In article , Roy Smith wrote:
You've got to go pretty big distances before GC errors start to become
significant. For example, to go from 38N/77W to 38N/122W (roughly
Washington, DC to San Francisco, CA), the rhumbline is 270 and the GC is
284. 14 degrees on a coast to coast trip.

The error will be less still on an aviation chart, which is a Lambert
Conformal Conic projection rather than Mercator. Over the distances of a
typical sectional chart, the difference between a GC and a line on the
chart is irrelevant.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"