The flight went well, it was the first time I've flown in this location, and the first time I've flown near mountains. I was in a canyon so the satellites were down to 9. Once I landed after a full flight, it was after I had powered it down that I realized I forgot to calibrate the compass. I was being super careful in preparation for this flight and it's something I totally forgot to do. I was under the impression that this should be done every time I'm flying in a new place. So this begs the question, if the flight went good and everything appeared normal, what is the real purpose for compass calibration?