The ATSB is investigating an in-flight upset involving a Boeing 737-8FE, registration VH-YQR, about 77 NM west of Ballina/Byron Gateway Airport, New South Wales on 6 September 2023.
Shortly before reaching cruise altitude, the aircraft's rudder trim was inadvertently activated, causing the aircraft to yaw and roll to the left. The pilot flying was controlling the aircraft through the autopilot and attempted to correct the roll through heading inputs. Shortly after, the autopilot was disconnected, and the aircraft returned to normal flight. An E/GPWS BANK ANGLE alert was triggered during the occurrence.
The evidence collection phase of the investigation will involve interviewing the flight crew, examining recorded flight data and the collection of other relevant evidence.
A final report will be released at the conclusion of the investigation. Should a critical safety issue be identified during the investigation, the ATSB will immediately notify the relevant parties, so that appropriate safety action can be taken.