WASHINGTON, June 15 The U.S. military has ordered mandatory inspections of all Lockheed Martin Corp F-35 fighter jets before further flights after a Marine Corps F-35B model suffered an in-flight emergency last week, a Pentagon spokesman said on Sunday.
Joe DellaVedova, spokesman for the F-35 program office, said the inspections had been ordered on Friday but that a large number of planes had already been inspected and cleared to resume flights on Monday.
He said the inspections, first reported by the Wall Street Journal, were focused on the oil flow management valve fitting on all F135 engines, which are built by Pratt & Whitney, a unit of United Technologies Corp. The valve provides oil flow to the engine bearing compartments.
News of the mandatory safety inspections came just days after Frank Kendall, the Pentagon's chief arms buyer, said the F-35 program was making progress but more work was needed on developing the jet's software and improving its reliability.
The inspections were ordered after an F-35B model suffered an in-flight emergency on June 10 caused by oil loss in the jet's engine at a Marine Corps base in Yuma, Arizona, where issues have now been found with a total of three valves, DellaVedova said.
He said the pilot returned to base safely and there were no injuries.
No issues have been discovered at the other bases where F-35s are flown in California, Florida, Arizona and Maryland, he said.
Pratt & Whitney spokesman Matthew Bates said the company was working closely with the Pentagon's F-35 program office to determine the cause of the issue. He said it took about 90 minutes to inspect each aircraft, and nearly all planes had been inspected and cleared for further flights.
DellaVedova said the source of that F135 engine oil leak appeared to be a supply line to engine bearings and a fitting that separated from the body of the valve in question.
It was not clear if the issue was maintenance-related. (Reporting by Andrea Shalal; Editing by Sandra Maler)