Engines
F135 Engine Failure Investigation Makes Progress
Pratt & Whitney has devised an interim fix and F-35s are flying agan, with borescope inspections mandated every three flying hours.
A Pratt & Whitney F135, the engine that powers the F-35 stealth fighter. (Photo: P&W) The inset shows the location of the plate seal, between the second and third fan stages, that rubbed excessively to cause an engine failure.
A Pratt & Whitney F135, the engine that powers the F-35 stealth fighter. (Photo: P&W) The inset shows the location of the plate seal, between the second and third fan stages, that rubbed excessively to cause an engine failure.

Root-cause analysis of the F135 engine failure that grounded the Lockheed Martin F-35 fighter fleet in July will be completed by the end of the month. Meanwhile, the problem is already sufficiently understood for Pratt & Whitney to have devised an interim fix. F-35s are flying again, but with borescope inspections mandated every three flying hours. The flight envelope restrictions that were previously imposed< now vary, with four key development aircraft cleared for greater maneuverability.

“Pratt & Whitney has put its ‘A-team’ on this problem and has taken accountability,” Lt. Gen. Chris Bogdan, F-35 program executive officer, told the Air Force Association conference this week. The company has agreed to pay for modifications to the fan section of the 150 engines already delivered, he added.