"Steven P. McNicoll" wrote in message

A straight north-south line is a great circle on all the common chart
projections.



Correct. Those are the two [possibly rare] exceptions to my post -- if you
happen to be flying a course of true north or south anywhere, or a course of
true east or west on the equator, then your course will layout as a straight
line and will be a great circle on any chart projection. I probably should
have mentioned it, lest someone get lost and run out of fuel.