More F-35 Engines Show Signs of Blade Rubbing

Pentagon officials on Monday shed new light on what caused a fire that led to a recent grounding of the F-35 fighter jet, but didn't say when – or whether – the aircraft will make its international debut this week at one of the world's biggest airshows.

A preliminary investigation into a fire that crippled an F-35A during takeoff June 23 at Eglin Air Force Base in Florida was due to excessive rubbing of fan blades in a certain section of the Pratt & Whitney-made F135 engine, according to Air Force Lt. Gen. Christopher Bogdan, who manages Joint Strike Fighter program.

The rubbing was far more severe than normal and led to higher temperatures, cracking and fatigue, Bogdan said. "That's what caused that engine to come apart," he said during a briefing with reporters at the first day of the week-long Farnborough International Air Show outside London.

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