hgu-56/p commercial helmet assembly

Operation and Maintenance Instructions
HGU-56/P COMMERCIAL
HELMET ASSEMBLY
Ó2010 GENTEX Corporation
Proper fitting, operation, and maintenance of the helmet is imperative for the safety
of the user.
Before you use or maintain the helmet, read this entire manual thoroughly. Follow all
Warnings and Cautions precisely.
When you replace components or install additional components on Gentex products,
always use genuine factory-new Gentex parts. This will ensure a correct fit and
maintain the safety of the product. Use of non-Gentex parts (salvage, refurbished,
etc.) for replacement or additional installation will void any product warranty and may
compromise the safety of the user.
Contents
OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SECTION 1: INTRODUCTION AND GENERAL DESCRIPTION . . . . . . . . . . . . 1
1-1. SYSTEM DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1-2 STANDARD COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1-3. OPTIONAL COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SECTION 2: PREPARATION FOR USE . . . . . . . . . . . . . . . . . . . . . . . . 4
2-1. SERVICE UPON RECEIPT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2-1.1. Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2-1.2. Inspecting Unpacked Equipment . . . . . . . . . . . . . . . . . . . . . . . 4
2-2. SELECTING HELMET SIZE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2-3. INSTALLING OPTIONAL COMPONENTS . . . . . . . . . . . . . . . . . . . . . . 7
2-3.1 Installing SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2-3.2 Installing Optional ANVIS Dual Visor Assemblies
(Quick-Disconnect or Direct-Mount). . . . . . . . . . . . . . . . . . . . . . . . . . 9
2-3.3 Installing ANVIS Attachment Kit
(for Quick-Disconnect ANVIS Dual Visor Assembly) . . . . . . . . . . . . . . . . 10
2-3.4 Installing ANVIS Attachment Kit
(for Direct-Mount ANVIS Dual Visor Assembly) . . . . . . . . . . . . . . . . . . . 12
2-3.5 Installing High-Contrast Visor . . . . . . . . . . . . . . . . . . . . . . . . . 16
2-3.6 Installing Flex Boom Microphone . . . . . . . . . . . . . . . . . . . . . . . 18
2-3.7. Installing Coiled Communications Cord . . . . . . . . . . . . . . . . . . . 20
2-3.8 Installing Maxillofacial Shield (MFS) . . . . . . . . . . . . . . . . . . . . . 21
2-4. HELMET FITTING AND OPERATION . . . . . . . . . . . . . . . . . . . . . . . . 27
2-5 TRIMMING MFS FOR ANVIS COMPATIBILITY . . . . . . . . . . . . . . . . . . . 35
2-6. TPL CUSTOM-FITTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
(Continued on next page)
i
Contents (continued)
SECTION 3: MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3-1. PREVENTIVE MAINTENANCE AND CLEANING . . . . . . . . . . . . . . . . . . 39
3-1.1. Pre-flight Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3-1.2. Post-flight Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3-1.3. Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3-2. TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3-3. COMPONENT REPLACEMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3-3.1 TPL or SCL Cloth Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3-3.2. Energy-Absorbing Liner
. . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3-3.3. Retention Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3-3.4 Earcups or Earphones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3-3.5. Microphone Boom/Cord/Swivel Assembly (Wire Boom) . . . . . . . . . . 55
3-3.6. Flex Boom Microphone . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3-3.7. Communications Cord. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3-3.8. Dual Visor Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
3-3.9 MFS Latch Assembly (on shield) . . . . . . . . . . . . . . . . . . . . . . . 62
3-3.10 MFS Striker (on helmet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
SECTION 4: REPLACEMENT PARTS . . . . . . . . . . . . . . . . . . . . . . . . 64
4-1 STANDARD COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4-2 OPTIONAL COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
ii
OVERVIEW
This manual provides fitting, operation, and maintenance instructions for the Gentex HGU-56/P
Commercial Helmet Assembly. The manual is divided into the following sections:
• Section 1: Introduction and General Description. This section provides basic
information about the helmet.
• Section 2: Preparation for Use. This section provides instructions for installing optional
components, fitting the helmet, and operating the helmet properly.
• Section 3: Maintenance. This section includes information for cleaning, troubleshooting,
performing preventive maintenance, and replacing components.
• Section 4: Parts List. This section provides information for ordering replacement parts.
SECTION 1: INTRODUCTION AND GENERAL DESCRIPTION
1-1. SYSTEM DESCRIPTION
The HGU-56/P Commercial Helmet Assembly (Figure 1-1) provides ear, eye, and head bump
protection for aircrew personnel. Through a custom-fitting process, the HGU-56/P Helmet
provides a stable mounting base for all modules and components.
Figure 1-1. HGU-56/P Commercial Helmet Assembly
1
1-2 STANDARD COMPONENTS
The helmet consists of the following standard components (Figure 1-2):
• Helmet Shell. Provides bump protection for the head via the shock-dampening
energy-absorbing liner.
• Boom and Microphone. Part of the communications system, which also includes two
earphones (one inside each earcup) and a communications cord.
• Earcups. Protect hearing by reducing noise and attenuating some side impacts.
• Retention Assembly. Stabilizes the helmet on the head; consists of earcup
retaining pads, a chinstrap with a buckle, and a nape strap pad with adjustable straps.
• Thermoplastic Liner (TPLâ). Optimizes fit and comfort; can be heat-softened and
custom-fitted if necessary.
• Energy-Absorbing (EA) Liner. Absorbs and reduces impact forces.
• Dual Visor Assembly. Protects the wearer’s eyes from sun glare, flash fires, ballistic
spall, dust, and foreign particles. Includes a clear inner visor and a neutral gray
(sunshade) outer visor.
• Headband Pad Kit. Used when necessary to improve helmet fit.
• Earcup Spacer Pad Kit. Used when necessary to improve earcup fit.
Headband pad kit
Earcup spacer pad kit
Dual visor assembly
Helmet shell
Energy-absorbing liner
TPL
Nape pad
Earcup (earphone inside)
Boom and microphone
Earcup retaining pad
Communications cord
Chin strap
Figure 1-2. Standard Components of HGU-56/P Commercial Helmet
TPLâ is a registered trademark of GENTEX Corporation.
2
1-3. OPTIONAL COMPONENTS
Optional components (Figure 1-3) include the following:
• ANVIS dual visor assemblies. Options include a quick-disconnect version, which allows
one-handed attachment and removal of the ANVIS mount; and a direct-mount version,
which has a raised area for direct mounting of the ANVIS V-1 mount.
• Super Comfort Liner (SCL). Provides the protective benefits of the TPL, but offers
enhanced comfort; conforms to individual head shapes through body heat to ensure
increased stability while nearly eliminating the need for additional custom-fitting.
• Maxillofacial Shield (MFS). Protects the lower face from rotor wash, flying debris, and
windblast during helicopter operations; has dual side release latches that provide for
positive lock and quick release of the shield from either side of the helmet.
• High-contrast visor. Provides enhanced vision for flying in low-light conditions, such as
snowy, foggy, overcast, hazy or cloudy environments; causes the blue portions of the
visible spectrum to appear black or dark while other colors appear nearly normal; available
for installation as an outer visor on the HGU-56/P.
• Flex boom. Permits ease and flexibility for positioning the microphone.
• 36" coiled communications cord. Similar to the standard communications cord, but
coiled for convenience; stretches to approximately 60 inches in length.
• Helmet bag. Larger than standard helmet bags; available in black, woodland camo, ACU
camo, and desert camo (see Page 71 for part numbers); has a thickly padded interior to
protect helmets and accessories; includes a shoulder strap and multiple pockets.
Quick-disconnect
ANVIS dual visor
assembly
Attachment kit for
quick disconnect
ANVIS dual visor
assembly
Direct-mount
ANVIS dual visor
assembly
SCL
Attachment kit for
direct-mount ANVIS
dual visor assembly
MFS
Helmet bag
High-contrast
visor, outer
36" coiled cord
Hardware kit for flex boom
Flex boom
Figure 1-3. Optional Components
3
SECTION 2: PREPARATION FOR USE
2-1. SERVICE UPON RECEIPT
This section contains instructions regarding the tasks to be performed upon receipt of the
helmet. These tasks include unpacking and inspecting unpacked equipment.
2-1.1. Unpacking
1. Open the over pack carton and remove all unit pack cartons. Unit pack cartons are labeled
according to their contents. Open each unit pack carton. Remove the sealed helmet and, if
supplied, the helmet bag.
2. Unseal the bag containing the helmet. Take the helmet, the earcup spacer pad set, the
headband fitting pad set, and the ANVIS mounting kit (if supplied) out of the bag. Remove
the wrapping from the helmet.
3. Open the sealed bag containing the helmet bag (if supplied), and remove the helmet bag.
2-1.2. Inspecting Unpacked Equipment
1. Check the helmet and all included items for any damage incurred during shipment. Report
any damage to your shipper.
2. Check the helmet and all other parts against the packing slip to determine if all parts have
been included. Report any discrepancies immediately to your shipper.
4
2-2. SELECTING HELMET SIZE
Tools and Materials Required
•
•
•
•
•
Carpenter’s combination square
Ruler
Marker
Wood block (2 inches by 4 inches by 8 inches)
Adhesive-backed hook-and-pile fastener
Proper fitting is essential to the functioning of the helmet, all of its components,
and, consequently, the safety of the wearer. Take as much time as necessary to fit
the helmet precisely. Use extreme care in taking measurements and checking fit.
1. Obtain a block of wood 2 inches thick by 4 inches wide by 8 inches long. Referring to
Figure 2-1, attach an 8-inch strip of hook fastener to the entire length of the center of one of
the 4-inch-wide faces. Attach a 12-inch strip of pile fastener, running vertically, to a wall
(bottom of the strip approximately 5 feet 4 inches above the floor) so that the block can be
adjusted for the various heights of user’s heads.
2. Attach the block of wood to the wall at the height of the wearer’s head when the wearer is
standing.
(Continued on next page)
8 inches
4 inches
Hook fastener
2 inches
Figure 2-1. Prepared Wood Block
5
3. Have the wearer stand with the back of the head against the block. Ensure that the
wearer's posture and body alignment are as straight as possible. The wearer should hold
his or her head in a comfortable position while focusing on a point directly ahead at eye
level.
4. Referring to Figure 2-2, View A, use a ruler to measure a distance 1-1/2 inches above the
wearer’s pupil. Using a marker, make a small mark at this point in the center of the wearer’s
forehead; this is the forehead reference point (FRP).
5. Referring to Figure 2-2, View B, use a combination square to measure from the FRP to the
block; this is the head length. Be careful to just touch the wearer’s skin at the FRP.
6. Select the correct helmet size based upon head length as follows:
HEAD LENGTH (INCHES)
HELMET SIZE
> 8-5/16
XL
8-1/16 - 8-5/16
L
7-3/4 - 8
M
7-7/16 - 7-11/16
S
7-1/8" - 7-3/8
XS
< 7-1/8
XXS
Wood block
Combination square
Ruler
Marker
1-1/2 inches
FRP
VIEW A
VIEW B
Figure 2-2. Determining Head Length
6
2-3. INSTALLING OPTIONAL COMPONENTS
Install optional components on the helmet as needed. Installation procedures are as follows:
• Installing SCL: Paragraph 2-3.1 (Page 8)
• Installing Optional Dual Visor Assemblies (Quick-Disconnect and Direct-Mount):
Paragraph 2-3.2 (Page 9)
• Installing ANVIS Attachment Kit (for Quick-Disconnect ANVIS Dual Visor Assembly):
Paragraph 2-3.3 (Page 6)
• Installing ANVIS Attachment Kit (for Direct-Mount ANVIS Dual Visor Assembly):
Paragraph 2-3.4 (Page 12)
•
•
•
•
Installing High-Contrast Visor: Paragraph 2-3.5 (Page 16)
Installing Flex Boom Microphone: Paragraph 2-3.6 (Page 18)
Installing 36" Coiled Communications Cord: Paragraph 2-3.7 (Page 20)
Installing Maxillofacial Shield: Paragraph 2-3.8 (Page 21)
When you replace components or install additional components on Gentex products,
always use genuine factory-new Gentex parts. This will ensure a correct fit and
maintain the safety of the product. Use of non-Gentex parts (salvage, refurbished,
etc.) for replacement or additional installation will void any product warranty and may
compromise the safety of the user.
7
2-3.1 Installing SCL
To install the SCL, you remove the
TPL from the helmet and insert the
SCL in place of the TPL.
Tools and Materials Required
SCL in one of the following sizes
(to match helmet size):
•
•
•
•
•
•
02D11531-8 (XX-Small)
02D11531-9 (X-Small)
Figure 2-3. SCL
02D11531-10 (Small)
02D11531-11 (Medium)
02D11531-12 (Large)
02D11531-13 (X-Large)
Procedure
Install the SCL (Figure 2-3) as
follows:
1. Remove the TPL from the
helmet.
2. Referring to Figure 2-4, place
the SCL in the helmet
3. Ensure that the holes in the
SCL are aligned with the holes
in the energy-absorbing liner
as shown in Figure 2-5. The
SCL should seat down against,
and align with, the front edge
of the energy-absorbing liner.
Figure 2-4. Installing SCL
4. Proceed to Paragraph 2-4
(beginning on Page 27) to
check the fit of the helmet.
NOTE: The SCL usually does
not require custom-fitting.
However, the SCL may be
custom-fitted, if necessary, as
described in Paragraph 2-6
(beginning on Page 36).
Figure 2-5. Aligning SCL
8
2-3.2 Installing Optional ANVIS
Dual Visor Assemblies
(Quick-Disconnect or
Direct-Mount)
Quick-disconnect
Direct-mount
Both types of ANVIS dual visor
assemblies (quick-disconnect and
direct mount, Figure 2-6) are
installed in the same manner (after
the existing dual visor assembly is
removed).
Tools and Materials Required
• ANVIS dual visor assembly,
Figure 2-6. ANVIS Dual Visor Assemblies
quick-disconnect (95B9246)
or
Thumb screw
(four places)
• ANVIS dual visor assembly,
direct mount (88D7611-1)
Procedure
Install the ANVIS dual visor
assembly (quick-disconnect or
direct-mount) as follows:
1. Loosen (do not remove) the four
thumb screws (Figure 2-7) on
the existing dual visor assembly
on the helmet.
Figure 2-7. Existing Dual Visor Assembly
2. Lift the entire existing dual visor
assembly away from the helmet
and set aside.
3. Align the thumbscrews of the
ANVIS dual visor assembly over
the four posts protruding upward
through the helmet (Figure 2-8).
4. Tighten the four thumb screws
on the ANVIS dual visor
assembly into the posts.
Ensure that the ANVIS dual visor
assembly is securely attached to
the helmet.
5. Install the ANVIS attachment kit
per Paragraph 2-3.3 (for
quick-disconnect) or Paragraph
2-3.4 (for direct-mount).
Thumb screw
(four places)
Post
(four places)
Figure 2-8. Installing ANVIS Dual Visor Assembly
(Quick-Disconnect Shown)
9
2-3.3 Installing ANVIS Attachment Kit (for Quick-Disconnect ANVIS Dual Visor
Assembly)
Before you can attach the ANVIS night vision goggles to the ANVIS dual visor assembly, you
must modify the ANVIS mount. An optional kit (Figure 2-9) contains the parts required for this
modification. Once modified, the mount will provide one-handed attachment and removal.
Tools and Materials Required
ANVIS Attachment Kit (96A9378)
Procedure
Referring to Figure 2-9, modify the ANVIS mount as follows:
1. Remove the nut from the right side (as worn) of the ANVIS mount, and place the strain relief
clamp over the ends of the screw threads.
2. Place the cable wires under the clamp arm, and replace the nut over the screw threads and
the clamp. Tighten the nut until it is secure.
3. Position the backing plate on the rear of the mount so that the screw holes line up and the
plate is flush with the top and bottom rear of the mount. Ensure that the wires extending
from the rear of the mount are aligned in the mount slots to prevent crushing of wires.
4. Apply a small amount of thread-locking adhesive to the end of each top locating pin
(identified by longer, tapered heads), and install these pins through the top holes of the
backing plate and into the rear of the mount. Repeat with the bottom locating pins, installing
them through the bottom holes. Tighten the pins until they are secure; do not tighten too
much.
5. Remove the backing from the hook fastener, and wrap it around the cable connector until
the ends meet.
(Continued on next page)
Hook
fastener
Top
locating pins
Pile
fasteners
Hook fastener
(wrapped around cable connector)
Bottom
locating pins
Pile
fastener
ANVIS mount
(customerfurnished)
Clamp
Locating
pins
Backing plate
Clamp arm
Backing plate
Kit
Figure 2-9. Modifying ANVIS Mount
10
Nut
6. Attach the 2 x 2-inch pile fastener (supplied with the ANVIS mounting hardware kit) to the
visor housing at the front of the helmet as shown in Figure 2-10. This fastener will anchor
the connector.
7. Attach the two 2 x 3-inch pile fasteners (supplied with the ANVIS mounting hardware kit) to
the back of the helmet as shown in Figure 2-10. These fasteners will hold the battery pack.
8. Referring to Figure 2-10, attach the mount to the ANVIS dual visor assembly as follows:
a. Align the locating pins with the slots in the mounting platform on the visor housing.
b. Insert the pins into the slots, and pull the mount down until it clicks into place.
c. Attach the hook fastener on the connector to the pile fastener on the visor housing.
9. To remove the mount from the visor housing, depress the tab on top of the mounting
platform, and lift the mount up and away from the housing.
Hook fastener on connector
Tab
Visor housing
Pile
fastener,
2x2
ANVIS mount
FRONT OF HELMET
Pile fasteners, 2 x 3
BACK OF HELMET
Figure 2-10. ANVIS Mount and Pile Fasteners Installed
11
2-3.4 Installing ANVIS Attachment Kit (for Direct-Mount ANVIS Dual Visor
Assembly)
Tools and Materials Required
•
•
•
•
•
Moleskin patches
#1 Cross-tip screwdriver
Pile fasteners
Jeweler’s screwdriver set
Dual Visor Assembly (88D7611-1)
V-1 ANVIS Mount
ANVIS Attachment Kit (93A8654)
Procedure
In this procedure, you will use the ANVIS
Attachment Kit (Figure 2-11) to attach
the ANVIS mount (not supplied with the
helmet) to the visor housing. Follow
these steps.
Screws
Figure 2-11. ANVIS Attachment Kit
Visor housing
1. Referring to Figure 2-12, remove the
visor housing as follows:
Thumbscrew
(four places)
a. Loosen the four thumbscrews to
remove the visor assembly from
the helmet.
b. Remove the thumbscrews from
the visor assembly.
c. Remove the visor housing from
the tracks.
2. Remove the four screws on the back
of the ANVIS mount.
3. Referring to Figure 2-13, place the
ANVIS mount against the front of the
visor housing. Align the four mount
holes with the four visor housing
holes.
Figure 2-12. Visor Assembly
Visor housing
ANVIS mount
4. Attach the mount to the housing by
inserting four 4-40 x 3/16" pan-head
screws (supplied in the ANVIS
attachment kit) through the inside of
the housing and into the mount.
Fasten the screws securely, but do
not tighten too much.
(Continued on next page)
12
Figure 2-13. ANVIS Mount Placement
Power cord cover
Back of housing
Screws
Figure 2-14. Power Cord Cover
5. Referring to Figure 2-14,
remove the two screws,
washers, and posts attaching
the power cord block and
power cord cover to the visor
housing.
6. Referring to Figure 2-15,
remove the moleskin patch on
the inside of the visor housing.
Beneath this patch is the
power cord cover retaining
screw.
7. Remove the screw from which
you removed the moleskin
patch in Step 6. This will
detach the power cord cover
from the housing.
8. Referring to Figure 2-16, align
the power cord cover on the
front of the housing, and route
the cord and connector under
the power cord cover.
Moleskin patch
Inside of housing
Figure 2-15. Moleskin Patch Covering Screw
Cord
Power cord cover
Front of housing
9. Reinstall the screw that you
removed in Step 7.
(Continued on next page)
Figure 2-16. Cord Routed Under Cover
13
CAUTION
When you install the screws in Step 10, be careful to tighten the screws just snugly
enough to secure the cover. Tightening the screws too much may damage the cover.
10. Referring to Figure 2-17, reattach the power cord cover and the power cord block to the
visor housing with the screws, washers, and posts removed in Step 8. Ensure that the red
dot on the connector points up and that the knurls on the connector are seated between the
ridges on the block.
Knurls
Red dot
Power cord cover
Ridges
Red dot
Power cord block
Screws
Power cord block
Figure 2-17. Reinstalling Power Cord Cover
11. Referring to Figure 2-18,
install moleskin patches
(supplied in the ANVIS
mounting kit) on the inside of
the visor housing in the
pattern shown.
12. Align the visor housing over
the bushings that protrude
upward through the tracks,
and install the thumbscrews
through the visor housing and
the bushings.
(Continued on next page)
14
Inside of visor
Moleskin
patches
Figure 2-18. Moleskin Patches Installed
13. Position visor housing assembly
on helmet, and start four
thumbscrews into helmet to attach
visor assembly as shown in
Figure 2-19. After all four
thumbscrews are started, tighten
them.
Thumbscrew
(four total)
14. Referring to Figure 2-20, attach
two 2-inch x 3-inch pile fastener
pieces (supplied in the ANVIS
mounting kit) to the helmet as
follows:
a. Position the two pile fastener
pieces at the rear of the helmet
as shown, and mark the area
with a pencil.
b. Clean the marked area with
isopropyl alcohol pads.
Figure 2-19. Visor Housing Assembly
Pile fastener
pieces
c. Affix the pile fasteners within
the marked area.
NOTE: If the pile fastener
pieces fail to stick to the
helmet shell, lightly sand the
area; then affix the pile
fasteners.
15. Install the ANVIS goggles
(Figure 2-21) in accordance
with TM 11-5855-263-10.
Figure 2-20. ANVIS Pile Fastener Pieces
Installed
16. Perform a continuity check
of the ANVIS goggles in
accordance with TM
11-5855-263-10.
Figure 2-21. ANVIS Mount with ANVIS
Goggles Installed
15
2-3.5 Installing High-Contrast
Visor
The high-contrast visor is an outer
visor that you install in place of the
existing outer visor on the dual visor
assembly. Follow these steps to
install the high-contrast visor.
Thumbscrew
(four places)
Tools and Materials Required
High-contrast visor (95A9302-5)
Helmet post
(four places)
Procedure
1. Referring to Figure 2-22,
remove the dual visor assembly
from the helmet as follows:
Figure 2-22. Removing Dual Visor Assembly
Visor housing
a. Loosen (do not remove) the
four thumbscrews on the
dual visor assembly.
Thumbscrew
(four places)
b. Lift the dual visor assembly
away from the helmet posts.
2. Referring to Figure 2-23,
remove the visor housing
as follows:
Tracks
(two places)
a. Remove the four
thumbscrews from the
visor housing.
b. Lift the visor housing away
from the tracks.
Figure 2-23. Removing Visor Housing
Inner visor
3. Referring to Figure 2-24,
remove the lower retaining ring
on the same side where the
outer visor knob is located.
(Continued on next page)
Outer visor
(to be replaced with
high-contrast visor)
Retaining ring
Outer visor knob
Figure 2-24. Removing Retaining Ring
16
4. Referring to Figure 2-25, remove
the existing outer visor as follows:
a. Push the outer visor knob
outward, and move the knob
downward along the tracks.
b. Lift the upper track slightly
to provide clearance for the
knob.
c. Slide the outer visor out of the
tracks on both sides.
5. Set the existing outer visor aside;
obtain the high-contrast visor.
Outer visor knob
Tracks
Outer visor (remove)
Upper track (lift slightly)
Tracks
Figure 2-25. Removing Existing Outer Visor
6. Referring to Figure 2-26, install
the high-contrast visor as follows:
a. Lift the upper track slightly,
and slide the high-contrast
visor into the tracks where
the previous outer visor
was removed.
b. Push the knob outward, and
slide the high-contrast visor
upward along the tracks.
c. Release the knob to lock the
visor in place.
Outer visor knob
Tracks
High-contrast visor (install)
Upper track (lift slightly)
Tracks
Figure 2-26. Installing High-Contrast Visor
7. Referring to Figure 2-27,
reinstall the retaining ring that you
removed in Step 3. Ensure that
the retaining ring is seated in the
groove on the bushing.
8. Referring to Figure 2-23
(previous page), reinstall the
thumbscrews through the visor
housing and the tracks.
9. Referring to Figure 2-22
(previous page), position the
dual visor assembly over the
helmet. Reinstall the four
thumbscrews into the helmet
posts. Tighten the screws evenly.
Retaining ring
Groove
on bushing
Figure 2-27. Installing Retaining Ring
17
2-3.6 Installing Flex Boom Microphone
In this procedure, you will remove the existing wire boom microphone from the helmet and
install the flex boom microphone with its associated hardware kit (Figure 2-28).
Tools and Materials Required
Hardware kit
• Flex boom (03B11804-16B)
• Hardware kit (04A11895-1)
• Cross-tip screwdriver
Flex boom
Procedure
Figure 2-28. Flex Boom and Hardware
1. Referring to Figure 2-29, unplug
the existing microphone from the
communications cord connector
at the rear of the helmet.
Connector
2. Referring to Figure 2-30, remove the
existing boom microphone as follows:
Microphone plug
a. Remove the center screw of the
swivel assembly.
b. Remove the interior screw that
attaches the swivel assembly
to the helmet.
(Continued on next page)
Figure 2-29. Microphone Cord and Connector
Helmet
Inside helmet
Outside helmet
Center
screw
Interior
screw
Swivel assembly
Swivel assembly
Center screw
Wire boom microphone
Figure 2-30. Existing Wire Boom Microphone and Swivel Assembly
18
3. Referring to Figure 2-31, do the following:
a. From outside the helmet, insert the screw through the flat washer, the flex boom mount,
and the microphone attachment hole in the helmet.
b. From inside the helmet, insert the nut through the lock washer, and attach the nut to the
screw.
c. Tighten the screw to prevent the flex boom mount from moving on the helmet. Re-check
the screw during periodic inspection to ensure tightness.
d. Plug the microphone into the connector at the rear of the helmet.
NOTE: You can install the flex boom
mount outside or inside the helmet
as shown here.
Helmet
Inside helmet
Outside helmet
Nut
Screw
Lock washer
Flat washer
Alternate location
of flex boom mount
Flex boom mount
Connector
Microphone
plug
Figure 2-31. Flex Boom Microphone
19
2-3.7. Installing Coiled Communications Cord
NOTE: See Figure 2-32 for a comparison of the standard communications cord and the coiled
communications cord.
To install the coiled communications cord (87B7491-2), you must first remove the standard
communications cord. This requires you to disassemble and remove several components from
the helmet.
Once you have disassembled these components, you can connect the coiled cord and then
reassemble and reinstall the components. You will refer to Paragraph 3-3.7 (Page 57) as
follows:
1. Remove the standard communications cord from the helmet by following the Removal
procedure in Paragraph 3-3.7.
2. Install the coiled communications cord into the helmet by following the Installation
procedure in Paragraph 3-3.7 .
Standard communications cord
Coiled communications cord
Figure 2- 32. Standard and Coiled Communications Cords
20
2-3.8 Installing Maxillofacial Shield (MFS)
To install the MFS (Figure 2-33), you must install hardware on the helmet for attachment of the
shield. (If ANVIS goggles are used, you might also need to trim the shield to accommodate the
goggles; refer to Paragraph 2-5 on Page 35.)
Tools, Equipment, and Materials Required
•
•
•
•
•
MFS (88C7626)
Compass
Screwdriver, cross-tip
Drill, electrical, portable
Drill bit, 1/16
•
•
•
•
•
• White glue
• Pencil
• Goggles,
Drill bit, 9/64
Drill bit, 3/16
Respirator
eye-protective
MFS with latches
Striker hardware kit
Procedure
1. Remove the dual visor assembly
from the helmet.
2. Set a compass to the value shown
below for your helmet size.
Small, XS, XXS: 3-1/8 inches
Medium: 3-3/16 inches
Large: 3-19/64 inches
X-Large: 3-21/64 inches
• 2x4 wood block
Latch
MFS
Latch
Striker
hardware
kit
Figure 2-33. MFS and Hardware
3. With the compass set to the
appropriate value as specified in
Step 2, position the point of the
compass in the dimple on one side of
the helmet, and draw an arc from
approximately 2 inches to 2-1/2
inches below the dual visor assembly
post as shown in Figure 2-34.
4. Repeat Step 3 for the other side of
the helmet.
5. Set the compass to the value shown
below for your helmet.
Small, XS, XXS: 2-9/64 inches
Medium: 2-9/64 inches
Large: 2-5/32 inches
X-Large: 2-9/64 inches
Dimple
Arc
(Continued on next page)
Figure 2-34. Drawing Arc from Helmet Dimple
21
6. With the compass set to the
appropriate value as specified
in Step 5, position the point of
the compass below the lower
dual visor assembly post on
one side of the helmet, and
draw an arc as shown in Figure
2-35 to intersect with the first
arc.
Post
Arc
7. Repeat Step 6 for the other side
of the helmet.
8. On one side of the helmet,
center punch the point at which
the arcs intersect. Repeat for
the other side.
Figure 2-35. Drawing Arc from Post
• Wear eye-protective goggles when drilling holes in Steps 9-11 to prevent eye injury.
• Use the 2x4 block of wood as described in Steps 9-11 to prevent hand injury.
CAUTION
• Be careful not to damage any components inside the helmet when performing Steps 9-11.
• Be sure to drill the helmet shell as specified in Steps 9-11, or delamination of the helmet
shell could result, making the helmet unserviceable.
• When performing Steps 9-11, hold the drill perpendicular to the helmet shell to prevent
damage to the shell and the energy-absorbing liner.
• Use the 2x4 block of wood as specified in Steps 9-11 to prevent damage to the helmet
shell.
9. On both sides of the helmet, at the center punched marks where the two arcs intersect,
firmly hold a 2x4 block of wood inside the helmet shell behind the drilling point. Use a
1/16-inch drill bit to drill a pilot hole. Continue to hold the block in this manner in Steps 10
and 11.
10. Use a 9/64 drill bit to drill through the pilot hole.
11. Finish drilling the hole with 3/16-inch drill bit.
(Continued on next page)
22
12. Referring to Figure 2-36,
attach a striker to one side
of the helmet by using one
screw and a post through
the lower hole of the striker
and the drilled hole in the
helmet, applying a drop of
white glue to the threads of
each screw. Leave the
screw just loose enough to
allow the striker to rotate.
13. Repeat Step 12 for the other
side of the helmet.
Drilled hole
Striker
Post
Screw
Helmet
Figure 2- 36. Striker Attachment
Downstop
locking screw
Downstop
locking screw
14. Reattach the dual visor
assembly to the helmet.
Referring to Figure 2-37,
use the two downstop
locking screws (one on each
side of the visor) to adjust
the visor downstop to the
lowest position.
15. Referring to Figure 2-38,
attach the MFS to the striker
and latch the MFS into place
as follows:
a. On one side, position the
pin on the MFS latch into
the slot of the striker,
and flip the latch against
the helmet shell. Ensure
that the latch is locked in
place.
b. Swing the MFS to the
closed position on the
other side, and fasten
the other latch in place.
Figure 2- 37. Downstop Locking Screws
Pin
Latch
Latch
MFS
Striker
Continued on next page
Striker
Slot
Figure 2-38. MFS Attachment to Helmet
23
16. Referring to Figure 2-39,
adjust the MFS position as
follows:
Inner visor knob
a. Lower the inner (clear)
visor to the full down
position. (Push the inner
visor knob outward and
down.)
b. Push up or down on the
MFS so that an even,
approximately 1/16-inch
clearance exists between
the inside surface of the
visor and the top edge
beading of the MFS
where they overlap. The
bottom edge of the visor
should align with the
bottom edge of the edge
beading on the MFS. The
MFS must not touch any
part of the dual visor
housing.
c. With the MFS in this
position, snug the two
lower striker screws.
Overlap between visor and MFS
(1/16-inch clearance needed)
Bottom edge
of MFS edge beading
Bottom edge
of visor
Figure 2-39. Inner Visor Lowered with MFS Attached
17. Check the MFS position as follows:
a. Raise the inner visor.
b. Unlatch one side of the MFS and swing the MFS out, ensuring that there is no
interference with with dual visor assembly. Re-latch the MFS, and repeat for the other
side.
c. Re-latch both sides of the MFS.
d. Lower the visor again to ensure that the alignment and clearance specified in Step 16
has been maintained. Readjust as necessary.
e. Raise and lower the inner visor again to ensure clearance and proper operation.
f.
Raise the visor again.
Continued on next page
24
• Wear eye-protective goggles when drilling holes in Steps 18 and 19 to prevent eye injury.
• Use the 2x4 block of wood as described in Steps 18 and 19 to prevent hand injury.
CAUTION
• Be careful not to damage any components inside the helmet when performing Steps 18
and 19.
• Be sure to drill the helmet shell as specified in Steps 18 and 19, or delamination of the
helmet shell could result, making the helmet unserviceable.
• When performing Steps 18 and 19, hold the drill perpendicular to the helmet shell to
prevent damage to the shell and the energy-absorbing liner.
• Use the 2x4 block of wood as specified in Steps 18 and 19 to prevent damage to the
helmet shell.
• When performing Step 19, ensure that both strikers are rotated out of the way before you
begin drilling. Do not drill through the strikers with the 3/16-inch drill bit.
18. Drill the pilot holes as follows:
a. With both sides of the MFS latched in place and the two lower striker fasteners snug,
firmly hold a 2x4 block of wood inside the helmet shell behind the drilling point.
b. Use a drill with a 1/16-inch drill bit to drill a pilot hole through the upper hole of both
strikers.
c. Continue to hold the wood block behind the drilling point, and drill the upper hole of both
strikers with a 9/64-inch drill bit.
19. Drill the final holes as follows:
a. Remove the MFS, loosen the two lower striker fasteners, and rotate both strikers out of
the way to allow access to the pilot holes drilled in Step 18.
b. Firmly hold a 2x4 block of wood inside the helmet shell behind the drilling point.
c. Using a drill with a 3/16-inch drill bit, drill through both pilot holes.
Continued on next page
25
20. Rotate the strikers back to
their previous positions.
Referring to Figure 2-40,
install the remaining screws
and posts through the upper
striker holes and the newly
drilled holes to attach the
strikers, applying a drop of
white glue to the threads of
each screw. Tighten all four
screws.
Screw
Post
Post
21. Reattach the MFS, lower the
inner visor, and check for
proper alignment on the
helmet. If the MFS does not
align properly, loosen all four
screws (with the MFS still
attached), realign the MFS as
necessary, and re-tighten the
screws.
22. Clean the inside of the helmet
to remove all debris resulting
from drilling.
Figure 2-40. Striker Attachment
23. Adjust the microphone boom
as necessary so that it can be
placed behind the MFS as
shown in Figure 2-41. To do
this, loosen the knurled knob
on the boom swivel, move the
boom forward or back until it
can be placed inside the
recessed space of the MFS,
and tighten the knurled knob.
NOTES:
• Ensure that the MFS is fitted
to the wearer during the
helmet fit check. Refer to
Paragraph 2-4, beginning on
Page 27.
• If the wearer uses night
vision goggles, the MFS may
require trimming. Refer to
Paragraph 2-5 (Page 35).
Microphone
(inside MFS)
Figure 2-41. Boom Adjustment
26
Screw
2-4. HELMET FITTING AND OPERATION
Following is the procedure for donning and fitting the helmet, operating the helmet components,
and removing the helmet.
Tools and Materials Required
• Needle and thread
• Small cross-tip screwdriver
Proper fitting is essential to the functioning of the helmet, all of its components,
and, consequently, the safety of the wearer. Take as much time as necessary to fit
the helmet precisely. Use extreme care in taking measurements and checking fit.
NOTES:
• Ensure that the correct helmet size has been selected as described in Paragraph 2-2
(Page 5).
• If night vision goggles are to be used, check helmet fit with the goggles attached.
• In preparation for the fitting procedure, females with long hair should arrange their hair so
that it is completely covered by the helmet and/or the flight suit. The hair must be worn the
same way thereafter.
Holes in energy-absorbing liner
Procedure
1. Before having the wearer
don the helmet, verify that:
• the TPL or SCL seats down
against, and is aligned
with, the front edge of the
energy-absorbing liner, and
that the TPL or SCL is
centered in the helmet.
• the holes in the front of the
TPL or SCL align with the
holes in the energy-absorbing
liner as shown in Figure 2-42.
(Continued on next page)
Holes in TPL or SCL
Figure 2-42. Alignment of TPL/SCL Holes
27
When donning the helmet, ensure that nape strap pad is completely pulled down and
that its attachment tab is taut. Failure to do so will decrease helmet stability and may
cause injury to the wearer.
CAUTION
When donning or removing the helmet, flex the helmet just enough to clear the head.
Excessive flexing may damage the helmet.
2. Have the wearer don the helmet as
follows:
a. Grasp the helmet as shown in
Figure 2-43, and flex the helmet
slightly to clear the head.
b. Position the helmet firmly against
the forehead; rotate the helmet
rearward and down onto the head.
c. Press the helmet down firmly with
both hands to ensure that the
helmet is properly positioned on the
head.
3. Align the front edge of the helmet with
the FRP (marked in Step 4 on Page 6).
Figure 2-43. Grasping Helmet
Headband fitting pads
4. Ask the wearer to evaluate the fit. As
applicable, do any of the following:
• If a pressure point exists in the center
of the forehead, refer to Figure 2-44
and add headband fitting pads
between the TPL or SCL and the
energy-absorbing liner to either side of
the pressure point to even the
pressure.
• If any pressure point remains, TPL
custom fitting may be required; refer to
Paragraph 2-6 (Page 36).
• If the fit is too loose, try a smaller-size
helmet and repeat Steps 2 through 4.
(Continued on next page)
28
Figure 2-44. Position of Headband Fitting
Pads
5. Adjust the earcups so that they cover
the wearer’s ears. Ask the wearer if
the ear is centered in the earcup.
NOTE: Earseals (Figure 2-45) should
be compressed evenly and to the
greatest degree possible without
causing discomfort. (Proper earseal
compression may be indicated by a
visible ring impression around the ear
when the helmet is removed. If no ring
is visible, check carefully to see that
none of the ear is pinched under the
earseal.)
6. Check the earseal compression. As
necessary, refer to Figure 2-46 and
Figure 2-47and do any of the
following:
Earseal
Figure 2-45. Earseal
Earcup
Helmet shell
• If earseal compression is too great
(causing discomfort) without earcup
spacer pads, select the next larger
helmet size.
Earcup
spacer pad
• If the earseals are not sufficiently
compressed, have the wearer remove
the helmet. Add one or more earcup
spacer pads (Figure 2-46) as needed
between the earcup retaining pad and
the helmet shell (NOT between the
earcup and the retaining pad). Then
have the wearer don the helmet;
recheck earseal compression.
Earcup
retaining pad
Figure 2-46. Placement of
Spacer Pad
NOTE: Earcup spacer pads
may be installed whole, cut in half
horizontally to adjust up/down earcup
tilt, cut in half vertically to adjust
forward/rearward earcup tilt, or
trimmed in any other manner that will
achieve proper earseal compression.
(See Figure 2-47 for examples.) You
may have to try various combinations
of pads to achieve proper
compression.
Continued on next page
Figure 2-47. Spacer Pad Trimming
29
ALWAYS wear the helmet with the chinstrap properly attached and adjusted. Failure
to secure the chinstrap will decrease helmet stability and allow the helmet to be
forced off of the head during flight operations, resulting in possible injury or death.
7. Referring to Figure 2-48, fasten the
chinstrap as follows:
Square receiver
a. Insert the toggle through the
square receiver, and allow the
toggle to lie flat against the square
receiver so that it will not separate.
b. Adjust the chinstrap for a snug fit.
c. Center the chinpad under the
wearer's chin; tack the chinpad
into place using suitable thread.
d. Attach the end of the chinstrap to
the chinpad.
8. Referring to Figure 2-49, adjust the
nape strap pad as follows:
Chinpad
Toggle
End of chinstrap
Figure 2-48. Chinstrap
a. Tighten the nape strap pad by
grasping the two pull tabs, pulling
to the back, and then pulling from
side to side until the nape strap is
snug.
NOTE: When the nape strap pad
is centered, both nape straps will
be the same length.
b. Check the fit of the pad by
inserting two fingers (index and
middle) between the pad and the
wearer’s head. The fingers should
just fit.
c. To loosen the nape strap, flip the
buckles towards the center of the
nape strap pad. The straps will
slide through the buckles easily.
Buckle
Nape strap
Nape strap pad
(Continued on next page)
Figure 2-49. Nape Strap
30
9. Referring to Figure 2-50, lower
the visors (to check centering
and nose clearance) as follows:
a. Use the left-hand knob to
move the outer visor. To use
the visor knob, brace your
thumb against the visor
track, squeeze the knob with
your forefinger, and move
the knob down or up.
b. Use the right-hand knob in
the same manner to move
the inner visor.
10. If necessary, adjust the visors as
follows:
a. Loosen the downstop locking
screws (Figure 2-50); one is
located on each side of the
visor. (Loosening the screws
allows the downstop to be
raised or lowered
approximately one inch for
visor-to-mask or facial
conformance.)
b. When the desired position is
attained, tighten the screws.
11. If night vision goggles are used,
place systems in normal
operating position and check for
full operational capability in
accordance with technical
manual supplied by the goggle
manufacturer.
Downstop
locking screw
Figure 2-50. Visor Operation
Ensure that the night vision system mounted on your helmet is working properly in
accordance with the appropriate technical manual prior to using it. Failure to check
the night vision goggles or to be able to see the low battery warning light when using
the night vision goggles may result in a critical loss of equipment use.
(Continued on next page)
31
12. Connect the helmet
communications system as
follows:
a. Referring to Figure 2-51,
ensure that the microphone
cord is plugged into the
communications cord
connector at the rear of the
helmet.
Communications cord
connector
Microphone
cord plug
b. Plug the helmet
communications cord into
the aircraft communications
device.
13. Referring to Figure 2-52, adjust
the microphone to the proper
operating position as follows:
Communications
cord
a. Loosen the swivel by
rotating it counterclockwise.
b. Rotate the boom up or
down.
Figure 2-51. Microphone Cord
and Connector
c. Slide the rear part of the
boom forward or back.
d. Tighten the boom swivel by
rotating it clockwise.
e. Adjust the front of the boom.
f.
Loosen the knurled screw
on the microphone, adjust
the microphone, and tighten
the knurled screw.
(Continued on next page)
Swivel
Knurled screw
Boom
Figure 2-52. Adjusting Microphone
32
14. If the MFS is used, refer to Figure 2-53 and check operation as follows:
a. To attach the MFS, position the pin on one side of the MFS into the slot of the striker,
and flip the latch against the helmet shell. Ensure that the latch is locked in place.
Repeat for the other side.
b. Adjust the microphone
boom as necessary so that
it can be placed behind the
MFS. To do this, loosen
the swivel, move the boom
forward or back until it can
be placed under the
recessed area of the MFS,
and tighten the swivel.
Striker
(on helmet)
Slot
Pin
Night vision
goggles
c. If night vision goggles are
used, remove the lens
caps and lower the night
vision goggles. If the
goggles clear the MFS and
are properly positioned
over the eyes, no trimming
is needed. If the goggles
contact the shield, trim the
shield as specified in
Paragraph 2-5 (Page 35).
d. To remove the MFS, flip
the latch on one side of the
MFS away from the helmet
shell, and remove the pin
from the slot. Repeat for
the other side.
Latch
(on MFS)
MFS
Microphone
(inside MFS)
Swivel
Boom
Figure 2-53. Operating MFS
NOTES:
• The helmet can be donned or doffed while the MFS is attached to either side and swung
open. However, if the ML-24 light (from Seitz Scientific Industries, Inc.) is attached, the
MFS should be swung open from the right side as worn to avoid disconnecting the light.
• The MFS can also be swung open while the helmet is worn, allowing the crewmember to
eat or drink.
• If the helmet is stowed with the MFS attached, the shield should be secured to the helmet
on both sides.
(Continued on next page)
33
When using the anti-fogging solution described below, avoid getting the liquid
solution into the eyes. Solution will irritate and may burn the eyes. In case of eye
contact, flush with fresh water for 15 minutes. Contact a physician if irritation persists.
See the package for other directions.
15. To help prevent the visor lenses from fogging when the MFS is worn, use Sea Dropsä
anti-fogging solution as follows:
a. Apply two drops of anti-fogging solution to the inside surface of each lens.
b. Rub the solution over the entire surface of the lens.
c. Wait 10 seconds, then buff with a Micronetä microfiber cloth or any soft, dry cloth until
the lens is clear.
NOTE: Sea Dropsä and Micronetä are available from McNett Corporation, 1411 Meador Ave.,
Bellingham, WA 98229, phone 360-671-2227. (www.mcnett.com)
16. Remove the helmet as follows:
a. Loosen the chinstrap by separating the free end from the chin pad and pushing the free
end of the strap back through the toggle as needed.
b. Grasp the helmet in the earcup areas, and flex the helmet just enough to clear the head.
c. Rotate the helmet forward and off the head.
17. After the first flight, recheck and adjust as necessary the helmet straps, TPL (or SCL), and
earcups as necessary to achieve a snug fit.
NOTE: If the wearer cannot be fitted according to these fitting instructions, contact Gentex
Corporation.
34
2-5
TRIMMING MFS FOR ANVIS COMPATIBILITY
If the night vision goggles contact the MFS (as described in the fitting procedure), trim the MFS
following the procedure below.
Equipment, Tools, and Materials Required
•
•
•
•
Pencil
Rotary tool kit
Drum, sanding
Band, abrasive
Procedure
1. Have the crewmember don the
helmet and attach the MFS.
2. Attach the night vision goggles to the
ANVIS mount.
3. Remove the lens caps and lower the
night vision goggles.
4. Mark a trim line on the shield by
tracing along the edge of the goggles
where they contact the shield.
Figure 2- 54 shows an example of
trim lines.
5. Stow the goggles; remove the shield.
Trim lines (typical)
Figure 2-54. Areas to be Trimmed on MFS
• Wear eye-protective goggles when trimming the MFS, or chips of the MFS may
injure the eyes.
• Wear a respirator when trimming the MFS, or harmful airborne particles may be
inhaled.
NOTE: Trim the MFS with the edge beading left in place. You will cut through the edge
beading and the shield. Trim no more than necessary to allow the night vision goggles to
clear the MFS.
6. Using a rotary cutting tool, trim the shield along the marked trim line.
7. Reattach the shield and lower the night vision goggles. Ensure that the goggles clear the
shield and are properly positioned over the eyes.
NOTE: Replace the abrasive band of the sanding drum on the rotary tool as necessary.
35
2-6. TPL CUSTOM-FITTING
Equipment, Tools, and Materials Required
•
•
•
•
•
•
•
Convection oven
Oven thermometer
Ruler
Timer
Masking tape
Cotton gloves
Helmet with TPL to be fitted
Proper fitting is essential to the functioning of the helmet, all of its components,
and, consequently, the safety of the wearer. Take as much time as necessary to fit
the helmet precisely. Use extreme care in taking measurements and checking fit.
CAUTION
If using an oven with upper heating elements to heat the TPL, ensure that the upper
heating elements do not activate during the heating process, or plastic TPL layers will
melt.
NOTE: Do not use a microwave oven; it will not heat plastic layers.
1. Referring to Figure 2-55, set the
oven rack to the lowest position;
heat the oven to 200°F ±5°F
(93.3°C ±2.8°C).
CAUTION
Before you place the TPL in the
oven, ensure that the cover is
attached properly to the plastic
layers (not on backwards).
2. Place the TPL in the center of the
rack in the heated oven, cloth
side on the rack.
(Continued on next page)
Figure 2-55. Correct Oven Temperature
and Rack Position
36
3. Ensure that the oven stabilizes at the temperature listed in Step 1 before starting the timed
sequence.
4. Set the timer, stopwatch, or equivalent for 10 minutes. Heat the TPL for approximately 10
minutes.
5. While the TPL heats, review steps 8 through 12 so that they may be completed in 30
seconds or less.
6. Using an oven thermometer, check the oven temperature every 3 to 5 minutes during the
heating process. Adjust the oven controls if the temperature falls outside the range
specified in Step 1.
7. Describe the fitting procedure to the wearer being fitted.
NOTE:
• If headband fitting pads are installed in the helmet, remove them.
• Cover the hook fastener on the nape strap pad with masking tape to ease installation of the
heated TPL, and loosen the nape strap pad.
• Steps 8-13 should be completed in less than 30 seconds.
Handle the heated TPL carefully; the plastic layers will be hot. Touch the fabric cover
only. Wear gloves if necessary.
8. Remove the TPL from the oven.
9. Squeezing sides of TPL together to clear
earcups, install liner in helmet as shown in
Figure 2-56. Ensure that label and holes
are positioned toward front of helmet.
10. Have the wearer hold the helmet upside
down. Insert the TPL so that the front
edge extends approximately ¼" past the
front edge of the energy-absorbing liner.
Ensure that the liner is centered in the
helmet.
Figure 2-56. Installing TPL
CAUTION
Do not deform the hot, soft TPL by pressing too hard in any one area when positioning
the liner in the helmet.
11. Position the top of the TPL in the helmet. Position the rear of the TPL against the top edge
of, but not down in front of, the nape strap pad while holding the nape strap pad taut.
(Continued on next page)
37
CAUTION
When donning or removing the
helmet, flex the helmet just enough
to clear the head. Excessive
spreading may damage the helmet.
12. Have the wearer grasp the helmet in
the earcup area and flex the helmet
slightly. Place the front of the helmet
against the FRP (marked on the
forehead in the procedure on
Page 6). Referring to Figure 2-57,
hold the edge of the TPL and the
nape strap pad with pull down. Have
the wearer don the helmet and rotate
the helmet rearward.
Figure 2-57. Holding TPL
and Nape Strap Pad
NOTE: Holding the TPL and the nape strap pad when donning the helmet with a
heat-softened TPL will prevent the TPL from bunching up in the rear.
13. Have the wearer pull downward with his or her hands on top of the helmet until it is seated
firmly on the head. Lower the visor to check nose centering and clearance. Fasten the
chinstrap and the nape strap as tightly as possible, without causing discomfort, to optimize
the wearer’s peripheral vision. Have the wearer maintain as much downward pressure as
possible, without causing discomfort, for 3-5 minutes.
NOTE: The TPL top should be compressed as much as possible; this will afford a low
center of gravity and long-lasting comfort.
14. Release pressure on top of the head and the remove helmet. Ensure that the TPL lies
smoothly in the helmet. Reposition the liner if necessary to maintain a ¼" protrusion at the
front of the helmet.
NOTE: If the TPL is not properly fitted, reheat the TPL, and repeat the custom-fitting
procedure.
15. Remove the masking tape from the nape strap pad hook fastener.
16. Have the wearer don the helmet. Adjust the earcups; tighten the nape strap and the
chinstrap.
17. Perform a final fit check. No pressure points should exist; if they do, remove the TPL from
the helmet and repeat the custom-fitting procedure.
18. If the fit is still too tight after the TPL has been custom-fitted, select the next larger helmet
size.
19. If the helmet fits properly, proceed to Step 2 of Paragraph 2-4 (Page 27).
38
SECTION 3: MAINTENANCE
This section provides instructions for maintaining the helmet to ensure that it remains in good
operating condition. Maintenance tasks are as follows:
• Preventive maintenance and cleaning (Paragraph 3-1, beginning on this page).
• Troubleshooting (Paragraph 3-2, beginning on Page 43)
• Component replacement (Paragraph 3-3, beginning on Page 47)
3-1. PREVENTIVE MAINTENANCE AND CLEANING
To keep the helmet in satisfactory operating condition, the user should perform preventive
maintenance to discover all deficiencies and have them corrected as soon as possible before
additional damage or failure occurs. The preventive maintenance procedure consists of
pre-flight and post-flight inspections.
The user should also keep the helmet clean. The cleaning procedure consists of various
cleaning tasks.
3-1.1. Pre-flight Inspection
Prior to each flight, the user shall inspect the helmet to see that it is in serviceable condition,
reporting any damage to the maintenance technician. Refer to Table 3-1, which begins on the
next page.
3-1.2. Post-flight Inspection
After each flight, the user shall inform the maintenance technician of any component
malfunction or damage to the helmet. Refer to Table 3-1, which begins on the next page.
3-1.3. Cleaning
The user shall clean the helmet as needed. Refer to Table 3-2 on Page 42.
39
TABLE 3-1. PREVENTIVE MAINTENANCE CHECKS AND SERVICES
B - Before (pre-flight)
ITEM
NO.
INTERVAL
B A C
1.
A - After (post-flight)
ITEM TO BE INSPECTED/
PROCEDURE
C - Every 120 calendar days
NOT FULLY MISSION CAPABLE IF:
Helmet shell.
WARNING
Do not repair or use any helmet that is
damaged beyond the limits set forth in
this PMCS chart. Injury or death may
result if you do.
x
x
x
Inspect surface for chipped paint with
penetration of fibers.
Surface has chipped paint with
penetration of fibers.
x
x
x
Inspect surface for delaminations larger
than an nickel, or cracks that are forked
or branched.
Surface has delaminations larger than a
nickel, or cracks that are forked or
branched.
x
x
x
Inspect surface for cracks, running front
to back, measuring longer than 2 inches,
or penetrating the light-colored inner
fiber layers.
Surface has cracks, running front to back,
measuring longer than 2 inches, or
penetrating the light-colored inner fiber
layers.
x
x
x
Inspect surface for cracks, running side
to side, measuring 1 inch or longer, or
penetrating the light-colored inner fibers.
Surface has cracks, running side to side,
measuring 1 inch or longer, or penetrating
the light-colored inner fiber layers.
x
x
x
Inspect the edge for cracks.
Edge has any cracks.
x
x
x
Inspect the eardome area for holes or
cracks.
Any cracks penetrate all fiber layers, or
any holes exist in the eardome area.
2.
TPL or SCL.
x
x
x
Check fit.
Loose fit or improperly fitted.
x
x
x
Inspect plastic layers for attachment.
Plastic layers have one or more plies that
have been separated from the stack.
x
Check for cover for dirt.
Cover is greasy, oily, or dirty.
3.
Energy-absorbing liner.
x
x
x
Check for holes and cracks.
(Continued on next page)
40
Energy-absorbing liner has holes or
compressions, gouges deeper than 1/4"
cracks in front, or cracks wider than ½" in
rear.
TABLE 3-1. PREVENTIVE MAINTENANCE CHECKS AND SERVICES (Continued)
B - Before (pre-flight)
ITEM
NO.
INTERVAL
B
A C
4.
A - After (post-flight)
ITEM TO BE INSPECTED/
PROCEDURE
C - Every 120 calendar days
NOT FULLY MISSION CAPABLE IF:
Earcups.
x
x
x
Check fit.
Earseals are not properly compressed
around wearer’s ears.
x
x
x
Check for holes, cracks, and tears.
Holes, cracks, or tears exist.
x
Inspect earcup for cracks, breaks, or
loose/missing hook fastener on back
Earcup is cracked or broken;
hook fastener is loose or
missing.
5.
Earseals.
x
6.
Inspect for cuts, tears, and
split seams.
Cuts or tears exist; seams are split,
inner foam is exposed.
Retention Assembly.
x
x
x
Check attachment.
Not properly attached to
helmet.
x
x
x
Check fit of nape assembly.
Nape assembly is improperly fitted.
x
x
x
Check buckles for breaks, straps for
tearing/fraying, and nape assembly for
holes and cracks.
Buckle is broken, strap is torn/frayed, or
nape assembly has holes or cracks.
x
Inspect for broken, loose, or missing
hardware; split seams; fraying; dirt.
Hardware is broken, loose, or missing;
seams are split; fabric is frayed, oily,
greasy, or dirty.
7.
Earphones.
x
x
x
8.
Check operation in aircraft.
Any malfunction exists.
Check earphone for malfunctions using
Test Set, Intercommunications Unit.
Earphones are malfunctioning.
Microphone/Boom Assembly.
x
x
Check the attachment of hardware
including set screws.
Hardware is loose or missing, or boom
fails to hold microphone in place.
x
x
Check operation in aircraft
Microphone is malfunctioning.
Check microphone for malfunctions using
Test Set, Intercommunications Unit.
Any malfunction exists.
x
(Continued on next page)
41
TABLE 3-1. PREVENTIVE MAINTENANCE CHECKS AND SERVICES (Continued)
B - Before (pre-flight)
ITEM
NO.
INTERVAL
B
A
C
9.
A - After (post-flight)
C - Every 120 calendar days
ITEM TO BE INSPECTED/
PROCEDURE
NOT FULLY MISSION
CAPABLE IF:
Visor assembly.
x
x
x
Check visors for dirt or scratches.
Dirt or scratches interfering with vision
exist.
x
x
x
Check operation of visors.
Visors do not move freely in tracks.
x
x
x
Check function of locking mechanism.
Visor fails to lock in desired position.
x
Check housing for holes and cracks.
Visor housing has any holes or cracks.
10.
Helmet Bag.
x
x
x
11.
Inspect for dirt, missing hardware,
broken stitching.
Fabric is dirty; hardware is missing;
stitching is broken.
MFS.
x
x
x
Check for holes, cracks, or other
damage.
MFS has holes, cracks, or any other
damage.
x
x
x
Check function of latches.
Latches do not function properly.
Table 3-2. CLEANING
COMPONENT
CONDITION
CLEANING
Helmet shell
Dirt, grease, scuff marks
Use mild detergent and clean cloth
Earcups
Dirt, perspiration
Wipe with a damp cloth; for
earphone protection, do not use too much water.
Communications cord
assembly
Dirt, grease
Wipe with damp cloth; dry thoroughly.
Visors
Dust, grease, perspiration
Use soft cloth and mild soap
solution; rinse thoroughly.
Visor housing, track,
knob
Sediment, dirt buildup,
grease
Use clean cloth dampened with mild soap solution.
Retention assembly
Dirt, grease
Use clean cloth dampened with water; allow to dry
thoroughly.
Cloth cover,
TPL or SCL
Dirt, stains
Machine wash (gentle cycle) or hand wash with
warm water; allow to air-dry. (Do not use dryer.)
Plastic layers,
TPL or SCL
Dirt
Wipe exterior layers with damp cloth. Replace
two-sided tape after cleaning.
MFS
Dirt, dust
Wipe with a clean cloth dampened with a mild soap
solution.
42
3-2. TROUBLESHOOTING
Table 3-3 provides an index of common malfunctions of helmet components and directs you to
the procedures required to eliminate those malfunctions. When examining this table, keep the
following in mind:
1. You should first find the malfunction that most closely describes the problem, then perform
the tests, inspections, and corrective actions in the order in which they are listed.
2. This manual may not list every possible malfunction. If you encounter a malfunction not
listed in the table and are unable to resolve it, notify your supervisor.
Table 3-3. Aviation Unit Maintenance Troubleshooting Procedures
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. UNABLE TO RAISE OR LOWER VISOR LENS.
Step 1. Inspect for sediment or dirt buildup in tracks.
Clean tracks in accordance with Table 3-2 (Page 42).
Step 2. Inspect for defective visor knob.
Replace defective visor in accordance with Paragraph 3-3.8 (Page 60).
Step 3. Inspect for defective visor tracks.
Replace defective visor tracks in accordance with
Paragraph 3-3.8 (Page 60).
Step 4. Inspect for defective visor housing.
Replace defective visor housing in accordance with
Paragraph 3-3.8 (Page 60).
Step 5. Inspect visor lenses for defects.
Replace defective lens in accordance with Paragraph 3-3.8 (Page 60).
2. UNABLE TO OPERATE ANVIS GOGGLES (ON OPTIONAL DUAL VISOR
ASSEMBLY).
Refer to the appropriate technical manual.
(Continued on next page)
43
Table 3-3. Aviation Unit Maintenance Troubleshooting Procedures
(continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
3. UNABLE TO FASTEN OR ADJUST CHINSTRAP.
Inspect retention assembly for defective hardware or webbing.
Replace retention assembly in accordance with Paragraph
3-3.3 (Page 51).
4. UNABLE TO ADJUST NAPE STRAP.
Inspect retention assembly for defective hardware or webbing.
Replace retention assembly in accordance with Paragraph
3-3.3 (Page 51).
5. UNABLE TO KEEP MICROPHONE IN POSITION.
Inspect boom/swivel assembly for loose screw.
If unable to tighten screw, replace in accordance with
Paragraph 3-3.5, Page 55 (wire boom), or Paragraph 3-3.6, Page 56 (flex boom).
6. UNABLE TO ATTACH MFS.
Inspect MFS latches and strikers for faulty hardware.
As needed replace latch hardware as in paragraph 3-3.9 (Page 62)
or striker hardware as in Paragraph 3-3.10 (Page 63).
7. UNABLE TO COMMUNICATE.
Ensure that communications cord is plugged into communications unit
and that unit is working. Ensure helmet connector on left rear side of
helmet is secured. If still unable to hear, perform continuity check as
follows:
Step 1. Disconnect microphone cable from microphone.
Step 2. Remove receivers.
(Continued on next page)
44
Table 3-3. Aviation Unit Maintenance Troubleshooting Procedures
(continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 3. Using a multimeter, refer to Figure 3-1 and perform Test 1 in accordance with
the chart below. If no failure is detected, proceed to Step 4. If a failure is detected,
replace the communication cord in accordance with Paragraph 3-3.7 (Page 57).
Proceed to Step 5.
NOTE: Numbers in the Test 1 chart correspond to numbered call-outs in Figure 3-1.
Test 1 Chart
FROM
TO
OPEN
SHORTED
1
1
1
1
2
2
2
5
2
3
5
6
4
5
6
6
Good
Bad
Good
Good
Bad
Good
Good
Good
Bad
Good
Bad
Bad
Good
Bad
Bad
Bad
(Continued on next page)
3
4
1
2
6
5
Figure 3-1. Test Points for Test 1
45
Table 3-3. Aviation Unit Maintenance Troubleshooting Procedures
(continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 4. Using a multimeter, refer to Figure 3-2 and perform Test 2 in
accordance with the chart below.
If no failure is detected, the communication cord is working. Replace the earphones or
the microphone as necessary. Proceed to step 5.
If a failure is detected, unscrew the plug cover and check for any loose connections or
cold solder joints. Resolder any defective connections. Proceed to step 5.
NOTE: Numbers in the Test 2 chart correspond to numbered call-outs in Figure 3-2.
Test 2 Chart
FROM
TO
OPEN
SHORTED
1 or 3
2 or 4
5
6
7
9
8
10
Bad
Bad
Bad
Bad
Good
Good
Good
Good
Step 5. Test the communications system by connecting it to a working radio.
Step 6. If the communications system still does not work, replace the
communications cord in accordance with Paragraph 3-3.7 (Page 57).
1
7
2
3
8
9
4
10
6
5
Figure 3-2. Test Points for Test 2
46
3-3. COMPONENT REPLACEMENT
Replace components that are damaged or worn. Component replacement procedures are as
follows:
• 3-3.1 TPL or SCL cloth cover (Page 48)
• 3-3.2 Energy-absorbing liner (Page 49)
• 3-3.3 Retention assembly (Page 51)
• 3-3.4 Earcups or earphones (Page 53)
• 3-3.5 Microphone-boom-cord-swivel assembly, wire boom (Page 55)
• 3-3.6 Flex boom microphone (Page 56)
• 3-3.7 Communications cord (Page 57)
• 3-3.8 Dual visor assembly (Page 60)
• 3-3.9 MFS latches on shield (Page 62)
• 3-3.10 MFS strikers on helmet (Page 63)
When you replace components or install additional components on Gentex products,
always use genuine factory-new Gentex parts. This will ensure a correct fit and
maintain the safety of the product. Use of non-Gentex parts (salvage, refurbished,
etc.) for replacement or additional installation will void any product warranty and may
compromise the safety of the user.
47
3-3.1 TPL or SCL Cloth Cover
Tools and Materials Required
• Scissors
• Double-sided tape
• TPL cloth cover (XX-Small, 85D7088-15; X-Small, 85D7088-16; Small, 85D7088-17;
Medium, 85D7088-18; Large, 85D7088-19; X-Large, 85D7088-20)
or
• SCL cloth cover (XX-Small, 02D11546-8; X-Small, 02D11546-9; Small, 02D11546-10;
Medium, 02D11546-11; Large, 02D11546-12; X-Large, 02D11546-13)
Removal
1. Detach the earcups from earcup retainer pads
by disengaging the hook-and-pile fasteners, and
passing them through the retention straps.
Allow the earcups to hang outside the helmet by
the communications cord.
2. Referring to Figure 3-3, squeeze the sides of
the TPL (or SCL) and remove the TPL (or SCL)
from the helmet.
3. Remove the TPL (or SCL) cloth cover (Figure
3-4) as follows:
a. Remove and discard the thread attaching
the cloth cover to the plastic layers.
Replacement of thread is not necessary.
Figure 3-3. Removing TPL (or SCL)
Layers
Double-sided tape
(both sides of layers)
b. Fold the sides of the cover down to expose
the double-sided tape.
c. Remove the cover from the layers.
Cover
d. Remove the double-sided tape from the
layers.
Thread
Figure 3-4. TPL (or SCL)
Installation
1. Cut two 2-1/2-inch pieces of double-sided tape.
2. Attach a piece of tape to each side of the layer assembly (where the old tape was removed).
3. Turn the replacement cloth cover inside out; place the cover inside the layer assembly; fold
the sides of the cloth cover over the layer assembly. Ensure that the cover is positioned
correctly.
4. Squeezing the sides of the TPL (or SCL) , reinstall it in the helmet, aligning the rear edge of
the TPL (or SCL) with the top edge of the nape strap pad. Ensure that the nape hanger
strap is taut and the hook-and-pile fasteners are engaged.
5. Reinstall the earcups.
6. Check the fit of the helmet per Paragraph 2-4, beginning on Page 27.
48
3-3.2. Energy-Absorbing Liner
Tools and Materials Required
• Flat-tip screwdriver
• Icing spatula
• Energy-absorbing liner (XX-Small, 89D7812-1; X-Small, 89D7812-2; Small, 89D7812-3;
Medium, 89D7812-4; Large, 89D7812-5; X-Large, 89D7812-6)
NOTE: Before performing this procedure, disengage the chinstrap buckle, and loosen the nape
strap pad. This will ease removal of the energy-absorbing liner.
Removal
1. Detach the earcups from the
earcup retaining pads by
disengaging the
hook-and-pile fasteners, and
pass the earcups through
the retention straps. Allow
earcups to hang outside the
helmet by communications
cord.
2. Referring to Figure 3-5,
squeeze sides of TPL (or
SCL) and remove it from
helmet by disengaging the
front and rear hook-and-pile
fasteners.
3. Referring to Figure 3-6,
remove the pan-head screw,
spring washer, and post
fastening the retention
assembly to the center rear
of the helmet shell. Retain
the screw, washer, and post
for reassembly.
Figure 3-5. Removing TPL (or SCL)
Screw
4. Loosen the nape strap pad
as much as possible.
(Continued on next page)
Figure 3-6. Rear Retention Screw
49
NOTE: Removing the energy-absorbing liner may require some practice.
5. Referring to Figure 3-7, use a spatula to separate the hook-and-pile fasteners attaching the
energy-absorbing liner to the helmet shell. Following the contour of the helmet shell,
carefully slide the energy-absorbing liner out of the helmet.
Figure 3-7. Removing Energy-Absorbing Liner
Installation
1. Position the front of the energy-absorbing liner at the rear of the helmet between the nape
strap pad assembly and the helmet shell.
2. Following the contour of the helmet shell, slide the energy-absorbing liner into the helmet.
Attach the pile fasteners on the energy-absorbing liner to the hook fasteners on the inside of
the helmet shell. Ensure front edge of liner is aligned with front edge of helmet shell.
NOTE: Installing the energy-absorbing liner may require some practice.
3. Reattach the nape strap pad to the helmet shell via the screw, washer, and post removed
previously.
4. Squeezing the sides of the TPL (or SCL), reinstall it in the helmet with the rear edge aligned
with the top edge of the nape strap pad. Ensure that the nape hanger strap is taught and
the hook-and-pile fasteners are engaged.
5. Reattach the earcups to the earcup retaining pads.
6. Check the fit of the helmet per Paragraph 2-4, beginning on Page 27.
50
3-3.3. Retention Assembly
Tools and Materials Required
• Screwdriver, flat-tip
• Spatula
• Retention assembly (95D9303-1)
Removal
NOTE: Ensure that the chinstrap is
disengaged from the D-rings, and
loosen nape strap pad adjustment.
This will provide easier access to the
helmet for installation.
1. Detach the earcups from earcup
retainer pads by disengaging
hook-and-pile fasteners, and pass
the earcups through the retention
straps. Allow earcups to hang
outside the helmet by
communications cord.
Figure 3-8. Removing TPL (or SCL)
Screw
2. Referring to Figure 3-8, remove the
TPL (or SCL) from the helmet.
3. Referring to Figure 3-9, remove the
pan-head screw, spring washer,
and post attaching the retention
assembly to the center rear of the
helmet shell. Retain the screw,
washer, and post for reinstallation.
Figure 3-9. Rear Retention Screw
4. Referring to Figure 3-10, use
a spatula to separate the
hook-and-pile fastener attaching
the energy-absorbing liner to the
helmet shell.
NOTE: Removing the energy-absorbing
liner may require some practice.
5. Carefully slide the energyabsorbing liner out through the
rear of the helmet, following the
contour of the helmet shell.
(Continued on next page)
Figure 3-10. Removing Energy-Absorbing
Liner
51
6. Inspect the energyabsorbing liner in
accordance with Table 3-1;
replace if necessary
following 3-3.1.
Screws
7. Referring to Figure 3-11,
remove the remaining two
pan-head screws, spring
washers, and posts
attaching the retention
assembly to each side of
the helmet shell.
8. Remove the entire
retention assembly from
the helmet.
Figure 3-11. Retention Assembly Attachment Points
Installation
1. Attach the retention assembly to the helmet shell by installing four screws, washers, and
posts at the attachment points indicated in Removal step 7.
2. Position the front edge of the energy-absorbing liner between the nape strap pad and the
helmet shell at the rear of the helmet. Following the contour of the helmet shell, slide the
liner into the helmet until the front edge of the liner is flush with the front edge of the helmet
shell. Ensure that the hook-and-pile fasteners are engaged.
NOTE: Ensure that the holes in the energy-absorbing liner align with the plenum
openings for air cooling. In addition, the square hole should be located to allow access
to the retention assembly mounting hardware.
3. Reinstall the screw, washer, and post removed in Removal step 3.
4. Squeezing the sides of the TPL (or SCL), reinstall it in the helmet with the rear edge aligned
with the top edge of the nape strap pad. Ensure that the nape hanger strap is taut and the
hook-and-pile fasteners are engaged.
5. Reinstall the earcups.
6. Check the fit of the helmet per Paragraph 2-4, beginning on Page 27.
52
3-3.4 Earcups or Earphones
Tools and Materials Required
• Jeweler’s screwdriver set
• Earcup (98C10337-1) or earphone (73B2619)
Removal
1. Referring to Figure 3-12, detach the
earcup from the earcup retaining pad.
2. Referring to Figure 3-13, do the
following:
a. Remove the earseal from the earcup
by stretching it carefully over the lip
of the earcup shell.
b. Remove the earphone holder from
the earcup.
c. Remove the earphone from the
earphone holder.
d. Using a jeweler’s screwdriver,
loosen (do not remove) the two set
screws on the back of the earphone;
remove the communications cord
leads from the earphone.
Figure 3-12. Earcup Detached
(Continued on next page)
Earcup
Filler pad
Receiver
Receiver retainer
Earseal
Communications cord leads
Figure 3-13. Earcup Assembly
53
e. Remove the foam filler pad from the earcup.
f.
If you are replacing the earcup, carefully remove the communications cord leads through
the hole in the earcup.
3. Inspect all earcup components in accordance with Table 3-1, and replace as necessary.
Installation
1. If you removed the communications cord leads (Step 2f), insert the communications cord
leads through the hole in the earcup.
2. Insert the communications cord leads into the receiver. Using a jeweler’s screwdriver,
tighten the two set screws.
3. Insert the filler pad into the earcup, ensuring that the slit in the pad is positioned toward the
earcup hole. Route the communications cord through the slit, ensuring that the receiver and
the communications cord leads are accessible.
4. Insert the earphone into the earphone holder, and insert both into the earcup.
5. Install the earseal on the earcup as follows: hook one end of the earseal over the lip of the
earcup shell. Carefully stretch the earseal over the remainder of the earcup.
6. Attach the earcup to the earcup retainer pad. Ensure that the earcup is securely attached.
7. Check earcup position per Paragraph 2-4, beginning on Page 27, and adjust as necessary.
54
3-3.5. Microphone Boom/Cord/Swivel Assembly (Wire Boom)
Tools and Materials Required
• Screwdriver, flat-tip
• Screwdriver, cross-tip
• Microphone boom/cord/swivel assembly, wire boom (95B9314-2)
Removal
Connector
1. Referring to Figure 3-14,
unplug the microphone cord
from the connector at the
rear of the helmet.
2. Referring to Figure 3-15,
remove the center screw
attaching the
microphone-boomcord-swivel assembly
to the helmet.
Microphone plug
Figure 3-14. Microphone Cord and Connector
Installation
1. Referring to Figure 3-15, attach the replacement microphone-boom-cord-swivel assembly
to the helmet. Ensure that the boom is seated within the grooves on the grooved washers.
2. Referring to Figure 3-14, plug the microphone cord into the connector at the rear of the
helmet.
Grooved
washers
Boom
Center
screw
Swivel
Figure 3-15. Microphone Boom/Cord/Swivel Assembly
55
3-3.6. Flex Boom Microphone
Tools and Materials Required
• Screwdriver, flat-tip
• Screwdriver, cross-tip
• Flex boom microphone (03B11804-16B)
Removal
Connector
1. Referring to Figure 3-16,
unplug the microphone
cord from the connector at
the rear of the helmet.
2. Referring to Figure 3-17,
remove the hardware
attaching the flex boom
microphone to the helmet.
Microphone plug
Figure 3-16. Microphone Cord and Connector
Installation
1. Referring to Figure 3-17, attach the replacement flex boom microphone to the helmet with
the hardware. Tighten the screw to prevent the flex boom mount from moving on the
helmet.
2. Referring to Figure 3-16, plug the microphone cord into the connector at the rear of the
helmet.
NOTE: You can install the flex boom
mount outside or inside the helmet
as shown here.
Helmet
Inside helmet
Outside helmet
Nut
Screw
Lock washer
Flat washer
Alternate location
of flex boom mount
Figure 3-17. Flex Boom Microphone
56
Flex boom mount
3-3.7. Communications Cord
Tools and Materials Required
•
•
•
•
•
•
•
Screwdriver, flat-tip
Screwdriver, cross-tip
Spatula
Jeweler’s screwdriver set
Heat gun
Small scissors
Communications cord (standard, 77C3523-1; or coiled, 87B7491-2)
Removal
1. Referring to Figure 3-16 (previous page), unplug the microphone cord from the connector
at the left rear of the helmet.
2. Perform Steps 1-3 of Paragraph 3-3.4 (beginning on Page 53) to remove and disassemble
both earcups and remove the earphones from the communications cord.
3. Perform Steps 1-5 of Paragraph
3-3.2 (beginning on Page 49) to
remove the TPL (or SCL) and
the energy-absorbing liner from
the helmet.
Post
Strain relief plate
Helmet
4. Referring to Figure 3-18,
remove the strain relief plate
(and the shrink tubing on the
connector) as follows:
Washer
Screw
a. Remove the screw, washer,
and post attaching the
communications cord strain
relief plate to the helmet
shell.
b. Untie the communications
cord from the strain relief
plate.
Shrink tubing
on connector
c. Cut the shrink tubing from
the connector.
(Continued on next page)
Figure 3-18. Strain Relief Plate
and Hardware
57
5. Referring to Figure 3-19,
bend the arms of the jack
holder slightly away from the
connector, and remove the
connector from the jack
holder.
Jack holder
Connector
Arms
Arms
6. Referring to Figure 3-20,
remove the two screws
attaching the jack holder and
plate to the rear of the helmet.
7. Referring to Figure 3-21,
remove the grommet from the
helmet, and remove the entire
communications cord from the
helmet through the grommet
hole.
Figure 3-19. Jack Holder and Connector
Screws
Installation
1. Referring to Figure 3-21,
insert the replacement
communications cord from the
outside of the helmet through
the grommet hole so that only
the connector and the
grommet are on the outside of
the helmet.
2. Insert the grommet so that it is
firmly seated in the hole.
3. Referring to Figure 3-20,
reattach the jack holder and
plate to the helmet with the
two screws.
Plate
(inside
helmet)
Jack holder
Figure 3-20. Jack Holder, Plate, and Screws
Grommet
4. Referring to Figure 3-19,
insert the connector into the
jack holder, and bend the
arms of the jack holder slightly
to help hold the connector in
place.
Communications cord
(Continued on next page)
58
Figure 3-21. Connector and Grommet
5. Referring to Figure 3-22,
place a 3/4”-long segment of
shrink tubing over the
connector.
6. Apply heat to shrink the tubing
to the connector. Trim the
shrink tubing as flush as
possible with the edge of the
connector.
Connector
Shrink tubing
7. Referring to Figure 3-23,
reinstall the strain relief plate
as follows:
a. Tie the cord to the strain
relief plate.
b. Reattach the strain relief
plate to the helmet with
the screw, washer and
post.
8. Perform Installation Steps
1-6 of Paragraph 3-3.2 (Page
50) to reattach the nape strap
pad and reinstall the TPL
(or SCL) and the
energy-absorbing liner.
Figure 3-22. Shrink Tubing and Connector
Post
Strain relief plate
Cord
Helmet
Washer
Screw
9. Perform Installation Steps
1-7 of Paragraph 3-3.4 (Page
54) to reattach the earphones
and reassemble and reinstall
both earcups.
10. Referring to Figure 3-16
(Page 56), plug the
microphone into the connector
at the left rear of the helmet.
Figure 3-23. Strain Relief Plate Hardware
59
3-3.8. Dual Visor Assembly
Tools and Materials Required
• Jeweler’s screwdriver set
• Screwdriver, cross-tip
• Dual visor assembly (plain, 95B9301-3; ANVIS quick disconnect, 95B9246; or ANVIS
direct-mount, 88D7611-1)
Removal
NOTE: Screws, retaining rings, tracks, and bushings are shown on one side only in Figure
3-24. A similar configuration exists for the other side.
1. Referring to Figure 3-24,
loosen the four
thumbscrews that attach
the visor assembly to the
helmet. Holding the tracks
and the housing together,
lift the visor assembly from
the helmet.
2. Remove the thumbscrews
from the visor assembly.
Outer
visor
3. Remove the housing from
the tracks.
4. Disassemble the visors and
the tracks by removing the
retaining rings and the
bushings. Repeat for the
other side.
NOTE: A nut plate on the
underside of the helmet shell
holds the posts in place. If the
post threads are stripped,
remove energy-absorbing liner
as directed in Paragraph 3-3.2
(Page 49), replace the nut
plate, and reinstall the
energy-absorbing liner.
5. Inspect the components in
accordance with Table 3-1,
and replace as necessary.
(Continued on next page)
60
Downstop
locking screw
Housing
Thumbscrews
Retaining
rings
Upper
track
Inner
visor
Middle
track
Lower
track
Bushings
Helmet shell
Nut plate
Figure 3-24. Dual Visor Assembly (Exploded View)
Installation
NOTES:
• When installing lenses, ensure lens guides are seated in track grooves.
• Ensure bushing mates with locking notch in lower track to prevent rotation when installing
or removing thumbscrews.
• If energy-absorbing liner was removed, replace it as directed in Paragraph 3-3.2 (after
replacing the nut plate).
1. Referring to Figure 3-24, insert the bushings upward through the lower track.
2. Place the inner visor over the lower track.
3. Place the middle track over the inner visor. Insert the bushings upward through the middle
track.
4. Place the upper track over the outer visor, and install it in place on the bushings.
5. Reinstall the retaining rings.
6. Attach the housing to the tracks by inserting the thumbscrews through the housing and
threading them through the bushings.
7. Install the four thumbscrews downward through the bushings and into the nut plate posts to
attach the visor assembly to the helmet. Tighten the thumbscrews evenly.
8. If necessary, adjust the visor as follows:
a. Loosen (do not remove) the downstop locking screws through the holes on each side of
the visor housing. (Loosening the screws allows the downstop to be raised or lowered
approximately 1 inch (25 mm) for visor-to-mask or facial conformance.)
b. When the desired position is attained, tighten the downstop locking screws.
61
3-3.9 MFS Latch Assembly (on shield)
Tools and Materials Required
• Screwdriver, cross-tip
• White glue
• MFS latch hardware kit (89C7816-2)
Removal
Screws
Referring to Figure 3-25, remove
the latch assembly by removing
the screws and posts that attach
the latch assembly to the MFS.
Installation
Referring to Figure 3-25, attach
the replacement latch assembly
to the shield with the screws and
posts (6-32 x 0.100”) provided in
the latch assembly kit, applying a
drop of white glue to the threads
of each screw.
62
Latch
assembly
Shield
Figure 3-25. Latch Assembly
3-3.10 MFS Striker (on helmet)
Tools and Materials Required
• Screwdriver, cross-tip
• White glue
• MFS striker hardware kit (89C7816-1)
Removal
Striker
Referring to Figure 3-26, remove
screws and posts attaching the
striker to be replaced.
Screws
Posts
Installation
Referring to Figure 3-26, install
the new striker with the screws
and posts (6-32 x 0.053”)
supplied in the hardware kit,
applying a drop of white glue to
the threads of each screw.
Helmet
Figure 3-26. Striker and Hardware
63
SECTION 4: REPLACEMENT PARTS
This section contains figures and lists of replacement parts for the HGU-56/P Commercial
Helmet Assembly. Each figure is associated with a parts list that includes quantities and part
numbers. Numbers in the ITEM NO. column of each list correspond to numbered call-outs in the
figures. For more information, contact:
GENTEX Corporation
P.O. Box 315
Carbondale, PA 18407
Phone: (570) 282-3550
Fax: (570) 282-8555
www.gentexcorp.com
4-1 STANDARD COMPONENTS
Figures 4-1 through 4-4 show standard components. (For optional components, see Figures
4-5 through 4-9, beginning on Page 70.)
2
1
19
20
18
5
22
10
21
9
4
8
3
7
6
16
11
14
12
17
9
8
15
13
Figure 4-1. Standard Components of HGU-56/P
64
ITEM NO.
(Figure 4-1)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
DESCRIPTION
Helmet Assembly, HGU-56/P Commercial, XX-Small
Helmet Assembly, HGU-56/P Commercial, X-Small
Helmet Assembly, HGU-56/P Commercial, Small
Helmet Assembly, HGU-56/P Commercial, Medium
Helmet Assembly, HGU-56/P Commercial, Large
Helmet Assembly, HGU-56/P Commercial, X-Large
Helmet Shell, Small (Used on XX-Small, X-Small, and Small Assemblies)
Helmet Shell, Medium
Helmet Shell, Large
Helmet Shell, X-Large
Hook Fastener, ½ inch x 1 inch (Not Shown)
Hook Fastener, ½ inch x 2 inches (Not Shown)
Dual Visor Assembly, Plain (Breakdown: Figure 4-2)
Nut Plate
Retention System
Earcup Assembly (Breakdown: Figure 4-3)
Post, 1/16 (For comm. cord strain relief plate)
Post, 8-32 x 3/16 (For retention assembly)
Screw, D-366 type, 8-32 x 1/4
Washer, Spring
Cord Assembly, 25" CIP, U174 plug
Strain Relief Plate
Grommet
Jack Holder
Shrink Tubing
Plate, Jack Holder
Screw, Fillister Head, #2-56 x 3/16
Earphone, 19-ohm
Microphone/Boom/Cord/Swivel
Energy-Absorbing Liner, XX-Small
Energy-Absorbing Liner, X-Small
Energy-Absorbing Liner, Small
Energy-Absorbing Liner, Medium
Energy-Absorbing Liner, Large
Energy-Absorbing Liner, X-Large
TPL, XX-Small (Breakdown: Figure 4-4)
TPL, X-Small (Breakdown: Figure 4-4)
TPL, Small (Breakdown: Figure 4-4)
TPL, Medium (Breakdown: Figure 4-4)
TPL, Large (Breakdown: Figure 4-4)
TPL, X-Large (Breakdown: Figure 4-4)
Spacer Pad Set
Headband Pad Kit
Instruction Booklet (Not Shown)
QTY.
PART NO.
1
1
1
1
2
1
1
2
1
2
1
5
6
6
1
1
1
1
1
1
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
95D9317-1
95D9317-2
95D9317-3
95D9317-4
95D9317-5
95D9317-6
95A9241-2
95A9242-2
95A9243-2
95A9244-2
90B8021-2
90B8021-3
95B9301-3
91B8181
95D9303-1
98C10338-1
69A2104-1
69A2104-3
75A3093-9
76A3443
77C3523-1
69A2060
67A1809-2
69B2035
69A2045-9
69A2037-2
69A2036
73B2619
95B9314-2
89D7812-1
89D7812-2
89D7812-3
89D7812-4
89D7812-5
89D7812-6
85D7087-15
85D7087-16
85D7087-17
85D7087-18
85D7087-19
85D7087-20
93B8541
78A4163-10
TP0113
65
1
11
8
10
3
6
7
5
2
4
9
Figure 4-2. Dual Visor Assembly, Plain
66
ITEM NO.
(Figure 4-2)
DESCRIPTION
QTY.
Dual Visor Assembly, Plain
PART NO.
95B9301-3
1
Visor Housing, Plain, White
1
88D7612-2
2
Inner Visor, Clear
1
88D7618-1
3
Outer Visor, Neutral
1
88D7619-1
4
Lower Track, Left-Hand
1
88D7615-1
Lower Track, Right-Hand (Not Shown)
1
88D7615-2
Middle Track, Left-Hand
1
88C7616-1
Middle Track, Right-Hand (Not Shown)
1
88C7616-2
Upper Track, Left-Hand
1
88C7617-1
Upper Track, Right-Hand (Not Shown)
1
88C7617-2
Adjustment Plate, Left-Hand
1
88B7622-1
Adjustment Plate, Right-Hand (Not Shown)
1
88B7622-2
8
Thumbscrew
4
93B8464
9
Bushing Sleeve
4
93B8463
10
E-Ring
4
MS16633-4018
11
Pan-Head Screw, 2-56 x 1/8
2
MS51957-1B
5
6
7
67
2
1
3
4
Figure 4-3. Earcup Assembly
ITEM NO.
(Figure 4-3)
DESCRIPTION
QTY.
Earcup Assembly
68
PART NO.
98C10338-1
1
Shell, Earcup Assembly
2
98C10337-1
2
Filler Pad
2
97B9974-1
3
Receiver Retainer
2
83C6573
4
Earseal
2
75C2990
1
2
Figure 4-4. TPL
ITEM NO.
(Figure 4-4)
-1
-2
DESCRIPTION
QTY.
PART NO.
TPL, XX-Small
85D7087-15
TPL, X-Small
85D7087-16
TPL, Small
85D7087-17
TPL, Medium
85D7087-18
TPL, Large
85D7087-19
TPL, X-Large
85D7087-20
Layer Assembly, Preformed, XX-Small
1
89D7779-1
Layer Assembly, Preformed, X-Small
1
89D7779-2
Layer Assembly, Preformed, Small
1
89D7779-3
Layer Assembly, Preformed, Medium
1
89D7779-4
Layer Assembly, Preformed, Large
1
89D7779-5
Layer Assembly, Preformed, X-Large
1
89D7779-6
Cover Assembly, XX-Small
1
85D7088-15
Cover Assembly, X-Small
1
85D7088-16
Cover Assembly, Small
1
85D7088-17
Cover Assembly, Medium
1
85D7088-18
Cover Assembly, Large
1
85D7088-19
Cover Assembly, X-Large
1
85D7088-20
69
4-2 OPTIONAL COMPONENTS
Figures 4-5 through 4-9 show optional components. (For standard components, see Figures
4-1 through 4-4, beginning on Page 64.)
1
3
5
4
2
6
11
10
7
9
8
Figure 4-5. Optional Components of HGU-56/P
70
ITEM NO.
(Figure 4-5)
DESCRIPTION
QTY.
PART NO.
1
Optional Dual Visor Assembly, ANVIS Quick-Disconnect
(Breakdown: Figure 4-6)
1
95B9246
2
Mounting Kit, ANVIS Quick-Disconnect
(Breakdown: Figure 4-6)
1
96A9378
3
Optional Dual Visor Assembly, ANVIS Direct-Mount
(Breakdown: Figure 4-7)
1
88D7611-1
4
Mounting Kit, ANVIS Direct-Mount
(Breakdown: Figure 4-7)
1
93A8654
5
SCL, XX-Small (Breakdown: Figure 4-8)
1
02D11531-8
SCL, X-Small (Breakdown: Figure 4-8)
1
02D11531-9
SCL, Small (Breakdown: Figure 4-8)
1
02D11531-10
SCL, Medium (Breakdown: Figure 4-8)
1
02D11531-11
SCL, Large (Breakdown: Figure 4-8)
1
02D11531-12
SCL, X-Large (Breakdown: Figure 4-8)
1
02D11531-13
Helmet Bag, Woodland Camouflage
1
92D8235
Helmet Bag, Desert Camouflage
1
92D8235-1
Helmet Bag, Black
1
92D8235-2
Helmet Bag, Universal Camouflage (ACU)
1
92D8235-3
7
Hardware Kit, Flex Boom
1
04A11895-1
8
Flex Boom
1
03B11804-16B
9
Coiled Communications Cord
1
87B7491-2
10
High-Contrast Visor, Outer
1
95A9302-5
11
MFS (Breakdown: Figure 4-9)
1
88C7626
6
71
12
18
1
17
15
13
11
16
14
8
10
3
6
7
5
2
4
9
Figure 4-6. ANVIS Quick-Disconnect Dual Visor Assembly
72
ITEM NO.
(Figure 4-6)
DESCRIPTION
QTY.
Dual Visor Assembly, Quick-Disconnect, ANVIS
1
PART NO.
95B9246
Visor Housing Assembly, Aircraft Green
1
95C9240-1
Visor Housing Assembly, Coast Guard Blue
1
95C9240-2
Visor Housing Assembly, White
1
95C9240-3
Visor Housing Assembly, O.D.
1
95C9240-4
Inner Visor, Clear
1
88D7618-1
Inner Visor, Neutral (Not Shown)
1
96A9416-1
Outer Visor, Neutral
1
88D7619-1
Outer Visor, Clear (Not Shown)
1
95A9302-2
Lower Track, Left-Hand
1
88D7615-1
Lower Track, Right-Hand (Not Shown)
1
88D7615-2
Middle Track, Left-Hand
1
88C7616-1
Middle Track, Right-Hand (Not Shown)
1
88C7616-2
Upper Track, Left-Hand
1
88C7617-1
Upper Track, Right-Hand (Not Shown)
1
88C7617-2
Adjustment Plate, Left-Hand
1
88B7622-1
Adjustment Plate, Right-Hand (Not Shown)
1
88B7622-2
8
Thumbscrew
4
93B8464
9
Bushing Sleeve
4
93B8463
10
E-Ring
4
MS16633-4018
11
Pan-Head Screw, 2-56 x 1/8
2
MS51957-1B
ITEM NO.
(Figure 4-6)
DESCRIPTION
QTY.
PART NO.
2
3
4
5
6
7
Modification Kit, ANVIS Quick-Disconnect
96A9378
12
Hook Tape, 1 inch x 1-1/8 inches (Connector)
1
90B8021-1
13
Top Locating Pin
2
90B7991
14
Bottom Locating Pin
2
90B7990
15
Clamp, ANVIS Strain Relief
1
90B8016
16
Backing Plate, ANVIS Mount
1
96B9377
17
Pile Fastener, 2 inches x 2 inches
1
90B7951-2
18
Pile Fastener, 2 inches x 3 inches
2
90B7951-1
Instruction Booklet
1
TP0127
73
14
12
1
11
13
15
8
10
3
6
7
5
2
4
9
Figure 4-7. ANVIS Direct-Mount Dual Visor Assembly
74
ITEM NO.
(Figure 4-7)
DESCRIPTION
QTY.
Dual Visor Assembly, ANVIS Direct-Mount
PART NO.
88D7611-1
1
Visor Housing
1
88D7613
2
Inner Visor, Clear
1
88D7618-1
3
Outer Visor, Neutral
1
88D7619-1
4
Lower Track, Left-Hand
1
88D7615-1
Lower Track, Right-Hand (Not Shown)
1
88D7615-2
Middle Track, Left-Hand
1
88C7616-1
Middle Track, Right-Hand (Not Shown)
1
88C7616-2
Upper Track, Left-Hand
1
88C7617-1
Upper Track, Right-Hand (Not Shown)
1
88C7617-2
Adjustment Plate, Left-Hand
1
88B7622-1
Adjustment Plate, Right-Hand (Not Shown)
1
88B7622-2
8
Thumbscrew
4
93B8464
9
Bushing Sleeve
4
93B8463
10
E-Ring
4
MS16633-4018
11
Pan-Head Screw, 2-56 x 1/8
2
MS51957-1B
ITEM NO.
(Figure 4-7)
DESCRIPTION
QTY.
PART NO.
5
6
7
Mounting Kit, ANVIS Direct-Mount
93A8654
12
Lens Guard
2
82A5653-1
13
Pad, Protector, Visor
1
94A8689
14
Screw, Machine
4
MS51957-12
15
Pile Fastener (ANVIS Battery Pack)
2
90B7951-1
75
1
2
Figure 4-8. SCL
ITEM NO.
(Figure 4-8)
-1
-2
76
DESCRIPTION
QTY.
PART NO.
SCL, XX-Small
02D11531-8
SCL, X-Small
02D11531-9
SCL, Small
02D11531-10
SCL, Medium
02D11531-11
SCL, Large
02D11531-12
SCL, X-Large
02D11531-13
Layer Assembly, Preformed, XX-Small
1
02D11663-1
Layer Assembly, Preformed, X-Small
1
02D11663-2
Layer Assembly, Preformed, Small
1
02D11663-3
Layer Assembly, Preformed, Medium
1
02D11663-4
Layer Assembly, Preformed, Large
1
02D11663-5
Layer Assembly, Preformed, X-Large
1
02D11663-6
Cover Assembly, XX-Small
1
02D11546-8
Cover Assembly, X-Small
1
02D11546-9
Cover Assembly, Small
1
02D11546-10
Cover Assembly, Medium
1
02D11546-11
Cover Assembly, Large
1
02D11546-12
Cover Assembly, X-Large
1
02D11546-13
3
1
2
Figure 4-9. MFS
ITEM NO.
(Figure 4-9)
DESCRIPTION
QTY.
Complete MFS (includes MFS and all hardware)
PART NO.
88C7626
1
MFS with Latches
1
96C9601
2
Hardware Kit (Helmet Strikers)
1
89C7816-1
3
Hardware Kit (Shield Latches)
1
89C7816-2
77
NOTES
PUBLICATION TP0113 REV. 5
APRIL 2010