The two engines on the Air India flight shut down within one second of each other before the Boeing 787 Dreamliner crashed last month in Ahmedabad, India, killing at least 260 people, according to a preliminary report released Friday.

A preliminary report on the Air India Boeing 787 crash in Ahmedabad reveals both engines lost power after a sudden fuel cutoff, leaving pilots unable to regain thrust before the disaster. The investigation continues as experts probe the cause.

An official report on the world’s deadliest aviation accident in a decade, seen by CNN, has answered one key question – but raised others.