Airbus A300-605R accident at Belle Harbor, New York, 12 Nov 2001 (N14053)

Accident narrative

On November 12, 2001, about 0916 eastern standard time, American Airlines flight 587, an Airbus Industrie A300-605R registered N14053, crashed into a residential area of Belle Harbor, New York, shortly after takeoff from John F. Kennedy International Airport (JFK). The airplane’s vertical stabilizer and rudder separated in flight, followed by the in-flight separation of both engines. All 260 people aboard the airplane and five people on the ground were killed, and the airplane was destroyed by impact forces and a postcrash fire.

**The flight**

Flight 587 was a regularly scheduled passenger flight to Las Americas International Airport in Santo Domingo, Dominican Republic. Aboard were two flight crewmembers, seven flight attendants, and 251 passengers.

The captain, 42, had accumulated 8,050 hours of total flying time, including 1,723 hours as an A300 pilot-in-command. He was the nonflying pilot. The first officer, 34, had accumulated 4,403 hours of total flying time, including 1,835 hours as an A300 second-in-command. He was the flying pilot.

Before takeoff, avionics technicians investigated a report that the number 2 pitch trim and yaw damper system would not engage. They found a fault with the number 2 flight augmentation computer, reset the circuit breaker, and detected no further faults.

**Sequence of events**

At 0901:33, the ground controller provided taxi instructions to runway 31L. During the taxi, the first officer performed a rudder pedal check, and flight data recorder (FDR) data showed the pedals reached maximum deflections of 3.7 inches right and 3.6 inches left before returning to neutral.

At 0911:36, the local controller cautioned the flight 587 pilots about wake turbulence from Japan Air Lines flight 47, a Boeing 747-400 that had just been cleared for takeoff, and instructed them to taxi into position and hold. At 0913:28, flight 587 was cleared for takeoff. The first officer asked the captain, "you happy with that distance?" The captain replied, "we'll be all right once we get rollin'. He's supposed to be five miles by the time we're airborne, that's the idea."

Flight 587 began its takeoff roll at 0913:51 and lifted off about 1 minute and 40 seconds after the Japan Air Lines airplane. The airplane climbed to 500 feet and entered a climbing left turn. At 0915:00, the captain contacted the departure controller, reporting an altitude of 1,300 feet, and was cleared to climb to 13,000 feet.

At 0915:36, the airplane experienced a first wake turbulence encounter, recording a 0.04 G drop in longitudinal load factor, a 0.07 G shift to the left in lateral load factor, and a 0.3 G drop in normal load factor. The control wheel moved a total of seven times, with peaks up to 37 degrees right and 34 degrees left, and the rudder pedals moved slightly. At 0915:44, the captain stated, "little wake turbulence, huh?" and the first officer replied, "yeah."

At 0915:51, the airplane experienced a second wake turbulence encounter. The bank angle moved to 25 degrees left wing down, the control wheel moved to 64 degrees right, and the rudder pedals moved to 1.7 inches right. Between 0915:52 and 0915:58.5, the rudder pedals moved from 1.7 inches right to 1.7 inches left, 1.7 inches right, 2.0 inches right, 2.4 inches left, and 1.3 inches right. The control wheel also moved significantly, mostly paralleling the directional movements of the rudder pedals.

At 0915:54, the first officer stated, "max power." The captain asked if he was all right, and the first officer replied that he was fine. The captain then stated, "hang onto it. Hang onto it."

At 0915:58.4, the vertical stabilizer's right rear main attachment fitting fractured, and the vertical stabilizer separated from the airplane immediately afterward. The cockpit voice recorder (CVR) recorded a loud bang at 0915:58.5. The airplane was traveling at an airspeed of about 251 knots.

Following the separation, the airplane's directional stability was reduced. At 0916:04, a stall warning repetitive chime sounded. At 0916:07, the first officer stated, "what the hell are we into...we're stuck in it." The captain stated, "get out of it, get out of it" at 0916:12, and the recording ended two seconds later.

**What the investigation found**

*Wreckage and structural analysis* The main wreckage was located at the intersection of Newport Avenue and Beach 131st Street. The vertical stabilizer and rudder were recovered from Jamaica Bay, about one mile north of the main wreckage area. Both engines had separated in flight and were found several blocks north and east of the main wreckage. Neither engine showed evidence of uncontainment, case rupture, or preimpact failure. The Board concluded that witnesses who reported observing the airplane on fire were most likely observing a fire from the initial release of fuel or the effects of engine compressor surges caused by the out-of-control motion disrupting airflow into the engines.

A wake vortex investigation by NASA-Langley determined that a wake vortex from Japan Air Lines flight 47 was likely transported into the flightpath of flight 587.

The vertical stabilizer and rudder were constructed primarily of carbon fiber reinforced plastics. The vertical stabilizer was attached to the aft fuselage by six main attachment fittings. Examination of the wreckage revealed that the right rear main attachment fitting fractured at the lughole in a cleavage-tension failure mode. The left side fittings fractured consistent with the vertical stabilizer bending to the left after the right side separated.

Structural analysis, including finite element analysis (FEA) and progressive failure analysis (PFA) by NASA-Langley and Airbus, as well as three postaccident static lug tests conducted in Hamburg, Germany, showed that the vertical stabilizer performed in a manner consistent with its design and certification. It fractured in overstress, starting with the right rear lug, while exposed to aerodynamic loads that were about twice the certified limit load design envelope and more than the certified ultimate load design envelope.

*The rudder control system* The Board concluded that the cyclic rudder motions after the second wake turbulence encounter were the result of the first officer's rudder pedal inputs. The investigation did not reveal any indication of a mechanical failure that could have caused these movements.

The A300-600 utilizes a variable stop rudder travel limiter system. Unlike a variable ratio design, which allows a constant range of pedal travel but reduces the maximum possible rudder deflection as airspeed increases, a variable stop design limits both rudder deflection and rudder pedal travel as airspeed increases. At 135 knots, full rudder deflection (30 degrees) required 4 inches of pedal travel and 65 pounds of force. At 250 knots, full rudder deflection (9.3 degrees) required only 1.2 inches of pedal travel and 32 pounds of force.

The Board concluded that the A300-600 rudder control system couples a rudder travel limiter system that increases in sensitivity with airspeed with the lightest pedal forces of all the transport-category aircraft evaluated during the investigation. Because of this high sensitivity, the system is susceptible to potentially hazardous rudder pedal inputs at higher airspeeds.

*First officer's actions and human performance* The Board concluded that the first officer's initial control wheel input in response to the second wake turbulence encounter was too aggressive, and his initial rudder pedal input response was unnecessary to control the airplane.

Interviews with other pilots indicated that the first officer had a tendency to overreact to wake turbulence by taking unnecessary actions, including making excessive control inputs. One 727 captain recalled a 1997 flight where the first officer responded to a momentary wake encounter by making a series of rapid, alternating full rudder pedal inputs, creating heavy side loads. When questioned, the first officer insisted that the company's Advanced Aircraft Maneuvering Program (AAMP) directed him to use the rudder pedals in that manner.

The Board determined that the first officer's initial overcontrol and lack of understanding regarding the airplane's response to rudder pedal inputs at higher airspeeds may have combined to serve as a pilot trigger for an adverse aircraft-pilot coupling (APC) event. The small pedal displacements of the A300-600 at 240 knots may have facilitated the large, rapid inputs.

*American Airlines Advanced Aircraft Maneuvering Program (AAMP)* The investigation found that American Airlines' AAMP ground school training encouraged pilots to use rudder to assist with roll control during recovery from upsets.

Furthermore, the AAMP excessive bank angle simulator exercise was unrealistic. During the exercise, the simulator depicted a wake turbulence encounter that quickly rolled the airplane beyond 90 degrees, and the simulator inhibited the effectiveness of the control wheel and rudder pedals during the initial portion of the upset. The Board concluded that this exercise could have caused the first officer to have an unrealistic and exaggerated view of the effects of wake turbulence, erroneously associate wake turbulence encounters with the need for aggressive roll upset recovery techniques, and develop control strategies that would produce a much different, and potentially surprising and confusing, response if performed during flight.

The investigation noted that airplane manufacturers had previously expressed concerns about the AAMP. In August 1997, representatives from Boeing, McDonnell Douglas, Airbus, and the FAA sent a joint letter to American Airlines stating that "the excessive emphasis on the superior effectiveness of the rudder for roll control vis-à-vis aileron and spoilers, in high angle of attack, is a concern" and that "sideslip introduced by rapid roll may result in departure from controlled flight." American Airlines' chief pilot responded in October 1997 disagreeing with their position. An internal American Airlines memorandum from the managing director of flight operations technical in May 1997 also expressed "grave concerns about some flawed aerodynamic theory and flying techniques that have been presented in the AAMP," but the training remained.

*Design maneuvering speed* The investigation found a widespread misunderstanding among pilots about the degree of structural protection that exists when full or abrupt flight control inputs are made at airspeeds below the design maneuvering speed (VA). The Board noted that operating at or below maneuvering speed does not provide structural protection against multiple full control inputs in one axis or full control inputs in more than one axis at the same time.

**Probable cause**

The National Transportation Safety Board determined that the probable cause of this accident was the in-flight separation of the vertical stabilizer as a result of the loads beyond ultimate design that were created by the first officer's unnecessary and excessive rudder pedal inputs. Contributing to these rudder pedal inputs were characteristics of the Airbus A300-600 rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Program.