Last year, the F.A.A. said it was also investigating claims by a Boeing engineer that parts of the fuselage, or body, of the Dreamliner were improperly fastened together, which the whistle-blower said could cause premature damage to the plane over years of use.

The Air India flight, carrying 242 passengers and crew members, crashed shortly after takeoff from Ahmedabad, India, en route to London Gatwick.