The abrupt dive of a Qantas A330-300 last week that injured scores of passengers wasn’t caused by a passenger’s electronic device, but by an internal breakdown in the Airbus’s flight-control computer system, the Australian Transport Safety Bureau said on Tuesday. The aircraft was flying at FL 370 en route from Singapore to Perth when the Inertial Reference System malfunctioned, which resulted in the autopilot automatically disconnecting, the ATSB said. However, the faulty unit continued to feed false information to the flight-control computers, which even with autopilot off, still command the control surfaces. Very high, random and incorrect values of the angle of attack led the computers to command a nose-down aircraft movement. The crew was able to recover within seconds, with a maximum altitude loss of 650 feet and a maximum pitch down of about 8.5 degrees, the ATSB said. Airbus told the ATSB it has never heard of a similar malfunction, but all operators of aircraft that use the system have been informed of the incident and provided guidance for a crew response to minimize the effect of any similar failure. The ATSB said its investigation is continuing.
A Preliminary Factual Report will be released within a month, the agency said. More than 70 passengers were hurt in the incident, with 14 treated for broken bones, concussions, and lacerations. The crew made an emergency landing at an air force base near Perth.
