Henry M.Y.
Second Officer
Flight distance : 11548839 ft
Hong Kong
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Compass calibration should only be done when needed. That is to say, after you've done it perfectly for the first time at your region you should rarely need to calibrate it again. The earth's magnetic field flux should be uniform locally in terms of flux direction and dip and if you are prompted to do a compass calibration you should first ask yourself whether or not there exists ferrous material nearly that fooled the compass. Try moving around to see if compass readings are good again. Steel reinforcement in concrete pavement, underground steel pipes, power lines and etc cannot be easily seen but they do affect the compass.
Not back to your question, since earth's magnetic field flux should be uniform locally in terms of flux and dip, as Richard said either method will work equally well.
Henry |
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