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.

Many questions have been left unanswered after Air India Flight 171 that was airborne for less than 40 seconds plummeted into a residential area in India. As investigators dig through the wreckage and decode the cockpit voice and flight data recorder of the aircraft, theories will be confirmed or denied as questions are answered.

Investigators believe the Air India Boeing Dreamliner had its emergency-power generator operating when it crashed last week in India's Ahmedabad, the Wall Street Journal reported on Wednesday citing people familiar with the probe.