball end into the Initiator ball socket
Tighten connector by rotating clockwise.
b.
Repair. Repair of the slippers consists of
removal of metal burrs from upper and lower slippers by
filing and smoothing Metal burrs on upper and lower
slippers may be removed provided edge radius is not
altered Metal burrs or gouges in the middle slipper
edges is cause for replacement.
Ensure cable ball end makes positive contact
with the ball socket.
(5) Safety the connector to the Initiator
housing and safety the upper connector to the dispenser
housing.
If any doubt exists concerning extent of damage
on any slipper, the slipper shall be replaced with
a new item.
5-28. Sticker Clips.
c. Installation.
Sticker clips are riveted to the outside of the seat
bucket side skin and provide attachment for the rigid
seat retention assembly sticker straps The sticker clips
maintain a 20 to 50 pound spring pressure on the sticker
straps to provide temporary restraint for the occupant in
the ejection seat after the harness and rigid seat
retention assembly are unlocked during ejection.
(1) Secure top slippers (5 figure 1-3),
middle slippers (12), and bottom slippers (10) to right
and left main beams (7 and 11) with washers and nuts.
(2) Tighten slipper nuts to a torque of 50
to 60 inch-pounds.
a.
Removal. Drill out four rivets securing
sticker clip to seat bucket and remove sticker clip.
5-30. Thigh Supports
b.
Installation. Position sticker clip to outside
surface of seat bucket side skin and secure with four
rivets.
The thigh supports are located on the leading
edge of the seat pan.
a. Removal.
c.
Maintenance Operational Check.
(1) Remove
thigh support pads by
opening zippers on both pads, connecting pads to seat
cushion, and pulling pads off thigh supports.
(1) Ensure sticker strap lugs are in their
respective spring clips on each side of seat bucket
assembly.
(2) Remove screws (figure 5-19) securing
thigh supports to thigh support brackets and remove
thigh supports.
(2) Check each spring clip for extraction
tension by attaching a spring scale to strap end of
sticker strap lugs and pulling on spring scale until each
lug releases from its spring clip (See figure 4-17).
b.
Cleaning.
(1) Spot-clean thigh supports using a
solution of 1 to 4 ounces of detergent (hand dishwashing
compound) to I gallon of water and apply sparingly.
NOTE
Release tension must be 35 +15 pounds.
5-29. Ejection Seat Slippers.
(2)
The inboard side of each main beam is fitted with three
rectangular slippers (5, 10, and 12, figure 1-3). The
slippers are bolted through the beams and are aligned
vertically so that they slide within the ejection gun guide
rails to provide the ejection seat with a firm ejectable
support without excessive lateral movement. On
Rinse cleaned area with clear water.
c.
Repair or Replacement. Replacement is
required if thigh supports are found defective during
inspection.
5-44
TM 55-1680-308-24
Figure 5-19. Thigh support removal
d.
Installation.
c
(1) Align thigh supports (figure 5-19) on
thigh support brackets and secure with screws.
(2) Replace thigh support pads by
zippering both pads to seat cushion and pressing pads
firmly to thigh supports velcro strips.
Installation
(1) Place roller (5, figure 5-20) between
right and left brackets (2 and 3) and align holes.
(2) Install screw (1) through right and left
brackets (2 and 3) and roller (5) and secure with nut (4).
5-31. Backplate Roller.
(3)
Ensure roller (5) rotates freely after
installation.
The backplate roller is located between two
brackets on the front of the seat behind the back
cushion.
a.
Removal.
(1) Remove nut (4, figure 5-20) from
screw (1) in right and left brackets (2 and 3).
(2) Hold roller (5) and slip screw (1) out of
right and left brackets (2 and 3) Remove roller (5) and
screw (1).
5-32. Ejection Seat and Ejection Gun Identification
Number.
The ejection seat and ejection gun identification
number is stenciled on their respective components to
facilitate accident investigation, ground handling, and
maintenance The identification number consists of the
symbol A/C followed by the aircraft serial number (less
fiscal designation) followed by a hyphen and the letter P
(pilot seat) or CP (copilot or observer seat) in 1/2-inch
high white letters Application should be accomplished in
accordance with figure 5-21.
b.
Repair or Replacement Replace roller if
found defective during inspection.
Change 6
5-45
TM 55-1680-308-24
Figure 5-20. Backplate roller
5-46
TM 55-1680-308-24
Figure 5-21. Ejection seat and ejection gun identification number location
5-47
TM 55-1680-30824
Section II. PREPARATION FOR STORAGE AND RESHIPMENT
(2)
5-33. Uncrating, Unpacking, Storage, and Reshipment
Instructions.
The following instructions are for complete
uncrating, unpacking, storage, and reshipment of the MKJSD Ejection Seat.
Remove packing straps.
(3) Remove red circled screws and corner
gussets in top of shipping container and remove cover.
(4) Remove two nuts and two washers
from bolts securing upper seat brace to shipping
container.
(5) Withdraw two bolts and remove upper
seat brace from shipping container.
Observe handling instructions printed on outside
of shipping container.
(6) Remove four screws from each block
securing lower seat brace.
a. Uncrating. (See Figure 5-22) To uncrate the
MK-JSD Ejection Seat, proceed as follows:
(7) Remove blocks and withdraw lower
seat brace from shipping container.
(1) Place shipping container in horizontal
position, facing up.
Figure 5-22. Ejection seat in container
5-48
TM 55-1680-308-24
(8) Remove two nuts and two washers and
withdraw two bolts securing wedge at top of ejection
seat. Remove wedge. (See figure 5-23.)
WARNING
Exercise care when lifting seat from
shipping container Shipping weight of
seat is approximately 125 pounds
(9) Remove ejection seat from shlppmg
container, lifting top of seat first, and place seat on
secure flat surface.
b Unpacking. (See figure 5-24) To unpack the MKJSD Ejection Seat, proceed as follows
(1) Open plastic bag at top of seat only and
remove seat from plastic bag.
(2) Remove items included with seat shipment
(Refer to table 5-2.)
NOTE
Retain plastic bag and two sacks of
desiccant from ejection seat bucket, for
use in repacking.
(3)
Remove remainder of wrappings from seat.
(4) Slide seat cradle mounting rail into position
on seat back and secure upper and lower quick release
pins.
(5) Mount ejection seat on seat cradle (See
figure
5-25 )
c. Storage. The methods and materials used in the
preparation of the MK-J5D Ejection Seat for storage are
identical with the methods and materials used in
preparing the ejection seat for reshipment
d.Reshipment. The following instructions for
preparation of the MK-J5D Ejection Seat for reshipment
are applicable to the Organizational level of
maintenance
(1) Place shipping pallet (figure 5-26) on level
area and locate ejection seat on top of shipping pallet.
Figure 5-23. Wedge at head of seat (in position)
5-49
TM 55-1680-308-24
Figure 5-24. Election seat with outer wrapping removed
(2) Install items listed in table 4-3 and two
sacks of desiccant in seat bucket. (Sacks of desiccant
were retained when seat was unpacked).
(3) Wrap seat securely in sheet of plastic (See
figure 5-24.)
(4) Insert seat in plastic bag. (Plastic bag which
was retained when seat was unpacked.)
(6) Install wedge at top of ejection seat (figure
5-23) Install two bolts, two washers and nuts to secure
wedge.
(7) Install lower seat brace (figure 5-22) and
secure each seat brace block with four screws.
(8) Install upper seat brace (figure 5-22) and
secure with bolts, washers, and nuts.
(9) Install shipping container cover and secure
with screws in red circles on cover.
WARNING
Exercise care when lifting seat. Shipping
weight of seat Is approximately 125 pounds.
(10) Install packing straps.
5-34. Repair Parts and Special Tools.
(5) Insert ejection seat, bottom first, into
shipping container.
Refer to TM 55-1510-204-23P, Appendix A.
Change 8
5-50
TM 55-1680-308-24
Table 5-2. Items Included With Seat Shipment
Nomenclature
Part No
Quantity
Handwheel
MBEU/26528
1
Retaining collar
MBEU/16711
1
Leg garter
MBEU/8507
1
Leg garter
MBEU/30-J5
1
Top latch plunger
MBEU/26609
1
Top latch plunger spring
MBEU/6617
1
Drogue shackle
MBEU/5940
1
Shackle bolt
MBEU/12064
1
Shackle nut
A 1264
1
Floor bracket
MBEU/3666
2
Quick-release pin
MBEU/1434
2
Quick-release pin
MBEU/3325
1
Quick-release pin
MBEU/3921
1
Operating rod
MBEU/400-24
1
Pin
SP4Y A2
2
Bushing for manual
override handle
MBEU/1081GRU5
Link
MB400-54
1
Pin
SP4Y-A3
1
Split pin
SP9-C4
3
Double cleat
MBEU/186J5
1
Mushhead bolt
A 133 1/2C
1
Stiffnut
A 126-C
1
Washer
SP.122-C
1
5-51
TM 55-1680-308-24
Figure 5-25. Ejection seat cradle part no. 105GT1040
Figure 5-26. Shipping Pallet for MK-J5D ejection seat
5-52
TM 55-1680-308-24
CHAPTER 6
DIFFERENCE DATA SHEETS
(Not Applicable)
Since only one model of the ejection seat is to be covered in this
manual, Difference Data Sheets are not applicable
6-1/(6-2 blank)
TM 55-1680-308-24
APPENDIX A
REFERENCES
NO.
TITLE
TM 9-1300-206
Care, Handling, Preservation and Destruction of Ammunition
TM 9-1377-200-20&P
Organizational Maintenance Manual (Including Repair Parts and Special
Tools List) Cartridges, Cartridge Actuated Devices and Propellant Actuated Devices
TM 10-1670-250-20
Organizational Maintenance Manual (Including Repair Parts and
Special Tools List) Parachute System used with Martin Baker MKJ5D Ejection Seat
TM 43-0001-39
Army Data sheets for Cartridges, Cartridge Actuated Devices and Propellant
Actuated Devices
TM 55-1500-204-25/1
General Aircraft Maintenance Manual
TM 55-1510-204-10/3
Operator's Manual' OV-1B Aircraft
TM 55-1510-204-10/4
Operator's Manual: OV-1C Aircraft
TM 55-1510-204-23P
Aviation Unit and Intermediate Maintenance Repair Parts and
Special Tools List (Including Depot Maintenance Repair Parts and
Special Tools)
TM 55-1510-213-10
Operator's Manual: OV-1D/RV-1D Aircraft
TM 55-1510-204-23
Aviation Unit and Intermediate Unit Maintenance Manual
OV-1B/OV-1C Aircraft
TM 55-1510-213-23
Aviation Unit and Intermediate Unit Maintenance Manual
OV-1D/RV-1D Aircraft
TM 55-1510-217-PMD
OV-1B, OV-1C, OV-1D and RV-1D Aircraft Preventive Maintenance Daily
TM 55-1510-217-PM
OV-1/RV-1 Series Aircraft Phased Maintenance Checklist.
DA PAM 738-751
Functional Users Manual for the Army Maintenance Management System Aviation (TAMMS-A)
Change 8
A-1/(A-2 blank)
TM 55-1680-308-24
APPENDIX B
BASIC ISSUE ITEMS LIST
(Not Applicable)
B1/(B-2 blank)
TM 55-1680-308-24
APPENDIX C
PRELIMINARY MAINTENANCE ALLOCATION CHART
C-1. General.
a.
The Maintenance Allocation Chart assigns
maintenance functions to the lowest level of
maintenance based on past experience and the
following consideration,
(2) If the lower level will require assistance or
technical supervision and on-site inspection.
(3)
If the authorization will be granted,
(1)
Skills available
(2)
Time required
g. Changes to the Maintenance Allocation Chart
will be based on continuing evaluation and analysis by
responsible technical personnel and on reports received
from field activities.
Tools and test equipment required and
C-2. Definitions.
(3)
available,
b. Only the lowest level of maintenance authorized
to perform a maintenance function is indicated.
a. Inspect To determine serviceability of an item
by company its physical, mechanical, and electrical
characteristics with established standards.
c. A maintenance function assigned to a
maintenance level will automatically be authorized to be
performed at any higher maintenance level.
b Test To verify serviceability and to detect
electrical or mechanical failure by the use of test
equipment.
d. A maintenance function that cannot be
performed at the assigned level of maintenance for any
reason may be evacuated to the
next
higher
maintenance organization. Higher maintenance levels
will perform the maintenance functions of lower
maintenance levels when required or directed by the
appropriate commander.
c. Service To clean, to preserve, to charge, and to
add fuel, lubricants, cooling agents, and air.
e. The assignment of a maintenance function will
not be construed as authority to carry the associated
repair parts in stock. Authority to requisition, stock, or
otherwise secure necessary repair parts will be as
specified in the repair parts appendix.
f. Normally there will be no deviation form the
assigned level of maintenance In cases of operational
necessity, maintenance functions assigned to a
maintenance level may, on a one-time basis and at the
request of the lower maintenance level, be specifically
authorized by the maintenance officer of the level of
maintenance to which the function is assigned. The
special tools, equipment, etc., required by the lower
level of maintenance to perform this function will be
furnished by the maintenance level to which the function
is assigned. This transfer of a maintenance function to
a lower maintenance level does not relieve the higher
maintenance level of the responsibility of the function.
The higher level of maintenance has the authority to
determine.
(1)
the work.
d. Adjust To rectify to the extent necessary to bring
into proper operating range.
e. Align To adjust specified variable elements of
an item to bring to optimum performance.
f. Calibrate To determine the corrections to be
made in the readings of instruments or test equipment
used in precise measurement.
Consists of the
comparison of two instruments, one of which is a
certified standard of known accuracy, to detect and
adjust any discrepancy in the accuracy of the instrument
or test equipment being compared with the certified
standard.
g Install To set up for use in an operational
environment such as an emplacement, site, or vehicle
h. Replace To replace unserviceable items with
serviceable assemblies, subassemblies, or parts
I. Repair
To restore an item to serviceable
condition through correction of a specific failure or
unserviceable condition. This includes, but is not limited
to, inspection, cleaning, preserving, adjusting, replacing,
welding, riveting, and strengthening
If the lower level is capable of performing
Change 6 C-1
TM 55-1680-308-24
j
Overhaul To restore an item to a completely
serviceable condition as prescribed by maintenance
serviceability standards prepared and published for the
specific item to be overhauled.
Maintenance levels higher than the level of
maintenance marked by the symbol are authorized to
per- form the indicated function. b. The symbol % %
applies to organizational maintenance and indicates that
the particular maintenance function may be performed
provided it is specifically authorized by the direct
support maintenance officer. In no case will the direct
support maintenance officer require the accomplishment
of a % % maintenance function by an organization or
unit and in no case will a % % function authorize
stockage of parts at organization level.
k. Rebuild To restore an item to a standard as
nearly as possible to the original or new condition m
appearance, performance, and life expectancy. This is
accomplished through the maintenance technique of
complete disassembly of the item, inspection of all parts
or components, repair or replacement of worn or
unserviceable
elements
(Items)
using
original
manufacturing tolerances and specifications, and
subsequent reassembly of the item.
c. The symbol (*) in column 3 and 4 of the MAC
denotes that a special tool is required to perform the
indicated maintenance function.
C-3. Symbols.
d. The symbols (1 and 2) in column 3 of the MAC
refer to footnotes on page (C-10) of the MAC.
a. The symbols 0, F, H, and D represent
Organizational maintenance (O), Direct Support
maintenance (F), General Sup- port maintenance (H),
and Depot maintenance (D) and when placed on the
Maintenance Allocation Chart, indicates the lowest level
of maintenance responsible for performing the particular
maintenance function.
C-2
TM 55-1680-308-24
C-3
TM 55-1680-308-24
C-4
TM 55-1680-308-24
C-5
TM 55-1680-308-24
C-6
TM 55-1680-308-24
C-7/C-8 blank)
The Metric System and Equivalents
Linear Measure
Liquid Measure
1 centiliter = 10 milliters = .34 fl. ounce
1 deciliter = 10 centiliters = 3.38 fl. ounces
1 liter = 10 deciliters = 33.81 fl. ounces
1 dekaliter = 10 liters = 2.64 gallons
1 hectoliter = 10 dekaliters = 26.42 gallons
1 kiloliter = 10 hectoliters = 264.18 gallons
1 centimeter = 10 millimeters = .39 inch
1 decimeter = 10 centimeters = 3.94 inches
1 meter = 10 decimeters = 39.37 inches
1 dekameter = 10 meters = 32.8 feet
1 hectometer = 10 dekameters = 328.08 feet
1 kilometer = 10 hectometers = 3,280.8 feet
Square Measure
Weights
1 sq. centimeter = 100 sq. millimeters = .155 sq. inch
1 sq. decimeter = 100 sq. centimeters = 15.5 sq. inches
1 sq. meter (centare) = 100 sq. decimeters = 10.76 sq. feet
1 sq. dekameter (are) = 100 sq. meters = 1,076.4 sq. feet
1 sq. hectometer (hectare) = 100 sq. dekameters = 2.47
1 centigram = 10 milligrams = .15 grain
1 decigram = 10 centigrams = 1.54 grains
1 gram = 10 decigram = .035 ounce
1 decagram = 10 grams = .35 ounce
acres
1 hectogram = 10 decagrams = 3.52 ounces
1 kilogram = 10 hectograms = 2.2 pounds
1 quintal = 100 kilograms = 220.46 pounds
1 metric ton = 10 quintals = 1.1 short tons
1 sq. kilometer = 100 sq. hectometers = .386 sq. mile
Cubic Measure
1 cu. centimeter = 1000 cu. millimeters = .06 cu. inch
1 cu. decimeter = 1000 cu. centimeters = 61.02 cu. inches
1 cu. meter = 1000 cu. decimeters = 35.31 cu. feet
Approximate Conversion Factors
To change
inches
feet
yards
miles
square inches
square feet
square yards
square miles
acres
cubic feet
cubic yards
fluid ounces
pints
quarts
gallons
ounces
pounds
short tons
pound-feet
pound-inches
To
Multiply by
centimeters
2.540
meters
.305
meters
.914
kilometers
1.609
square centimeters 6.451
square meters
.093
square meters
.836
square kilometers
2.590
square hectometers
.405
cubic meters
.028
cubic meters
.765
milliliters
29,573
liters
.473
liters
.946
liters
3.785
grams
28.349
kilograms
.454
metric tons
.907
Newton-meters
1.356
Newton-meters
.11296
To change
ounce-inches
centimeters
meters
meters
kilometers
square centimeters
square meters
square meters
square kilometers
square hectometers
cubic meters
cubic meters
milliliters
liters
liters
liters
grams
kilograms
metric tons
To
Newton-meters
inches
feet
yards
miles
square inches
square feet
square yards
square miles
acres
cubic feet
cubic yards
fluid ounces
pints
quarts
gallons
ounces
pounds
short tons
Temperature (Exact)
°F
Fahrenheit
temperature
5/9 (after
subtracting 32)
Celsius
°C
temperature
Multiply by
.007062
.394
3.280
1.094
.621
.155
10.764
1.196
.386
2.471
35.315
1.308
.034
2.113
1.057
.264
.035
2.205
1.102
PIN: 022314 - 000
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