U.S. Military Grounds F-35 Fighter Jets

F-35

CALIFORNIA (CNN) – The Pentagon’s most expensive weapons system is going to spend some time on the bench.

The U.S. military on Friday grounded the F-35 fighter jet due to a crack in an engine component that was discovered during a routine inspection in California. The fighter is currently being tested.

The Pentagon said in a statement that it was too early to assess the impact on the nearly $400 billion fleet of jets designed for use by the Navy, Air Force and Marines.

The program has been beset by cost overruns and various technical problems during development.

Currently, there 51 planes in the F-35 fleet.