One of the pieces of evidence to surface when Larry Carr opened up the case to amatuer slueths was the notorious “FBI Map” that Carr believed was the flight path, as recorded by the military using the SAGE radar system at McChord AFB. Nothing else was really known about the map, it was not labeled and came with no notations. It had a solid grease pen mark running through tiny “x’s” along Victor 23, and time markings.
Analysis of the map done by Sluggo and Robert Nicholson showed the map had a lot of problems. The distance between some of the markings is too short to represent the distance 305 would have traveled in one minute of flying time (about three miles). There appears to be a “missing minute” as well, though this can’t be verified since the map’s lack of notation make it difficult to interpret. The grease pen mark connecting the hashes creates an angular and unnatural-looking flight path that “doesn’t look right” in the words of my father, a former airline pilot.
However, remove the grease mark and you have something very similar to what the radar operators at McChord were looking at:
(Screenshot of SAGE Radar Display from Motherboard)
It looks like someone tried to mark the map with the same “x” marks seen on their radar display. This means the map was almost certainly created by someone either looking at such a screen, or a photograph of the screen (we know from former SAGE operators that they would photograph their screens to keep a record if something of interest happened). Further, it appears more than one person handled the map and attempted to mark the flight path. (There are red and black markings underneath the grease pen.) The position of the aircraft at 8:11 matches the grid later given to search crews. In the forty-five years since the hijacking, no other map or information about the flight path has surfaced.
Since the map was marked by hand, without precise measurements and without GPS, it is going to have errors on it. I see the hash marks as a general guideline, a probability field approximating where flight 305 was at the times recorded on the map. These timestamps are themselves rough estimates, since the radar would have given a return several times per minute. So the margin of error on the timestamps will be plus-or-minus a minute.
Looking at the map, the plane appears to move along the center of the Victor 23 corridor, with some variance caused by the fact the co-pilot was flying the plane without the aid of the auto-pilot. As the plane nears PDX, it drifts off the centerline of Victor 23, only to do a fairly major correction to get back on course just before it passed over the Columbia River.
A recreation of flight 305 needs to be done in a proper flight simulator to smooth out some of the map’s rough edges. This will help align the timestamps to the flight path and confirm where the plane really was during the important 8:11 to 8:15 time period. Regardless, the map is the best evidence we have for figuring out where Cooper jumped and solving some of the mystery surrounding this case.