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.

An investigation is underway as to what caused an Air India airliner carrying 230 passengers and 12 crew members to crash shortly after takeoff on Thursday.

There have been cases of a very small number of survivors in very serious accidents, but it is "very rare" for there to be only one, a professor told Newsweek.