I installed a new Garmin G5 recently. I noticed that when i dialed-in the same altimeter setting on the G5 and on my Dynon D-180, the altitude reported by the two units differs by about 20 ft (when the ALTADJ offset of the D-180 s set to zero). In the Dynon there is simple way to adjust the altitude offset (I assume there is in the G5 as well).
Is there a DIY method for calibrating an altimeter precisely? I would need to know a precise elevation of the aircraft at some position on the ground, plus a precise and current altimeter setting. As for the former, I suppose the best way is to go to an airport that is absolutely flat, and use the published elevation. This would have to be an airport with a METAR and use a fresh altimeter setting just after a METAR is published. BUT - altimeter settings and physical altimeters are based on standard atmosphere... So on a day that is very warm or very cold (non-standard atmosphere), an altimeter set to current local altimeter setting might not read the true elevation (maybe off by tens of feet?). So many variables... is there a DIY way to fairly precisely calibrate our altimeters without specialized (expensive) equipment?
Is there a DIY method for calibrating an altimeter precisely? I would need to know a precise elevation of the aircraft at some position on the ground, plus a precise and current altimeter setting. As for the former, I suppose the best way is to go to an airport that is absolutely flat, and use the published elevation. This would have to be an airport with a METAR and use a fresh altimeter setting just after a METAR is published. BUT - altimeter settings and physical altimeters are based on standard atmosphere... So on a day that is very warm or very cold (non-standard atmosphere), an altimeter set to current local altimeter setting might not read the true elevation (maybe off by tens of feet?). So many variables... is there a DIY way to fairly precisely calibrate our altimeters without specialized (expensive) equipment?
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