the first officer's possible misunderstanding of the aircraft's response to full rudder at high airspeeds. Light rudder pedal forces and small pedal displacement of the A300-600 rudder pedal system increased the airplane's susceptibility to rudder misuse. Most aircraft require increased pressure on the rudder pedals to achieve the same amount of rudder control at a higher speed. The Airbus A300 and later Airbus A310 models do not operate on a fly-by-wire flight control system, but instead use conventional mechanical flight controls. The NTSB asserted that the A300-600 rudder control system was vulnerable to unnecessarily excessive rudder inputs. The Allied Pilots Association, in its submission to the NTSB, argued that the unusual sensitivity of the rudder mechanism amounted to a design flaw that Airbus should have communicated to the airline. The main rationale for their position came from a 1997 report that referenced 10 incidents in which A300 tail fins had been stressed beyond their design limitation. Airbus charged that the crash was mostly American Airlines' fault, arguing that the airline did not train its pilots properly about the characteristics of the rudder. Aircraft tail fins are designed to withstand full rudder deflection in one direction when below maneuvering speed, but this does not guarantee that they can withstand an abrupt shift in rudder from one direction to the other, let alone multiple abrupt shifts, like those generated by the first officer on this flight. The NTSB indicated that American Airlines' Advanced Aircraft Maneuvering Program (AAMP) tended to exaggerate the effects of wake turbulence on large aircraft, creating a simulation scenario whereby turbulence from a 747 creates a 90° roll (rather than the likely 5 to 10° roll, though not explaining this to the pilots) to maximize the training challenge. Therefore, pilots were being inadvertently trained to react more aggressively than was necessary. According to author Amy Fraher, this led to concerns of whether it was appropriate for the AAMP to be placing such importance on "the role of flight simulators in teaching airplane upset recovery at all." Fraher states that the key to understanding the crash of Flight 587 ultimately lay in "how the accident pilots' expectations about aircraft performance were erroneously established through 'clumsy' flight simulator training in American's AAMP." Statement of probable cause From the NTSB report of the accident: The National Transportation Safety Board determines that the probable cause of this accident was the in-flight separation of