The preliminary report into the probe of an Air India plane crash in Ahmedabad last month raises several questions but does not provide any answers, the International Federation of Air Line Pilots' Associations (IFALPA) has said.

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

A preliminary assessment in last month’s disaster focusing on fuel being cut to both engines only deepened the mystery for people grieving loved ones.