The investigation report says Air India did not carry out those inspections - prompting speculation that the accident could have been caused by faulty switches being flipped by accident. However, in an internal note seen by the BBC, the FAA has since reiterated its belief that the issue did not compromise safety.

Weeks before the Air India 787 crash, UK regulators flagged fuel valve issues on Boeing jets, prompting urgent checks. New details raise questions about missed warnings and maintenance lapses.

The simultaneous transition of both engines' fuel switches suggests a sudden shutdown of fuel supply, which investigators believe could be a key piece in understanding the crash on June 12.