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.

Tragedy struck this week when a plane crashed in the city of Ahmedabad just shortly after takeoff, leaving investigators and aviation officials with many questions.

Officials are analyzing both black boxes of the Boeing 787 Dreamliner that crashed in India, killing all but one passenger.