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.

The US Federal Aviation Administration has issued a notice to its international counterparts that fuel control switches in Boeing aeroplanes like the Dreamliner involved in last month’s fatal Air India crash do not pose a safety issue.

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