Indonesian divers on Tuesday recovered the flight data recorder from a Sriwijaya Air jet that crashed into the Java Sea with 62 people on board.
The team was aided by a remotely operated underwater vehicle as they resumed the search for clues and the remains of the victims from the crash.
The Boeing 737-500 plane crashed minutes after taking off from Jakarta's main airport on Saturday afternoon.
Military chief Air Chief Marshal Hadi Tjahjanto said the plane's other "black box," the cockpit voice recorder, was expected to be close by as its beacon was being emitted in the same area.
Authorities managed to narrow down the approximate location of the black boxes, after picking up signals from the devices. The recovered black box records information about the speed, altitude, and direction of the plane. The one that has yet to be located contains a recording of the last conversations on the flight deck.
But the search has been hindered by the tons of plane debris and layers of sea mud underneath which the boxes may be buried in waters about 23 meters (75 feet) deep.
The recordings could prove crucial to understanding what caused a catastrophic loss of control after take-off.
While the remote-controlled vehicles scoured the seabed, navy vessels with sonar searched from the surface.
Once the black boxes are retrieved, Indonesia's National Transportation Safety Committee (KNKT) expects to be able to read the information in three days.
About 160 divers are part of the 3,600 personnel involved in the search operation.
"They've got to go through garbage and other debris [on the seafloor] and the mud and visibility are also a challenge," Yusuf Latif, a spokesman for Indonesia's search-and-rescue agency Basarnas, said on Tuesday.
The searchers, assisted by 13 helicopters, 54 large ships, and 20 small boats, have found parts of the plane and have sent scores of body bags containing human remains to police identification experts who on Monday identified their first victim.
Flight attendant Okky Bisma, 29, was identified by his fingerprints, a police official said.
What happened to Flight SJ182:
- The plane took off from Jakarta's Soekarno-Hatta Airport at about 2:36 p.m. (07:36 UTC) Saturday.
- The flight was bound for the city of Pontianak, northwest of Jakarta
- There were 62 people on board, including 10 children
- The flight last made contact around 2:40 pm
- The plane lost more than 3,000 meters (10,000 feet) of altitude in less than a minute, according to FlightRadar24
- Investigators say the crew did not report difficulties or declare an emergency over the radio before its dive
- A sea-and-air search effort was launched, including 11 navy ships, two helicopters, and 300 personnel
The Sriwijaya Airplane was nearly 27 years old, much older than Boeing's problem-plagued 737 MAX model.
The SJ182 was the third Indonesian budget airline crash since 2014.
It was the second major air crash in Indonesia since 2018 when 189 passengers and crew were killed after a Lion Air Boeing 737 MAX also plunged into the Java Sea soon after taking off.
adi,rc/msh (AP, AFP, Reuters)