After an engine fire in June grounded the entire U.S. military fleet of Lockheed Martin F-35 fighter jets, Navy and Air Force officials have approved a limited flight clearance to run engine inspections and restricted flight drills.

The cause of the fire is still not known, and the Pentagon, along with engine manufacturer Pratt & Whitney, has been trying to assess whether the malfunction was an isolated incident, or indicative of a fleet-wide problem. Pentagon press secretary Rear Adm. John F. Kirby said in a statement, “Additional inspections of F-35 engines have been ordered, and return to flight will be determined based on inspection results and analysis of engineering data.”

Defense Department spokesman Mark Wright said in a statement Tuesday the flight limitations would “remain in effect until the root cause of the June 23 engine mishap is identified and corrected.”

There were hopes the F-35 would make it to the famed Farnborough air show in England, which commenced Monday, but Rear Adm. John Kirby revealed Tuesday that the jets won’t make it.

#F35 Returns to Limited Flight, Officials Rule Out Farnborough, http://t.co/XfSV5nUdcZ pic.twitter.com/fV9wAK0UWQ

— U.S. Dept of Defense (@DeptofDefense) July 15, 2014

“The Department of Defense, in concert with our partners in the U.K., has decided not to send Marine Corps and U.K. F-35B aircraft across the Atlantic to participate in the Farnborough air show,” Kirby commented. “This decision was reached after a consultation with senior leaders and airworthiness authorities, despite the decision by airworthiness authorities to clear the aircraft to return to flight – to limited flight.”

Here is a documentary on the F-35:

The Lockheed Martin F-35, which has variations designed for the Air Force, Navy and Marine Corps, is a multirole fighter designed to perform ground attack, reconnaissance and air defense missions with stealth capability. The F-35 is the only fifth-generation fighter jet available for export from the United States, and orders have been placed by the U.K. (138 planes), Australia, Canada (which ordered 65), Israel, Italy, Japan, the Netherlands, Norway and Turkey.

The F-35 initiative was a $400 billion joint venture between Lockheed Martin and the Pentagon, the most expensive in Defense Department history. The engine fire mishap is the latest controversy surrounding a plane that has garnered significant international attention.

Image via Wikimedia Commons