The Pentagon office that runs the program said the crack in the turbine blade was discovered on Tuesday in a routine inspection. The crack occurred on a test plane at Edwards Air Force Base in California. The blade is being shipped to a plant in Connecticut, where the engine manufacturer, Pratt & Whitney, will inspect it and look for the problem’s cause.

Matthew C. Bates, a spokesman for Pratt & Whitney, said none of the other F-35s had suffered any cracks. The F-35 program office in the Pentagon said in a statement that it had suspended the flights as a precaution until the investigation was completed and the cause of the cracking was fully understood.

The turbine problem, first reported by Politico Pro, arose as the Pentagon has sought to persuade Congress to cancel the automatic cuts, which could force the military to reduce its budgets by about $500 billion over the next 10 years. The first installment of the cuts is scheduled to start on Friday, and it may force the Pentagon to delay buying three of the approximately 30 F-35 planes it had planned to order this year.

“We don’t know the severity of the problem with the turbine blade,” said Richard L. Aboulafia, an aviation analyst at the Teal Group in Fairfax, Va. “It could be a one-off or it could be something that needs more attention. But either way, given the political scrutiny and the concerns about the plane’s cost and performance, this is a very bad time to have a problem.”

The F-35 was conceived as the Pentagon’s silver bullet in the sky — a state-of-the art aircraft with advances that would easily overcome the defenses of most foes. The radar-evading jets would dodge sophisticated antiaircraft missiles and give pilots a better picture of enemy threats while enabling allies, who want the planes, too, to fight more closely with American forces.