The “ready for combat” F-35 has run into headwinds again, with 15 of the F-35A variant grounded in America because cooling line insulation is cracking up.
Various reports state that the problem is non-conforming insulation in lines carrying coolant in the plane's wings. The F-35 passes its poly-alpha-olefin (PAO) coolant through the fuel tanks to chill it.
During maintenance, the insulation around PAO lines was found to be “peeling and crumbling”, and leaving residue in the tanks.
So far, 13 aircraft belonging to the US Air Force have been grounded, and two more belonging to Norway. According to Bloomberg, the problem also affects 42 aircraft currently on the production line.
The US Air Force says the “non-conforming” insulation is the fault of a contractor supplying the cooling lines.
Ten of the aircraft are at Hill Air Base in Utah, the US Air Force's first “combat-ready” squadron of the Toothless Tiger Moths.
As Defense One notes, the grounding happens a week ahead of the annual Air Force Association convention.
Defense One says the F-35 program office said the unnamed third-party supplier used “nonconforming material” for the insulation, and made mistakes during its manufacturing processes.
The material used is “not compatible with fuel”. ®