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.

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.

An Air India Boeing 787, the same kind of plane that crashed 4 days earlier, was forced to turn around after a midair "technical issue," the airline says.