The U.S. National Transportation Safety Board (NTSB) is probing two recent incidents involving Airbus A330 commercial transports that appear to have suffered similar failures reported on Air France Flight 447, which crashed into the Atlantic Ocean on June 1, claiming 228 victims.
The probe into the disappearance of the Airbus A330 has focused on the apparent failures of air pressure sensors—pitot tubes—that measure an aircraft’s speed. Data messages sent from the aircraft to an Air France maintenance computer indicated that the sensors failed minutes before the plane went down.
Last year, Airbus advised airlines to replace Thales-made pitot tubes on A330s because they could provide erroneous readings in bad weather, but many airlines have not completed the switch since EASA did not issue an emergency airworthiness directive.
The Safety Board says it is investigating dual incidents in which airspeed and altitude indications in the cockpits of Airbus A-330 aircraft may have malfunctioned.
The first incident occurred May 21, 2009, when TAM Airlines Fight 8091 (PT-MVB) flying from Miami, FL 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 says another incident may have 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.
Meanwhile, the French aviation safety agency probing the mid-Atlantic crash said it would release an initial report on its findings on July 2.
The Investigation and Analysis Bureau (BEA) leading the technical inquiry into the June 1 crash said it would present the report at a press conference at its headquarters in the Paris suburbs.
Air France said earlier that the plane’s pilot and one of its stewards have been identified among the 51 bodies pulled out of the sea so far.
Hopes of finding the flight data and cockpit voice recorders are fading because the locator beacons are due to lose power around the end of June. In the absence of distress calls and black boxes the investigators must rely on the data messages, known as Acars, which the aircraft sent to Charles de Gaulle airport.
Searchers have seen no sign of the doomed plane’s black boxes. Faint pings heard by electronic devices were not from the missing FDR and CDR.
“No signals transmitted by the flight recorders’ locator beacons have been validated up to now,” French investigators said in a statement. “In the context of the sea searches that are under way, work is undertaken on a regular basis that is aimed at eliminating any doubts related to any sounds that may be heard, and any findings will be made public.”