On Monday, the hunt for the black boxes of the crashed Sriwijaya Air jet intensified to improve the inquiry into what caused the aircraft carrying 62 people to nosedive into the Java Sea at high speed. Minutes after taking off from Jakarta, Indonesia's capital, during heavy rain on Saturday, the Boeing 737-500 jet disappeared and the search so far has yielded plane parts and human remains, but no trace of survivors.
Authorities said signals were observed between two islands in the Thousand Island chain just north of Jakarta's coast from the boxes containing the cockpit voice and flight data recorders. Officials said they marked a spot where the sounds were emitted from the black boxes that separated the aircraft from the tail as it plunged into the sea.
Conversations between pilots are kept by the cockpit voice recorder, and electronic information such as airspeed, altitude, and vertical acceleration is recorded by the data recorder. They will be transported to port when discovered and handed over to the National Transportation Safety Committee overseeing the inquiry into the accident.
Since Sunday, more than a dozen helicopters, 53 naval vessels, 20 ships, and 2,600 rescue personnel have searched and found parts of the aircraft in the water at a depth of 75 feet, leading rescuers to continue searching the area.
Among the pieces recovered, news coverage showed landing gear, wheels, and a jet engine, while other rescuers took a dozen body bags containing human remains for the identification process to a police hospital in eastern Jakarta.
The chief of the National Search and Rescue Agency, Bagus Puruhito, said divers were searching for an identified target under 65 feet of seabed mud using high-tech "ping locator" equipment.
Soerjanto Tjahjono, chairman of the transport committee, said the black boxes might provide investigators with useful information. It will take three to five days to dry and clean the devices and download the data once the devices are identified and taken to the investigator's facility, Tjahjono said.
He said more time could be needed to analyze the data, "depending on the complexity of the problem."
Nurcahyo Utomo, the committee's prosecutor, said that as part of their inquiry into the cause of the accident, they had obtained recordings and transcripts of the conversation between the pilot and air traffic controllers.
Utomo said that his team was still investigating radar data on the movements of the aircraft and had questioned the air traffic officers in charge of the ill-fated flight. In the near future, more interviews with witnesses, including airline technicians, fishermen, and specialists, should be conducted.
All parts of the aircraft discovered by searchers on the seafloor were scrutinized by investigators, including the Ground Proximity Alert System, a device that can notify the pilot if the aircraft is too close to the ground, a radio altimeter, and many other parts, mainly from the lower side of the tail of the aircraft, Utomo said.
He said the Transport Safety Investigation Bureau of Singapore would support his committee in the hunt for the black boxes and would join the National Transportation Safety Board of the United States in investigating the accident.