Air France and Airbus Face Involuntary Manslaughter For Crash
A French appeals court has ruled Air France and Airbus must face involuntary manslaughter charges for the crash twelve years ago of an Air France Airbus en route from Rio to Paris. Air France is charged with insufficient training of its pilots. Airbus is charged with underestimating the seriousness of a known speed indication problem.
The plunge of this airliner into the ocean was — and still is — particularly troubling to persons with fear of flying. It resonates with their terror of “falling out of the sky.” Since this problem developed due to weather conditions, it reinforces the fear that bad weather could cause their plane to crash. For some time it appeared the wreckage might never be found. The idea that the people on the plane could be lost forever prevented fearful fliers from being able to reach psychological closure about this crash.
As the plane flew through a storm area, the plane’s speed sensors iced up which caused inaccurate speed information to be fed into the plane’s computerized flight control system. These sensors, called “pitot tubes,” are open at the end protruding into the airstream. Onrushing air causes pressure to build up inside the tube. The faster the plane is flying, the higher the pressure. The amount of pressure is used to determine how fast the plane is flying. Since a plane must fly neither too fast nor too slow, this information is vital.
If a pitot tube becomes clogged the amount of pressure inside the tube may not accurately reflect the speed of the plane. To keep ice from clogging the tube, the tubes are heated during flight. Nevertheless, the pitot tubes used on the Air France A330s occasionally became blocked in icing conditions.
Air France told its pilots that if icing caused unreliable speed information to maintain the plane’s altitude and power setting, and wait for the tubes to unfreeze, which took only a minute or so.
When Air France 447 entered a storm area, ice crystals clogged the pitot tubes. Because the amount of blockage varied between the three pitot systems, each system showed a different airspeed. The autopilot recognized the disparity and disconnected.
Suddenly, and unexpectedly, the pilots were forced to fly the plane manually using the sidestick. Airspeed discrepancies caused the plane’s computerized flight control system to switch to a mode that made the plane difficult to fly at high altitude and disabled the plane’s stall protection system.
Lacking both correct airspeed information and stall protection, the pilots flew the difficult-to-control plane into a stall which caused the plane to lose altitude. It appears neither pilot was sure whether the stall was due to flying too fast or flying too slow. At one point, the two copilots applied opposite joystick inputs to the flight computer. The stall continued and the plane descended into the water belly-first.
News reports have emphasized that the captain was on his rest break and claimed the copilots were inexperienced. But both copilots were experienced. One copilot had three times more flight time in the A330 than the captain had.
After the crash, Air France reminded its pilots of the unreliable speed procedure, as if to say following the procedure would have prevented the crash. This missed the point that the pilots would, before turning to the procedure, have to realize the speed readings were incorrect. It also misses the point that control of the plane is difficult when airspeed discrepancies cause a shift in flight control system response.
As expected, both Air France and Airbus objected to the court’s decision. What might be unexpected is the statement released by the French Nation Union of Airline Pilots. Instead of being supportive of the French airline and the French planemaker, the union said the court ruling was a “fundamental decision for air transport safety.”