F-35 at Farnborough: Everything Except The Jet 16 Jul 2014 Chris Pocock
"...“We understand what happened, now we’re trying to figure out why,” said Lt. Gen. Chris Bogdan, head of the F-35 program office here on Tuesday. He said that borescope inspections of all 98 Pratt & Whitney F135 engines already delivered to the F-35 program has revealed nothing that would indicate a recurrence of the excessive rubbing of the inner cowl by the integral bladed rotor (IBR) in the third stage of the fan, that caused the failure in the F-35A. “Some blades are designed to rub, but this was more severe, leading to excessive temperatures, microcracking, and high-cycle fatigue, causing that part of the engine to come apart,” he explained...."
F-35 at Farnborough: Everything Except The Jet | Aviation International News