5.8 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Air data inertial reference unit | 2/2 | https://en.wikipedia.org/wiki/Air_data_inertial_reference_unit | reference | science, encyclopedia | 2026-05-05T12:51:20.018096+00:00 | kb-cron |
On 12 September 2006, Qantas Flight 68, Airbus A330 registration VH-QPA, from Singapore to Perth exhibited ADIRU problems but without causing any disruption to the flight. At 41,000 feet (12,000 m) and estimated position 530 nautical miles (980 km) north of Learmonth, Western Australia, NAV IR1 FAULT then, 30 minutes later, NAV ADR 1 FAULT notifications were received on the ECAM identifying navigation system faults in Inertial Reference Unit 1, then in ADR 1 respectively. The crew reported to the later Qantas Flight 72 investigation involving the same airframe and ADIRU that they had received numerous warning and caution messages which changed too quickly to be dealt with. While investigating the problem, the crew noticed a weak and intermittent ADR 1 FAULT light and elected to switch off ADR 1, after which they experienced no further problems. There was no impact on the flight controls throughout the event. The ADIRU manufacturer's recommended maintenance procedures were carried out after the flight and system testing found no further fault.
=== Jetstar Flight 7 ===
On 7 February 2008, a similar aircraft (VH-EBC) operated by Qantas subsidiary Jetstar Airways was involved in a similar occurrence while conducting the JQ7 service from Sydney to Ho Chi Minh City, Vietnam. In this event - which occurred 1,760 nautical miles (3,260 km) east of Learmonth - many of the same errors occurred in the ADIRU unit. The crew followed the relevant procedure applicable at the time and the flight continued without problems. The ATSB has yet to confirm if this event is related to the other Airbus A330 ADIRU occurrences.
=== Airworthiness directive 2008-17-12 === On 6 August 2008, the FAA issued airworthiness directive 2008-17-12 expanding on the requirements of the earlier AD 2003-26-03 which had been determined to be an insufficient remedy. In some cases it called for replacement of ADIRUs with newer models, but allowed 46 months from October 2008 to implement the directive.
=== Qantas Flight 72 === On 7 October 2008, Qantas Flight 72, using the same aircraft involved in the Flight 68 incident, departed Singapore for Perth. Some time into the flight, while cruising at 37,000 ft, a failure in the No.1 ADIRU led to the autopilot automatically disengaging followed by two sudden uncommanded pitch down manoeuvres, according to the Australian Transport Safety Bureau (ATSB). The accident injured up to 74 passengers and crew, ranging from minor to serious injuries. The aircraft was able to make an emergency landing without further injuries. The aircraft was equipped with a Northrop Grumman made ADIRS, which investigators sent to the manufacturer for further testing.
=== Qantas Flight 71 ===
On 27 December 2008, Qantas Flight 71 from Perth to Singapore, a different Qantas A330-300 with registration VH-QPG was involved in an incident at 36,000 feet approximately 260 nautical miles (480 km) north-west of Perth and 350 nautical miles (650 km) south of Learmonth Airport at 1729 WST. The autopilot disconnected and the crew received an alert indicating a problem with ADIRU Number 1.
=== Emergency Airworthiness Directive No 2009-0012-E === On 15 January 2009, the European Aviation Safety Agency issued Emergency Airworthiness Directive No 2009-0012-E to address the above A330 and A340 Northrop-Grumman ADIRU problem of incorrectly responding to a defective inertial reference. In the event of a NAV IR fault the directed crew response is now to "select OFF the relevant IR, select OFF the relevant ADR, and then turn the IR rotary mode selector to the OFF position." The effect is to ensure that the faulted IR is powered off so that it no longer can send erroneous data to other systems.
=== Air France Flight 447 === On 1 June 2009, Air France Flight 447, an Airbus A330 en route from Rio de Janeiro to Paris, crashed in the Atlantic Ocean after transmitting automated messages indicating faults with various equipment, including the ADIRU. While examining possibly related events of weather-related loss of ADIRS, the NTSB decided to investigate two similar cases on cruising A330s. On a 21 May 2009 Miami–São Paulo TAM Flight 8091 registered as PT-MVB, and on a 23 June 2009 Hong Kong-Tokyo Northwest Airlines Flight 8 registered as N805NW each saw sudden loss of airspeed data at cruise altitude and consequent loss of ADIRS control.
=== Ryanair Flight 6606 ===
On 9 October 2018, the Boeing 737-800 with registration EI-GJT, operating the flight from Porto Airport to Edinburgh Airport suffered a left ADIRU failure that resulted in the aircraft pitching up and climbing 600 feet. The left ADIRU was put in ATT (attitude-only) mode in accordance with the Quick Reference Handbook, but it continued to display erroneous attitude information to the captain. The remainder of the flight was flown manually with an uneventful landing. The UK's AAIB released the final report on 31 October 2019, with the following recommendation:It is recommended that Boeing Commercial Aircraft amend the Boeing 737 Quick Reference Handbook to include a non-normal checklist for situations when pitch and roll comparator annunciations appear on the attitude display.
== See also == Acronyms and abbreviations in avionics Synthetic air data system
== References ==
== Further reading == Dave Carbaugh; Doug Forsythe; Melville McIntyre. "Erroneous flight instrumenent information". Aero Magazine. Boeing. Archived from the original on 6 September 2008. Retrieved 2008-10-16. Melville Duncan W. McIntyre, Boeing (2003-11-25). "US Patent 6654685 - Apparatus and method for navigation of an aircraft". United States Patent Office. Retrieved 2008-10-16.