Hi all, Bit of a silly question I guess but I need to find out (before I make a massive dent in something expensive). Once the compass has been successfully calibrated before flight could it go out of calibration during a flight if you got too close to something with loads of steel such as a ship or large steel reinforced concrete structure. Also if taking off from a concrete structure which contains a lot of steel I would guess the compass would not be calibrated. Would it sort itself out once airborne and away from the structure? Any help appreciated.