Tuesday, March 6, 2007


It was there, it was recovered and successfully transcribed, some had access to the data, and the altitude readings from it, at least, were published. But the initial report was not released in the August batch, even as its Flight 93 counterpart was trumpeted. There are no press releases or news accounts on this FDR study, as far as I’ve seen, but it is, after all, available. The NTSB report, like its Flight 93 counterpart, was titled “Specialists’ Factual Report of Investigation: Digital Flight Data Recorder,” and was completed on January 31 2002, shortly before that other report. Like 93’s “specialist study,’ it noted “an examination of the recovered data indicated that the recorder operated normally.”
[direct NTSB PDF download link]
Flight 77 FDR Research Thread I started @ Above Top Secret,: Great insights, explanations, and fumbling.

Two shots from the Specialist’s Study of the very FDR in its casing and in the lab.

The FDR recovered and received on the 14th was a Loral Fairchild model F2100. It used flash memory, could encode 256 12-bit words per second, and hold at least 25 hours of memory. The report broke down all parameters of the plane, every switch and setting each assigned a code. Recovered data was converted from binary form to engineering units via the NTSB’s Recovery Analysis and Presentation System. Of note is the fact that the report included “only validated parameters.” The others “either were not recorded properly or were not confirmed to have been recorded properly.” [p 2] I’m not sure what these parameters were and what effect it may have on the final readings…

Everything else, including speed, heading, and altitude were charted out on the final flight timeline over sixteen pages. Below is page 26.
right-click, new window, for full-screen, readable view.

Airspeed (near bottom, green) near the end was about 300 knots, or roughly 350 mph, but climbs sharply near the end, corresponding with witness accounts of the pilot “gunning it,” appearing to top out at over 550 mph as it slammed into the building. Altitude (near bottom, black): unlike the animation (which has serious alitude questions), it starts and ends evenly at about zero, showing no sudden changes. The red line that descends steadily is weight: one of the few things a plane does steadily is burn fuel...

Perhaps the most interesting is the magnetic Heading line (dark blue, near bottom). This seems to represent direction, though it’s hard to read for sure. It starts out steady west, then switches in the middle to eastbound, the turnaround after the takeover. At the end it goes haywire, apparently the big near-full circle loop – east-south-west-north-northeast, then impact. As for the flight path this represents, it corresponds with the pilots’ video fairly well, but it’s impossible for me to tell from this whether it was north or south of the Citgo.

The “new” flight path seems possible, but it was heading northeast from southwest by this, as the official story maintains, and so seems at least as likely that it came in on the official path and indeed clipped the light poles and caused the building damage. Call it a hunch, or a bias. If I get anything better than that, it’ll of course warrant an update.

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