An interim report on the investigation into the disappearance of Malaysia Airlines Flight MH370 exactly one year ago has just been released in Kuala Lumpur.

The 584-page report reveals that the battery on the beacon of the flight data recorder had expired more than a year before the plane vanished on March 8 last year.

The report on the findings of the international safety investigation team was released today (Sunday) to comply with International Civil Aviation Organisation requirements.

The document contains extremely detailed technical information, but gives no clue as to what might have happened to the Boeing 777, which disappeared en route from Kuala Lumpur to Beijing with 227 passengers and 12 crew on board.

The relatives and friends of those on board are still awaiting concrete evidence of what happened to their loved ones. Despite a massive international search, no debris has been found on land or in the ocean.

“The sole objective of the investigation of an accident or incident shall be the prevention of future accidents or incidents,” the statement that accompanies the interim report points out. “It is not the purpose of this activity to apportion blame or liability.”

The report states that, according to maintenance records, the battery on the beacon attached to the flight data recorder expired in December 2012. “There is some extra margin in the design to account for battery life variability and ensure that the unit will meet the minimum requirement,” the report said.

However, the report adds that, once the battery’s expiry date has passed, the effectiveness of the Underwater Locator Beacon (ULB) decreases so it may operate for a reduced time period until the battery finally discharges.

“While there is a definite possibility that a ULB, will operate past the expiry date on the device, it is not guaranteed that it will work or that it would meet the 30-day minimum requirement,” the report adds. “There is also limited assurance that the nature of the signal (characteristics such as frequency and power) will remain within specification when battery voltage drops below the nominal 30-day level.”

There is no evidence, the report said, to suggest that the battery on the beacon of the data recorder had been replaced before the expiry date. However, the battery on the beacon of the plane’s cockpit voice recorder was replaced, as scheduled, with the next expiry date in June 2014.