Point/Counterpoint - The Airbus Position

Air Safety Week,  March 29, 2004  

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"I have grave concerns abut some flawed aerodynamic theory and flying techniques that have been presented in the AAMP ... In no uncertain terms pilots are told to use rudders as the primary means of roll control in unusual attitude recoveries ... This is not only wrong, it is exceptionally dangerous."

Encounter with second wake vortex [on the accident flight]: Almost immediately, the first officer applied what apparently was a conditioned upset recovery response ... He used full right control wheel and full right rudder, in the same direction as taught by the AAMP for wake vortex upset recovery. These combined inputs generated a large lateral acceleration felt in the cockpit, of a magnitude far greater than that perceived in the simulator during AAMP training. This large lateral acceleration, totally unexpected by the first officer, probably triggered the subsequent reversal of inputs.

He believed from AAMP that the aircraft might go beyond 90[degrees] angle of bank unless he applied full rudder as taught. Due to this negative training, he most probably never realized that the aircraft movements and accelerations were simply due to his own control inputs.

It cannot be argued that he was somehow misled by overly light pedal forces and too small displacements, since he was applying exactly the same control behavior in the roll axis as well.

The accident would not have happened had the first officer simply taken his feet off the rudder pedals at any time prior to ... structural overload.

Factors to Consider - Emanating from the crash of American Airlines Flight 587, an Airbus A300-600

Item: Digital flight data recorders (DFDR) - From the Airbus submission (p. 58): "Filtering of rudder pedal and rudder position as used in the A300B4-605R DFDR did not preclude precise reconstruction of the time history and aircraft response."

Comments: Some industry observers are skeptical, asserting that such reconstructions from filtered DFDR recordings reflect a "best fit" that might only show what may have happened. Many pilots insist that no transport category airplane pilot would kick the rudder back and forth as allegedly recorded on the DFDR.

Item: Simulators - From the Airbus submission (p. 5): "Due to simulator limitations ... the use of flight simulators for upset recovery training is potentially highly misleading."

Comments: Flight simulators are renowned for their infidelity as far as reproducing flight characteristics - especially at or beyond flight envelope limits. Airbus is correct in regard to the negative training and conditioning that can occur in flight simulators.

Item: Training - From the Airbus submission (p. 5): "American Airlines, without Airbus approval, effectively nulled all roll control inputs for a limited but critical period ... 'forcing' the pilot to use full or nearly full rudder." Comments: All training technique proposals need to be cleared and validated with the manufacturer, whether carried out in airplanes or in simulators.