united states air force aircraft accident investigation board report

UNITED STATES AIR FORCE
AIRCRAFT ACCIDENT INVESTIGATION
BOARD REPORT
MQ-1B, T/N 00-3068
11th Reconnaissance Squadron
432d Air Expeditionary Wing
Creech Air Force Base, Nevada
LOCATION: Creech Air Force Base, Nevada
DATE OF ACCIDENT: 28 April 2009
BOARD PRESIDENT: Lieutenant Colonel Gary A. Toppert
Conducted IAW Air Force Instruction 51-503, Chapter 11
EXECUTIVE SUMMARY
AIRCRAFT ACCIDENT INVESTIGATION
MQ-1B, T/N 00-3068, CREECH AIR FORCE BASE, NEVADA
28 APRIL 2009
On 28 April 2009, at 0804:49 local (L) time, the mishap remotely piloted aircraft (MRPA), a
MQ-1B Predator, tail number 00-3068, crashed 1 ½ miles west of Creech Air Force Base,
Nevada, approximately 1 ½ minutes after takeoff. The crash site was uneven desert terrain with
scrub brush. The MRPA’s structure and mechanical components were damaged as a result of the
mishap. The estimated cost of repair is $543,178.30. This includes replacement cost for the
engine and training hellfire missile and repair cost for the multi-spectral targeting system
(MTS-A) and other structural damage. There were no injuries and there was no damage to other
government or private property.
After normal maintenance and pre-flight checks, the MRPA taxied and departed at 0803:22L.
Approximately 1 minute into the flight, the MRPA’s engine began to oscillate. The MRPA was
travelling at a speed of 74 knots indicated airspeed and at an estimated altitude of 240 feet above
ground level. As the engine speed oscillated between 5633 and 1145 revolutions per minute, the
MRPA quickly approached stall speed and began to descend at a high rate. The MRPA impacted
the ground 29 seconds after the first engine oscillation. The MRPA rolled across uneven desert
terrain with scrub brush for 4 seconds. Its landing gear then collapsed, causing it to spin before
coming to rest 6 seconds after initial impact.
The Accident Investigation Board (AIB) President determined by clear and convincing evidence
that the cause of the mishap was the failure of the Manifold Absolute Pressure (MAP) reference
vacuum line that became disconnected at a “T” fitting. The AIB President determined that the
installation of the vacuum line was in accordance with Air Force technical orders (T.O.). The
T.O.s did not provide guidance on length or routing of the vacuum lines. However, the vacuum
line attached to the plenum was cut too short based upon the location of the “T” fitting, which
put extra tension on the carburetor vacuum lines. The extra tension caused the plenum vacuum
line to work itself loose from the “T” fitting. At 0804:20L the vacuum line disconnected in
flight. This resulted in loss of reference MAP supplied to the carburetors, leaning the air fuel
mixture entering the engine’s cylinders. The lean mixture caused the engine to begin oscillating,
which caused the MRPA to rapidly lose airspeed and altitude. Due to the low airspeed and
altitude and having no engine power, the mishap pilot was unable to take action to prevent the
MRPA from impacting the ground. In the 29 seconds the mishap pilot had to react, he
maintained control of the MRPA, analyzed the situation, and selected the most appropriate
landing location. Immediately prior to impact, he pulled the MRPA’s nose up to try to protect
the MTS-A attached to the front of the MRPA. The MTS-A was functioning subsequent to the
mishap and has been assessed to be repairable. Due to the terrain the MRPA landed on, damage
to the structure and engine of the aircraft was unavoidable.
Under 10 U.S.C. 2254(d), any opinion of the accident investigators as to the cause of, or the factors
contributing to, the accident set forth in the accident investigation report may not be considered as
evidence in any civil or criminal proceeding arising from the accident, nor may such information be
considered an admission of liability of the United States or by any person referred to in those
conclusions or statements.
SUMMARY OF FACTS AND STATEMENT OF OPINION
MQ-1B, T/N 00-3068
28 APRIL 2009
TABLE OF CONTENTS
TABLE OF CONTENTS ................................................................................................................. i
COMMONLY USED ACRONYMS AND ABBREVIATIONS .................................................. iii
SUMMARY OF FACTS ................................................................................................................ 1
1. AUTHORITY, PURPOSE, AND CIRCUMSTANCES .....................................................1
a. Authority ........................................................................................................................1
b. Purpose...........................................................................................................................1
c. Circumstances ................................................................................................................1
2. ACCIDENT SUMMARY ....................................................................................................1
3. BACKGROUND .................................................................................................................2
a. 432d Wing......................................................................................................................2
b. 11th Reconnaissance Squadron......................................................................................2
c. MQ-1B Predator System ................................................................................................2
4. SEQUENCE OF EVENTS ..................................................................................................3
a. Mission...........................................................................................................................3
b. Planning .........................................................................................................................3
c. Preflight..........................................................................................................................3
d. Summary of Accident ....................................................................................................4
e. Impact ............................................................................................................................4
f. Life Support Equipment, Egress and Survival ...............................................................5
g. Search and Rescue (SAR) ..............................................................................................5
h. Recovery of Remains .....................................................................................................5
5. MAINTENANCE ................................................................................................................5
a. Forms Documentation ....................................................................................................5
b. Inspections .....................................................................................................................5
c. Maintenance Procedures ................................................................................................5
d. Maintenance Personnel and Supervision .......................................................................6
e. Fuel, Hydraulic and Oil Inspection Analysis .................................................................6
f. Unscheduled Maintenance .............................................................................................7
6. AIRCRAFT AND AIRFRAME ..........................................................................................7
a. Condition of Systems .....................................................................................................7
b. Testing............................................................................................................................8
c. Functionality of Equipment ...........................................................................................9
d. Post Mishap Component Testing ...................................................................................9
7. WEATHER ..........................................................................................................................9
8. CREW QUALIFICATIONS ................................................................................................9
a. Mishap Pilot ...................................................................................................................9
MQ-1B, T/N 00-3068, 28 April 2009
i
(1) Training ................................................................................................................... 9
(2) Experience............................................................................................................... 9
b. Mishap Sensor Operator ..............................................................................................10
(1) Training ................................................................................................................. 10
(2) Experience............................................................................................................. 10
9. MEDICAL .........................................................................................................................10
a. Qualifications ...............................................................................................................10
b. Health ...........................................................................................................................10
c. Toxicology ...................................................................................................................11
d. Lifestyle .......................................................................................................................11
e. Crew Rest and Crew Duty Time ..................................................................................11
10. OPERATIONS AND SUPERVISION ..............................................................................12
11. HUMAN FACTORS .........................................................................................................12
12. GOVERNING DIRECTIVES AND PUBLICATIONS ....................................................12
a. Primary Operations Directives and Publications .........................................................12
b. Maintenance Directives and Publications ....................................................................12
c. Known or Suspected Deviations from Directives or Publications...............................13
13. NEWS MEDIA INVOLVEMENT ....................................................................................13
14. ADDITIONAL AREAS OF CONCERN ..........................................................................13
STATEMENT OF OPINION ....................................................................................................... 14
1. OPINION SUMMARY .....................................................................................................14
2. DISCUSSION OF OPINION ............................................................................................14
INDEX OF TABS ......................................................................................................................... 16
MQ-1B, T/N 00-3068, 28 April 2009
ii
COMMONLY USED ACRONYMS AND ABBREVIATIONS
11 RS
432 WG
432 OG
ACC
AEW
AF
AFB
AFETS
AFI
AFTO
AGL
AIB
ALT
BFS
BSA
C
CAMS
COMACC
CONUS
Dash 1
EGT
GA ASI
GCS
GDT
HUD
In Hg
IPI
IQT
KIAS
11th Reconnaissance Squadron
432d Wing
432d Operations Group
Air Combat Command
Air Expeditionary Wing
Air Force
Air Force Base
Air Force Engineering and Technical
Services
Air Force Instruction
Air Force Technical Order
Above Ground Level
Aircraft Investigation Board
Altitude
Battlespace Flight Services
Basic Surface Attack
Centigrade
Consolidated Aircraft Maintenance
System
Commander Air Combat Command
Continental United States
T.O. 1Q-1(M)B-1 Flight Manual
Exhaust Gas Temperature
General Atomics Aeronautical
Systems, Incorporated
Ground Control Station
Ground Data Terminal
Heads Up Display
Inches of Mercury
Initial Process Inspection
Initial Qualification Training
Knots Indicated Airspeed
kPa
KTL
L
Lbs
LOS
LR
LRE
MAJCOM
MAP
MDT
MP
MRPA
MSL
MSO
MTS
NV
PSI
RPM
SAT
SATCOM
SPMA
TCTO
T/N
T.O.
UAS
U.S.
U.S.C.
USAF
VPP
VSI
WG
Vapor Pressure
Key Task List
Local Time
Pounds
Line of Sight
Launch and Recovery
Launch and Recovery Element
Major Command
Manifold Absolute Pressure
Mountain Daylight Time
Mishap Pilot
Mishap Remotely Piloted Aircraft
Mean Sea Level
Mishap Sensor Operator
Multi-spectral Targeting System
Nevada
Pounds per Square Inch
Revolutions Per Minute
Satellite
Satellite Communications
Sensor Processor Modem Assembly
Time Compliance Technical Order
Tail Number
Technical Order
Unmanned Aerial System
United States
United States Code
United States Air Force
Variable Pitch Propeller
Vertical Speed Indication
Wing
The above list was compiled from the Summary of Facts, the Statement of Opinion, the Index of
Tabs, and Witness Testimony (Tab V).
MQ-1B, T/N 00-3068, 28 April 2009
iii
SUMMARY OF FACTS
1. AUTHORITY, PURPOSE, AND CIRCUMSTANCES
a. Authority
On 10 June 2009, Major General R. Michael Worden, Vice Commander, Air Combat Command,
United States Air Force (USAF), appointed Lieutenant Colonel Gary A. Toppert as the Accident
Investigation Board (AIB) President to investigate the 28 April 2009 crash of a MQ-1B Predator,
tail number (T/N) 00-3068, near Creech Air Force Base (AFB), Nevada (NV). An abbreviated
AIB was conducted at Nellis AFB, NV, from 10 June 2009 through 22 June 2009, pursuant to
Chapter 11 of Air Force Instruction (AFI) 51-503, Aerospace Accident Investigations. Technical
Advisors appointed to the AIB were Lieutenant Colonel James P. Moffett (Maintenance
Member), Captain Jason R. Smith (Legal Advisor) and Technical Sergeant Dustin L. Smith
(Recorder). (Tab T-3)
b. Purpose
The purpose of this investigation is to provide a publicly releasable report of the facts and
circumstances surrounding the mishap, to include a statement of opinion on the cause or causes
of the mishap; to gather and preserve evidence for claims, litigation, disciplinary, and
administrative actions; and for other purposes. This report is available for public dissemination
under the Freedom of Information Act, Title 5, United States Code, Section 552.
c. Circumstances
The AIB was convened to investigate the accident involving a MQ-1B Predator, T/N 00-3068,
assigned to the 11th Reconnaissance Squadron (RS), 432d Wing (WG), Creech AFB, NV, which
crashed on 28 April 2009. (Tab T-3) The Class level of the accident cannot yet be determined
due to repair estimates that are still pending.
2. ACCIDENT SUMMARY
After normal maintenance and pre-flight checks, the mishap remotely piloted aircraft (MRPA)
taxied and departed from Creech AFB runway 26 at approximately 0803 local (L) time for a
training mission. Approximately one minute into the flight, the MRPA began to experience
engine oscillations. The MRPA quickly lost airspeed approaching stall speed. The mishap crew
(MC) consisting of the mishap pilot (MP) and mishap sensor operator (MSO) could not prevent
the rapid descent of the MRPA. 29 seconds after the first engine oscillation, the MRPA
impacted uninhabited terrain 1 ½ miles off the west end of runway 26. The estimated cost of
repair for the MRPA is $543,178.30. (Tab P-3,7-8) This includes replacement cost for the
engine and training hellfire missile and repair cost for the multi-spectral targeting system (MTSA) and other structural damage. There were no injuries or damage to personal property.
MQ-1B, T/N 00-3068, 28 April 2009
1
3. BACKGROUND
The MRPA was an asset of the 11 RS, 432 WG, Creech AFB, NV. (Tab B-3) The 432 WG has
dual reporting responsibilities to Ninth Air Force and USAF Central Command at Shaw AFB,
South Carolina, as well as to Twelfth Air Force and USAF Southern Command at DavisMonthan AFB, Arizona. (Tab Z-3)
a. 432d Wing
The 432 WG, also known as the 432d Air Expeditionary Wing "Hunters",
consists of combat-ready Airmen who fly the MQ-1B Predator and MQ-9
Reaper aircraft to support United States and Coalition warfighters. The
432 WG conducts unmanned aircraft system (UAS) initial qualification
training for aircrew, intelligence, weather, and maintenance personnel.
The 432 WG oversees operations of the 432d Operations Group
(432 OG), 432d Maintenance Group, 11 RS, 15th Reconnaissance Squadron,
17th Reconnaissance Squadron, 30th Reconnaissance Squadron, 42d Attack Squadron,
432d Aircraft Maintenance Squadron (432 AMXS), 432d Maintenance Squadron, and the
432d Operations Support Squadron. The 432 WG is the Air Force's first UAS wing. (Tab Z-3)
b. 11th Reconnaissance Squadron
The 11 RS operates the MQ-1B remotely piloted aircraft, a mediumaltitude multi-sensor armed reconnaissance platform. The 11 RS is the
formal training unit that conducts all Predator aircrew initial qualification
training as well as instructor upgrade training. (Tab Z-5)
c. MQ-1B Predator System
The MQ-1B Predator aircraft is a medium-altitude,
long endurance, remotely piloted aircraft. Its primary
mission is interdiction and conducting armed
reconnaissance against critical perishable targets.
(Tab Z-7)
The MQ-1B Predator is a fully operational system, not
just an aircraft. This system consists of four aircraft
(with sensors), a Ground Control Station (GCS), a
Predator Primary Satellite Link (PPSL), and operations
and maintenance personnel for deployed 24-hour operations. The basic crew for the MQ-1B
Predator is one pilot and one sensor operator. They fly the MQ-1B Predator from inside the GCS
via a line-of-sight (LOS) radio data link and via a satellite data link for beyond LOS flight. A
ground data terminal antenna provides LOS communications for takeoff and landing while the
PPSL provides beyond LOS communications during the remainder of the mission. (Tab Z-7)
MQ-1B, T/N 00-3068, 28 April 2009
2
The aircraft is equipped with a color nose camera (generally used by the pilot for flight control),
a day variable-aperture television camera, a variable aperture infrared camera (for low
light/night), and other sensors, as required. The cameras produce full-motion video. The MQ1B Predator also carries the Multi-Spectral Targeting System which integrates electro-optical,
infrared, laser designator and laser illuminator into a single sensor package. (Tab Z-7)
The MQ-1B Predator is manufactured by General Atomics Aeronautical Systems Inc. (GA ASI)
headquartered in San Diego, California. (Tab Z-8)
4. SEQUENCE OF EVENTS
a. Mission
The mission was a MQ-1B Initial
Qualification Training (IQT) sortie
conducted by the 11 RS. Launch and
recovery of the MRPA was to be
accomplished from a GCS at Creech
AFB with the MC handling launch
duties. (Tab R-7) Launch and
recovery operations are conducted by
a LOS radio link using a Ground Data
Terminal located on the ground at the
airfield. The MP and MSO were
instructors assigned to the 11 RS.
(Tab G-3, G-83) Both instructors had
students who were scheduled to
accomplish a Basic Surface Attack
BSA-1 syllabus sortie. (Tab R-7) The
Diagram displaying typical system components of MQ-1B Predator
MC was responsible for launching the
MRPA followed by 1 hour and 50 minutes of BSA-1 training in Restricted Area R-4806 before
handing off the MRPA to a follow-on crew via satellite data-link. (Tabs K-3 thru K-5, R-7)
b. Planning
The MC performed mission planning and briefing to include launch and BSA procedures with
their MQ-1B IQT students. (Tab R-7) The mission planning was normal. (Tab K-6, R-7)
c. Preflight
The MP and MSO stepped from the Operations Desk at 0645L. (Tab V-5.1) The MP proceeded
to the flightline and performed the operational pre-flight checks on the MRPA and two other
aircraft then joined the MSO in the GCS. (Tab R-3) The MRPA’s engine was started at 0735L
with no anomalies noted. (Tabs R-3, R-6) The MP began taxi of the MRPA at 0753L. The MP
and MSO did not note any problems with the MRPA during taxi. (Tabs R-3, R-6)
MQ-1B, T/N 00-3068, 28 April 2009
3
d. Summary of Accident
The MRPA taxied into position on runway 26 for a static takeoff. Takeoff roll and initial climb
were uneventful. The MSO noted the engine Manifold Absolute Pressure (MAP) at 38 inches of
Mercury (In Hg) at the time of rotation at 0803:22L. (Tab R-6) Flight data confirms engine
speed and MAP remained approximately 5500 revolutions per minute (RPM) and 38-39 In Hg,
respectively, from takeoff until the first engine oscillation. (Tab J-7) During climb out the MP
turned on the sensor processor modem assembly (SPMA) in preparation for switching control of
the MRPA from radio link to satellite data-link. (Tab R-4) At 0804:20L the MRPA was
travelling at 74 KIAS and climbing at 320 feet per minute (fpm). (Tab J-11) The MRPA was at
an estimated altitude of 240 feet above ground level (AGL). (Tabs J-6, J-7, J-11, J-12, R-4)
Suddenly, the engine speed began to decay. (Tabs J-6, J-7, J-11, J-12, R-4) The MP’s first
indication of loss of engine speed was a warning buzzer. (Tab R-4) The MP looked at the
heads-down display (HDD) and noted the engine speed had dropped to 2600 RPM, then it spiked
back to 5500 RPM before falling again. (Tab R-4) In response to the engine speed decaying,
propeller pitch automatically decreased from 30.5 degrees to 20 degrees. The propeller pitch
remained at 20 degrees for the remainder of the flight. (Tab J-12) At this time the MRPA was at
66 KIAS and 0 feet vertical speed indication (VSI). (Tab J-11) The MP thought the SPMA
might be causing the engine problems, so he turned it off. (Tab R-4) Then, the MP looked back
up and noted that airspeed had dropped to 61 KIAS, 4 KIAS above stall and 10 KIAS below
glide speed. (Tab R-4) At this point the MRPA was at 220 feet AGL and -600 feet VSI. (Tab J11) The MSO noted the RPMs fluctuated in conjunction with the MAP which had dropped and
did not come back up. (Tab R-7) Following the third engine oscillation, the MSO noted the
MRPA was passing 180 feet AGL with a 500 fpm and increasing sink rate. (Tab R-7) As the
MRPA was passing through 100 feet AGL, the MP called the air traffic control tower to declare
an emergency. (Tab R-4) The tower acknowledged the emergency and diverted other aircraft in
the pattern. (Tab N-10) The MP kept the throttle position at 100% throughout oscillations.
(Tabs J-12, R-4) The MRPA’s engine oscillations occurred once every five seconds and were
nearly identical in magnitude and form ranging from 5633 RPM to 1145 RPM. A total of seven
oscillations were recorded with five taking place in flight and two after impact. (Tab J-12)
During the rapid descent, the MP maintained control of the MRPA and analyzed the situation.
(Tab R-4) He attempted to select a landing location somewhat flat and void of rocks. (Tab R-4)
e. Impact
At 0804:49L, the MRPA impacted uninhabited terrain 1½ miles off the west end of runway 26.
(Tabs B-3, S-4) The MP raised the nose of the MRPA just before impact in an effort to
minimize damage to the MTS-A. (Tab R-7) The right and left main landing gears (MLG)
touched down first with the MRPA in a four degrees nose high attitude. (Tab R-1.1) The MRPA
rolled out on the uneven desert terrain with scrub brush for approximately 4 seconds before
striking heavier brush. Once the MRPA ran into the heavier brush, the left MLG sheared off and
the nose landing gear (NLG) and right MLG collapsed. (Tab S-9, S-10) The MRPA continued
to slide for an additional 2 seconds swinging approximately 160 degrees in a counterclockwise
direction before it came to rest. (Tab S-5, S-9) The MP then turned off the engine power switch.
(Tab R-4) The impact damaged the MRPA’s structure and engine. The MSO noted that the
MTS-A was still operating. The supplier of the MTS-A, Raytheon, assessed the damage and
MQ-1B, T/N 00-3068, 28 April 2009
4
determined that it was repairable. (Tab R-7) The training hellfire damage sustained damage, but
it has not been determined if it is repairable. The estimated cost of repair for the MRPA is
$536,178.30. (Tab P-3) This includes $67,348 for engine replacement, $7,000 for replacement
of a training hellfire missile, $268,830.30 for structural repairs, $200,000 for MTS-A repairs.
f. Life Support Equipment, Egress and Survival
Not applicable.
g. Search and Rescue (SAR)
Not applicable.
h. Recovery of Remains
Not applicable.
5. MAINTENANCE
a. Forms Documentation
All forms were documented in accordance with (IAW) Technical Order (T.O.) 00-20-1. There
were no open discrepancies noted on the aircraft maintenance forms.
Delayed discrepancies are those maintenance discrepancies identified as requiring correction at a
future date. There was one delayed discrepancy in the aircraft maintenance forms for a small
chip/dent on the left aileron trailing edge approximately 2 feet from the wing tip. It was speed
taped as a short term fix, and the MRPA was assessed to be fully mission capable. (Tab D-21)
There is no evidence to suggest that this delayed discrepancy contributed to the mishap.
b. Inspections
All scheduled inspections were accomplished within scheduled time limits, and there were no
overdue aircraft Time Compliance Technical Orders (TCTO). The next scheduled inspections
for the MRPA were a 28 day dry-cell nicad battery reconditioning that was due on 6 May 2009
and a right hand tail servo time change that was due after 50 more engine hours. (Tab D-19)
c. Maintenance Procedures
On 23 April 2009, the MRPA was removed from service for a 1080 hours engine time change
IAW T.O. 1Q-1(M)B-6. (Tab D-36) Engine serial number E9145 was replaced with engine
serial number E8231. (Tab D-36) There are three different engines available for MQ-1B
Predators: block 5, block 10 and block 15. Engines E9145 and E8231 were both block 5
engines. Engine E8231 was overhauled by Battlespace Flight Services (BFS) employees,
operating under the 432 AMXS Raven Flight, on 11 November 2008. (Tab D-44 thru D-47)
The engine change was completed IAW T.O. 1Q-1(M) B-2-72JG-00-1. (Tab D-36) In process
MQ-1B, T/N 00-3068, 28 April 2009
5
inspections (IPI) and Quality Assurance (QA) inspections were completed IAW T.O. 1Q-1(M)
B-2-61JG-00-1. (Tab D-36, D-37) After the engine installation was completed, an engine run
for operational checks was completed IAW T.O. 1Q-1(M)B-2-72CL-1. (Tab D-38) No defects
were found. (Tab D-38)
Engine E8231 had undergone 360 and 720 hour inspections on 11 November 2008 IAW T.O.
1Q-1(M) B-6 WC-2. (Tab D-44, D-46) The engine had 706.4 hours on it at the time. (Tab D-3)
These inspections involve an overhaul of the engine. A work card for the 360 hour inspection
has a caution that states, “Vacuum Tubing must be secure to prevent chafing. Tubing must not
be crushed to prevent engine malfunction.” (Tab X-4) Item 11 on the work card requires new
vacuum tubing to be installed from the plenum chamber to the “T” fitting, from the “T” fitting to
each carburetor, and from the plenum chamber to the fuel pressure regulator. (Tab X-4) No
guidance is provided on length to cut the tubing or routing for the tubing. After the 360 and 720
hour inspections were completed, a QA inspection was accomplished on the engine with no
defects noted. (Tab D-47)
After engine E8231 was overhauled, it was placed into the Supply system. (Tab D-8) On 23
April 2009, engine E8231 was issued from Supply to be installed on the MRPA. The engine
change was completed IAW technical data. (Tab D-36) Engine run and leak check were
completed with no discrepancies noted. (Tab D-36 thru D-38) The MRPA was returned to
service on 23 April 2009. (Tab D-8) Preflight inspections were completed on 23 April 2009.
(Tab D-8) On 27 April preflight inspections were again completed along with pre- and postload, battery and tire inspections. (Tab D-15 thru D-17)
No other maintenance procedures were relevant to this mishap.
d. Maintenance Personnel and Supervision
Engine E8231 was overhauled by BFS employees. The employees who performed the overhaul
were qualified on these tasks. (Tab G-12) The AIB could not verify the qualifications of the
employee who inspected the completed work as he had been terminated from BFS. (Tab G-180)
The MRPA was maintained by employees of BFS assigned to 432 AMXS Raven flight. The
1080 hour engine change was completed by two BFS employees. One was a Mechanic (Mech)
III, and one was a Mechanic I in training. (Tab AA-6, AA-8) There were also two QA
Inspectors observing the engine change. (Tab V-1.4) The Mech I and Mech III were trained and
qualified to perform the task. The post installation engine run was performed by another fully
qualified Mech III on the next shift. (Tab AA-4)
The training records for the maintenance personnel who performed relevant maintenance on the
MRPA show that they were properly qualified on the maintenance tasks performed. There is no
evidence to suggest that qualifications or supervision of personnel were a factor in the mishap.
e. Fuel, Hydraulic and Oil Inspection Analysis
Maintenance personnel properly serviced fuel tanks and oil reservoirs IAW technical data.
MQ-1B, T/N 00-3068, 28 April 2009
6
The MRPA’s fuel load was listed on the Air Force Technical Order Form 781A Information
Notes and the 781H as having 303 pounds of fuel in the forward tank and 203 pounds in the aft
tank for a total of 506 pounds of fuel prior to takeoff on 28 April 2009. (Tab D-14) The Air
Force Petroleum Laboratory at Wright-Patterson AFB tested a fuel sample from the MRPA. The
sample failed the vapor pressure (kPa) test. Acceptable range is 38.0 to 49.0 kPa, and the sample
result was 34.3 kPa. Although the vapor pressure was low it was not a factor in the mishap.
(Tab U-3, U-4)
On 23 April 2009, the oil level was checked on the MRPA and found to be full at 8 quarts. An
oil sample was taken from the MRPA subsequent to the mishap for testing. The findings could
not be analyzed as there was no previous oil sample testing from the MRPA and no established
technical data to compare the sample results against. (Tab D-3)
There is no evidence to suggest petroleum, oils or lubricants contributed to the mishap.
f. Unscheduled Maintenance
There were no unscheduled maintenance actions on the MRPA.
6. AIRCRAFT AND AIRFRAME
a. Condition of Systems
The MRPA’s structure and engine were damaged as a result of the mishap. (Tab S-7)
MTS-A
Training hellfire missile
Aircraft structural damage includes: left and right wing; left and right tail; vertical stabilizer; left
and right MLG; NLG; left and right fillet; engine cowling; numerous mounts and attachments;
bulkheads 5, 6, 7, and 10; aft fuel door; and upper and lower fuselage skin damage. (Tab P-4)
The $1.2 million MTS-A sustained minimal damage, and has been deemed repairable. (Tab S-7,
S-10, S-18) The training hellfire missile was damaged when it became dislodged from the rail.
(Tab S-10) Repair cost will exceed replacement cost.
MQ-1B, T/N 00-3068, 28 April 2009
7
A thorough inspection of the engine
after the mishap revealed that the MAP
reference vacuum line disconnected
from plenum chamber at a “T” fitting.
There was approximately one half inch
between the end of the vacuum line
connected to the plenum and the “T”
fitting.
“T” fitting
The block 5 engine is a carbureted
engine. Carburetors cannot precisely
meter the amount of fuel entering the
carburetor venturi and being fed to the
Right carburetor
engine with changes in air pressure.
Plenum vacuum line
Air pressures vary at different altitudes. vacuum line
The MAP reference vacuum line allows the carburetor to more precisely meter the amount of
fuel entering the carburetor venture to account for variations in air pressure at different altitudes.
On the MQ-1B Predator manifold pressure is produced by a turbocharger driven by engine
exhaust metered by a wastegate. As MAP increases the air entering the carburetor becomes
denser allowing more fuel to be metered into the venturi resulting in increased engine power. If
the vacuum line opens, i.e. becomes disconnected, the pressure sensed by the carburetors become
that of the ambient (from the surrounding environment) atmosphere. If the MAP is higher than
the ambient pressure, the amount of fuel metered into the venturi will decrease. This will lean
the air fuel mixture entering the engine cylinders, which will lead to engine oscillations and
decrease power.
The “T” fitting that connects the MAP reference vacuum line is situated such that the foot
connects to a rubber vacuum line attached to the engine plenum and the arms connect to rubber
vacuum lines for the left and right carburetors. The vacuum lines from the “T” fitting to the
carburetors were cut to a length to allow for no slack, and as such they were under tension. This
is to avoid rubbing and chafing. The section of vacuum line from the plenum to “T” fitting was
installed IAW Air Force technical orders, but it was cut to a length that required pulling the “T”
fitting one half inch toward the plenum to connect the vacuum line to the “T” fitting. This
placed additional tension on the carburetor vacuum lines.
b. Testing
While the MQ-1B Predator is airborne, it constantly transmits the status of aircraft systems and
sensors to the GCS, where the flight data is recorded. Flight data is recorded against a time
stamp (in seconds) that begins during aircraft preflight when the aircrew powers on the
recorders. The MRPA’s flight data was retrieved from the GCS and provided to GA ASI for
analysis. (Tab J-3 thru J-5, J-16 thru J-17)
MQ-1B, T/N 00-3068, 28 April 2009
8
c. Functionality of Equipment
The flight data shows that approximately 1 minute after takeoff the MRPA began experiencing
multiple engine oscillations between 1145 RPM and 5633 RPM in 5 second intervals. (Tabs J-7,
J-12) Exhaust gas temperature (EGT) steadily declined and MAP decayed from 38 In Hg to no
more than 27 In Hg during the recorded surges. (Tab J-4) As the airspeed of the MRPA
approached near stall speed, the MRPA became less responsive to control inputs from the MP.
(Tab J-4, J-15)
The GCS was inspected subsequent to the mishap and determined to have been functioning
properly at the time of the mishap. (Tab J-16, J-17)
d. Post Mishap Component Testing
A different MQ-1B Predator with a block 5 engine was tested to see how it would react if the
MAP reference vacuum line were disconnected while the engine was running. The test results
were captured in the aircraft’s flight data. This data revealed that the aircraft experienced a loss
of engine performance similar to the MRPA. (Tab W-4)
7. WEATHER
The surface winds at Creech AFB at the time of the mishap were blowing from the north at 5
knots. This did not affect the launch of the MRPA. Weather was within operational limits, and
there was no evidence to suggest weather was a factor in the mishap. (Tabs F-14, N-9)
8. CREW QUALIFICATIONS
a. Mishap Pilot
(1) Training
The MP has been a qualified MQ-1B pilot since 17 November 2006. He upgraded to mission
instructor pilot on 16 November 2008. Additionally, the MP was qualified as a launch and
recovery (LR) pilot since 23 April 2007 and as a LR instructor pilot since 17 March 2009.
(Tab G-3)
(2) Experience
The MP’s total flight time is 2698.5 hours, which includes 1148.7 hours in the MQ-1B.
(Tab G-6) Prior to flying the MQ-1B, the MP was a C-130 pilot. (Tab G-6) He had completed
7 MQ-1B launches since 1 October 2008 with his last one being on 13 April 2009. (Tab G-15)
MQ-1B, T/N 00-3068, 28 April 2009
9
The MP’s flight time during the 90 days before the mishap is as follows (Tab G-7):
MP
Last 30 Days
Last 60 Days
Last 90 Days
Hours
15.2
22.2
49.4
Sorties
9
13
25
b. Mishap Sensor Operator
(1) Training
The MSO has been a qualified MQ-1B sensor operator since 13 July 2005. (Tab G-149) He
completed his instructor sensor operator upgrade training on 6 August 2006. (Tab G-147)
Additionally, the MSO was qualified as a LR sensor operator since 15 October 2007 and as a LR
instructor since 3 April 2008. (Tab G-83)
(2) Experience
The MSO’s total MQ-1B flight time is 1397.8 hours. Prior to flying the MQ-1B, the MSO was
an AC-130 sensor operator from 1996 to 2005. No records are available showing his active duty
flying time. (Tab G-84, G-144)
The MSO’s flight time during the 90 days before the mishap is as follows (Tab G-85):
MSO
Last 30 Days
Last 60 Days
Last 90 Days
Hours
24
31.6
56.7
Sorties
12
16
28
There is no evidence to suggest crew qualifications were a factor in this mishap.
9. MEDICAL
a. Qualifications
At the time of the mishap, all personnel were fully medically qualified for flight duty without
medical restrictions or waivers.
b. Health
The 72-hour histories, and 14-day histories for the MP and MSO revealed no significant health
concerns. There is no evidence to suggest that the health of the MP or the MSO were relevant to
the mishap.
MQ-1B, T/N 00-3068, 28 April 2009
10
c. Toxicology
Immediately following the mishap, commanders directed toxicology testing for all personnel
involved in the flight and the launch of the MRPA. Blood and urine samples were submitted to
the Armed Forces Institute of Pathology (AFIP) for toxicological analysis. This testing included
carbon monoxide and ethanol levels in the blood and drug testing of the urine.
Carboxyhemoglobin saturations of zero to three percent are expected for non-smokers and three
to ten percent for smokers. Saturations above ten percent are considered elevated and are
confirmed by gas chromatography. The carboxyhemoglobin saturation in the blood samples of
MP and MSO were within normal limits.
AFIP examined the blood for the presence of ethanol at a cutoff of twenty milligrams per a
deciliter. AFIP detected no ethanol in the blood of the MP or MSO.
Furthermore, AFIP screened the urine of MC members and maintenance members for
amphetamine, barbiturates, benzodiazepines, cannabinoids, cocaine, opiates and phencyclidine
by immunoassay or chromatography. AFIP detected none of these drugs in the MP, MSO or
maintenance members. (Tab Y-3 thru Y-13)
d. Lifestyle
There is no evidence that unusual habits, behavior or stress on the part of the MP, MSO or
maintenance crew members contributed to this mishap. Witness testimonies, 72-hour histories,
and 14-day histories revealed no evidence that suggests lifestyle factors, including unusual
habits, behavior or stress contributed to the mishap.
e. Crew Rest and Crew Duty Time
Air Force Instructions require pilots have proper “crew rest,” as defined in AFI 11-202, Volume
3, General Flight Rules, 16 February 2005, prior to performing in-flight duties. AFI 11-202
defines normal crew rest as a minimum 12-hour non-duty period before the designated flight
duty period (FDP) begins. During this time, an aircrew member may participate in meals,
transportation or rest as long as he or she has the opportunity for at least eight hours of
uninterrupted sleep.
A review of the duty cycles of the MP and MSO leading up to the mishap indicated that they had
adequate crew rest. The MP and MSO complied with the crew rest and duty day requirements
on the day of the mishap. None of the crew indicated they suffered from stress, pressure, fatigue
or lack of rest prior to or during the mishap sortie. The MP and MSO also stated that they were
adequately rested and not suffering from any illnesses at the time of the mishap. (Tab K-7)
There is no evidence to suggest that fatigue was a factor in this mishap.
MQ-1B, T/N 00-3068, 28 April 2009
11
10. OPERATIONS AND SUPERVISION
The operations tempo was moderate for the 11 RS at the time of the mishap. Permanent party
instructors fill normal deployment rotations in support of Operation ENDURING FREEDOM
and Operation IRAQI FREEDOM. Sorties flown by the 11 RS are broken into two hour blocks.
Instructors typically fly two of these two hour blocks per week. There were no issues with
supervision in the 11 RS at the time of the mishap. There is no evidence to suggest that
operations tempo or supervision were a factor in the mishap.
11. HUMAN FACTORS
A human factor is any environmental or individual physical or psychological factor a human
being experiences that contributes to or influences his performance during a task. There is no
evidence to suggest that any human factors contributed to this mishap.
12. GOVERNING DIRECTIVES AND PUBLICATIONS
a. Primary Operations Directives and Publications
1. Air Force Instruction (AFI) 11-2MQ-1, Volume 1, MQ-1 Crew Training, 4 May 2007
2. AFI 11-2MQ-1, Volume 2, MQ-1 Crew Evaluation Criteria, 28 November 2008
3. AFI 11-2MQ-1, Volume 3, MQ-1 Operations Procedures, 29 November 2007
4. AFI 11-202, Volume 3, General Flight Rules, 5 April 2006
5. AFI 11-401, Aviation Management, 7 March 2007, incorporating Change 1,
13 August 2007
6. AFI 11-418, Operations Supervision, 21 October 2005, incorporating Change 1,
20 March 2007
7. T.O. 1Q-1(M)B-1, USAF Series MQ-1B and RQ-1B Systems, 1 November 2003,
incorporating Change 13, 8 April 2009
8. T.O. 1Q-1(M)B-1CL-1, USAF Series MQ-1B and RQ-1B Systems Flight Checklist, 1
November 2003, incorporating Change 15, 8 April 2009
b. Maintenance Directives and Publications
1. AFI 21-101, Aircraft and Equipment Maintenance Management, 29 June 2006
2. T.O. 00-20-1, Aerospace Equipment Maintenance Inspection, Documentation,
Policies, and Procedures, 30 April 2003, incorporating Change 4, 1 September 2006
3. 1Q-1(M)B-6, MQ-1B Technical Manual, Aircraft Scheduled Inspection and
Maintenance Requirements, 21 August 2008
4. 1Q-1(M)B-2-72JG-00-1, MQ-1B Job Guide, Engine Reciprocating, General –
Volume I, 1 September 2007
5. 1Q-1(M)B-2-53JG-00-1, MQ-1B Job Guide, Fuselage, Structures – General,
1 December 2006
6. 1Q-1(M)B-2-05JG-10-1, MQ-1B Job Guide, Aircraft General Ground Handling,
1 December 2006, incorporating Interim Operational Supplement, 17 April 2007
MQ-1B, T/N 00-3068, 28 April 2009
12
7. 1Q-1(M)B-6WC-1, MQ-1B Inspection Workcard, Preflight, Thruflight, Basic
Postflight, Combined Basic Postflight/Preflight Inspection Requirements, 15 January
2007, incorporating Change 1, 5 March 2007
8. 1Q-1(M)B-6WC-2, MQ-1B Inspection Workcard, Aircraft Periodic Inspections and
Maintenance Requirements, 21 August 2008
The AFIs listed above are available digitally on the AF Departmental Publishing Office internet
site at: http://www.e-publishing.af.mil.
c. Known or Suspected Deviations from Directives or Publications
There are no known or suspected deviations from directives or publications by the MC or
maintenance members.
13. NEWS MEDIA INVOLVEMENT
The 432 WG Public Affairs office issued a short official press release for this mishap. There has
been local media coverage and no national media coverage. One news article was posted in the
Las Vegas Review Journal. (Tab Z-9)
14. ADDITIONAL AREAS OF CONCERN
None.
22 June 2009
GARY A. TOPPERT, Lieutenant Colonel, USAF
President, Accident Investigation Board
MQ-1B, T/N 00-3068, 28 April 2009
13
STATEMENT OF OPINION
MQ-1B, T/N 00-3068, ACCIDENT
28 APRIL 2009
Under 10 U.S.C. 2254(d), any opinion of the accident investigators as to the cause of, or the factors
contributing to, the accident set forth in the accident investigation report may not be considered as
evidence in any civil or criminal proceeding arising from the accident, nor may such information be
considered an admission of liability of the United States or by any person referred to in those conclusions
or statements.
1. OPINION SUMMARY
I find by clear and convincing evidence that the cause of the mishap was a failure of the
Manifold Absolute Pressure (MAP) reference vacuum line that supplied both carburetors on the
mishap remotely piloted aircraft’s (MRPA) engine. The MAP reference vacuum line
disconnected at the plenum side of the “T” fitting approximately one minute after takeoff when
the MRPA was at an estimated 240 feet above ground level (AGL). The loss of actual MAP
vacuum to both carburetors impacted the fuel to air ratio being supplied to all four engine
cylinders. As a result the engine speed initially dropped from 5500 revolutions per minute
(RPM) and began oscillating between 1145 RPM and 5633 RPM. The loss of engine power
resulted in a loss of airspeed leading to a high sink rate. The MRPA impacted the ground 29
seconds after the initial drop in engine speed. In this short time span the mishap pilot maintained
control of the MRPA, analyzed the situation, selected the most appropriate landing location and
performed a landing that prevented total loss of the MRPA.
2. DISCUSSION OF OPINION
A thorough inspection of the post crash engine revealed the “T” fitting had pulled approximately
one half inch away from the end of the vacuum line connected to the plenum chamber. The “T”
fitting is situated such that the foot connects to a rubber vacuum line attached to the engine
plenum and the arms connect to rubber vacuum lines for the left and right carburetors. The
vacuum lines from the “T” fitting to the carburetors were under tension. The section of vacuum
line from the plenum to the “T” fitting was installed in accordance with Air Force technical
orders (T.O.). The T.O.s did not provide guidance on length or routing of the vacuum lines.
However, the vacuum line attached to the plenum was cut too short based upon the location of
the “T” fitting. Connecting the plenum line required pulling the “T” fitting one half inch toward
the plenum placing additional tension on the vacuum lines attached to the carburetors. The
resultant force allowed the “T” fitting to pull free of the plenum vacuum line.
The MRPA was approximately one minute into flight at an estimated altitude of 240 feet AGL
with 74 knots of indicated airspeed (KIAS) when the MAP reference vacuum line separated.
With the vacuum line open, the pressure sensed by the carburetors became that of the ambient
atmosphere. This resulted in a decrease in the amount of fuel being metered into the venturi and
MQ-1B, T/N 00-3068, 28 April 2009
14
leaned the air fuel mix entering the cylinders. With less fuel being supplied, engine speed
rapidly declined.
In response to the initial engine speed rollback, the variable pitch propeller automatically
adjusted from 30.5 degrees to 20 degrees pitch and the wastegate opened decreasing
turbocharger output in an effort to maintain engine speed. The leaned air fuel mixture and wide
open throttle led to engine oscillations. Flight data revealed that the MRPA’s engine oscillations
occurred once every five seconds, were nearly identical in magnitude and form, and varied
between 1145 RPM and 5633 RPM. A total of seven oscillations were recorded with five taking
place in flight and two after impact.
Within six seconds of initial rollback, the MRPA’s airspeed had dropped to 61 KIAS, only 4
knots above stall speed. As a result of this slow speed and lack of engine power, the MRPA
rapidly developed a sink rate in excess of 500 feet per minute resulting in the MP being unable to
take action to prevent the MRPA from impacting the ground. Passing through 100 feet AGL, the
MP called the tower to declare an emergency. Prior to impact the MP raised the nose of the
MRPA and touched down on the main landing gear followed by the nose landing gear. This
prevented the MTS-A from being destroyed. Other damage was unavoidable due to the rough
terrain the MRPA landed on.
I arrived at my opinion by examining the MRPA and associated components; an Engineering
Memorandum from General Atomics Aeronautical Systems, Incorporated; recorded MRPA
flight data; witness testimony; and recorded test data from a similarly induced failure on an
engine during a ground run. All evidence points to a failure of the MAP reference vacuum line.
In the 29 seconds from initial engine failure to impact, the mishap pilot properly maintained
control of the MRPA, analyzed the situation, selected the most appropriate location to land and
performed a landing that prevented total loss of the MRPA.
22 June 2009
GARY A. TOPPERT, Lieutenant Colonel, USAF
President, Accident Investigation Board
MQ-1B, T/N 00-3068, 28 April 2009
15
INDEX OF TABS
DISTRIBUTION LETTER AND SAFETY INVESTIGATOR INFORMATION ............................................... A
USAF MISHAP REPORT, AF FORM 711B ........................................................................................................... B
PRELIMINARY MESSAGE REPORT ................................................................................................................... C
MAINTENANCE REPORT, RECORDS, AND DATA .......................................................................................... D
THIS TAB NOT USED .............................................................................................................................................. E
WEATHER AND ENVIRONMENTAL RECORDS AND DATA ........................................................................ F
PERSONNEL RECORDS ......................................................................................................................................... G
EGRESS, IMPACT, AND CRASHWORTHINESS ANALYSIS........................................................................... H
DEFICIENCY REPORTS .......................................................................................................................................... I
RELEASABLE TECHNICAL REPORTS AND ENGINEERING EVALUATIONS .......................................... J
MISSION RECORDS AND DATA........................................................................................................................... K
DATA FROM ON-BOARD RECORDERS ............................................................................................................. L
DATA FROM GROUND RADAR AND OTHER SOURCES .............................................................................. M
TRANSCRIPTS OF VOICE COMMUNICATIONS .............................................................................................. N
ANY ADDITIONAL SUBSTANTIATING DATA AND REPORTS..................................................................... O
DAMAGE AND INJURY SUMMARIES ................................................................................................................. P
AIB TRANSFER DOCUMENTS .............................................................................................................................. Q
RELEASABLE WITNESS TESTIMONY ............................................................................................................... R
RELEASABLE PHOTOGRAPHS, VIDEOS, AND DIAGRAMS ......................................................................... S
DOCUMENTS APPOINTING THE AIB MEMBERS ........................................................................................... T
AIRCRAFT MAINTENANCE RECORDS (not included in Tabs D or O)…….………………………………...U
WITNESS TESTIMONY AND STATEMENTS ..................................................................................................... V
PHOTOGRAPHS (not included in Tab S) .............................................................................................................. W
GOVERNMENT DOCUMENTS AND REGULATIONS ...................................................................................... X
TOXICOLOGY REPORTS………………………………………………………………………………………… Y
MQ-1B, T/N 00-3068, 28 April 2009
16
FACT SHEETS AND MEDIA COVERAGE…………………………………………………………………… Z
PERSONNEL RECORDS NOT INCLUDED IN TAB G……………………………………………………… AA
MQ-1B, T/N 00-3068, 28 April 2009
17
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