However, the fifth-generation stealth fighter made by Lockheed Martin Corp. is still expected to make its first international appearance next month at the Farnborough Air Show in the United Kingdom, officials said.
Both the Air Force and the Marine Corps halted flights of the aircraft after the rear of an F-35A caught fire while preparing to take off around 9:15 a.m. Monday at Eglin Air Force Base, Florida, officials said. The F-35A is the Air Force's version of the plane and designed to take off and land on conventional runways.
"The F-35As are continuing their temporary suspension of flight operations," 1st Lt. Hope Cronin, a spokeswoman for the 33rd Fighter Wing, said in a telephone interview. "That's in the interest of safety right now, as we continue to investigate the cause of the mishap."
The Navy reportedly hasn't yet decided whether to issue a temporary stand-down of the F-35C, designed to take off and land on aircraft carriers. A spokesman didn't immediately return an e-mail request for comment.
The Marine Corps, which flies the F-35B, which can take off like a plane and land like a helicopter, also opted to pause test flights, according to Capt. Richard Ulsh, a spokesman for the Corps at the Pentagon.
"We will resume flying once we know more about the cause of the F-35A fire that occurred at Eglin AFB earlier this week," he said. The directive doesn't technically constitute a grounding of the plane because it was voluntary and came from the Corps, not the Pentagon, he added.
The Defense Department still plans to fly four F-35Bs to the Farnborough Air Show, Ulsh said. The event runs from July 14 to July 20 outside London. The planes, assigned to Marine Fighter Attack Squadron 121 at Marine Corps Air Station Yuma, Arizona, will likely fly across the country to Naval Air Station Patuxent River, Maryland, before flying on to Fairford, England.
Meanwhile, the Air Force F-35A that caught fire at Eglin was towed to a hangar on the base, and debris from the runway was also collected for analysis, Cronin said. The runway, which the Air Force shares with Northwest Florida Regional Airport, was temporarily closed after the incident but has since reopened, she said.
Investigators are still trying to determine what caused the fire, where exactly it originated and how badly it damaged the aircraft, which cost more than $100 million apiece.
The F-35 Joint Strike Fighter Program is the Defense Department’s most expensive weapons acquisition program, estimated to cost almost $400 billion for a total of 2,457 aircraft for the Air Force, Navy and Marine Corps.
The pilot, who hasn't been identified, remains in good health, Cronin said. He was able to shut down the engine and escape from the plane unharmed. Emergency responders extinguished the fire with foam spray.
Operational flights of the aircraft are scheduled to begin next year.