The Occurrence
On 10 March 2015, an Airbus A330-343X, registered as 9M-XXM and operated by Air Asia X, was scheduled to operate a passenger service from Sydney, New South Wales to Kuala Lumpur, Malaysia. The flight departed from gate 54 of Sydney Airport International Terminal. The cockpit crew consisted of a captain and a first officer.
During pre-flight preparation, the captain completed the cockpit preparation while the first officer conducted the external inspection. The captain manually entered the gate coordinates into the flight management and guidance system (FMGS) via the multipurpose control and display unit (MCDU). However, the ATSB found that the captain inadvertently entered the wrong longitudinal position of the aircraft. This data entry error adversely affected the onboard navigation systems.
After departure from runway 16R, air traffic control observed the aircraft entering the departure flight path of the parallel runway 16L and advised the crew. The flight crew identified a problem with the onboard navigation systems. Attempts to troubleshoot and rectify the problem resulted in further degradation of the navigation system, as well as the flight guidance and flight control systems.
The crew elected to discontinue the flight but could not return to Sydney because weather had deteriorated and the available systems limited the flight to approaches in visual conditions. The aircraft was radar vectored to Melbourne, Victoria, and the flight was completed in visual conditions.
Findings
The ATSB found that the captain inadvertently entered the wrong longitudinal position when initialising the air data and inertial reference system (ADIRS). This error was not detected despite several opportunities. The aircraft was not fitted with an upgraded flight management system that would have prevented such errors. The crew's troubleshooting under heavy workload, combined with limited checklist guidance, led to further errors in diagnosing and actioning flight deck switches. Effective monitoring and assistance by air traffic control reduced the risk to the occurrence aircraft and other aircraft.
Safety Action
In response, Air Asia X developed a training bulletin and package emphasising correct operation and alignment of the ADIRS, and shared lessons from its internal investigation with all pilots via a flight safety notice.