The US Air Force (USAF) has ordered a “temporary pause” in flight operations for 15 Lockheed Martin F-35A Lightning II combat aircraft following discovery of “peeling and crumbling insulation” in avionics cooling lines within the jets’ fuel tanks.
The grounded aircraft include jets fielded at Hill Air Force Base, Utah; Luke Air Force Base, Arizona; and Nellis Air Force Base, Nevada. A spokesman for F-35 prime contractor Lockheed Martin confirmed that two aircraft at Hill belong to Norway. Of the remaining 42 production aircraft affected by the issue, 28 belong to the United States and partner nations, while 14 are Foreign Military Sales (FMS) aircraft.
Engineers from F-35 Joint Program Office, Lockheed Martin and Hill Air Force Base are inspecting eight of the aircraft and are “developing procedures to resolve or mitigate the issue prior to release of affected production aircraft to the field and the return of affected operational aircraft to flight operations”.
Only one batch of parts is affected by the issue, according to Lockheed Martin:
“This issue was discovered during depot maintenance on one of the impacted jets where loose insulation was discovered. The issue is confined to one supplier source and one batch of parts.”
The company intends to resolve it for the 42 F-35As in assembly prior to delivery.