The National Transportation Safety Board is investigating two recent incidents in which airspeed and altitude indications in the cockpits of Airbus A330 aircraft may have malfunctioned.

The first incident occurred May 21, 2009, when TAM Airlines Flight 8091 (PT-MVB) flying from Miami to Sao Paulo, Brazil, experienced a loss of primary speed and altitude information while in cruise flight.  Initial reports indicate that the flight crew noted an abrupt drop in indicated outside air temperature, followed by the loss of the Air Data Reference System and disconnections of the autopilot and autothrust, along with the loss of speed and altitude information.  The flight crew used backup instruments and primary data was restored in about five minutes.  The flight landed at Sao Paulo with no further incident and there were no injuries and damage.

The Safety Board has become aware of another possibly similar incident that occurred on June 23 on a Northwest Airlines A-330 flying between Hong Kong and Tokyo.  The aircraft landed safely in Tokyo; no injuries or damage was reported.  Data recorder information, Aircraft Condition Monitoring System messages, crew statements and weather information are being collected by NTSB investigators.

The Safety Board investigation comes about as a result of the fatal crash of an Air France A330 into the Atlantic during a flight from Brazil to France.