Data entry errors in the FMGS of an Airbus A330 caused navigational issues shortly after takeoff from Sydney Airport, according to an ATSB investigation report.
On 10 March 2015 an Airbus A330, registered 9M-XXM and operated by Malaysian‑based airline AirAsia X, was conducting a regular passenger service from Sydney, Australia to Kuala Lumpur, Malaysia. On departure from runway 16R the aircraft was observed by air traffic control to enter the departure flight path of the parallel runway 16L. Following advice from air traffic control, 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 to the aircraft’s flight guidance and flight control systems. The crew elected to discontinue the flight but were unable to return to Sydney as the weather had deteriorated in the Sydney area and the available systems limited the flight to approaches in visual conditions. The aircraft was instead radar vectored to Melbourne and the flight completed in visual conditions.
The ATSB found that when setting up the aircraft’s flight management and guidance system, the captain inadvertently entered the wrong longitudinal position of the aircraft. This adversely affected the onboard navigation systems however, despite a number of opportunities to identify and correct the error, it was not noticed until after the aircraft became airborne and started tracking in the wrong direction. The ATSB also found that the aircraft was not fitted with an upgraded flight management system that would have prevented the data entry error via either automated initialisation or automatic correction of manual errors.
The flight crew attempted to troubleshoot and rectify the situation while under heavy workload. Combined with limited guidance from the available checklists, this resulted in further errors by the flight crew in the diagnosis and actioning of flight deck switches.
Finally, the ATSB identified that effective monitoring and assistance by air traffic control reduced the risk to the occurrence aircraft and other aircraft in the area.
In response to this occurrence the aircraft operator undertook safety action, including:
- the development of a training bulletin and package for its flight crews that emphasised the correct operation and alignment of the air data and inertial reference system
- sharing the lessons learnt from the operator’s internal investigation with all pilots and reviewing the recovery procedures to be undertaken in the form of a flight safety notice.