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 granddaughter of a victim of the Air India Flight 171 crash has said a preliminary report into the incident was "incomplete" and that she "can't be at peace" without those responsible being held accountable.

Investigators released a preliminary account of the crash, describing how the plane struggled after its fuel supply was cut.