Prolonged Friction Caused F-35 Engine Fire

Prior to awarding a $592 million contract for 36 additional F135 engines, a joint Defense Department and Pratt & Whitney “investigative team met and reviewed the identified cause” of a June engine fire at Eglin AFB, Fla., which led to the grounding of the entire fleet. The team concluded the fire was caused by “prolonged rubbing into the material in the stator,” which then “decomposed and superheated the titanium rotor leading to excessive heating.” The excessive heating “started very small cracks in a titanium seal and then led to failure of the third stage fan rotor,” according to a joint statement, issued late Tuesday along with the contract notification. Under terms of the latest contract, the JPO and P&W are now “executing a plan to modify the current fielded operational and test engines, and [will] implement a long-term solution for production engines.”