Entire F-35 fleet grounded by engine issues

Just nine days after the Pentagon cleared the F-35B variant of the Joint Strike Fighter to resume test flights after a monthlong suspension, and one day after the first local flight here in Yuma, the Lightning II has been grounded once again, this time by a cracked engine blade.

Unlike the past suspension, which was only for the B jump jet variant designed for the Marine Corps, this suspension is for all versions of the F-35 fleet, including the F-35A Air Force conventional takeoff version and the F35-C carrier variant for the Navy — a total of 51 planes.

The problem was discovered during what the Pentagon called a routine inspection Tuesday at Edwards Air Force Base, Calif., of an F-35A.

In a brief statement, the Pentagon said it is too early to know the full impact of the newly discovered problem.

The F-35 is the Pentagon's most expensive weapons program at a total estimated cost of nearly $400 billion. The Pentagon envisions buying more than 2,400 F-35s, but some members of Congress are balking at the price tag.

Friday's suspension of flight operations will remain in effect until an investigation of the problem's root cause is determined.

The engine in which the problem was discovered is being shipped to a Pratt & Whitney facility in Connecticut for more thorough evaluation to determine what caused the engine blade to crack. That engine had 700 total operating hours, with 409 of those accrued in flight. The engine analysis should take “roughly” a week, officials said.

Both F-35 suspensions, now, are due to problems with the engines. The F-35B variant was initially grounded after a Jan. 16 test flight at Eglin Air Force Base, Fla., was aborted due to a problem later identified as a fueldraulic system failure.

That failure was caused by an improperly crimped fueldraulic line. After an investigation by the Joint Strike Fighter Program Office and engine manufacturer Pratt & Whitney, six non-compliant lines were discovered.

Thursday's flight of an F-35B variant at Marine Corps Air Station Yuma marked the first time a flight was conducted by the Marine Corps or any service branch primarily responsible for the maintenance of the aircraft.

MCAS Yuma is home to VMFA-121, the world's first operation F-35 squadron. The squadron, once fully staffed, will consist of approximately 300 Marines. While the squadron currently has three Lightning IIs, it is expected to receive additional F-35s throughout the next eight to 12 months, with a total of 16 aircraft scheduled to arrive by late 2013.

The Associated Press contributed to this article. James Gilbert can be reached at jgilbert@yumasun.com or 539-6854. Find him on Facebook at www.Facebook.com/YSJamesGilbert or on Twitter @YSJamesGilbert.