The National Transportation Safety Board has launched investigations into two recent incidents in which airspeed and altitude indications in Airbus A330s might have malfunctioned, adding to the suspicion that an instrument failure could have led to the June 1 loss of an Air France A330-200 (Flight 447) in the Atlantic Ocean, killing 228 people.  

The first incident occurred on May 21, when TAM Airlines Flight 8091, flying from Miami, Fla., to São Paulo, Brazil, lost primary speed and altitude information while in cruise flight. The flight crew reported 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 crew used backup instruments for five minutes, before they restored primary data and landed in São Paulo with no further incident. 

The NTSB said a similar incident might have occurred in a Northwest Airlines A330 during a June 23 flight from Hong Kong to Tokyo. That aircraft also landed safely. Investigators have begun collecting data recorder information, aircraft condition monitoring system messages, crew statements and weather information from both cases.

Meanwhile, search crews have
recovered 51 bodies from the downed Air France jet, including Flight 447’s captain and one of its flight attendants. Authorities have called off the search for bodies; however, the search continues for the airplane’s flight recorders, suspected to lie at least 15,000 feet below the surface. Designed to emit so-called “pings” for only about a month, the flight recorders will stop signalling within a week, at which time the chances of finding them will diminish to virtually nil.