As the trial involving the fatal crash of Air France Flight 447 begins today, prosecutors will argue that Air France (the airline flying the plane) and Airbus (the manufacturer of the plane) are liable for their role in the fatal 2009 crash. Both companies face charges of manslaughter and negligence in the incident that killed 228 passengers and crew. France’s air accident investigation agency (BEA) concluded that technical malfunctions of the speed sensors (pitot tubes) and faulty computer readings led to pilot error resulting in the crash.
The obstruction of the Pitot probes by ice crystals was KNOWN BUT MISUNDERSTOOD BY THE AVIATION COMMUNITY at the time of the accident. From an operational perspective, the total loss of airspeed information that resulted from this was a failure that was classified in the safety model. After initial reactions that depend upon basic airmanship, pilots are expected to rapidly diagnose it and manage where necessary by precautionary measures on the pitch attitude and the thrust, as indicated in the associated procedure.
The failure in the context of flight in cruise completely surprised the pilots of flight AF 447. The apparent difficulties with airplane handling at high altitudes in turbulence led to excessive handling inputs in roll and a sharp nose-up input by the co-pilot. The destabilization that resulted from the climbing flight path and the evolution in the pitch attitude and vertical speed was added to the erroneous airspeed indications and ECAM messages, which did not help with the diagnosis.