The Australian Transport Safety Bureau was advised on 27
December 2008 of an occurrence that day involving a Qantas Airbus
A330-300 aircraft while in cruise at FL360 (36,000 ft) enroute from
Perth to Singapore.
At about 0829 UTC (1729 Local Time), the autopilot disconnected
and the crew received an ECAM message (NAV IR 1 Fault) indicating a
problem with ADIRU Number 1. The crew actioned the Airbus
Operations Engineering Bulletin (OEB) procedure by selecting the IR
1 push-button to OFF and the ADR 1 push-button to OFF. Both OFF
lights illuminated. The crew elected to return to Perth and an
uneventful overweight landing was conducted. At the time that the
autopilot disconnected, the aircraft was approximately 260 nautical
miles (NM) North-West of Perth airport and approximately 350 NM
South of Learmonth airport.
It is very early in the investigation and too soon to draw any
conclusions as to specific causal factors involved in this
incident. As it appears to be a similar event to a previous event
involving an A330 aircraft (AO-2008-070 on 7 Oct 2008) it will be
included as part of the earlier investigation. The ATSB
investigation will explore all aspects of the operation of the
aircraft, including examination of recorded data, and any
commonalities with past occurrences.
While the investigation is likely to take a number of months,
the ATSB has been working with a number of national and
international parties on this investigation and plans to release an
Interim Factual report by about mid-February 2009.
Should any critical safety issues emerge that require urgent
attention, the ATSB will immediately bring such issues to the
attention of the relevant authorities who are best placed to take
prompt action to address those issues.
ADIRU = Air Data Inertial Reference Unit
ECAM = Electronic Centralized Aircraft Monitor
IR = Inertial Reference
ADR = Air Data Reference
NAV = Navigation Media contact: 1800 020 616