UPDATED: The fleet-wide grounding by the US Department of Defense of the F-35 Lightening II has been lifted, following the completion of engineering analysis on the cracked blade. The cautionary flight suspension was implemented on February 21 following the discovery of a 15.24mm crack on a third stage turbine blade during routine inspections of a test aircraft F135 engine.
In a media statement, the F-35 JPO said flight operations had been cleared to resume following fleet wide engine inspections.
Comprehensive tests on the blade were conducted at the Pratt & Whitney facility in Middletown, Connecticut. The engine in question is part of the F-35 test aircraft fleet and had been operated for extended time in the high-temperature environment in its mission to expand the F-35 flight envelope,” the statement read.
“Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack. No additional cracks were found during inspections of the remaining F135 inventory.”