NTSB focuses on two A330 jet incidents
WASHINGTON -- U.S. aviation accident investigators have launched probes into two recent incidents aboard Airbus A330 jets that appear to have similarities to the failures reported on the Air France jet that disappeared over the Atlantic Ocean on June 1.
The National Transportation Safety Board (NTSB) said Thursday it is looking into incidents on Northwest Airlines and Brazil's TAM Airlines in which pilots on the long-range, wide body jet received apparently erroneous airspeed and altitude data.
The investigation into the disappearance of Air France Flight 447, an A330 with 228 people aboard, has focused on the apparent failures of air pressure sensors that measure a jet's speed. The sensors are known as Pitot tubes. Data messages sent from the jet to an Air France maintenance computer indicated that the sensors failed minutes before the plane went down.
The failure of external air pressure sensors occur relatively frequently on all types of aircraft without serious consequences, according to federal aviation data bases. However, the failures can lead to critical problems if pilots do not respond properly and such failures have been linked to at least four fatal crashes around the world.
The NTSB, which is assisting French investigators in the Air France investigation, said it is looking into a Northwest flight from Hong Kong to Tokyo on Tuesday during which apparent similar failures occurred. The NTSB is collecting flight recorders, maintenance data, weather information and statements from the crew, the agency said. The flight landed safely in Tokyo.
In another incident on May 21, TAM Flight 8091 from Miami to São Paulo lost speed and altitude information in the cockpit, the NTSB said.
The crew noticed a rapid drop in outside temperature while cruising, followed by several abrupt failures. The autopilot and throttle controls disconnected and the crew lost speed and altitude information, the NTSB said.
The crew was able to fly the plane using backup instruments. Speed and altitude information returned after about five minutes and the plane landed safely in São Paulo.
