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F-35 grounded after electrical system failure thus joining the F-22

August 5, 2011 (by Lieven Dewitte) - For the third time in less than a year, the Pentagon has grounded all F-35 joint strike fighters because of a mechanical problem. The F-35s thus join the F-22 Raptors in stand down mode.

A crew chief from the 33rd FW guides F-35A #08-0747 to its final parking position on July 14th, 2011. The aircraft is the first production F-35 to be delivered to the wing. AF-9 arrived at 13.18hrs CDT after launching on its 90-minute ferry flight from Fort Worth. [Lockheed Martin photo by Angel DelCueto]

All flight and ground operations for the Joint Strike Fighter were ceased after the integrated power package (IPP) on a U.S. Air Force variant test aircraft failed on August 2nd during a ground maintenance run at Edwards Air Force Base.

The 20 operational test and training aircraft were parked and will stay that way until engineers and technicians can find why a power system that starts and cools the aircraft failed during an engine ground test Tuesday at Edwards Air Force Base in California. Flight and ground tests could potentially be suspended for a few weeks.

Suspending flights "is the prudent action to take at this time until the F-35 engineering, technical and system safety teams fully understand the cause of the incident," the F-35 Joint Program Office said in a statement. The program office oversees contractors and military test teams.

Few details of the incident were released, but the program office said that once the power system failed "the engine was immediately shut down and the jet was secured. No injuries to the pilot or ground crew occurred."

The F-22 Raptors have been grounded since May after several pilots experienced hypoxia-like symptoms. Air Force officials do not yet know the cause but suspect carbon monoxide and toxins seeping into the cockpits.

This isn't the first (or second) time the F-35 has been grounded within the last year. A software glitch that could shut down fuel pumps in flight shelved the planes last October while an electrical issue put them out of service again this March.

The system that failed this week, the integrated power package, was on the same plane whose electrical generator failed in March. The particular aircraft is an AF-4, which is a conventional takeoff and landing version of the multi-role aircraft.

The failure occurred in the integrated power pack (IPP), which is used to start the main jet engine, provide air conditioning for the cockpit and numerous electrical systems, and generate backup electrical power.

The cessation or limiting of specific operations during the test program is not particularly unusual, but putting a halt to ground operations is less common. Overall, the F-35 is ahead of its latest schedule, which was put in place in January. Margins have been built into it to accommodate these kinds of incidents that occur in a development effort.

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