Human Error Caused MQ-9 Reaper Crash in Nevada

A series of errors led to the crash* of an MQ-9 Reaper in an unpopulated area three miles northeast of Mount Irish, Douglas County, Nevada, Dec. 5, 2012, according to an Air Combat Command Abbreviated Accident Investigation Board report released on Tuesday.

When the accident occurred, the MQ-9 crew was flying a survellience mission supporting the final exercise of the crew’s curriculum at the U.S. Air Force Weapons School. During the flight, the mishap pilot used a series of autopilot modes to control the aircraft toward the military airspace. When the pilot attempted to change the aircraft’s altitude by taking the throttle position to less than fully forward, the misconfigured throttle commanded the aircraft engine to produce reverse thrust. The pilot perceived an engine problem and commanded the aircraft to return to base, during which time the aircraft decelerated below stall speed and crashed in an unpopulated area.

According to the report, prior to the mission, contract technicians improperly configured the Pilot/Sensor Operation station throttle quadrant settings in the Ground Control Station (GCS) when it was reconfigured from the MQ-1B Predator to the MQ-9 Dec. 4. Adjusting the throttle controls was necessary because the Reaper, unlike the
Predator, has a reverse-thrust capability activated by the throttle position. On the day of the mishap, the pilot conducting the pre-flight inspection did not execute all parts of the checklist required to identify that the throttle was functioning properly.

The Accident Investigation Board President therefore found by clear and convincing evidence that the causes of the mishap were:

1) prior to the flight, the throttle-quadrant settings were improperly configured during the reconfiguration of the GCS from MQ-1 to MQ-9 operations

2) this throttle change went unrecognized because the mishap pilot did not personally execute the checklists on his control rack prior to gaining control of the aircraft, and

3) the pilot stalled the aircraft due to an unrecognized, commanded reverse-thrust condition that existed whenever the pilot’s throttle was at any position except fully forward.

Additionally, the AAIB found by a preponderance of evidence that the mishap pilot failed to execute his GCS preflight in accordance with technical order procedures, substantially contributing to the mishap.

At the time of the mishap, the aircraft and crew were assigned the 26th Weapons Squadron, 57th Wing at Nellis Air Force Base, Nev. The GCS was maintained by Science Applications International Corporation (SAIC).

The aircraft, one inert Guided Bomb Unit, a Hellfire training missile, a Mission Kit, and one M299 missile rail were destroyed.The loss is valued at approximately $9.6 million. There were no injuries or damage to other government or private property.

*The MQ-9 Reaper remotely piloted aircraft assigned to the 57th Wing at Nellis AFB, Nevada, crashed on Wednesday, December 5th on the Nevada Test and Training Range during a combat training mission. The mishap occurred at approximately 7:14 p.m. Nevada time in a remote location west of Hiko.
Source: US Air Force

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