The National Transportation Safety Committee (KNKT) said that the authority sent five parts of the crashed plane, including the recently found autothrottle system, for further examination in the United Kingdom and the United States. The authorities would help Indonesian investigators to solve the puzzle of why the Sriwijaya Air Boeing 737 crashed in the Java Sea.
According to Soerjanto Tjahjono, the chairman of the KNKT, the search for the Cockpit Voice Recorder (CVR)’s memory unit has continued, while the Flight Data Recorder (FDR) was found. The investigators managed to recover the data of the flight in January 2021.
“If we only have the FDR, we do not know why the [autothrottle] parameter changed, what was the reason. […] We need confirmation from the components that we sent to the US and UK and the CVR,” Tjahjono told Reuters. According to him, the preliminary crash report could come as soon as February 9, 2021, a month after the fatal accident.
On January 21, 2021, the Indonesian investigators found out that a malfunctioning autothrottle system could have one of the reasons behind why the pilots lost control of the aircraft. Based on the “black box” data, a person familiar with the investigation process disclosed that during the flight, the autothrottle produced unequal thrust in one of the two engines during the climb stage following the 737’s departure from Jakarta, Indonesia.
However, the flight crew did not declare an emergency and did not report any technical problems before the Boeing 737 disappeared from radars. In addition, both engines of the crashed jet were still operational when the plane hit the sea.
Meanwhile, Nurcahyo Utomo, the lead investigator at Indonesia’s National Transportation Safety Board (NTSC) outlined that even though the autothrottle malfunction was one of the factors the authority was looking at, it was not yet clear if it was a key factor for the aircraft to crash.