Scout Vertical Compass Card Question

Misterskylane182

Misterskylane182

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Jan 2, 2019
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Wondering if anyone who has installed a vertical compass card into thier American Champion Scout and if so are they getting excessive magnetic deviation from internal frame. I am thinking of changing out to the vertical card but looking for anyone's advice
 
Vertical card compass will have the same deviation as any other compass if installed in same location.
Most of it usually can be corrected by deviation screws, just try to avoid placing compass near electric wires and loads like gyros and radios.
 
I've got one that came with my 7ECA, and it seems to be pretty darn decent. I really should do a compass swing sometime, to be sure, but I find that I rarely even look at the compass - other than to initially set (and re-set, and re-set, and re-set...) the DG that is powered by venturis that seem to "come alive" only at about 50 mph...

PS - I do not have the "external balls" that are intended to allow proper calibration when it won't calibrate without them...
 
Once you swing a compass, you will discover why the compass rose does not have a line. The critical part is the deviation card - make sure you have one of those, and use the GPS.
 
Anyone put one in a Decathlon? Do they handle acro okay?

Got misoriented and made a complete ass of myself at an unfamiliar class D airport today. Part of it was poor comms due to being on a handheld, so I missed the instruction for right pattern. However, the bigger problem was I got confused trying to visualize multiple runways and their relationship to my heading. In other aircraft I would use the DG as a visual aid to assist with back headings and the like. Without one in my decathlon, am thinking a vertical card compass might serve the same purpose.
 
How about a cheapo hand held GPS? We have a collection of Garmin 295/296/496 older units mounted in the airplanes, making compassi almost obsolete. All have an HSI mode with horizontal flight director.
 
Bob Turner said:
How about a cheapo hand held GPS? We have a collection of Garmin 295/296/496 older units mounted in the airplanes, making compassi almost obsolete. All have an HSI mode with horizontal flight director.
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That's a good idea. I can run the HSI mode as a secondary window on my iPad.
 
I have one in my 7KCAB and I wasn't sure until after it was compensated it whether it would work well with all the tubing. However compensation was straight forward with errors less than 5 degrees on all the cardinal headings. In the event you have issues with compass compensation PAI sells a set of balancing balls that mount on the compass to adjust out the larger errors, and then fine tune it with the adjustments on the compass.

Being able to visualize traffic patterns was one of the reasons I opted for the vertical card format. The other is that it's much more stable in turbulence than a wet compass.

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Big Ed said:
Does the vertical card compass hold up well to acro?
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It hasn't broken yet.

It'll stick until I'm within 20-25 degrees or so of wings level, and then catch up quickly with no overshoot.

That also means it isn't particularly good at tracking your heading while you are in a turn if it is much more than a standard rate turn.
 
Bob Turner said:
I want your airport.
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I like it too. It's convenient and I like grass strips. There are about 50 grass strips within 50 miles of the field, most of them private but open to people using them. There are a few in the 2500'-3000' range, but most are about 1200' so, many with threes or power lines at each end. That makes the home field here pretty decadent.

On the other hand with 1800', soil that gets very soft when wet, 80' trees at each end, summer temps in the 90s, I'm still glad I got a 150 hp Citabria rather than a 115 hp Citabria when I have a passenger and close to full fuel. Departing to the east the trees are cut back about 1200' from the threshold with a county road and some houses in between so that's not a problem. To the west the trees are cut back about 400' and at an angle to the runway, so departures in that direction are more interesting for the J-3s and Champs on the field in the summer if they have two people on board. And of course, I wouldn't be getting out of some of the shorter strips with trees on each end without the extra power, at least in the summer.
 
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Ok, so thinking I probably do want to switch to vertical card compass. Aircraft is in the avionics shop now for a new radio. Should I go ahead and have them install a new compass? Or will I take it in the shorts on labor? Is that something I can do myself with an A&P sign off?
 
Big Ed said:
Ok, so thinking I probably do want to switch to vertical card compass. Aircraft is in the avionics shop now for a new radio. Should I go ahead and have them install a new compass? Or will I take it in the shorts on labor? Is that something I can do myself with an A&P sign off?
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I'd get a quote from them first The compass must be swung and here are a few different methods to do that, but the compass has to be swung by an A&P or instrument shop with the appropriate ratings, and it requires a log book entry.

This advisory circular covers pretty much all of it:

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_43-215.pdf

Personally, I think pretty stupid to require an A&P as it's not hard to swing a compass. It has also gotten much easier with GPS units that display a magnetic heading. The net effect of this requirement that keeps compass swinging out of the realm of owner maintenance is a large number of compasses that have not been swung in decades. AC 43.13-1B lists several instances when a compass swing must be performed. These include:

- Whenever the accuracy of the compass is suspected
- After a cockpit modification or major replacement involving ferrous metal
- Whenever a compass has been subjected to a shock; for example, after a hard landing or turbulence
- After aircraft has passed through a severe electrical storm
- After a lightning strike
- Whenever a change is made to the electrical system
- Whenever a change of cargo is likely to affect the compass
- After an aircraft has been parked on one heading for more than a year
- When flux valves are replaced.

Honestly, when was the last time you swung a compass after flight in turbulence or a hard landing?
The FAA lists all the things that should prompt a compass swing, but there is no calendar requirement to swing a compass, so it frankly never gets done.

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I have confirmed the calibration of my compass using a large open area on our grass airport, my GPS and Flight Plan Go on my iPad. It's pretty straight forward:
1) taxi north for however long it takes you to get 0 degrees on the GPS magnetic heading display while tracking straight;
2) stop and adjust the N-S screw on the compass to align the compass on 0 degrees;
3) taxi south for however long it takes you to get 180 degrees on the GPS magnetic heading display while tracking straight;
4) stop and adjust the N-S screw on the compass to remove 1/2 the error between what the compass reads and 180 degrees;
5) taxi west for however long it takes you to get 00 degrees on the GPS magnetic heading display while tracking straight;
6) stop and adjust the E-W screw on the compass to align the compass on 90 degrees;
7) taxi north for however long it takes you to get 270 degrees on the GPS magnetic heading display while tracking straight; and then
8) stop and adjust the E-W screw on the compass to remove 1/2 the error between what the compass reads and 180 degrees.

You can then taxi on each cardinal heading using the GPS and read the indicted compass heading to determine the compass error.

At some point I hope the FAA evolves this into owner maintenance given the ease at which it can be done. Until then, if you can get an A&P to sign off on it, that would be the way to go.
 
BB57 said:
I'd get a quote from them first The compass must be swung and here are a few different methods to do that, but the compass has to be swung by an A&P or instrument shop with the appropriate ratings, and it requires a log book entry.


At some point I hope the FAA evolves this into owner maintenance given the ease at which it can be done. Until then, if you can get an A&P to sign off on it, that would be the way to go.
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Good info, thanks. I just got a ballpark quote of $700. A TSO compass costs around $350 on AC Spruce, so that is approx 2.5 hours of labor. Does that sound reasonable? I could save on labor by doing it with my A&P friend, but he is a busy guy so nailing him down might prove difficult. Am inclined to go ahead and get it done while in the shop. Thoughts?

I wonder if the FAA will revisit the requirement at some point, much as they did for slip balls. GPS navigators and EFIS with built-in magnetometers make the compass triple redundant and obsolete. Redundancy is never a bad thing, but triple redundancy may be pushing it a bit.
 
I swung my compass once prior to GPS. What a colossal waste of time! Aligning the aircraft is not really easy, and once aligned the tail hss to be raised and the engine has to be running. You do that a minimum of 16 times. 2 1/2 hours seems about right, and still it is a joke.
Piper had an accurate turntable, and I suspect it was 15 minutes by relatively unskilled technicians.
BB is correct; GPS makes this really easy. I have done it airborne - two pilots, one with a brass screwdriver. Still takes a half hour, but a lot more accurate.
But again with GPS, the compass has become useless except in emergencies. That's why in modern jet aircraft it is stowed out of sight.
 
If the compass is obsolete, then kind of dumb for me to be spending 700 bucks on a new one. I'll save that money for an electronic DG/HSI when such things become more readily available on the used market. The only reason I really wanted it was to help visualize multiple runways relative to my flight path. As Bob suggested earlier, I can do that on my iPad. Thanks, I think this discussion saved me some dough.
 
Big Ed said:
If the compass is obsolete, then kind of dumb for me to be spending 700 bucks on a new one. I'll save that money for an electronic DG/HSI when such things become more readily available on the used market. The only reason I really wanted it was to help visualize multiple runways relative to my flight path. As Bob suggested earlier, I can do that on my iPad. Thanks, I think this discussion saved me some dough.
Click to expand...

I wouldn't go so far as to call a compass obsolete. On my first flight in my 7KCAB bringing it home from about 3 hours away, the external GPS antenna broke on my Stratux (I've replaced it with an antenna with a USB connection) and the airplane indicating my position froze on the map display, as did airspeed, altitude, heading etc. While my iPad will happily display my route taken from home to hangar using it's internal display and then connect to the Stratux and its external antenna, it won't default back to the internal antenna if the external antenna fails.

This left me with the electronic map and a back up sectional, but also left me with a wet compass that was actually dry and basically useless for indicating a course anymore refined than about +/- 30 degrees. I'd planned to replace it but that first trip moved it to the top of my punch list.

Now, with a vertical card compass and a moving map display and heading information on my iPad I'll take off and steer the expected course from point A to point B, using the compass, then cross check it on the iPad to ensure the aircraft indicator is tracking on the course line (or toward it, etc as appropriate) on the iPad. If needed, I'll adjust the course accordingly and then hold the heading using the compass.

In other words, the compass is still my primary source of heading information in my turn and slip only equipped 7KCAB. It doesn't rely on batteries and there's basically nothing to break or fail.

I also plan to get an AV-30 or G5 at some point as part of an overall panel overhaul, but the vertical card compass will still be above that panel. If the power fails, I still want a heading instrument.
 
Well sure, but since I already have a functioning compass, I don't think it is a good investment to spend $700 bucks on a better compass. Also, I have 3 different sources of GPS.
 
Big Ed said:
Well sure, but since I already have a functioning compass, I don't think it is a good investment to spend $700 bucks on a better compass. Also, I have 3 different sources of GPS.
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It functions, but the vertical card compass functions so much better. For example the wife and I took a cross country flight a couple days ago in moderate turbulence and it was still totally usable. To me, it was totally worth it. Then again my total investment was about $250 for a used PAI 700 and a hard to define labor cost based on an A&P sign off from a semi-retired A&P that only charges $50 per hour.
 
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