Civil and Military Air Group

At about 1730 local on 27 December, a Qantas Airbus A330-300 returned to Perth for an overweight landing after suffereing a navigation system failure.

The aircraft was en route to Singapore with 277 passengers.  It was 260 NM NW of Perth at FL360 (~36,000 ft) when it turned back; the overweight landing was uneventual.

The autopilot disconnected and the crew received warning of a problem with one of its Air Data/Inertial Reference Units.  Both the air data and inertial reference units were switched off and the crew elected to return to Perth.

The Australian Transport Safety Bureau (ATSB) says that this incident appears to be similar to a previous event involving an A330 aircraft on 7 Oct 2008 - it will be included as part of the earlier investigation.

The ATSB plans to release an Interim Factual Report by mid-February 2009.

The non-aviation press is pointing to the possibility that both events could have been caused by electrical interference from the Harold E Holt naval base at Exmouth - a joint Australian-US facility used for naval communications.

Details from ATSB