The US Air Force says a strong tailwind is behind the flight line fire that has grounded yet another of its F-35 fighter aircraft.

The F-35A caught fire while getting ready to fly an exercise from Mountain Home Air Force Base in Idaho. It was one of seven at the base for surface-to-air training.

The fire happened while the pilot was starting the F-35; the pilot exited the aircraft while it was extinguished, and the US Air Force says there were no injuries.

While the cause of the fire is still under investigation, Aviation Week says “initial assessments point to a tailpipe fire due to strong tailwinds as the engine was starting.”

If accurate, that would point to a buildup of excessive heat in the jet's tailpipe. Aviation Week says at the time, winds were gusting up to 70 km/h (45 mph) from the northwest to west-by-northwest.

Last week's fire appears unrelated to an incident in 2014, when an F-35 at Eglin Air Force Base caught fire due to excessive blade rubbing in the jet's Pratt & Whitney F135 engine.

The US Air Force grounded the whole F-35 fleet after the 2014 incident, until the problem was fixed. ®