No Cause Yet for Qantas Upset

Australian air safety investigators say a fault in one of three Northrop Grumman air data inertial reference units is likely to have caused a Qantas A330-300 to dive twice in October, injuring more than 40 people. Flight QF72 from Singapore to Perth abruptly lost altitude on Oct. 7. The A330 then made an emergency landing in Manila. The Australian Transport Safety Bureau said in its preliminary report, citing flight data recorder information, that the ADIRU likely fed incorrect information to the main flight computer. The three ADIRUs will undergo comprehensive testing at the manufacturer’s factory starting Nov. 17. But the ATSB continues to explore whether interference from a low-frequency U.S.-Australian naval submarine communications transmitter or even a passenger's laptop caused the Qantas jetliner upset. Another possible source of the interference is portable electronic devices, such as cell phones, Australian Transport Safety Bureau director Kerryn Macaulay said. “This is unlikely, especially if the problem is clearly identified during the ADIRU system testing, she added. The ATSB said “most components on modern aircraft, including ADIRUs, are highly reliable and there has only been a small number of occasions where ADIRUs of different types made by varying manufacturers have had some form of failure. It is extremely rare for any such failures to have an effect on an aircrafts flight controls.”