F-35s Cleared to Return to Flight

The F-35 joint program office lifted the cautionary flight suspension of the F-35 fleet after engineers completed analysis of a cracked F-135 turbine blade. “Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack,” states the JPO’s March 1 release. The engine in question “had been operated for extended time in the high-temperature environment in its mission to expand the F-35 flight envelope,” states the release. Inspections found “no additional cracks” in the remaining F135 inventory, states the release. The JPO instituted the fleet-wide standdown on Feb. 21 after finding the 0.6 inch crack on a 3rd stage turbine blade during a routine inspection of an F-35A test aircraft at Edwards AFB, Calif. F135 supplier Pratt & Whitney conducted comprehensive tests of the blade at its facility in Middletown, Conn., according to the JPO. F-35 test aircraft operate at Edwards and Patuxent River NAS, Md.; F-35 training aircraft fly at Eglin AFB, Fla., and MCAS Yuma, Ariz. (See also AFPS report by Amaani Lyle.)