WASHINGTON (Reuters) - The U.S. Navy on Friday maintained a grounding order for F-35 B-model and C-model fighter jets built by Lockheed Martin Corp given that it remained unclear what had caused a massive engine failure on an Air Force F-35 jet on June 23.
"At this time, I do not have sufficient information to return the F-35B and F-35C fleet to flight," Vice Admiral David Dunaway, who heads the Navy's Air Systems Command, said in an updated directive obtained by Reuters. "There is no discernible event that represents a root cause."
Until the grounding is lifted, the U.S. Marine Corps and Britain will not be able to ferry four F-35B aircraft to Britain for the fighter jet's planned international debut at two air shows in Britain this month.
Dunaway said the Navy and other services continued to investigate the incident, and planned to update the flight directive no later than July 16 - two days after the start of the high-profile Farnborough air show outside London.
(This story corrects to make clear order is maintained, not lifted)
(Editing by Sandra Maler)