The preliminary report into the crash referred to a 2018 FAA advisory, which recommended that operators of several Boeing models inspect the locking feature of the fuel-cutoff switches. The report said Air India did not carry out the inspections.

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.