Thanks MikeEcho,
Unfortunately that video is now out of date. It refers to height discrepancies between the released FDR file data, in the form of a CSV file, and the observations of the plane hitting the light poles and the Pentagon. It also refers to a discrepancy between the angle of approach of the plane in an animation and the track angle observed in the damage.
It has now been shown that the last frame of data was missing in the CSV file given to the public.
This frame has now been decoded from the raw data file and the Radalt shows the plane descending and hitting the light poles and the Pentagon, exactly as reported by eyewitnesses and as seen in the damage. There is thus no longer any discrepancy about height.
There never was a discepancy in the file regarding direction of approach as the file track angle corresponded with the damage track angle. The discrepancy was between the file data and the animation. It appears that a conversion error was made in construction of the animation. It is interesting that while the animation depicts the plane at the wrong approach angle, the compass shows the plane is at the right angle, strongly suggesting a mathematical error. The NTSB has said the animation was not used in any official procedure.
Unfortunately there are people who insist that the FDR file is not authentic. One of their complaints is that there is no ID of the aircraft in the file. There is of course ID in the file. The trouble is that it seems very hard for the public to confirm that the ID reported is for the right aircraft. Somewhere there must be a file which relates the reported ID numbers to a tail number. How can we find it?