Compass is one of the most complicated instruments to master in the aircraft because it behaves differently depending on many factors: where you are, where you

Compass is one of the most complicated instruments to master in the aircraft because it behaves differently depending on many factors: where you are, where you turn, and are you going up or down: https://en.wikipedia.org/wiki/Aircraft_compass_turns https://en.wikipedia.org/wiki/Aircraft_compass_turns However if you do, then you have a backup instrument that never fails.