News have emerged that a fan in the front stage section of a F135 engine failed during ground tests in December.
Officials from the Pentagon and Pratt & Whitney are playing down the incident as the failure occurred after 2,200 hours of testing.
F-35 program manager, Lt. Gen. Christopher Bogdan, said a redesign of the first stage had already started when the failure happen. The lesson learn from this failure will be incorporated into the redesign.