The cause of the Air India Boeing jet’s crash is unknown, but it comes amid the plane maker trying to rebuild trust on safety issues.

Boeing stock fell sharply in premarket trading after an Air India plane crashed in what's thought to be the first such incident involving a 787.

Air India Flight 171 crashed shortly after takeoff from Ahmedabad, in western India, according to preliminary flight-path data. There were 242 passengers and crew aboard the Boeing 787 Dreamliner. The cause of the crash wasn't immediately known and could take months to determine.