MH370 report: Underwater locator beacon battery had expired

KUALA LUMPUR, Malaysia - The first comprehensive report into the mystery of Malaysia Airlines Flight 370 on Sunday revealed that the battery of an underwater locator beacon had expired more than a year before the plane vanished on March 8, 2014.

Apart from that anomaly, the detailed report devoted pages after pages to describe the complete normality of the flight, shedding little light on aviation's biggest mystery.

"The sole objective of the investigation is the prevention of future accidents or incidents, and not for the purpose to apportion blame or liability," the report said.

The significance of the expired battery on the beacon of the Flight Data Recorder was not immediately apparent, except indicating that searchers would have had lesser chance of locating the aircraft in the Indian Ocean, where it is believed to have crashed, even if they were in its vicinity. However, the report said that the battery on the locator beacon of the cockpit voice recorder was working.

Even though the battery on the beacon had expired, the instrument itself was functioning properly and would have in theory captured all the flight information.

The two instruments are critical in any crash because they record cockpit conversation and flight data, leading up to the end of the flight.

The 584-page report by an independent investigation group went into minute details of the crew's lives _ their medical and financial records, their training before detailing the aircraft's service record _ as well as maintenance schedule, weather, communications systems and other aspects that showed nothing unusual except for the one previously undisclosed fact of the battery's expiry date.

It said that according to maintenance records, the battery on the beacon attached to the Flight Data Recorder expired in December 2012, but because of a computer data error it went unnoticed by maintenance crews. "There is some extra margin in the design to account for battery life variability and ensure that the unit will meet the minimum requirement," it said.