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.

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.

India's aviation safety watchdog said on Tuesday surveillance conducted on Air India's Boeing 787 fleet did not reveal any major safety concerns, days after one of its jets crashed, killing at least 271 people.