NTSB Describes Importance Of Unpublished 9/11 FDR Part Numbers And Serial Numbers
The following is information obtained from the National Transportation Safety Board via online public inquiry requests, regarding Flight Data Recorder (FDR) part numbers and unique serial numbers required to facilitate the data readouts obtained from the FDRs recovered from American Airlines flight 77 and United Airlines flight 93, destroyed during the terrorist attacks of September 11, 2001. Such numbers were not published within NTSB reports regarding FDRs for these flights.
Within a June 5, 2008 response from the NTSB, it is explained why unique FDR serial numbers are required to obtain correct FDR data readout:
"The exact serial number of the unit delineates manufacturing break points. The serial number is used to identify when a recorder manufacturer switched from a certain memory configuration to another. This information is necessary to perform the correct recovery of the data."
Within a May 5, 2008 response from the NTSB, it is indicated that FDR part and serial numbers are normally obtained directly from FAA and airline aircraft records:
Because the FBI was the lead investigative agency regarding the terrorist attacks of September 11, 2001, FAA and airline aircraft records would have presumably been brought under the control of and made available by the FBI.
Within a June 11, 2008 reply from the NTSB, the NTSB indicates that when FDR part and serial numbers are not known, they are not contained within NTSB published reports:
"The Safety Board will include the manufacturer, the part number and the serial number of the recorder in its formal reports (if known)."
The NTSB reports regarding the FDR's recovered from AA 77 and UA 93 are virtually the only ones during the past 20 years of major U.S. aviation mishaps, within which FDR part and serial numbers were not published (the complete list is provided below) Because each essential FDR part and serial number were not published, they were presumably not made available to the NTSB.
American airlines flight 77 FDR report:
United airlines flight 93 report:
However, because each AA 77 and UA 93 FDR model and manufacturer is known and published within the AA 77 and UA 93 FDR reports, it would seem that the NTSB obtained limited access to information contained within FAA and airline aircraft records for AA 77 and UA 93. Why the NTSB was apparently unable to also obtain the FDR part and serial numbers required to generate proper FDR data readout is unknown. Presumably, if the recovered AA 77 and UA 93 FDR's did not possess the memory configurations indicated within FAA and airline aircraft records, a mismatch could become apparent to NTSB investigators.
According to the NTSB "Flight Data Recorder Handbook for Aviation Accident Investigations", FDR serial numbers are required for data readout:
"Specifically, the following information is required to facilitate data readout: ... FDR Part number and Serial Number"
FAA records that would contain the FDR part numbers serial numbers for AA 77 and UA 93 are unavailable for release by the FAA under the Freedom of Information Act:
The FAA's response to a Freedom of Information Act request for these aircraft records was described as "unlawful" by a FOIA expert with the "Reporters Committee for Freedom of the Press":
“"[W]e are not in a position to release the said records at this time,” certainly isn’t an exemption any where in the Freedom of Information Act, and I can’t think of any case law that supports that answer either."
Within a reply to a 2007 FOIA federal lawsuit, the FBI indicated that it did not possess any records pertaining to the 9/11 aircraft, containing aircraft component or serial numbers:
Additional FDR information provided by the NTSB within its June 11, 2008 reply, revealing the significance of the apparently unknown part and serial numbers of the FDRs belonging to AA 77 and UA 93, required to generate FDR data readouts:
"Each recorder does have a unique serial number that is assigned by the manufacturer at the time it is made. In addition to the unique serial number there is a part number that associates the unit with a particular family of recorders. Every recorder has a dataplate affixed to the outside of the unit stating the serial number, part number, date of manufacturer, TSO certification, power requirements and weight. The part number will stay the same even though subtle changes may be made during the manufacturing lifecycle of the recorder. The manufacturer may change some components within the unit as long as the functionality and interchangeability of the unit remain the same. This is where the serial number becomes important. If a recorder with the same part number comes in we need to know what parts were used to make it and that is tracked by individual serial numbers of the recorder."
Flight data recorder information provided by the NTSB, for all major U.S. commercial passenger aircraft crashes within U.S. territory, involving major aircraft and/or loss of life, since 1988, with noted FDR serial numbers:
Comair Flight 5191, August 27, 2006, CRJ-100, 49 Dead, Fairchild Model F-1000 FDR, Serial Number: 102368
Chalk's Ocean Airways Flight 101, December 19, 2005, Grumman G-73, 20 Dead (Not equipped with a FDR)
Corporate Airlines Flight 5966, October 19, 2004, HP Jetstream, 13 Dead, Fairchild Model F-1000 FDR, Serial Number: 00511
Pinnacle Airlines Flight 3701, October 14, 2004, CL-600-2B19, 2 Dead, Fairchild Model F-1000 FDR, Serial Model: 01094
US Airways Express Flight 5481, January 8, 2003, Beechcraft 1900, 21 Dead, Fairchild Model F-1000 FDR, Serial Number: 01110
American Airlines Flight 587, November 12, 2001, Airbus 300, 260 Dead, Fairchild Model FA-2100 FDR, Serial Number: 1186
Alaska Airlines Flight 261, January 31, 2000, Boeing MD-83, 88 Dead, Sundstrand Model FDR, Serial Number: 9182
American Airlines Flight 1420, June 1, 1999, McDonnell Douglas MD-82, 11 Dead, L3 Model FA-2100 FDR, Serial Number: 00718
COMAIR Flight 3272, January 9, 1997, Empresa Brasileira de Aeronautica, 29 Dead, Loral Fairchild Model F-1000 FDR, Serial Number: 997
TWA Flight 800, July 17, 1996, Boeing 747, 230 Dead, Sundstrand Model FDR, Serial Number: 10291
Valu Jet Flight 592, May 11, 1996, McDonnell Douglas DC-9, 110 Dead, Loral Fairchild Model F-800 FDR, Serial Number: 6132
Atlantic Southeast Airlines Flight 529, August 21, 1995, EMB-120RT, 8 Dead, Fairchild Digital Model F-800 FDR, Serial Number: 04856
American Eagle Flight 4184, October 31, 1994, ATR 72, 68 Dead, Loral/Fairchild Model F-800 FDR, Serial Number: 4838
US Air Flight 427, September 8, 1994, Boeing 737-300, 133 Dead, Loral/Fairchild Data Systems Model F-1000 FDR, Serial Number: 442
US Air Flight 1016, July 2, 1994, McDonnell Douglas DC-9, 37 Dead, Fairchild S-703 FDR, Serial Number: 00880
US Air Flight 405, March 22, 1992, Fokker F-28, 27 Dead, Fairchild F-800 FDR, Serial Number: 154
Atlantic Southeast Airlines Flight 2311, April 5, 1991, Embraer EMB 120, 23 Dead, (Not equipped with a FDR)
United Airlines Flight 585, March 3, 1991, Boeing 737, 25 Dead, Fairchild Model F-800 FDR, Serial Number: 4016
US Air Flight 1493, February 1, 1991, Boeing 737, 22 Dead, Sundstrand Model FWUS FDR, Serial Number: 692
United Airlines Flight 232, July 19, 1989, McDonnell Douglas DC 10, 111 Dead, Sundstrand Model 573 FDR, Serial Number: 2159
Delta Air Lines Flight 1141, August 31, 1988, Boeing 727, 14 Dead, Lockheed Model 109-D, FDR, Serial Number: 654
The only other instance of undocumented FDR serial numbers following a major U.S. commercial aircraft crash within U.S. territory during this 20 year period, seems to be a little known mishap that oddly, occurred on September 11, 1991, exactly 10 years before the September 11, 2001 terrorist attacks. This report also did not list a FDR manufacturer or model number, possibly because the accident was immediately determined to be the result of negligence on the part of aircraft maintenance personnel.
Continental Express Flight 2574, September 11, 1991, EMB 120, 14 Dead, FDR Manufacturer, Model & Serial Number Not Available.
NTSB Major Airline Crash Reports Of Last 10 Years:
NTSB Major Airline Crash Reports Prior To Past 10 Years:
Notable Crashes Of Commercial Aircraft: