JAKARTA - Indonesian navy divers on Tuesday (Jan 12) found the flight data recorder of the Sriwijaya Air Boeing 737-500 which plunged into the Java Sea shortly after take-off from Jakarta on Saturday, killing all 62 people aboard.
The device containing key data such as air speed and altitude is one of two black boxes that will play a key role in investigations into the air crash. The flight data recorder covers up to 25 hours of flight, while the cockpit voice recorder monitors sound, including conversations between the pilot and co-pilot.
The head of the military, Air Chief Marshal Hadi Tjahjanto, told a press briefing on Tuesday, the fourth day of the search and rescue mission, that efforts were under way to recover the other black box soon.
The Indonesian National Transportation Safety Committee (KNKT) chief said the ill-fated plane did not explode or break apart before crashing into the sea just minutes into the flight.
Based on the field data, the wreckage was found in an area of 300m to 400m by 100m, said KNKT chief Soerjanto Tjahjono.
In a televised briefing about the committee's initial findings, he said: "The data about the spread of the wreckage reveals that the impact occurred at one point, or was very localised. This suggests that explosion or breakage did not happen prior to impact."
The plane departed from Indonesia's main gateway, Soekarno-Hatta International Airport, on the outskirts of Jakarta, en route to Pontianak, the provincial capital of West Kalimantan, in the afternoon.
It ascended to 10,900ft four minutes after take-off, but then descended steeply over the next 21 seconds, according to flight tracking website Flightradar24. The final piece of data received from the aircraft was when it reached 250ft above the water's surface.
Mr Soerjanto noted that this data indicated the aircraft system was functional, and he suspected that its engine was still operating before it hit the water.
On Tuesday, more than a dozen helicopters, 54 navy ships and around 3,600 personnel were deployed in the rescue effort. The search for the black boxes was narrowed to a region off the Thousand Islands, north of Jakarta's coast.
The search and rescue had been hampered in the past few days by bad weather and the effort to retrieve the black boxes from the seabed was hindered by mud and aircraft wreckage.
Air Chief Marshal Hadi said the flight recorder, along with its underwater locator beacon, as well as another one, was found at 4.40pm Jakarta time (5.50pm Singapore time).
He said: "The search for the cockpit voice recorder will be done without assistance from the beacon. But as the underwater locator beacon from the cockpit voice recorder was found around the area, we are highly confident it will soon be found too."
KNKT's Mr Soerjanto said it would take two to five days to download the data from the flight data recorder.