Lockheed Martin and the US Air Force have finished repairs on the last of 13 F-35As affected by a faulty insulation issue earlier this year, though work continues on Lockheed’s production aircraft.

The coolant line glitch hit 57 aircraft in September, including 15 fielded F-35As and 42 production aircraft. Repairs to the fielded jets began 7 October and later that month, two F-35As at Hill Air Force Base, Utah were returned to flying operations. In early November, the USAF also fixed one Norwegian jet stationed at Luke AFB, AZ.

Meanwhile, Lockheed has completed repairs on seven aircraft on its production line and is working on four more jets, a Lockheed spokesman tells FlightGlobal.

In September, the USAF discovered insulation from an avionics cooling line within an F-35A fuel tank was found detached. Lockheed and the USAF have maintained the problem was a supply chain issue, rather than a design flaw. Lockheed’s supplier used the wrong coating for the insulation, which deteriorated when it met fuel.

In total, the USAF and Lockheed have repaired ten aircraft at Hill AFB, one at Nellis AFB, NV and two Norwegian jets stationed at Luke AFB.

Source: FlightGlobal.com