Cracks in the armor? Another F-35 fighter jet catches fire in US

An F-35A Lightning II Joint Strike Fighter © Randy Gon / U.S. Air Force photo
Another F-35A fighter jet - touted as the future of military aviation - caught fire during an exercise at Mountain Home Air Force Base, Idaho, the US Air Force has confirmed.

An investigation has been launched into what caused the fire, which was located in "the aft section of the aircraft," according to a statement from the Air Force.

The jet was one of seven F-35As dispatched from Luke AFB, one of the bases responsible for joint strike fighter pilot instruction, as part of surface-to-air training at Mountain Home between September 10 and 24.

No injuries have been reported, but questions are being raised as to whether the fire may have originated in the F-35's F135 engine, manufactured by Pratt & Whitney, as was the case in 2014.

This is the latest hiccup for the $1.12 trillion project and comes only a week after the US Air Force revealed it was grounding 13 F-35s and was pausing production of 42 more, blaming “improper manufacturing processes.”

Poorly built insulation material being used in the construction of the warplanes is said to be “crumbling” into fuel tanks, according to a statement from the US Air Force.

A 2015 report into a fire that destroyed an F-35A Lightning II at Eglin Air Force Base, Florida in June 2014, which resulted in the grounding of the entire fleet of the fifth generation fighter jet for almost a month, found the fire was caused by “catastrophic engine failure.”

The damage was estimated to be more than $50 million.

READ MORE: F-35 fleet grounded for the eighth time over unknown engine issue

US lawmakers used the 2014 incident to highlight issues with the overall F-35 program. The fire also reignited a discussion on Capitol Hill of whether a competitor to the Pratt & Whitney F135 engine should be restarted.

The F-35 joint program office has repeatedly expressed confidence that the cause of the fire is isolated and has been repaired.

The single-engine, fifth-generation F-35 fighter jet may well be the largest single global defense program in history.  

Of the original nine partner countries - Australia, Canada, Denmark, Italy, the Netherlands, Norway,Turkey, the United Kingdom and the United States – six have received their first jets.

Two of the three foreign military sales (FMS) customers, Israel and Japan, have taken delivery of their aircraft while South Korea will receive their first jets in 2018.