page_title: American Airlines Flight 587
section_title: Findings
hierarchical_section_title: American Airlines Flight 587 / Investigation / NTSB investigation / Findings
caption_attribution_description: w:American Airlines Flight 587
context_page_description: American Airlines Flight 587 was a regularly scheduled international passenger flight from John F. Kennedy International Airport to Las Américas International Airport in Santo Domingo, the capital of the Dominican Republic. On November 12, 2001, the Airbus A300B4-605R flying the route crashed into the neighborhood of Belle Harbor, on the Rockaway Peninsula of Queens, New York City shortly after takeoff. All 260 people aboard the plane were killed, along with 5 people on the ground. It is the second-deadliest aviation incident involving an Airbus A300 and the second-deadliest aviation accident in U.S. history behind only 1979's American Airlines Flight 191.
  The location of the accident, and the fact that it took place two months and one day after the September 11 attacks on the World Trade Center in nearby Manhattan, initially spawned fears of another terrorist attack. However, the National Transportation Safety Board attributed the disaster to the first officer's overuse of rudder controls in response to wake turbulence from a preceding Japan Airlines Boeing 747-400 that took off minutes before it.
context_section_description: According to the official accident report, the first officer repeatedly moved the rudder from fully left to fully right. This caused increasing sideslip angles. The resulting hazardous sideslip angle led to extremely high aerodynamic loads that separated the vertical stabilizer. If the first officer had stopped moving the rudder at any time before the vertical stabilizer failed, the aircraft would have leveled out on its own, and the accident would have been avoided. The aircraft performance study indicated that when the vertical stabilizer finally detached, the aerodynamic loads caused by the first officer's actions produced 203,000 pounds of force on the rudder, meaning that the vertical stabilizer did not fail until far in excess of the 100,000 pounds of force defined by the design envelope. The vertical stabilizer's structural performance was determined to be consistent with design specifications and exceeded certification requirements.
  There were contributing factors to the crash as well. The first officer's predisposition to overreact to wake turbulence caused panic. American Airlines incorrectly taught pilots to use the rudder for wake turbulence recovery, resulting in the first officer's likely 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-degree roll (rather than the likely 5-to-10-degree roll, though not explaining this to the pilots) in order 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."
caption: Photo showing the crash site
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