GPS/Compass discrepency

[revporl]

I'm using the flight1 172R. The heading shown by the internal compass is always about 5 degrees left of that shown by the GPS and shift/z. Is setting the compass to the right heading part of pre-flight checklist. If so, what do I use to align it to? I check my "true" heading with shift/z before takeoff and adjust the compass to that but feel I'm cheating in some way...

[lnuss]

I'm using the flight1 172R. The heading shown by the internal compass is always about 5 degrees left of that shown by the GPS and shift/z. Is setting the compass to the right heading part of pre-flight checklist. If so, what do I use to align it to? I check my "true" heading with shift/z before takeoff and adjust the compass to that but feel I'm cheating in some way...

Setting the directional gyro (you can't set a magnetic compass) is always part of the pre-takeoff checklist. Unless you have a slaved DG (not common on light aircraft), it will gradually precess off the correct setting over time, so needs periodic resetting before flight and, periodically, in flight. The simplest way, in FS, to set a DG is by pressing the "D" key. In real life, it is set by comparing it to the magnetic compass and double checked before takeoff against runway heading, using the rotating knob at the bottom of the instrument.

[revporl]

thanks for that. I knew about the "b" key for the altimeter, but not the D key.