Originally Posted by Genghis the Engineer
And without true track, how do you work out your quadrantal or semicircular rule altitude?
1) On magnetic track, as same as everybody else, since the quadrantal / semicircular rules are based on magnetic tracks
2) For en-route airways, you plan the directions the airways chart or Eurocontol allow. You fly what ATC clears you to. Only outside controlled airspace quadrantals are realy relevant.