Created Thursday, Jan 13th 2022 18:06Z, last updated Thursday, Jan 13th 2022 18:06Z
On Jan 13th 2022 the KNKT released their first interim statement adding information about the CVR (quoted in full):
On 30 March 2021, the Cockpit Voice Recorder (CVR) Crash Survivable Memory Unit (CSMU) was recovered by the search team. The CVR CSMU was transported to the KNKT recorder facility for data downloading.
The CVR data was successfully downloaded by KNKT investigators and contained four separate channels with two hours of audio data recorded in each channel. The CVR captured audio recorded from the flight preparation until the end of the accident flight.
The configuration of the audio channels was as follow:
- Channel 1 recorded the passenger announcement system,
- Channel 2 recorded the SIC station audio,
- Channel 3 recorded the PIC station audio,
- Channel 4 recorded the cockpit area microphone.
The CVR download revealed that:
- Channel 1 recorded is the same as Channel 2.
- Channel 2 recorded all SIC voice communications throughout the flight and the communications between tower with another aircraft.
- Channel 3 recorded the PIC voice communication with the ground engineer. During the flight, the PIC voice was not recorded. The PIC voice was recorded in Channel 2 from the SIC’s headset microphone when the PIC’s voice was loud enough.
- Channel 4 recorded a prominent tone with frequency of around 400 Hz. This tone interfered with all other audio signals and the recorded audio data was unintelligible.
The data from CVR with part number 2100-1020-00 and serial number 000286507 was downloaded in 2019 and 2020 for renewal of the Certificate of Airworthiness (C of A). The CVR download was performed at Garuda Maintenance Facility in 2019, the downloaded audio from the Channel 4 recorded noise with a frequency of 400 Hz. In 2020, the download was performed at Sriwijaya Air facility. The results for both recordings were stated as normal.
The KNKT further reported that the recovered GPWS unit was severly damaged, the memory chip was missing.
The statement mentions a number of tests that were conducted, however, all results will only be included with the final report.
The statement states:
On 30 March 2021, the aircraft manufacturer issued a Boeing Multi Operator Message (MOM) number MOM-MOM-21-0145-01B9(R2) regarding the Potential for Latent Flap Indication System Wiring Failure and Impacts to the Autothrottle System. Following issuance of this MOM, the Federal Aviation Administration (FAA) issued Airworthiness Directive AD-2021-08-14. (editorial note: for the AD see the part of this coverage released on May 18th 2021 19:17Z)
