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Old 09-12-2017, 03:11 PM
Piper J3's Avatar
Piper J3 Piper J3 is offline
Join Date: Nov 2014
Location: Hinckley, Ohio
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Default General EFIS Question…

I have a Dynon D-180 and I just calibrated the compass. Dynon has you enter Magnetic Inclination and Intensity before setting the four cardinal headings using Magnetic North. I did all that. My question is – if we fly via magnetic headings then why is it necessary for the instrument to have reference to True North? I hope I’m not showing my total ignorance here…
Jim Stricker
Hinckley, Ohio
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N68203
1130 hrs Flying 46 Piper J-3 Cub N6841H
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Old 09-12-2017, 03:19 PM
BobTurner BobTurner is offline
Join Date: Dec 2011
Location: Livermore, CA
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Magnetic inclination has nothing to do with east, west, north, etc. It's the angle up-down of the actual field lines in 3-D (e.g. At the magnetic pole the lines are vertical). Your efis looks at the earth's magnetic field in all 3 dimensions, and uses that data to help provide long term stability.
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Old 09-13-2017, 09:28 PM
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RV7A Flyer RV7A Flyer is offline
Join Date: Jul 2013
Location: US
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Just to add a bit more explanation for the OP...

You're thinking of magnetic DEClination. As noted, the EFIS is asking you for INClination.

Declination is also known as variation.
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