Compass Deviation Card

[Rod Callison]

I have a 1999 M20R. It has a semi-circle compass-deviation card under the mag compass. My A/P just re-calibrated the compass after an avionics upgrade, and tacked a square white paper tag on the compass that looks really kludgy. Are semi-circle metal cards still available?

[RLCarter]

Print one

[carusoam]

Welcome aboard Rod!

Do you have a favorite MSC?

The compass card is supplied by the compass manufacturer...

Expect airpath to be the brand name...

The right model number will reveal the proper deviation card...

like this one.... or similar to this one...

https://www.airpathcompass.com/J30/index.php/catalog/commercial/c-2400-l4vm-12-b-detail

 

Other short cuts... you might try Dan at Lasar... or you might contact Airpath directly to see where to buy it...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Rod Callison]

Thank you!  Favorite MSC is Don Maxwell.  You've given me 3 sources to try, and I'm sure I'll get this solved.

[jaylw314]

Out of curiosity, I asked the Google lady and couldn't find anything.  Aircraft Spruce sells a paper card holder that is marginally better than a sticker.  Obviously, finding a deviation plate from a salvage yard won't help, and buying a new compass would be silly (I also wonder if Airpath only sells new ones with that paper card holder instead of the deviation plate now).

Probably the easiest thing to do would be to print out the deviation card on a label shaped like the deviation plate, trim it to size and apply it to the metal plate.  You could print the card with white text on a black background to make it look better.  If it doesn't stick well or if your plate is in bad shape, it wouldn't be too hard to fabricate a new one out of aluminum sheet.

[Immelman]

It could be a rainy day computer project to recreate the card in the correct dimensions in a word processor or power point.

 

[Rod Callison]

Thanks for the suggestions everyone!  Airpath had trouble matching my 22-year-old compass.  Plan B: scanned the deviation card, used photo-editing to change deviation numbers to current values, printed it on label paper, cut out the semi-circular deviations, and stuck it on the original aluminum deviation card.  Good as new.

[Yetti]

I would do something silly like cutting a thin piece of alum and then using number punches to make a mark

[carusoam]

Great follow-up Rod!

Let us know when you actually use it...   

Best regards,

-a-

[N201MKTurbo]

On 12/23/2020 at 4:03 PM, Rod Callison said:

I have a 1999 M20R. It has a semi-circle compass-deviation card under the mag compass. My A/P just re-calibrated the compass after an avionics upgrade, and tacked a square white paper tag on the compass that looks really kludgy. Are semi-circle metal cards still available?

Read the help files for Word....

[Hank]

I took a picture of mine, measured it, then fired up Excel and typed the numbers. Put lines  around / between them to match, then copied it into several places. Make each one a different font size and print the sheet. Take it to the plane, see which one fits best, cut it out and "laminate" both sides with clear packing tape and go for it!

[1964-M20E]

I know it is required to have it in the plane.  However, how many people have actually used the compass deviation card ever even during PPL training? 

I can't recall ever using it.

I have rarely used the magnetic deviation lines on sectionals since here in New Orleans it is only 1 degree W at the current time.  A couple of years ago it was 0 and when I got may PPL it was only 2 maybe 3 E.

[Hank]

3 minutes ago, 1964-M20E said:

I have rarely used the magnetic deviation lines on sectionals since here in New Orleans it is only 1 degree W at the current time.  A couple of years ago it was 0 and when I got may PPL it was only 2 maybe 3 E.

I used to use the little dotted purple lines all the time. The change from WV to WY was signficant, too. But I just checked--they don't appear on my EFB! So I went to Airnav, checked a secional there, no mag deviation lines. Checked the airport writeup, no mention there, either, just gives the actual magnetic heading of the runway.

What are they teaching these days???

[MikeOH]

It's 12 degrees here in southern California...that's a 12 mile error over 60 miles travelled!  Better take that into account

Back in my PPL days (1978) pre-GPS and out of range of a VOR, you'd best take a four degree compass error into account, as well.

[carusoam]

Our runway number changed once... From 27 to 28.

Probably happens every century or so...

Best regards,

-a-