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.

Investors and the wider public are looking for answers after Thursday’s crash of an Air India 787 jet. Both of the plane’s black boxes have been recovered.

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.