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.

Air India Flight 171 crash has placed Boeings 787-8 Dreamliner under fresh scrutiny. While investigations continue, past safety concerns and whistleblower warnings now resurface regarding Boeing Dreamliner's safety.