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.

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.