The Cockpit Door
Michael Jones discusses the idea that "the Flight Data Recorder indicates that Flight 77's cockpit door was never opened?"
Rob Balsamo of Pilots for 9/11 Truth announced on Nov. 27, 2009:
The announcement doesn't name the "independent researcher and computer programmer", nor provide any link to his research, but in the ensuing forum discussion, it is revealed that it is Warren Stutt. According to Stutt's webpage, he is from New Zealand, although he now resides in Australia. Perhaps Balsamo omitted his name because Stutt has refuted Balsamo's claims in the past with his analysis of the flight data recorder (FDR) data.
The report that accompanies the data from the NTSB, the Specialist's Factual Report of Investigation - Digital Flight Data Recorder, summarizes the data and explains some technical aspects about its format. It lists all of the parameters in the data, and groups them into "Parameters Plotted" and "Parameters Not Working or Unconfirmed", although the report doesn't explain the criteria by which a parameter can be "not working or unconfirmed". The data parameter Balsamo is citing for his evidence, "FLT DECK DOOR", is on the list of "Parameters Not Working or Unconfirmed", which he didn't mention in his announcement.
Initially, the inclusion of the cockpit door parameter on the list "not working or unconfirmed" left room for speculation as to why it was considered "not working or unconfirmed". Although it seems that there is more than one reason for a parameter to be classed as such, in this case the evidence strongly suggests that there simply was no cockpit door sensor:
1. The FDR contained data not only for flight 77, but also for the 11 previous flights. In 41 hours of data, the parameter never changed from '0'. It seems unlikely, although not impossible, that the cockpit door wasn't opened once during any of this time.
2. According to the NTSB's "Specialist's Factual Report", the data frame '757-3B' was used (see p.2, footnote #1) for the FDR. Stutt was given a data frame layout file, 757-3b_1.txt, and accordingly used the data frame layout "757-3" for his analysis. Stutt also obtained a Boeing document via his FOIA request, "Digital Flight Data Acquisition Unit 757 - Databases Interface Control and Requirements", with much more detail about the data formats for FDRs in 757's. This document has a table, "Data Frame Revision History" (10.1.3, p.16), which shows that this data frame format was first "released on" 3/26/99. But the AA77 was a 757-2 built in 1991, and according to the "Data Frame Revision History" table, by that time only data frames 757-1 and 757-2 had been released. This same document lists the details of each of these data frames. Appendices A and B list parameters in the 757-1 and 757-2 data frames, which have no "FLT DECK DOOR" parameter. Appendix C lists parameters in the 757-3 data frame, which does have the "FLT DECK DOOR" parameter (p. C111). Since the FDR was using data frame 757-3, the FDR was newer than the plane, equipped to record the cockpit door parameter when available, but was also backwards compatible so that it could be installed in older models, such as the AA77 plane, which didn't have the cockpit door sensor.
3. The only possibility then for the FDR to have recorded valid data would be if the sensor were installed later. There is no reason to assume that this happened, given that it was not and is not one of the FAA's required parameters. Balsamo hasn't claimed that the sensor was installed later, and so of course hasn't provided any evidence to this effect.
If we had expected valid cockpit door data, Balsamo's claim would've had two potential implications: First, if the FDR was indeed from flight 77, then the account of terrorists getting access to the cockpit seems implausible. Second, if flight 77 didn't even crash into the Pentagon, which Balsamo has alleged on other occasions (and which has been refuted by Stutt's analysis), then the alleged data from flight 77's FDR is forged anyway. Balsamo's claim would've suggested that the people responsible for counterfeiting the data overlooked the cockpit door data, and Balsamo had uncovered their careless mistake. Now that we know not to expect valid data from a cockpit door sensor on AA77, what does this really prove?
It doesn't prove that terrorists entered the cockpit door. And it doesn't prove that all of the data from the FDR is consistent with the commonly accepted account.
It does prove that Rob Balsamo was at best so eager to publicize his discovery that he didn't sufficiently research the data. The NTSB report gave a very clear clue by labelling the cockpit door data "Not Working or Unconfirmed", but Balsamo either overlooked this or ignored it. Perhaps his haste and carelessness could be forgiven. Much worse is that within two days of his announcement, the truth about the cockpit door sensor as presented here had been discovered in internet forums (JREF and abovetopsecret) which Balsamo was participating in, and yet over 3 years later (Jan. 24, 2013), he has yet to retract his "discovery".
Contributed by Michael Jones