- The Pentagon is expected to soon decide whether the F-35B will be allowed to fly at the Royal International Air Tattoo and the Farnborough Airshow in the United Kingdom
- The US government is continuing its investigation into a 23 June F-35A fire
The Pentagon grounded the entire Lockheed Martin F-35 Lightning II fleet on 3 July, just days before the short take-off and vertical landing (STOVL) variant was supposed to make its international debut in the United Kingdom.
Pentagon officials "issued a directive to ground the F-35 fleet based on initial findings" from the investigation of a 23 June fire aboard an F-35A at Eglin Air Force Base in Florida, according to Pentagon Press Secretary Rear Admiral John Kirby. The conventional take-off and landing (CTOL) A-model and the carrier variant C-model had previously been temporarily suspended from conducting flight operations over safety concerns.
"The root cause of the incident remains under investigation," said Rear Adm Kirby. "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."
The US Marine Corps (USMC) announced on 3 July that it would forego a heavily anticipated flyby at the 4 July naming ceremony of the Queen Elizabeth carrier in the United Kingdom with the F-35B. However, the Pentagon will still consider allowing flying displays of the F-35B at the Royal International Air Tattoo (RIAT) and the Farnborough Airshow in the United Kingdom. "Preparations continue for F-35 participation in international air shows in the United Kingdom," said Rear Adm Kirby. He said that a final decision on air show participation would be made early during the week commencing 7 July.
The pilot involved in the 23 June incident was preparing to conduct a training mission but aborted on the runway just prior to take-off, and emergency responders extinguished the fire with foam. The fire occurred in the rear of the aircraft where the engine is located, but the cause of the incident has yet to be announced.
F-35 prime contractor Lockheed Martin and engine manufacturer Pratt and Whitney both said they are aiding in the ongoing investigation but referred further questions to the government.
Earlier in June an F-35B near Marine Corps Air Station Yuma in Arizona suffered a major engine oil leak due to a separated oil inlet line from the oil flow management valve Rosan fitting. The 14 June incident was resolved quickly and all but three aircraft returned to flight status within days. Those three F-35s underwent repairs to deal with a faulty part.