I have not looked at the IGC file nor US airspace.
However I do use the UK AIP to produce airspace files for my LX5000 and
SeeYou for the UK.

In the UK airspace lateral boundaries are given, primarily in terms of
reference points and
Airway widths. I translate that information into boxes of airspace.

I am aware that in the UK there are at least four potential errors for
airspace boundaries:

1) Out out date airspace files
2) typographical errors
3) issues with converting from points and widths to boxes
4) issues with straight lines - rhumb lines v great circle routes

I don't know how you create your US airspace files.

I have identified a number of UK airspace boundaries where the
discrepancy on the straight edge of an airspace
Boundary with accurately plotted end points can be significant.

I have identified some errors of upto 400m on boundaries measuring only
100km or so.
If you are looking at boundaries with endpoints further apart then the
straight line errors will be larger.

So from what I read, you may wish to debate the niceties of what is a
straight line.

Or preferably, just applaud an excellent flight.

Rory


Subject: IMPORTANT- Seeyou V's Strepla and airspace violations.
Author: Marc Ramsey
Date/Time: 18:20 10 September 2006

The airspace problem is more complicated, we're talking a hundred or so

feet either side of the boundary. Given that there are not two, but
actually three pieces of software involved (SeeYou, Strepla, and
WinPilot), minor calculation errors in any of them could put one on
either side of the boundary. I have no desire to put any energy into
figuring out how the fixes in the IGC file relate to the published
airspace boundary, but perhaps someone else does.