On November 12, 2001, American Airlines flight 587 crashed at Belle Harbor, N.Y., shortly after taking off from John F. Kennedy International Airport. All 260 people on board the airplane and five people on the ground were killed. The investigation began pointing to the likelihood that the airplane’s vertical stabilizer and rudder broke off because of full-rudder deflection. As the evidence became overwhelming that the vertical stabilizer separated because it was exposed to aerodynamic loads that were about twice its certified design limit and greater than its ultimate design limit, investigators had to figure out how those loads could have been produced.
Flight 587 was scheduled from New York to Los Americas International Airport in Santo Domingo, Dominican Republic. The flight was operated under Part 121 on an IFR flight plan. Visual meteorological conditions existed at JFK International Airport. The flight left the gate at 9 a.m., and followed a Japan Airlines Boeing 747 to runway 31L.
At 9:11:08, the local controller cleared the Japan Airlines airplane for takeoff. At 9:11:36, the local controller cautioned the flight 587 pilots about wake turbulence and instructed them to taxi into position and hold for runway 31L. At 9:13:05, the local controller instructed the Japan Airlines pilots to fly the “bridge climb.” At 9:13:21, the flight 587 captain said to the first officer, “You have the airplane.”
At 9:13:28, the local controller cleared flight 587 for takeoff. At 9:13:35, the first officer asked the captain, “You happy with that [separation] distance?”
The captain replied, “We’ll be all right once we get rollin’. He’s supposed to be five miles [ahead] by the time we’re airborne. That’s the idea.”
The NTSB’s airplane performance study determined that flight 587 started its takeoff roll about 9:13:51 and lifted off at 9:14:29, which was one minute and 40 seconds after the Japan Airlines airplane. At 9:14:43, the local controller instructed the flight 587 pilots to turn left, fly the “bridge climb” and contact departure. At 9:15, the captain radioed the departure controller, advising that they were at 1,300 feet and climbing to 5,000 feet. At 9:15:05, the departure controller instructed flight 587 to climb to and maintain 13,000 feet. At 9:15:29, the CVR recorded the captain’s statement of “clean machine,” indicating that the gear, flaps and slats have been retracted.
At 9:15:35, flight 587 was climbing through 1,700 feet with its wings approximately level. One second later, the controller instructed flight 587 to turn left and proceed direct to the WAVEY intersection. The captain acknowledged. The controller didn’t receive any further transmissions from flight 587.
FDR data indicated that at 9:15:36, the airplane began excursions consistent with a wake turbulence encounter. Between 9:15:36 and 9:15:41, the FDR recorded movement of the control column, control wheel and rudder pedals.
At 9:15:48, the first officer indicated that he wanted the airspeed set to 250 knots, which was the maximum speed for flight below 10,000 feet MSL. At that point, the airplane was at 2,300 feet. FDR data indicated that at 9:15:51, there were more excursions consistent with a wake turbulence encounter. Throughout the turbulence encounters, there were numerous rudder-pedal, control-column and control-wheel movements. Then, the CVR recorded the sound of a thump, a click and two more thumps. At 9:15:54, the first officer stated, in a strained voice, “Max power.” At that point, the airplane was traveling at 240 knots. The CVR recorded the sound of a snap at 9:15:57, with the first officer saying, “Let’s go for power, please.”
There was a loud thump a second later. According to the airplane performance study, the vertical stabilizer’s right rear main attachment fitting fractured at 9:15:58, and the vertical stabilizer separated from the airplane immediately afterward.
At 9:15:59, the cockpit voice recorder recorded the sound of a loud bang. At that time, the airplane was traveling at an airspeed of about 251 knots.
According to the FDR, there were more left- and right-rudder pedal and control-wheel movements. At 9:16, the CVR recorded a sound similar to a grunt. At 9:16:04, the CVR recorded a sound similar to a stall warning chime, which lasted for 1.9 seconds.
At 9:16:08, the first officer stated, “What the hell are we into? We’re stuck in it.”
At 9:16:13, the captain stated, “Get out of it. Get out of it.” The CVR recording ended two seconds later.
In the immediate vicinity of the impact area, about four miles from the runway, four houses were destroyed and six others were damaged. The in-flight separation of the engines resulted in property damage where the engines fell. The stabilizer and rudder fell into water about 3⁄4 of a mile before the main wreckage site.
The captain, age 42, held an ATP certificate and an FAA first-class medical certificate with no limitations. He had accumulated 8,050 hours of total flying time, including 3,448 hours as pilot in command and 1,723 hours as an A300 pilot in command.
The first officer, age 34, held an ATP certificate and an FAA first-class medical certificate with a limitation that required him to wear corrective lenses. He had accumulated 4,403 hours of total flying time, including 1,835 hours as an A300 second in command.
An American Airlines captain who flew several times with the first officer on Boeing 727s told investigators that during one flight sometime in 1997, the first officer had been “very aggressive” on the rudder pedals after a wake turbulence encounter. At the public hearing on this accident, Airbus officials testified that the ailerons and spoilers, not the rudder, should normally be used to control roll. An American Airlines official testified that before the flight 587 accident, he didn’t think that any pilot would have thought that full-rudder deflection could be gained from about 11⁄4 inches of pedal movement and 10 pounds of pressure (above the breakout force) at an airspeed of 250 knots.
During the Advanced Aircraft Maneuvering Program (AAMP) training that the first officer attended in March 1997, pilots were instructed that the rudder could be used to assist in controlling an airplane’s roll angle during upsets and unusual attitudes. Further, the AAMP flight-training booklet, which was used at the time, discussed wake turbulence as a factor that had caused an increase in loss-of-control accidents and incidents, and reiterated the use of rudder as the most effective roll-control device at high angles of attack. Training also suggested that even full-rudder inputs could be appropriate in certain extreme situations.
In a simulator-training exercise, pilots were told they were taking off behind a heavy 747 and were issued the appropriate wake turbulence warnings. The simulator was programmed so that it wouldn’t initially respond to control inputs, suggesting that an external influence (the wake) was overpowering the controls. This deprived the pilot of an opportunity to experience how the airplane would respond to control inputs (including side-load accelerations), thus leaving the pilot with a misperception of the real effects of the control inputs. According to the NTSB, the scenario was unrealistic and might cause a pilot to develop control strategies that were effective in the simulator, but might be inappropriate or even dangerous in an actual airplane.
The NTSB determined that the probable cause was the in-flight separation of the vertical stabilizer as a result of loads beyond the ultimate design created by the first officer’s unnecessary rudder-pedal inputs. Contributing to these rudder-pedal inputs were the characteristics of the Airbus A300-600 rudder system design as well as elements of the American Airlines AAMP training.
Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.