A fractured engine rotor caused an F-35 to catch fire during takeoff for a training mission last summer, according to an Air Force investigation released Friday.
The June 23 fire — on an Air Force F-35A assigned to the 58thth Fighter Squadron at Eglin Air Force Base, Florida — prompted a brief grounding of the F-35 fleet and caused the Pentagon to cancel the F-35's appearance at the 2014 Farnborough Airshow in England. The grounding got headlines around the world as Eglin is the hub for all F-35 pilot training.
The pilot was able to abort takeoff and exit the aircraft. Emergency crews were able to extinguish the fire.
The cause of the mishap was catastrophic engine failure, according to the Air Education and Training Command Accident Investigation Board report. The third-stage forward integral arm of a rotor fractured and broke free during the takeoff roll. Pieces cut through the engine's fan case, engine bay, internal fuel tank and hydraulic and fuel lines before leaving through the aircraft's upper fuselage. Leaked fuel and hydraulic fluid ignited the fire, which burned the rear two-thirds of the aircraft, according to the report.
F-35A, tail number 10-5015, burns on the flightline at Eglin Air Force Base, Florida.
Photo Credit: Air Force
Total damage is estimated to be more than $50 million, according to AETC.
Officials with the F-35 Joint Program Office had been open about the cause of the fire before the investigation report was released due to pressure from Capitol Hill, with lawmakers using the incident as an example of issues with the overall F-35 program. The House version of the fiscal 2016 National Defense Authorization Act includes a provision requiring the Pentagon to review the lone engine program for the F-35, including a specific review of the fire.
The mishap also reignited a discussion on Capitol Hill of whether a competitor to the Pratt & Whitney F135 engine should be restarted, though that move has not been made in any proposed legislation.
The F-35 joint program office has repeatedly expressed confidence that the mishap's cause is isolated and has been repaired.