The preliminary finding gives investigators a new line of inquiry as they study a crash that killed all but one of the plane’s passengers.

The crash of an Air India Boeing 787 Dreamliner seconds after takeoff from Ahmedabad city, killing all but one of the 242 people on board, is the world's worst aviation disaster in a decade. At least 30 people were also killed on the ground as the airliner crashed into a medical college hostel near the airport.

Investigators in India are studying the black boxes of a Boeing 787 Dreamliner after recovering them from the aircraft wreckage to ascertain the cause of last week's plane crash that left at least 270 people dead.