WASHINGTON (Reuters) - The U.S. Marine Corps on Friday resumed flights of its Lockheed Martin Corp F-35B jets that were suspended following a fire on an Air Force F-35A and prepared for the jet's global debut in Britain next month after the discovery of engine pieces from the F-35A pointed to an issue with that specific model.
"We are continuing with our plans to deploy to the UK next month," said Marine Corps spokesman Captain Richard Ulsh. He said the Marine Corps resumed F-35B flights on Friday.
Four F-35B jets arrived early evening on Friday at an air base in southern Maryland, where they will be readied for their first trans-Atlantic flights, according to sources familiar with the program. The jets came from a Marine Corps base in Yuma, Arizona.
The deployment of the jets to Britain had been called into question after a fire broke out in the rear of an Air Force A-model F-35 on Monday as the pilot was preparing to take off for a training flight.
The Air Force on Thursday suspended flights of all F-35 A-model jets while it investigates the fire. Flights of some Navy jets were also suspended, but others continued to fly, according to Navy officials.
Sources familiar with the situation said engine pieces and fragments were found on the runway at Eglin Air Force Base in Florida after the fire, the first confirmation that the fire involved the plane's engine, which was built by Pratt & Whitney, a unit of United Technologies Corp.
The Air Force has not released any details about its investigation and a spokeswoman had no immediate comment on the report that engine components were found.
Pratt builds the engines for all three models of the F-35: the Air Force's conventional takeoff A-model, the Marine Corps' B-model, which can land vertically, and the Navy's C-model, which is for use on aircraft carriers.
The sources, who were not authorized to speak publicly, said the discovery of the engine parts did not point to a specific cause of the fire and said the investigation was continuing.
But they said it cleared the way for the Marine Corps and Navy to resume flights since their B- and C-model jets have a different engine.
Pratt & Whitney spokesman Matthew Bates said his company was ready to assist in the Air Force investigation, and referred all further questions to the Air Force.
Lockheed also said it was ready to assist with the investigation, but declined to comment on the latest news.
One of the sources said discovery of engine fragments on the runway after the fire could point to several different possible causes, including a manufacturing quality issue affecting just the engine in question, which had flown for about 150 hours.
Engine damage could also stem from debris in the engine, or a maintenance problem, the sources said.
(Reporting by Andrea Shalal; Editing by Dan Grebler)