Accident Overview
On 19 October 2022, at approximately 18:08:36 local time, a United States Air Force F-35A Lightning II, tail number 15-5197, crashed during landing at Hill Air Force Base, Utah. The aircraft was assigned to the 421st Fighter Squadron, 388th Fighter Wing, and was operating out of Hill AFB.
There were no fatalities. The mishap pilot ejected safely before impact and sustained minor injuries. The aircraft was destroyed upon impact, with a total loss valued at $166,340,000.00. Debris fanned out, with most of the aircraft impacting within the airfield boundaries.
Sequence of Events
The mishap flight consisted of four F-35A aircraft. The mishap aircraft was flying as the #3 aircraft. After an uneventful training sortie, the formation returned to Hill AFB for landing on Runway 14, with the #3 aircraft in one nautical mile trail of the #1 aircraft.
On final approach, the mishap pilot experienced a slight rumbling due to wake turbulence from preceding aircraft. This air flow disturbance resulted in erroneous inputs to the air data application (ADA) of the F-35 flight control system. The erroneous inputs caused a condition where the aircraft flight controls did not respond correctly for the actual conditions.
Recognizing the inappropriate response, the pilot selected full afterburner power to attempt recovery. Due to low altitude, low airspeed, and sideslip, the pilot was unable to regain controlled flight and initiated ejection. The pilot ejected before impact and landed north of the base, outside the Hill AFB boundary fence, and was recovered by emergency responders.
Cause
The accident investigation board president found, by a preponderance of the evidence, the cause of the mishap was that the aircraft departed controlled flight due to air data system errors immediately prior to landing, and there was no opportunity to recover the aircraft to controlled flight.
Contributing Factor
One significantly contributing factor was identified: the mishap pilot did not increase landing spacing from preceding aircraft in accordance with wake turbulence procedures.
Aircraft and Pilot
The mishap aircraft was an F-35A, tail number 15-5197, operated by the 421st Fighter Squadron, 388th Fighter Wing. The mishap pilot, also assigned to the 388th Fighter Wing, ejected safely and sustained minor injuries.