U.S. Navy maintains grounding order for F-35 fighter jets

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, saying it was still not clear what 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 update to a fleetwide grounding order issued by U.S. officials on July 3. A copy of the document was obtained by Reuters.

Dunaway said in the document that he was committed to returning the F-35 fleet to flight as soon as possible, but there was "no discernible event that represents a root cause."

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