As an outgrowth of its continuing investigation into the November 12 crash of American Airlines Flight 587 in New York City, the NTSB has recommended that the FAA order manufacturers and operators of transport-category airplanes to revamp pilot-training programs with regard to rudder use.
The Safety Board said that pilots should be warned that a full or nearly full rudder deflection in one direction followed by a full or nearly full rudder deflection in the opposite direction–or certain combinations of sideslip angle and opposite rudder deflection–can result in potentially dangerous loads on the vertical stabilizer, even at speeds below the design maneuvering speed.
Further, the pilot-training programs should explain that, on some aircraft, as speed increases, the maximum available rudder deflection can be obtained with comparatively light pedal forces and small pedal deflections.
Although pilots may believe that rudder-limiter systems, which limit rudder travel as airspeed increases to prevent a single full rudder input from overloading the structure, also prevent sequential full opposite rudder deflections from damaging the structure, the structural certification requirements do not take such maneuvers into account.
Flight 587, an Airbus A300-600, had just taken off from New York JFK International Airport on a flight to the Dominican Republic when it crashed in a residential area of Belle Harbor, N.Y., killing all 260 on board and five people on the ground. Before it crashed, the vertical stabilizer and rudder separated from the fuselage.
Preliminary calculations by the NTSB and Airbus engineers show that large sideloads were likely present on the vertical stabilizer and rudder at the time they separated from the airplane.
The Safety Board recommended the FAA require that manufacturers and operators establish and implement pilot-training programs that explain the structural certification requirements for the rudder and vertical stabilizer on transport-category airplanes and require revisions to airplane and pilot operating manuals that reflect and reinforce the new training.
But the NTSB also cautioned the FAA to ensure that this training does not compromise the substance or effectiveness of existing training regarding proper rudder use, such as during engine failure shortly after takeoff or gusty crosswind takeoffs or landings.
The Board called for a careful review of all existing and proposed guidance and training provided to pilots of transport-category airplanes concerning special maneuvers intended to address unusual or emergency situations and, if necessary, require modifications to ensure that flight crews are not trained to use the rudder in a way that could result in dangerous combinations of sideslip-angle rudder position or other flight parameters.