Ron Lee wrote:

"Marco Leon" mmleon(at)yahoo.com wrote:


So how far off an airway is an aircraft when they are following a GPS flight
plan with every intersection and VOR? Is there an article or study somewhere
that includes metrics to back it up? For example, "a non-WAAS GPS-derived
line direct btween two intersection xx miles away will differ from the
airway between those same two intersections by x.x statute miles." How do
the error allowances play into this?



Since unaugmented GPS (not using WAAS) is accurate to 10 meters or so
(plus/minus) and an airway is plus/minus four MILES (or is is two?)
the navigation source (GPS) is not a major error source.

Ron Lee

VOR airway's primary is plus/minues 4 to 51 miles, where it expands at
4.5 degrees. The secondary is an additional 2 miles, which expands at
6.7 degrees at 51 miles.