NTSB To Investigate A330 Air Data Anomalies
Investigators recently reported that the crew of Air France Flight 447, lost earlier this month with all aboard, may have been fed faulty air data, and Friday the NTSB announced that it is investigating "two recent incidents" in which A330 instruments may have malfunctioned. Earlier this month, after it was publicly disclosed that Airbus had recommended changes to the jets' pitot tubes, some pilots for Air France were urged by their union to refuse flights on A330/A340 series aircraft if their pitot sensors had not yet been replaced. Of the two incidents the NTSB will be investigating, the first involved a TAM Airlines flight out of Miami May 21, bound for Sao Paulo. The airliner lost "primary speed and altitude information" during cruise. Pilots reported the event was precipitated by an abrupt drop in indicated outside air temperature. Soon after, the Air Data Reference System was lost and the autopilot and autothrust disconnected. The crew flew the jet on backup instruments for about five minutes until primary data was restored. The flight continued to a Sao Paulo, where it landed without incident. A Northwest Airlines A330 flying between Hong Kong and Tokyo on June 23 may have experienced a similar event. The NTSB in its statement did not draw any connection between these investigations and the Air France disaster.
The NTSB is collecting weather and data recorder information, as well as Aircraft Condition Monitoring Systems messages and crew statements, to evaluate the incidents. The board will release information on both incidents as it becomes available.