Indonesia’s Transport Minister announced that investigators have recovered the cockpit voice recorder (CVR) of the crashed Sriwijaya Air Boeing 737 aircraft following almost three months of searching effort.
On March 31, 2021, Indonesia’s National Transportation Safety Committee (KNKT) confirmed that the CVR was found and recovered but did not disclose the exact conditions of the device. According to KNKT, the memory module was found in the Java Sea at a14 meters depth, below 16 centimeters of mud. The location is up to 500 meters off the coast of Laki Island.
During the press conference, the KNKT estimated that it could take up to a week to download the CRV data. The Committee also announced that after the data is downloaded in a lab and synchronized together with the data from the Flight Data Recorder (FDR), the authorities will make a transcript that should allow investigators to analyze what exactly happened on the day of the crash.
The Sriwijaya Air Boeing 737, registered as PK-CLC, crashed about five minutes after takeoff for flight SJ182 to Pontianak Supadio Airport (PNK), Indonesia, on January 9, 2021. The jet was flying over the Java Sea near Laki Island and was carrying 62 people on board, including two pilots, four flight attendants, 50 passengers, and 6 crew members traveling as passengers when it lost the altitude and plunged 10,000 feet in less than a minute.
The flight crew did not declare an emergency and did not report any technical problems before the Boeing 737 disappeared from radars.
What do we know so far about the flight SJ182 crash causes?
The preliminary report of the accident, released in February 2021, pointed out that an autothrottle malfunction resulting in a thrust imbalance in the plane engines could be the main reason why the jet crashed into the Java Sea.
The investigators found that following takeoff, the thrust in the left engine decreased while the right engine remained unaffected. At about 10,900 feet, “the autopilot system disengaged […] and the aircraft rolled to the left”, the report read. The thrust imbalance deepened as the lever position of the left engine decreased while the right lever remained unaffected. The autothrottle system disengaged about 20 seconds before the Flight Data Recorder stopped recording.
The investigation also found that days before the crash, on January 3 and 4, 2021, the “autothrottle was unserviceable” at least twice, leading to a rectification on January 5, 2021. Additionally, a flight crew member operating the aircraft a month prior had reported a malfunction in the first officer’s Mach/Airspeed Indicator, which was subsequently replaced.
Meanwhile, Chairman of the KNKT Soerjanto Tjahjono had said that both engines were still running when the aircraft hit the Java Sea.