The report shed no new light on the mystery, clearing the pilot and flight crew of any behavioral abnormalities or habits and also noting that nothing alarming was found in an investigation of maintenance records.
The only unusual finding was that the battery powering the plane’s location beacon had expired a year before the disappearance. This was not noted until after MH370 disappeared, and Malaysia Airlines engineers carried out a fleet-wide inspection of underwater locator beacons to ensure that the records for all of its aircraft were updated.
However, the failure of the beacon does not affect the recorder itself, and the investigation team did not point out any problems with the black boxes.