The US National Transportation Safety Board today said it is investigating two recent incidents involving possible malfunctioning of airspeed and altitude indications in the cockpits of Airbus A330 aircraft.

Four days after the 1 June crash of an Air France Airbus A330 off the coast of Brazil, French investigators confirmed automatic messages transmitted by the aircraft show the jet was experiencing conflicting airspeed information from onboard sensors.

The first incident under NTSB scrutiny occurred on 21 May, and involved a TAM A330 operating from Miami to Sao Paulo, Brazil. The A330 experienced a loss of primary speed altitude in cruise. Initial reports indicate the crew observed an abrupt drop in indicated outside air temperature followed by the loss of the air data reference system. Both the autopilot and autothrust disconnected, and speed and altitude information were lost.

NTSB says the TAM flight crew used backup instruments, and primary data was restored in five minutes. The flight landed in Sao Paulo with no further incidents.

"The safety board has become aware of another possibly similar incident that occurred on June 23 on a Northwest Airlines A330 flying between Hong Kong and Tokyo," says NTSB. "The aircraft landed safely in Tokyo; no injuries or damage was reported."

Investigators are collecting data recorder information, aircraft condition monitoring system messages, and weather information from the flight.

Source: Air Transport Intelligence news