Battery of MH370's 'black box' beacon had expired a year before plane vanished: report

KUALA LUMPUR - The first comprehensive report into the mystery of Malaysia Airlines flight MH370 has revealed that the battery of the underwater locator beacon of the aircraft's Flight Data Recorder had expired more than a year before the plane vanished, the Associated Press reported.

The finding, detailed in a 584-page report by an independent investigation group released on Sunday, could mean that searchers would have had lesser chance of locating the aircraft in the Indian Ocean, where it is believed to have crashed, AP said.

A year-long multinational search operation for the Boeing 777 jet, which disappeared with 239 people on board while flying from Kuala Lumpur to Beijing on March 8 last year, has been fruitless so far.

The investigation report said maintenance records showed that the battery on the beacon attached to the Flight Data Recorder, commonly known as the "black box", expired in December 2012, AP reported.

"There is some extra margin in the design to account for battery life variabilty and ensure that the unit will meet the minimum requirement," the report said according to AP.

However, the report said that the battery on the locator beacon of the cockpit voice recorder was working.

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