Pratt & Whitney Finds Fix for F-35 Engine Issue

Problems with harmonic resonance had halted delivery of fighter jet engines for two months.

Pratt & Whitney said it has developed a solution for its F135 engines that have experienced problems with harmonic resonance vibrations. The engines, which power the Lockheed Martin F-35 (NYSE: LMT) Lightning II fighter, have been under scrutiny following the December 15, 2022, accident involving an F-35B at the Naval Air Station Joint Reserve Base Fort Worth in Texas. 

“The potential for the harmonic resonance issue occurring was limited to a small number of aircraft. The actions the government and industry team are taking will ensure incorporation of mitigation measures that will fully address/resolve this rare phenomenon in impacted F135 engines,” said a spokesman for the Department of Defense’s F-35 Joint Program Office, or JPO.

The spokesman also said the JPO has authorized engine deliveries to the F-35 production line to resume, and is working with Lockheed Martin to get the fleet flying again. Pratt & Whitney did not respond to requests for comment.

The F-35B Lightning II STO/VL model is flown by the U.S. Marine Corps and is designed for operation in remote areas. The aircraft involved in the Fort Worth incident was hovering before descending and making a hard landing on a runway that Lockheed Martin shares with the military base. The pilot ejected and the aircraft came to rest after the partial collapse of its landing gear.

The Pentagon stopped deliveries of F-35s and the aircraft’s engines following the accident.


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