The entire F-35 fleet is being grounded owing to an engine issue, to avoid what U.S. Naval Air Systems Command (Navair) calls a potential “catastrophic failure.”

A crack on the 3rd stage low-pressure turbine airfoil was found Feb. 19 during an inspection of a conventional F-35A at Edwards AFB, Calif., says Matthew Bates, a spokesman for Pratt & Whitney, which makes the stealthy, single engine fighter’s F135 engine.

“As a precautionary measure, all F-35 flight operations have been suspended until the investigation is complete,” the Pentagon said in a statement. “It is too early to know the fleet-wide impact of the recent finding.”

Bates also describes the grounding as a “precautionary measure.” The damaged turbine module and associated hardware are being shipped to the manufacturer’s facility in Middletown, Conn., for investigation. This engine had 700 total hours of service, 400 of which were executed in flight, before the crack was found, he says.

The company hopes to figure the issue out and return the fleet to safe flight as soon as possible, Bates adds.

Navair’s commander, Vice Adm. David Dunaway, says an update on the issue is not expected for Congress earlier than March 1.

This grounding, if extended, could cripple the pace in flight testing that was pleasing prime contractor Lockheed Martin and government customers. And it could delay the testing of critical systems — including the 2B software needed for an initial operational capability declaration by the Marine Corps.

The news comes just after the lifting of a grounding of the short-takeoff-and-vertical-landing F-35B fleet that was blamed on improperly crimped fueldraulic lines also managed by Pratt & Whitney.

The grounding may provide a small measure of satisfaction to proponents of General Electric’s failed effort to provide an alternate F-35 engine. After years of tough debate and lobbying spanning two presidential administrations, the Pentagon finally secured Congress’ agreement to terminate the GE/Rolls-Royce F136 alternate engine in 2011.