The U.S. Air Force has suspended flight operations of 15 Lockheed Martin F-35A fighters to repair insulating material around an avionics cooling line in a fuel tank, the F-35 Joint Program Office (JPO) announced on September 16. The problem also affects 42 fighters on the production line.
During recent depot modification of an F-35A at the Ogden Air Logistics Center at Hill Air Force Base, Utah, insulating material from an avionics cooling line was found detached from the line. Under certain conditions, the material could obstruct fuel flow in and out of various fuel tanks, the JPO said.
“The root cause of the problem was determined to be use of nonconforming material for the tubing insulation and improper manufacturing processes during fabrication of the cooling lines,” the office stated. “The nonconforming material that was used is not compatible with fuel, causing degradation of the insulation and resulting in it falling off the tubing.”
The Air Force declared initial operational capability of the F-35A in August. The affected aircraft include 10 fighters at Hill AFB, two U.S. and two Norwegian fighters at Luke AFB, Arizona, and one F-35A at Nellis AFB in Nevada, Defense News reported. F-35Bs and F-35Cs are not affected.
“This is not a technical issue with the performance of the aircraft, but a quality escape that affects only a small subset of the 104 operational F-35As in the fleet,” the program office said. “The F-35 JPO and Lockheed Martin have a proven track record of solving issues and we’re confident we’ll continue to do so. The government and industry team is now developing repair procedures to remedy the problem and return the affected aircraft back to safe flying operations.”