FAA NPRM: Airbus Rudder Pedal Inputs
On Nov. 12, 2001, American Airlines Flight 587 crashed in Queens, N.Y., killing all 260 on board, plus five on the ground, and now an FAA NPRM aims to address one of the accident's causal factors -- over the next four years. The NTSB found that Flight 587, an Airbus A300 out of JFK for Santo Domingo, had lost its vertical tail in flight, due in part to pilot control inputs, before the aircraft fell out of control. Data suggests the first officer managed to overload the vertical tail with rudder pedal inputs of less than 2.5 inches. The proposed Airworthiness Directive (AD) would incorporate a design change to prevent excessive rudder movement that could lead to overload and failure of the vertical stabilizer. Affected aircraft include about 215 jets, all of which are models of the Airbus A300 and A310. Compliance is required within 48 months after the effective date of the AD. Comments are due by July 5.
According to the NTSB, loss of the tail was due in part to pilot inputs made during a wake turbulence encounter that began at about 2,300 feet during initial climb. According to the flight's data recorder, the pilot had made rudder inputs of no more than 2.4 inches, but had cycled inputs between the left and right rudder pedals. The NTSB found (PDF) that the aircraft's rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Program were contributing factors. Evaluation of the accident prompted a series of safety actions from the FAA. In October 2010, the FAA published "An International Survey of Transport Airplane Pilots' Experiences and Perspectives of Lateral/Directional Control Events and Rudder Issues in Transport Airplanes (Rudder Survey)" (PDF). The proposed AD stipulates that "there are no service instructions to address this unsafe condition." One option under consideration is a modification to the rudder control system called the pedal travel limiter unit.