More than two years after Air France Flight 447 fell out of the sky over the Atlantic, French investigators have determined that a lack of pilot training played a key role in the harrowing nighttime crash that killed all 228 aboard.
This week the French BEA authority released its final report into the accident, which occurred on June 1, 2009 as Flight 447 was en route from Rio de Janeiro to Paris. The 224-page document concluded that the plane plunged into the ocean after a series of events led the crew to stall the plane near its cruising altitude and “the lack of any actions that would have made recovery possible.”
The long-awaited report confirmed what many in the industry had suspected: the current training regime for pilots is insufficient for dealing with so-called “loss of control” incidents that result from aerodynamic stalls, which are caused when a plane’s wings lose lift—usually because the plane is flying too slowly or trying to climb too steeply.
Needless to say, such accidents aren’t supposed to happen. Stall prevention and recovery is part of a pilot’s basic training. In general, the rule is to point the nose of the aircraft down and increase thrust until the plane’s airspeed is sufficient to restore lift to the wings. However, a Maclean’s investigation last year found that many pilots faced with a fatal mid-air stall not only failed to respond properly, but often appeared to do the exact opposite of what they were supposed to. The Maclean’s investigation also revealed that a combination of factors may be responsible for the seemingly unthinkable behaviour, ranging from the way pilots are trained in flight simulators to the increasing complexity and automation of today’s modern jetliners.
In the case of Air France, the sequence of events that led to the crash began when the plane flew through a band of thunderstorms. The pilots slowed the aircraft in anticipation of turbulence and then suddenly lost their airspeed indicators after the plane’s external sensors, called pitot tubes, failed—likely because they had become clogged with ice. But while the loss of accurate airspeed readings presented the pilots with a mid-air crisis, it should not have been fatal. French accident investigators found that the Air France pilots responded to the emergency in a disorganized fashion and unwittingly put the plane into a stall after the autopilot clicked off, as it was designed to do in the absence of accurate airspeed readings. More importantly, the co-pilot who was at the controls when the plane went down (the captain had left the cockpit on a rest break, only to return in the final minutes before the crash) repeatedly tried to point the plane’s nose upward despite the fact that the plane’s stall warning system kept sounding, albeit intermittently. The aircraft might have been saved had he done the exact opposite.
Among other things, French investigators recommended key changes to how pilots are trained to recognize and respond to stalls, including improved training when it comes to flying an aircraft manually at high altitude. The report also suggested changes to the design of some of the Airbus’s cockpit safety systems to make it easier for pilots to recognize when they’ve entered a stall. That includes the addition of an angle-of-attack indicator that shows the angle of the wing relative to the air flowing around it. “Only a direct readout of the angle of attack could enable crews to rapidly identify the aerodynamic situation of the aeroplane and take the actions that may be required,” the report said.
Friday, July 6, 2012