The Pentagon has decided to formally ground all three variants of the F-35 Joint Strike Fighter after one of the aircraft caught fire on June 23.

A directive to ground the type was issued by the airworthiness departments of the Navy and Air Force as a result of the initial findings into the cause of a fire involving the Air Force F-35A at Eglin AFB, Florida.

Until now, the decision to ground the aircraft had been in the hands of local commanders at each of the F-35 main operating bases, but the Pentagon’s directive now overrides those local orders and forces the grounding of the whole fleet including the three Marine Corps F-35Bs and single U.K. Royal Air Force F-35B due to fly across the Atlantic to make the type’s international debut at the Royal International Air Tattoo (RIAT) at RAF Fairford and the Farnborough International Airshow next week.

In a defense department statement, made late on July 3, Press Secretary Rear Admiral John Kirby said: “The root cause of the incident remains under investigation. 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 leadership supports this prudent approach,” he added.

Kirby added that preparations for the F-35’s participation in the U.K. shows are continuing but added that a final decision will come next week.

The groundings have caused haywire in the complex plan to get the jets to the U.K. Three Marine Corps aircraft from MCAS Yuma, Arizona positioned to, NAS Patuxent River, Maryland, in late June and have been waiting for the arrival of the British aircraft, BK-3 from Eglin AFB, Florida, but the grounding and the reported involvement of the U.K. Military Aviation Authority has prevented the aircraft from making the journey to Maryland. North Atlantic storms and the formation of Hurricane Arthur off the East Coast have also impacted on flight planning.

The aircraft had initially been due to arrive at RAF Fairford on June 29, but that has been progressively pushed back. While Lockheed Martin and the DoD have always said their stated aim was to get the aircraft over for the two airshows, there was hope that an early arrival would allow one of the F-35s to take part in the flypast at the naming ceremony of the U.K.’s new aircraft carrier HMS Queen Elizabeth on July 4, but that opportunity has now been missed.

The U.K. deployment now faces several challenges including getting the British aircraft from Eglin to Patuxent River, and then getting all four aircraft over non-stop in order to be able to perform a display validation sortie which covers the performance for both airshow appearances. It is hoped that the aircraft’s international debut can still be made on July 11 at RAF Fairford.