The National Transportation Safety Board today released the following updated information on its investigation of the November 12, 2001, crash of American Airlines flight 587 in Belle Harbor, New York, which resulted in the deaths of all 260 persons aboard and 5 persons on the ground.
Vertical Stabilizer and Rudder
Examination continues on the accident aircraft's vertical stabilizer and rudder at NASA's Langley Research Center in Hampton, Virginia. Although the work is still in the non-destructive phase, several small coupons (samples) have been removed from the stabilizer in preparation for destructive testing, which is expected to begin next week.
A used rudder from another A300-600 aircraft has been located and purchased by the Safety Board for use as an exemplar as the examination of the accident components continues. The Board is still searching for a used vertical stabilizer to use for the same purpose.
1997 Airbus Event
Upon re-examination of the data from a 1997 event, the investigation team has determined that another American Airlines Airbus A300-600 (N90070) likely experienced high vertical stabilizer airloads. On May 12, 1997, American Airlines flight 903 was near West Palm Beach, Florida, when it entered a series of pitch, yaw, and roll maneuvers as the flight controls went through a period of oscillations for about 34 seconds, during which the aircraft dropped from 16,000 to 13,000 feet. The Safety Board determined that the probable causes of this incident were the flight crew's failure to maintain adequate airspeed during leveloff, which led to an inadvertent stall, and their subsequent failure to use proper stall recovery techniques. A factor contributing to the accident was the flight crew's failure to properly use the autothrottle.
As the Safety Board's February 8, 2002, safety recommendation to the FAA pointed out, rapid reversing movements of an aircraft's rudder can, under certain circumstances, jeopardize the structural integrity of the vertical stabilizer. The Board is now reviewing the flight recorder data from that incident flight to calculate the forces to which the stabilizer was subjected. As a safety precaution, Airbus and American Airlines are removing the vertical stabilizer of that aircraft for non-destructive inspection; Safety Board investigators will be present later this week when the stabilizer undergoes ultrasonic inspection to determine whether the stabilizer sustained any damage during that incident.
"Bogus" Parts Case in Italy
According to widely reported news media accounts, earlier this year authorities discovered a cache of replacement parts for Airbus aircraft in Italy that might have been destined for U.S. distributors and that might not have proper paperwork documenting their history. Safety Board investigators have traced the source of all major components associated with flight 587's tail assembly and have found that they had either been on the plane since its manufacture or came from the original equipment manufacturers; there is no indication that any of the components came from secondary sources.