A mis-selected rudder trim switch caused a Virgin Australia Boeing 737-800 to suffer an in-flight upset that slightly injured a cabin crew member.
The incident occurred during the late afternoon of 6 December 2023 as the aircraft (VH-YQR) approached cruising altitude after departing from Brisbane on a service to Melbourne, according to the Australia Transport Safety Bureau.
Approaching 38,000ft, a member of the cabin crew requested access to the cockpit. The captain reached across the centre aisle stand to activate the flightdeck door switch.
“Immediately after, the aircraft appeared to momentarily roll and/or yaw, which drew the crew’s attention but, as nothing abnormal was apparent, the [captain] continued to maintain the switch selection while looking at the door and waiting for it to open.,” says the ATSB.
“After about 5 seconds, the aircraft began to roll to the left.”
The first officer’s attempt to address the roll with autopilot input was unsuccessful, but a “large manual corrective roll input” brought the wings back to level as the captain released the switch.
The bank angle peaked at about 42° left, triggering the bank angle alert.
As the crew tried to identify the cause of the upset the first officer maintained “significant right wing down aileron” to keep the wings level.
Finally, at the first officer’s suggestion, the captain checked the rudder trim, which was displaced to the left by 5°.
The trim was returned to neutral and the aircraft continued to Melbourne without further incident. One member of the flight crew suffered minor injuries during the incident, which the ATSB rates as “serious”.
The ATSB report shows that the rudder trim control and flight deck door switch are in proximity on the aircraft’s centre console.
The incident saw Virgin Australia implement changes to its flight deck door entry procedures to limit the time that the door unlock switch was to be held in the unlocked position.
“When selecting and activating any control or switch, it is critical that flight crew ensure that the intended control or switch is positively identified and actually selected before activating it,” says the ATSB.
“Further, it is important that any mis-selection of switches be reported not only to the operator, but also to the manufacturer, as a continuing record of switch mis-selection across a fleet type may indicate a design error that needs correcting.”
SIA A380 IN PARKING MISHAP
A Singapore Airlines Airbus A380 (9V-SKR) suffered a rollback at Delhi airport on 25 November.
The incident occurred after the aircraft was parked at the gate, and the aircraft’s pilot immediately applied the brakes.
The aircraft was subsequently towed the gate and all passengers disembarked normally, although a cabin crew member suffered a bruised thigh.
There was no damage to the aircraft.
