What happened
On 24 June 2020, an MQ-9A, tail number 08-4051, crashed within the United States Africa Command (USAFRICOM) Area of Responsibility. The aircraft, assigned to the 162d Wing, Arizona Air National Guard, was being operated by the 214th Attack Squadron Mission Control Element based at Davis-Monthan AFB.
The incident began at approximately 0640Z when the ground control station issued warnings regarding low fuel levels in the header tank. As the pilot and sensor operator attempted to resolve the fault, they discovered that calculated fuel levels were significantly lower than expected. A visual inspection via the aircraft's primary camera revealed a severe fuel leak originating from the fuselage.
By 0ert723Z, the crew attempted to return the aircraft to base at maximum airspeed. However, the leak was determined to be catastrophic. Following coordination with the Combined Air Operations Center (CAOC), the crew was directed to perform a controlled crash to minimize the risk of unintended outcomes. The aircraft ran out of fuel at 0914Z, and the pilot managed the remaining glide to an impact point at 0933Z. There were no fatalities or injuries reported, though the loss of government property was valued at over $11 million.
The investigation
The Abbreviated Aircraft Accident Investigation Board (AAIB) examined the mechanical failures and operational procedures leading to the crash. The investigation focused on the fuel delivery system, specifically looking at why the crew was unable to identify the leak before fuel exhaustion became inevitable. The board reviewed data logs, video evidence, and maintenance records regarding known aircraft deficiencies.
Findings
- A fuel leak from the Forward Electric Fuel Heater caused the aircraft to run out of fuel before it could reach the Launch and Recovery Element.
- A delinquent Time Compliance Technical Order (TCTO) meant a known deficiency in the MQ-9 had not been corrected.
- The design of the fuel leak detection system was insufficient, as it failed to alert the crew to the discrepancy between calculated and measured fuel levels.
- There was a lack of standardized guidance or established tolerances for pilots regarding acceptable differences between the aircraft's two independent fuel monitoring systems.