F-35 fleet cleared for ground operations - Air Force News | News from Afghanistan & Iraq - Air Force Times

F-35 fleet cleared for ground operations

The F-35 Lightning II fleet has been cleared to resume ground operations after a preliminary investigation found the cause of an electrical subsystem failure, but a Pentagon official refused to speculate when the next-generation fighters will be back in the air.

Investigators on Aug. 10 determined a malfunctioning control valve caused the integrated power package of AF-4, the fourth conventional takeoff and landing version, to fail Aug. 2, said Joe DellaVedova, a spokesman for the F-35 program.

The IPP, built by Honeywell International, combines the functions that are performed by an auxiliary power unit, emergency power system and environmental controls. Lockheed Martin makes the aircraft.

All 20 of the Lightning IIs have been parked for the past week, the second grounding this year because of electrical problems. In March, faulty maintenance procedures caused a dual generator on the same AF-4 to shut down.

Ground operations will now continue at Edwards Air Force Base, Calif., where the AF-4 that malfunctioned is assigned, and Naval Air Station Patuxent River, Md., DellaVedova said. However, the training unit at Eglin Air Force Base, Fla., is not cleared to resume ground operations because they are not a test organization. The Eglin aircraft are not wired with test instrumentation.

“We are in development tests of this airplane. There will be discoveries, we want to find discoveries,” he said. “We want to find and implement fixes to get this airplane flying again. Today was one step down that road.”