Pilot error blamed for exhaust that led to US F-35B flying unmanned for 73 miles

An incident that led to an F-35B pilot ejecting – but the plane continued to fly unmanned for 73 miles before crashing – has been blamed on pilot error.

A US Marine Corps investigation said the pilot had misdiagnosed an out-of-control flight emergency and ejected from an “airworthy aircraft”.

It said the pilot had landed and switched the plane to hover mode, but then had several electrical malfunctions, causing his display to turn off and reappear.

He then pressed the buttons to switch out of hover to normal flight mode and had the display malfunction again for the third time – and that’s when he decided to eject.

The aircraft then proceeded to switch from hover to normal flight mode and then flew away for 11 minutes and 21 seconds, covering 64 nautical miles – 73 standard miles.

The incident occurred during a period of heavy rain when the pilot was flying on instruments near Joint Base Charleston in South Carolina last year.

The US Marine Corps said: “The pilot safely ejected from the aircraft while attempting to perform an exit during a missed approach.”

The investigation accepted that there were contributing factors including an “in-flight electrical incident which induced failure of both primary radios, the transponder, the tactical air navigation system and the instrument landing system, and the likelihood that the helmet-mounted display and panoramic cockpit display were not operational for at least three different periods”.

“This caused the pilot to become disoriented in challenging instrument and meteorological conditions,” it added.

The accident resulted in no ground-related injuries.

There was some property damage in the form of lost forested land and crops.

And the USMC report found that “no punitive action was recommended”.