The National Transportation Safety Board today released the following updated information on its investigation of the November 12 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.
The aircraft's wreckage has been removed from the temporary hangar at Floyd Bennett Field. Except as described below, the majority of the wreckage is now in storage containers in a secure facility in Harrison, New Jersey.
Vertical Stabilizer and Rudder
The empennage (tail section), including the vertical stabilizer and rudder, was delivered to NASA Langley Research Center in Hampton, Virginia during the week of December 3.
The stabilizer and rudder underwent preliminary inspections in New York before being transported to NASA Langley. There are six primary attachment points between the vertical stabilizer and the empennage. Each empennage attachment point has a double lug, through which a metal pin connects the empennage to the stabilizer. All six pins were found properly positioned in the double lugs following the crash. Photographs of these attachment points and the tail assembly can be found on the Board's web site.
Nondestructive inspections - ultrasound, thermography (a form of photography using infrared film) and tap testing - of the vertical stabilizer and rudder have commenced. A plan for further testing of the composite components is being developed.
Both engines were transported to an American Airlines heavy maintenance facility in Tulsa, Oklahoma. An engine "teardown," or detailed examination, was conducted from November 28 to December 4. There was no evidence found of an uncontained engine failure, case rupture, inflight fire, foreign object damage such as a bird strike, or pre-impact malfunction.
The auxiliary power unit (APU), an engine used to provide power for aircraft systems while on the ground and also for emergency electrical backup during flight, was taken to its manufacturer, Honeywell Engineering and Systems, Inc., in Phoenix, Arizona for examination, which occurred December 13. The disassembly revealed no evidence of rotational damage to the compressor impellers and turbine rotors or any evidence of inflight fire, case rupture, uncontainment, or a hot air leak. Tests will be conducted on an examplar aircraft to determine what type of heat a vertical stabilizer is exposed to during APU operation.
The aircraft's maintenance records were reviewed by investigators in Tulsa, Oklahoma last month. According to the records, the last visual inspection of the vertical stabilizer and rudder was conducted on December 9, 1999 during a heavy maintenance check. This inspection is required every 5 years. Nothing was noted during the visual inspection.
The last "B" check (every 425 flight hours) on the aircraft was conducted October 3, 2001; the last "A" check (every 65 flight hours) was conducted November 9, 2001; the last "periodic service," (every second flight day) the lowest level of scheduled maintenance, was conducted November 11, 2001, the day before the accident.
A review of the aircraft's maintenance log shows that on the morning of the accident, a pitch trim control and the yaw damper would not engage during a pre-flight check. The computer controlling those components was re-set by a mechanic, which resolved the problem. There were no open maintenance items regarding the vertical stabilizer and rudder system when the aircraft took off.
Before departing New York, the witness group had collected and reviewed approximately 85 interview summary forms obtained from the FBI. The forms and any other pertinent interview summaries obtained from local authorities are being examined now. They will be made part of the public record when the Board's public docket on this investigation is opened.
Investigative Work in Europe
As previously reported, the Safety Board's aircraft performance group chairman was dispatched to Toulouse, France, to work with his counterparts at Airbus Industrie and the Bureau Enquetes Accidents (BEA - the French NTSB) on aerodynamic loads affecting the vertical stabilizer during the accident sequence. The work is based upon data recorded by ground radar and the flight data recorder from the accident airplane.
The systems group traveled to Toulouse to familiarize themselves with the operation of the A-300-600 rudder system, including a detailed examination of rudder travel limiting systems installed on the airplane. Airbus is refurbishing a systems simulator to assist the investigation in simulating possible malfunction scenarios within the rudder system of the aircraft.
Also, the structures group chairman traveled to Toulouse and Hamburg, Germany, to familiarize himself with the history of the composite vertical stabilizer design and ideas for testing the failed tail components of the accident airplane.
A weather observation taken about 8 minutes after the accident stated that the winds were out of 270 degrees at 8 knots, with 10 mile visibility. There were a few clouds at 4,800 feet. The temperature was 6 degrees Centigrade, dew point -6 C, and the altimeter setting was 30.44 inches of mercury.
The systems group will travel to NASA Langley this week to begin forensic examination of the rudder system actuators and limiting system components. Components will be removed for eventual shipment to manufacturers, where they will be examined under NTSB supervision.
Each of the NTSB's investigative groups will prepare factual reports on their activities, which will be placed in the Board's public docket. This process generally takes 7 to 9 months. Final reports on Safety Board investigations usually take 18 to 24 months. However, during the course of its investigations, the Safety Board will issue immediate safety recommendations at any time if it finds issues that require immediate attention by either industry or government.
The Safety Board has been in contact with the Federal Bureau of Investigation since the first day of this investigation. To date, nothing has been found to indicate that the crash of flight 587 was not an accidental event.