Qantas suffers second A330 ADIRU failure:
The mystery surrounding what is now dubbed the Ningaloo Triangle centered at Western Australia's North West Cape near Exmouth deepened last week when it was confirmed that Qantas experienced a second air data inertial reference unit failure in just four months in the area.
The Australian Transport Safety Bureau said it was advised on Dec. 27 of an occurrence that day involving a QF A330-300 cruising at 36,000 ft. on its way from Perth to Singapore. Some 260 nm. northwest of Perth the autopilot disconnected and the crew received an Electronic Centralized Aircraft Monitor message (NAV IR 1 fault) indicating a problem with ADIRU No. 1. The crew implemented the new Airbus Operations Engineering Bulletin procedure by selecting the IR 1 and ADR 1 pushbuttons to off. The aircraft returned to Perth. ATSB said the incident "appears to be a similar event to a previous event involving an A330 aircraft." In the October incident, 70 of the 313 people onboard the A330 flying from SIN to PER were injured when the aircraft pitched up and then dove twice after a failure of ADIRU 1.
An ATSB preliminary report issued in November suggested the possibility that transmissions from a naval communications station interfered with onboard systems. A Malaysia Air Lines 777 experienced a similar upset in 2005 in the same area. With 177 passengers on board, the aircraft was climbing through FL370 when it suddenly pitched up and climbed to FL 410 with the airspeed decaying to 185 kts activating the stall warning and stick shaker. The crew battled the autopilot for some minutes before regaining control.
The mystery surrounding what is now dubbed the Ningaloo Triangle centered at Western Australia's North West Cape near Exmouth deepened last week when it was confirmed that Qantas experienced a second air data inertial reference unit failure in just four months in the area.
The Australian Transport Safety Bureau said it was advised on Dec. 27 of an occurrence that day involving a QF A330-300 cruising at 36,000 ft. on its way from Perth to Singapore. Some 260 nm. northwest of Perth the autopilot disconnected and the crew received an Electronic Centralized Aircraft Monitor message (NAV IR 1 fault) indicating a problem with ADIRU No. 1. The crew implemented the new Airbus Operations Engineering Bulletin procedure by selecting the IR 1 and ADR 1 pushbuttons to off. The aircraft returned to Perth. ATSB said the incident "appears to be a similar event to a previous event involving an A330 aircraft." In the October incident, 70 of the 313 people onboard the A330 flying from SIN to PER were injured when the aircraft pitched up and then dove twice after a failure of ADIRU 1.
An ATSB preliminary report issued in November suggested the possibility that transmissions from a naval communications station interfered with onboard systems. A Malaysia Air Lines 777 experienced a similar upset in 2005 in the same area. With 177 passengers on board, the aircraft was climbing through FL370 when it suddenly pitched up and climbed to FL 410 with the airspeed decaying to 185 kts activating the stall warning and stick shaker. The crew battled the autopilot for some minutes before regaining control.
