The National Transportation Safety Board released updated information on its investigation of the Nov. 12 crash of American Airlines flight 587 in Belle Harbor, N.Y., which resulted in the deaths of all 260 passengers and crew and five people on the ground.
So far, investigators appear to have found no equipment failure that accounts for the crash of the plane.
According to the board, the aircraft's wreckage was removed from the temporary hangar at Floyd Bennett Field. The majority of the wreckage is now in storage containers in a secure facility in Harrison, N.J..
The empennage (tail section), including the vertical stabilizer and rudder, was delivered to NASA Langley Research Center in Hampton, Va., during the week of Dec. 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.
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, Okla. An engine "teardown," or detailed examination, was conducted from Nov. 28 to Dec. 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, Az., for examination, which occurred Dec. 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 last month. According to the records, the last visual inspection of the vertical stabilizer and rudder was conducted on Dec. 9, 1999 during a heavy maintenance check. This inspection is required every five years. Nothing was noted during the visual inspection.
The last "B" check (every 425 flight hours) on the aircraft was conducted Oct. 3, 2001; the last "A" check (every 65 flight hours) was conducted Nov. 9, 2001; the last "periodic service," (every second flight day) the lowest level of scheduled maintenance, was conducted Nov. 11, 2001, the day before the accident.
A review of the aircraft's maintenance log showed 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 leaving New York, investigators 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.
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.
edited by Sandy Smith ([email protected])