The Air Force and Navy versions of the F-35 were not affected.
WASHINGTON — The Pentagon and U.S. Navy on Friday ordered a temporary grounding of the Marine Corp.'s version of Lockheed Martin Corp's F-35 fighter jet after an incident that occurred during a training flight at Eglin Air Force Base in Florida on Wednesday.
The Pentagon's F-35 program office said the grounding affected all 25 F-35B model jets, while flights of the Air Force's A model and the Navy's C model were unaffected. Ground operations of the model B planes continued, it said.
The program office ordered the suspension of flight operations after a propulsion line associated with the F-35B's exhaust system failed prior to takeoff. The pilot aborted the takeoff without incident and cleared the runway, the program office said in a statement. There were no injuries to the pilot or ground crew.
The incident came just days after the Pentagon's director of testing and evaluation released an 18-page report detailing an array of problems that he said underscored the "lack of maturity" of the $396 billion fighter program.
Matthew Bates, spokesman for Pratt & Whitney, a unit of United Technologies Corp. that builds the engines for the single-engine, single-seat fighter jet, said an initial inspection discovered a detached propulsion line in the rear part of the engine compartment.
The fueldraulic line is not used in the A or C models, which are still permitted to fly.
"A team of Pratt & Whitney and Rolls-Royce engineers is investigating the cause of the incident and working closely with Lockheed Martin and the F-35 Joint Program Office to resolve the matter," Bates said in a statement provided to Reuters.
He said there had been no previous issues with the component that triggered the grounding.
Reporting by Andrea Shalal-Esa.