Airbus 330 data entry ~6,000 NM in error
At Sydney Airport, the captain entered a starting longitude of 15° 19.8’E, although the aircraft gate coordinate was 151° 9.8’ E.
The Kuala Lumpur-bound AirAsiaX A330, on the gate at Sydney Airport, required an initial position to be inserted simultaneously into the 3 air data and inertial reference systems (ADIRS) on start-up. Unfortunately, the captain's inserted longitude was a factor of 10 out, giving the systems a false initial starting point about 36º longitude out - off South Africa, ~5,940 NM away.
Although there were 2 GPS receivers in the navigation fit, the rather old configuration in this aircraft did not allow them to override the manual input (in current configurations, they actually provide the starting point).
This incorrect longitude created a series of downstream problems, one being that the displayed magnetic heading - derived from true inertial heading and variation - was ~38º in error. Further problems involved false activation of the enhanced ground proximity system (EGPWS), which believed that the aircraft was abut to fly into terrain.
Unfortunately, all these problems did not arise until after take-off. On departure, the aircraft was observed by air traffic control (ATC) to enter the departure flight path of the parallel runway. Following advice from ATC, the flight crew identified problems with their navigation systems, but attempts to troubleshoot and rectify them 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 - they were instead radar vectored to Melbourne in visual conditions.
After almost 3 hours on the ground, the aircraft departed for Kuala Lumpur with the original flight crew, who inserted the correct gate position. The flight to Kuala Lumpur was reported as uneventful.
Although this occurred on 10 March 2015, the report has just been published; it can be found at the Australian Transport Safety Bureau (ATSB) link below . .