AIB Report on F-35A Engine Fire Released

“Catastrophic engine failure” caused the June 23, 2014, engine fire in an F-35A strike fighter assigned to the 58th Fighter Squadron at Eglin AFB, Fla., according to a summary of the accident investigation board report, released June 5. “The engine failed when the third stage forward integral arm of a rotor fractured and liberated during the takeoff roll,” according to a USAF release. “Pieces of the failed rotor arm cut through the engine’s fan case, the engine base, an internal fuel tank, and hydraulic and fuel lines before exiting through the aircraft’s upper fuselage” causing an “excess of $50 million” in damage. After the fire, F135 engine maker Pratt & Whitney “immediately” developed two “remedies” allowing the fleet to safely resume flying within 25 days, according to a company release. “The first involved a short-term rub-in maneuver, conducted in flight, to increase the gap between the second stator and the third stator integral arm seal,” states the release. Secondly, the company completed a “redesign to pre-trench the stator,” a remedy that is currently being incorporated into fielded and production engines and is slated for completion in early 2016. “The nature of development testing is to uncover challenges of new designs and technologies to ensure the dependability and reliability of the fielded product,” said the company, adding its “No. 1 priority is to deliver the highest quality, most reliable engines to the warfighter.”