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

Relatives of some of the 260 victims of last month’s Air India disaster have hit out at the airline and the Indian government over the initial investigation report, saying they have rushed to blame pilots while hiding failings that led to the crash.

Preliminary findings into last month’s Air India plane crash suggest the aircraft’s fuel control switches were turned off, causing a loss of engine thrust shortly after takeoff.