What happened
On 10 April 2019, an MQ-9A, tail number 08-4035, crashed at an undisclosed location within the United States Central Command (USCENTCOM) Area of Responsibility. The aircraft was being operated by the 42d Attack Squadron Mission Control Element, based at Creech Air Force Base, Nevada, under the 432d Wing.
The incident began at approximately 0156Z when the Ground Control Station (GCS) began transmitting simultaneous, conflicting control inputs to the aircraft. These erroneous commands included instructions to close the fuel shut-off valve and feather the propeller. As a result, the engine's torque, oil pressure, and propeller speed decreased, leading to an engine shutdown.
While the pilot and sensor operator initially attempted to follow emergency procedures for an engine failure, the situation escalated when the crew disabled autopilot hold modes to perform critical actions. Once these modes were deactivated, the aircraft began executing erratic pitch, roll, yaw, and rudder commands sent from the GCS. The rapid changes in attitude caused multiple stalls and eventually a permanent loss of datalink, resulting in the aircraft impacting the terrain. There were no fatalities or injuries reported, though the loss of government property was valued at over $11 million.
The investigation
The Abbrevied Aircraft Accident Investigation Board (AAIB) conducted an examination involving engineering analysis of data logs and visual inspections of the Ground Control Station. Laboratory testing was also performed by General Atomics Aerospace Systems, Inc. on the hardware components involved in the mishap, specifically the Control Console Assembly (CCA) and the Control Console Serial Module (CCSM).