The Malaysia Airlines flight that went missing one year ago Sunday had an underwater locator beacon whose battery had expired in December 2012, according to an interim report on the incident.

Flight 370 was also carrying 221 kilograms (487 pounds) of lithium-ion batteries that didn’t undergo the normal security screening, according to the report. The 584-page report by a team with representatives from China, Australia and other countries was released by Malaysia, which led the investigation under International Civil Aviation Organization guidelines.

The compendium of flight details and data sheds little light on what might have caused MH370 to veer suddenly off its scheduled path less than an hour into its flight to Beijing from Kuala Lumpur, losing contact with air-traffic controllers and radar. The report was released as relatives and friends of the 239 passengers and crew gathered in Malaysia and China to commemorate the event.

“As we mark the first anniversary of MH370, my heart goes out to the families and loved ones of those on board,” Transport Minster Liow Tiong Lai said in a statement. “Malaysia together with the international community stands in solidarity with the next of kin during this trying time.”

The Malaysian government on Jan. 29 declared the disappearance an accident and said all on the flight were presumed dead. Prime Minister Najib Razak said in the days after the plane went missing that it was believed to have been deliberately steered off course.

Australia is leading efforts to locate debris in some of the deepest and most remote parts of the Indian Ocean in what is already the longest search for a jet in modern aviation history. Australian Prime Minister Tony Abbott said Sunday he’s reasonably confident the plane would eventually be found.

Beacon Battery

Scores of family and friends of missing passengers and crew gathered at Publika mall in Kuala Lumpur and Lama Temple in Beijing to mark a year without their loved ones and demand that the search continue. In Kuala Lumpur, they wrote messages to relatives on white balloons and released them into the air.

“We don’t care about the interim report saying recorder batteries were out or not,” said Kelly Wen, who lost her husband and represents Chinese families. “All we want is for them to go to sea and find the plane.”

Ships equipped with sonar submersibles have scanned more than 26,000 square kilometers of the ocean floor where MH370 is believed to have crashed into the sea. So far, they have found no trace of the plane.

According to the report, it’s possible the underwater beacon’s battery could have continued to operate past the December 2012 expiration date, but its “effectiveness decreases so it may operate for a reduced time period until it finally discharges.” An expired battery wouldn’t explain why the plane went missing, but could’ve hampered efforts to locate the aircraft in the weeks after.

Flight Transcripts

The plane was also carrying lithium batteries that were loaded without going through security screening, according to the report. The batteries were packed and physically inspected by the airline’s cargo officials in Penang, Malaysia, where they originated.

Transcripts included in the report show that the last words from MH370’s pilots, at 1:19 a.m. on March 8, were “Good night, Malaysian Three Seven Zero.” It wasn’t clear whether the pilot or co-pilot made the comment.

The transcripts reflect the confusion among air traffic controllers across Southeast Asia as the flight left Malaysian airspace but then failed to make contact with air-traffic controllers in Vietnam. At one point, air-traffic controllers speculated the plane might have strayed into Cambodian airspace or might have continued along its flight path well into China.

Four months after MH370 disappeared, another Malaysia Airlines flight was shot down over eastern Ukraine in July, killing 298 people. Malaysia’s sovereign wealth fund Khazanah Nasional Bhd. ultimately was forced to take the flag carrier private ahead of a restructuring.

“Until this saga has some closure, it’s going to be very difficult for the new CEO to revamp the company,” Shukor Yusof, founder of aviation research firm, Endau Analytics, said Sunday. “It will be impossible to move on with this hanging.”