Boeing investors finally have details from a preliminary accident report for Air India flight 171, which crashed on June 12 less than a minute after taking off from an airport in Ahmedabad, India.

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

The cockpit voice recorder captured a pilot questioning the other with, “Why did you do the cut-off?”, to which the other replied he hadn’t. It remains unclear who made the statement. At the time, the co-pilot was flying the aircraft while the captain was monitoring.