Pentagon grounds fleet of F-35 jet fighters

The Pentagon grounded on Friday its entire 51 fleet of F-35 fighter jets after a routine inspection revealed a crack on an engine blade of one of the aircraft.

It is the second grounding of the warplane in two months and another setback for the Pentagon's biggest and most expensive weapons program, ABC News reported.

The latest problem was discovered on February 19 during what the Pentagon called a "routine inspection" at Edwards Air Force Base, California, AP reported.

The inspection “revealed a crack on a low-pressure turbine blade of an F-35 engine” and the office took the “precautionary measure” of suspending all F-35 flight operations, the F-35 Joint Strike Fighter program office said in a statement Friday.

“The F-35 Joint Program Office is working closely with [engine maker] Pratt & Whitney and [primary plane manufacturer] Lockheed Martin at all F-35 locations to ensure the integrity of the engine, and to return the fleet safely to flight as soon as possible,” the statement continued.

While the F-35 program office said it was too early to know if this was a fleet-wide issue, it had decided to suspend all flight operations until an investigation of the problem's root cause was determined, Reuters reported. 

"Given the political scrutiny they're under and given the concerns about cost and performance, this is not welcome news," said aerospace analyst Richard Aboulafia with Virginia-based Teal Group.

He said another lengthy grounding could thwart the program's ability to complete an aggressive flight test schedule this year.

In a brief written statement, the Pentagon said an investigation was under way and it was not known what the full impact of the discovery would be on the fleet.

The F-35 is the Pentagon’s most expensive weapons program at a total estimated cost of nearly $400 billion.