Magnetic compass way off

[rainman 195]

The Airpath Compass on my 1979 231 was leaking fluid. So my local shop got a repair kit and replaced the gaskets and fluid. I can’t recall how accurate it was before, but as soon as I got it reinstalled I noticed a problem. When he placed the compass back in the plane it was 30 degrees off when facing north, and the adjustment screw would not compensate for it. The compass is relatively accurate outside the plane(when not installed). My portable compass also showed the same deviation when placed in position inside the plane. Moving the compass around the interior showed significant compass swings near the center windscreen mounting post and other places near the front seat side window frames. My local guy tried to degauss the metal windscreen frame post where the compass mounts. No help. My safety frame appears to be magnetized? I have a G500 and two 430 Ws in my panel. What am I to do? I called Dugosh and my two local avionics shops, Pippen-York and Crystal Avionics, and no one can help. I live near San Antonio. Can I install a G5 and get rid on this compass? Thanks, Ray

[N201MKTurbo 5,646]

You need to find where it is magnetized and degauss it. It may not be the post, BTW the post isn't steel. 

I think there is a Mooney service bulletin about the procedure.

https://cdn2.hubspot.net/hubfs/4147179/technical_documents/service_bulletins/sbm20-150a.pdf

 

[testwest 167]

We had this issue. The center post is non magnetic stainless steel, but our compass mounting bracket was regular carbon steel and highly magnetized! Replaced it with an aluminum bracket and non magnetic fasteners and the problem was solved.

[carusoam 12,446]

Seeing if @rainman is coming by...

Norman (above) has outlined an interesting detail that may cause mg compasses to have challenges...

Best regards,

-a-

[testwest 167]

How magnetic? This magnetic:

 

 

[OR75 227]

what is for sure is that you cannot install a G5 and get rid of the whiskey compass

I would find it surprising that the post would have become magnetized all of a sudden after the repaired compass was reinstalled

my suggestions would be:

1) make sure you don't have something like an iphone/ipad near the compass

2) see if you can borrow a compass known to work and test it (short of buying a new one)    

[Raptor05121 1,997]

I thought I made a post on here about it, but I had the same issue and had to degauss my plane. Here is my post from the Mooney Pilots Facebook group

 

Edited November 30, 2020 by Raptor05121