The entire fleet of approximately 104 F-35A, B and C models was grounded for parts of last week after an in-flight emergency of a USMC F-35B at MCAS Yuma on June 10.
The emergency was attributed to an oil warning light on the aircraft, and prompted a 90-minute inspection of all development, training and operational test F-35s currently in service.
A June 13 statement by the JSF Project Office confirmed all the aircraft would be inspected and likely returned to flight on June 14, and that similar faults had been found on three F-35Bs at Yuma, but on no other aircraft.
A report in the Wall Street Journal said the oil warning was traced to the oil flow management unit which provides oil to the engine bearing compartment on the P&W F135 engine.
