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.

An Air India Boeing 787-8 flight headed for New Delhi returned to Hong Kong shortly after takeoff Monday because of a "technical issue," Indian media reported.

That's how long Air India Flight 171 was airborne before it plunged into a densely populated neighbourhood in Ahmedabad in one of India's rarest aviation disasters in recent memory. Investigators now face the grim task of sifting through the wreckage and decoding the cockpit voice and flight data recorders of the Boeing 787 Dreamliner to piece together what went catastrophically wrong in the seconds after take-off.