Vertical Compass

[netconn]

Has anyone gotten a vertical compass to work right in your Maule?? If so, how?? I have one on the middle of my glare shield that is so far off it's useless. I tried another from my C-120, that works fine in my C-120, and it's no better in the Maule than the first one.

[Kirk]

Curious to hear about this also. Considering a panel mount location if/when the panel upgrade happens. The factory original old style Airpath mounted on the glareshield is working fine.

I just think the panel mount would be a more meaningful and useful backup to an electronic flight display.

Kirk

[JEM1968]

The PAI vertical card compass seems to work well.

[Andy Young]

Most likely the problem is stray magnetic fields from the various electric components in the panel. That might be why many (most?) Maules came with the compass mounted on top of the glare shield. I moved mine to the panel many years ago because having it on top of the glare shield was a serious impediment to safe landings at short, rough off-field spots. It doesn’t work properly in the panel, but I have honestly never had the slightest sense that I needed it for anything. The only reason it’s still in the airplane at all is to satisfy the legal requirement.

So this an honest question, and not meant to be at all snarky. What use do you folks find for a mechanical compass? What is its purpose in this modern age, when we have much more accurate and reliable direction information on our phones, never mind the sophisticated electronics (or even the simplest GPS) in or on the panel?

For reference, I’m not someone who only flies a stripped-down, VFR-only backcountry plane. My plane is IFR-legal, and I am an ATP who flies IFR at work. Though I don’t often use the IFR capabilities in my Maule, I have on occasion, and I do fly it plenty in marginal weather.

[Kirk]

So this an honest question, and not meant to be at all snarky. What use do you folks find for a mechanical compass? What is its purpose in this modern age, when we have much more accurate and reliable direction information on our phones, never mind the sophisticated electronics (or even the simplest GPS) in or on the panel?

Don’t mean to distract from the O.P.’s original question but since you asked… and hope this is helpful. I am IFR equipped and fly a fair amount of IFR, especially over east TN/KY.

Present configuration is KLN-94 GPS approach certified, VOR/ILS and non-slaved Directional Gyro. For that, the old glareshield mount whiskey compass is used to set the DG and reset as needed every 20 minutes or so.

Planned configuration is slaved DG incorporated in EFIS, probably Garmin 7” G3X. For that, I agree that it is there because it’s required and it does get an occasional glance to check all the magic is still working. I would consider putting a PAI vertical compass on the panel to make the backup instruments more useful. (Horizon and CDI). Having it on the periphery of the instrument scan helps orientation to heading change or turn rate. Also, it will just look a little more cool with the panel but not sure that will justify it to the spousal accounting audit.

I’ve seen installs of the PAI working great on the glareshield. I also think it’s way too big up there. I have seen in panel installs, just have not heard how hard it was to get it to function in a Maule panel or how well it performs.

[andy]

All that chrome-moly steel tubing in Maules is ferrous material subject to magnetic fields. Cessnas use non-magnetic riveted aluminum semi-monocoque construction for the most part. The vertical card compass has more internal mechanical mechanism than the liquid filled horizontal compass so friction, mechanical loss, temperature expansion and contraction can affect its accuracy. Installing any compass in the panel exposes it to numerous nearby magnetic influences. In my opinion a vertical card compass mounted on the glare shield obscures too much of the view so I've stuck with my ancient liquid filled Airpath. As far as usefulness, I agree that it's not too useful unless there's a total electrical failure. Even then I have the 4-hour backup battery in my Garmin G5 HSI and independent electronic compasses in my iPad Mini 5 and iPhone 12 Pro Max which run Foreflight. That gives me several hours to get down on the ground safely.

The G5 has an electronic compass in the wing tip so I never need to worry about syncing a DG with the compass.

[Kirk]

Andy,

Does the G5 still display heading while on standby power in total loss of electrical or does the magnetometer require power?

I understand about the steel tubing in the panel area. That’s why I’m asking for any experience in making it work well there. Or for that matter, will it work well mounted next to a G3 display with all its electrons running around?

Kirk

[JEM1968]

"What use do you folks find for a mechanical compass? "
Reasonable question Andy. For myself, none. It is there for one reason. The AI/DG remain on GPS TRK.

[netconn]

Legally a working compass and compass card are required for an annual.

[Andy Young]

Legally a working compass and compass card are required for an annual.

Yes, that is the one and only purpose I have found for it. It’s an anachronism.

[andy]

Kirk, I did some research on the G5 and it looks like the magnetometer isn't powered by the G5's backup battery based on posts in pilotsofamerica, beechtalk and reddit. So I wouldn't be able to use it for navigation in a total electrical failure. That's not a major issue for me because I have an iPad Mini 5 and iPhone 12 Pro Max that have their own electronic compasses and GPS with Foreflight installed. However, it highlights that need for the old compass in that situation since the iPad and iPhone aren't legal ways of navigating under IFR. Of course, if I had a total electrical failure under IFR, I would declare an emergency and use Foreflight to land at the nearest VFR airport.

[netconn]

Out of curiosity I tried a whiskey compass in the Maule. It's just as bad as the vertical card, it will shift as much as 60 degrees the closer to the glare shield posts I move it. Maybe my Maule is more magnetized than others. I would think every Maule was delivered with a working compass. (Maybe).

[Kirk]

Andy,

Thanks for checking. That would have made a nice all in one standby with the G5 or GI-275. All the portable stuff will certainly help with a complete loss of electrical. The required IFR standby of turn coordinator or A/I and compass is most certainly a bare bone’s minimum. Agreed that it’s just a bad day or night out if it comes down to that.

My installed whiskey compass on the glareshield works as well as any compass I’ve seen in GA airplanes. I did notice that the shop that did the restoration before I bought it degaussed the forward fuselage tubing. I was pleased to see that attention to detail.

Kirk

[Andy Young]

Out of curiosity I tried a whiskey compass in the Maule. It's just as bad as the vertical card, it will shift as much as 60 degrees the closer to the glare shield posts I move it. Maybe my Maule is more magnetized than others. I would think every Maule was delivered with a working compass. (Maybe).

Sounds like you might need to degauss your airframe if you want a working compass. I had to do that once on a PA-12, on which the compass always pointed south. At the time (more than 20 years ago) I was able to find a place that rented the degausser, and sent it in the mail. The rental price was minimal, and I just had to mail it back when I was done. It’s quite a process on an assembled plane though; you’d have to take everything electronic out of your panel first.

[gbarrier]

Bought one several years ago. As I remember the price was quite reasonable. Either Amazon or Ebay.