The latest interim report issued by the Australian Transport Safety Bureau (ATSB) has confirmed that the sudden drop in altitude of Qantas Flight 72 over Western Australia last autumn was caused by computer error. Shortly after the autopilot was switched off, one of the Airbus’ air data inertial reference units (ADIRUs) started providing “erroneous data spikes.” One crew member and eleven passengers sustained serious injures. Although there was speculation in the days after the incident that electromagnetic interference from a nearby U.S. military installation, the Harold E. Holt Communication Station, susceptibility testing of ADIRUs would seem to rule out that possibility as a cause. Not all those aboard have been surveyed about use of passenger electronics so that possible source of interference will require further inquire. Testing of ADIRU 1 is ongoing and will include further EMI testing, including frequencies associated with onboard transmitters and other onboard systems that have been nominated by the investigation team for particular attention. This testing will be completed before unit disassembly to prevent disturbance to the unit’s hardware that could otherwise be detrimental to the EMI testing. After disassembly, individual modules will be tested separately.Both Australian authorities and the ADIRU manufacturer will continue the investigation. The next phase of inquiry will focus on the aircraft’s primary flight control computer and two secondary computers. A theoretical analysis of the ADIRU software and hardware will be carried out to identify possible fault origins.See the original announcement and a link to the entire 65-page report on the ATSB website.
Qantas Airbus Plunge
