The U.S. Air Force's top officer cautioned against an "alarmist" reaction to last month's F-35 engine fire that resulted in a temporary fleet-wide grounding of the fighter jet and delay of its international debut.
The Pentagon's entire fleet of about 100 fifth-generation fighters made by Lockheed Martin Corp. was grounded for weeks following a June 23 engine fire aboard an Air Force F-35A model at Eglin Air Force Base, Florida. The aircraft subsequently missed its first planned appearances in the United Kingdom, including the Farnborough International Air Show outside London.
The fire was traced to excessive rubbing of fan blades in a section of the Pratt & Whitney-made F135 engine known as the integrally bladed rotor. While subsequent inspections revealed similar rubbing in several other engines, the phenomenon was far milder than in the engine that caught fire, leading Pentagon officials to conclude the problem wasn't systemic.
"It would be a little alarmist to assume we have a problem with the F-35 engine," Air Force Gen. Mark Welsh said during a news conference on Wednesday at the Pentagon. "Pratt and Whitney's been making pretty darn good engines for single-engine airplanes for a long time."
He added, "What we found in the program so far with these almost 9,000 sorties now is this engine works pretty well, too. That day it didn't, and we have to figure out why."
The general dodged a question on whether the Pentagon should have continued development of an alternative engine, the F136, made by General Electric Co. and Rolls-Royce Plc. "I'd like to have 1,763 F-35s, with an engine that works really well every single day," he said in response to the question, referring to the service's planned acquisition quantity. "That's the goal."
Welsh appeared at the briefing alongside Air Force Secretary Deborah Lee James, who said she expects the flight restrictions on the F-35 to ease up as investigators identify exactly what caused the engine fire.
"It's not unusual in a development program to have something like this happen," she said. "It's happened before. I think we're all very optimistic that we will be working through it. So I do not believe ... that this is in any way a show-stopper. It was unfortunate that it happened, but we're going through and trying to narrow down a root cause."
The Joint Strike Fighter is the Pentagon’s most expensive acquisition program, estimated to cost nearly $400 billion for 2,443 aircraft. Keeping the planes flying over the next half-century may cost another $1 trillion in sustainment.
Eight countries have committed to help develop the F-35, including the U.K., Italy, the Netherlands, Turkey, Canada, Australia, Denmark and Norway. Also, Israel, Japan and South Korea plan to buy production models of the aircraft.