by Plurb » Sat Nov 13, 2004 11:12 pm
All US airways, runways, and VOR courses are laid out in reference to magnetic north. The reason is the mag. compass is a basic nav. instrument. Since magnetic north is slightly offset from true north. The amount of variaton differs in different locations around the world.
Magnetic heading is directly read from the compass. To get true north one has to factor in variaton. Magnetic course is the course has one would lay it out on a chart.
For what it's worth unless ATC is reading a TWEB all headings they provide, including wind, are given in magnetic.