Compass Calibration

[BlueCH750]

Is it possible to do a ground calibration of the the compass on other than cardinal headings of North South East and West. In other word, does the process allow for entering a known magnetic heading; i.e. known runway mag alignment

Thanks!

 

[dynonsupport]

It is not. However, we display ground track from the GPS so you can do it this way if you can find a place you can taxi.

A runway isn't a good idea anyway as you'd need to know the heading to the degree, and they are often full of rebar. Plus, you have to go at least 4 directions, so sitting sideways on the runway would be kind of odd

 

[CGameProgrammer]

Airports generally have a compass rose on the ground somewhere so that makes it easy. And what Dynon was describing is the fact that runway numbers are only rounded to the nearest 10 degrees; the runway isn't necessarily exactly at that heading.

 

[mrdaud]

I would point out, a lot of small GA airports do not have a compass rose.   The magnetic values change over time and I've been told by several FBO's it is not economical for them to maintain a CR.  What I have done, as well as many others, is to use a good quality hand-held compass and temporarily attach it so it is accurately aligned with the centerline of the aircraft.  In my case, I attached it to the wing.  Then rotate the plane through cardinal headings.  As Dynon states, try to perform the calibration in an area with minimal metal interference.  I know of at least a dozen or so other aircraft that have used the hand-held compass method, and it provides very good ground calibration and is simple to use.  One caveat, all calibrations I know about were performed on composition airplanes.  One may have to verify the accuracy of the hand-held in a before-and-after attachment to the plane if used on a metal fuselage.

 

[BlueCH750]

Thanks all, my Phase I test area does not include any airports with a compass rose. There are many grass strips, with some listed in the AF/D with accompanying surveyed runway mag data. That is/was my plan anyway. Easy enough to align down the runway and crossways if I had the option to input known values that differed from N,S E and W. Guess I could lay out a pattern with a compass or smartphone (?) on a seldom used strip and go at it from there. :

 

[swatson999]

Thanks all,  my Phase I test area does not include any airports with a compass rose.  There are many grass strips, with some listed in the AF/D with accompanying surveyed runway mag data.  That is/was my plan anyway.  Easy enough to align down the runway and crossways if I had the option to input known values that differed from N,S E and W. Guess I could lay out a pattern with a compass or smartphone (?) on a seldom used strip and go at it from there.  :

Or you could just ignore it until finishing Phase I , then go find an airport with a rose and do it then.

You have Dynon equipment, so IIRC, you can "swing" it in flight, no? Even if the results would be better by first doing it on the ground, should be close enough for whatever sort of needs you have during Phase I for a mag compass indication...

 

[Raymo]

I did the calibration during the first flight in the air. Worked fine.

 

[dynonsupport]

It does sound like the in-air would be best in this situation. Actually, it's best in almost all situations.

 

[BlueCH750]

OK, thanks all for the discussion, much appreciated! We'll see how it goes...