Findings American Airlines Flight 587

photo showing crash site

according official accident report, after first officer made initial rudder pedal input, made series of alternating full rudder inputs. led increasing sideslip angles. resulting hazardous sideslip angle led extremely high aerodynamic loads resulted in separation of vertical stabilizer. if first officer had stopped making these inputs @ time before vertical stabilizer separation, natural stability of airplane have returned sideslip angle near 0°, , accident have been avoided. airplane performance study indicated when vertical stabilizer separation began, aerodynamic loads 2 times loads defined design envelope. can determined vertical stabilizer s structural performance consistent design specifications , exceeded certification requirements.

contributing factors include following: first, first officer s predisposition overreact wake turbulence; second, training provided american airlines have encouraged pilots make large flight control inputs; third, first officer not understanding airplane s response large rudder inputs @ high airspeeds or mechanism rudder rolls transport-category airplane; finally, light rudder pedal forces , small pedal displacement of a300-600 rudder pedal system increased airplane s susceptibility rudder misuse.

most aircraft require increased pressure on rudder pedals achieve same amount of rudder control @ higher speed. airbus a300 , later airbus a310 not operate on fly-by-wire flight control system, instead use conventional mechanical flight controls. ntsb determined because of high sensitivity, a300-600 rudder control system susceptible potentially hazardous rudder pedal inputs @ higher speeds . allied pilots association, in submission ntsb, argued unusual sensitivity of rudder mechanism amounted design flaw airbus should have communicated airline. main rationale position came 1997 report referenced 10 incidents in a300 tail fins had been stressed beyond design limitation.

airbus charged crash american airlines fault arguing airline did not train pilots characteristics of rudder. aircraft tail fins designed withstand full rudder deflection in 1 direction when below maneuvering speed, not guarantee can withstand abrupt shift in rudder 1 direction other. ntsb indicated american airlines advanced aircraft maneuvering program (aamp) tended exaggerate effects of wake turbulence on large aircraft. therefore, pilots being trained react more aggressively necessary. according author amy fraher, led concerns of whether appropriate aamp placing such importance on role of flight simulators in teaching airplane upset recovery @ all. fraher states key understanding crash of flight 587 lay in how accident pilots expectations aircraft performance erroneously established through clumsy flight simulator training in american s aamp.

statement of probable cause

from ntsb report of accident:

national transportation safety board determines probable cause of accident in-flight separation of vertical stabilizer result of loads beyond ultimate design created first officer’s unnecessary , excessive rudder pedal inputs. contributing these rudder pedal inputs characteristics of airbus a300-600 rudder system design , elements of american airlines advanced aircraft maneuvering program (aamp).

since ntsb s report, american airlines has modified pilot training program. previous simulator training did not reflect actual large build-up in sideslip angle , sideloads accompany such rudder inputs in actual airplane , according ntsb final report.