The plots on the map are from radar reports, correct. I forget how many times it revolves in a minute so this could be the reason for the extended plots or the difference in distance between the minutes?
Shutter shot me a call earlier today and we talked about this.
It is a fool's errand to attempt to discern a 5-10 MPH ground speed difference based upon the radar plots on the yellow map.
First off, this is a basic yellow map with penciled radar plots from some dude 48 hours after the fact. To somehow suggest that there is any great degree of accuracy based upon a map that some guy could buy at a Texaco and throw down some plots with a pencil two days after the fact is ludicrous.
Additionally, the larger issue is that the radar in those days would make six rotations a minute--one every 10 seconds. Therefore, there are six radar plots for each one-minute time period.
So, you can see on the yellow map that some of the dots are closer than others. That is not because the pilots were F'ing around and speeding up and slowing down the jet. That is because some of the plots may have been the first plot of six, others may have been the sixth plot of six, still others may have been the third plot of six.
My point being, you cannot, with any degree of accuracy, measure the speed of 305 by simply looking at the penciled plots on a paper map.
