I work in a strange place, a basalt volcanic field where the magnetic field can vary significantly over distances of meters. About half of my flights start from the calm desert floor and end uneventfully. Others are from cone ridges where lightning strikes have made quite powerful natural bar magnets and the Mavic cannot be calibrated because of the interference. I move and calibrate somewhere else. All of those flights ended with a hand-catch, the reason for which is obvious from the image. One day, I flew from the inside of a crater, surrounded by basalt walls. Calibration worked, I got my pictures, and did not drop the drone into an explosion pit.