Accidents

Loss of MQ-9 Reaper

The ground control station was mis-configured following a change from MQ-1 to MQ-9 operations. The misconfiguration was not spotted. It caused any throttle position aft of full forward to command negative thrust. The aircraft decelerated below stall speed and impacted ground in unpopulated area.

On 5 December 2012, an MQ-9 Reaper remotely piloted aircraft crashed in an unpopulated area three  miles north-east of Mount Irish, Douglas County, Nevada. The crash occurred due to a stall, which was  the result of an unrecognised reverse thrust condition. The aircraft and a number of pieces of ancillary  equipment were destroyed. The total damage to United States government property was assessed at over  $9 million.

The investigation board concluded that the throttle settings of the Ground Control Station (GCS) were  incorrectly configured. This misconfiguration arose as the GCS was converted from supporting MQ-1  operations to supporting MQ-9 operations. It persisted despite the presence of a checklist, the completion  of which should have identified the error. The misconfiguration meant that reverse thrust was commanded  whenever the pilot’s throttle was in any position except full forward.

This incident highlights the importance of the consistency Data Property, with respect to the differences  between the GCS settings and the aircraft it was meant to be controlling. It also highlights the importance  of the verifiability Data Property, with respect to the GCS settings (and, in particular, the limitations of using  checklists to verify data).

Links 

http://www.airforcemag.com/AircraftAccidentReports/Documents/2013/  120512_MQ-9_Nevada_full.pdf
(accessed 29 November 2017).