Indonesian navy divers retrieved the black box flight data recorder from the wreck of an AirAsia passenger jet on Monday, a major step towards investigators unravelling the cause of the crash that killed all 162 people on board.
Flight QZ8501 lost contact with air traffic control in bad weather on Dec. 28, less than halfway into a two-hour flight from Indonesia's second-biggest city of Surabaya to Singapore.
"At 7:11, we succeeded in lifting the part of the black box known as the flight data recorder," Fransiskus Bambang Soelistyo, the head of the National Search and Rescue Agency, told reporters at a news conference.
The second so-called black box, containing the cockpit voice recorder, has been located but not yet retrieved, Madjono Siswosuwarno, the main investigator at the National Transportation Safety Committee (NTSC), told Reuters.
The black boxes, found near the wrecked wing of the plane in the northern Java Sea, contain a wealth of data that will be crucial for investigators piecing together the sequence of events that led to the airliner plunging into the sea.
The national weather bureau has said seasonal storms were likely a factor in AirAsia's first fatal crash.
The flight data recorder was brought by helicopter to Pangkalan Bun, the southern Borneo town that has been the base for the search effort, and then flown to Jakarta for analysis.
The black box looked to be in good condition, said Tatang Kurniadi, the head of the transport safety committee.
Investigators may need up to a month to get a complete reading of the data.
"The download is easy, probably one day. But the reading is more difficult ... could take two weeks to one month," the NTSC's Siswosuwarno said.
Over the weekend, three vessels detected "pings" that were believed to be from the black boxes, but strong winds, powerful currents and high waves hampered search efforts.
Dozens of Indonesian navy divers took advantage of calmer weather on Monday to retrieve the flight recorder and search for the fuselage of the Airbus A320-200.
Forty-eight bodies have been retrieved from the Java Sea and brought to Surabaya for identification. Searchers believe more bodies will be found in the plane's fuselage.
"I told our soldiers that the search isn't over yet," Armed Forces Chief Moeldoko told reporters. "I am sure the remaining victims are in the body of the plane. So we need to find those."
Indonesia AirAsia, 49 percent owned by the Malaysia-based AirAsia budget group, has come under pressure from authorities in Jakarta since the crash.
The transport ministry has suspended the carrier's Surabaya-Singapore licence for flying on a Sunday, for which it did not have permission. However, the ministry has said this had no bearing on the crash of Flight QZ8501.
President Joko Widodo said the crash exposed widespread problems in the management of air travel in Indonesia.