Anybody have a G5 with GMU 11?

Lamboflyer

Lamboflyer

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Joined
Mar 21, 2019
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This is a similar question to the Uavionix magnetometer thread: I'm planning the installation of 2 G5s (they've only been in my closet collecting dust for 2 years!), and I'm curious where and how (tray/bracket) anyone has mounted the GMU 11? If you have pics to post, even better! I'm doing the installation on an '02 7GCAA.

TIA
 
That would be great! I'm hoping to make some progress soon, and properly locating the GMU 11 is one of the hurdles.
 
I'd love to hear about your GMU11 location. It's something we're considering in ours as well. At the annual, I was trying to figure a good place and not seeing any obvious place. Thanks!
 
I recently got a Garmin GI275 installed with the GMU11 magnetometer. The avionics shop installed the GMU11 on the left wingtip, within a foot of the Whelen strobe power supply.
side view reduced.webp

The GMU11's performance is excellent. When turning the strobes on or off, there is no discernable difference in the magnetic heading. When turning the Nav lights on and off, sometimes I will see a deviation of one degree (but not always). The shop told me that they tested this fairly extensively as well, and were pleased with results. They, too, found that the Nav lights produced a small amount of interference, but the strobes did not. In their testing the Nav light interference showed up momentarily when they were turned on, then disappeared.

In flight, the GI275 and GMU11 is rock solid. To test, I lined up on both an east/west and then north/south road, then performed humpty dumpties to get the aircraft to rapidly accelerate and decelerate. The magnetic heading remained solidly accurate through all phases of the testing.

Please let me know if you have an questions or would recommend any additional tests.

One more picture, looking down:
from the top reduced.webp
 
Thanks for the pics! I wish my wingtips came off, but that probably means mine will go in the baggage area using the ACA kit. I'll post, if I ever get to the G5s!
 
Lamboflyer said:
Thanks for the pics! I wish my wingtips came off, but that probably means mine will go in the baggage area using the ACA kit. I'll post, if I ever get to the G5s!
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Don’t suppose you have gone down this road yet? I have a GMU-less G5 install and I’m curious how much goes into adding that (and the OAT probe, I miss TAS and winds aloft on long trips).

ACA sells a mounting kit for us wingtip-removal-challenged folks?
 
FlyingScot said:
Don’t suppose you have gone down this road yet? I have a GMU-less G5 install and I’m curious how much goes into adding that (and the OAT probe, I miss TAS and winds aloft on long trips).

ACA sells a mounting kit for us wingtip-removal-challenged folks?
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What did you decide to do, wingtip or baggage compartment? I'm planning on installing a G5 in our SuperD and want to add a GMU11. I don't want to have to cut into fabric. It seems like a wingtip mount or a baggage compartment mount solves that problem.
 
mamontb said:
What did you decide to do, wingtip or baggage compartment? I'm planning on installing a G5 in our SuperD and want to add a GMU11. I don't want to have to cut into fabric. It seems like a wingtip mount or a baggage compartment mount solves that problem.
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It has remained at the bottom of the to-do list, and dealing with JPI on fixing the engine monitor I just installed under warranty has eaten away any enthusiasm I had for more shop time.

I think I'll have no choice but to use the baggage area (or behind the baggage bulkhead) when I do bite the bullet. My ELT is already conspicuously hanging out in the baggage compartment. I'd like some info/drawings on the ACA kit I hear about, but asking them for that info hasn't been productive.
 
Thanks! I'm expecting that we won't be able to fly much in February, so that would be an ideal time to install the G5 and the GMU11. I think that an installation in the baggage compartment (because that's an ACA design and component) will help me if I pursue an AFM change (after more time and many for $) to remove the "-only" from VFR and add IFR.
 
I thought the 7GCAA could go IFR with equipment per the applicable FAR. Can they restrict it with an AFM in spite of the type certificate?

if so, why would they do that? Liability?
 
Bob Turner said:
I thought the 7GCAA could go IFR with equipment per the applicable FAR. Can they restrict it with an AFM in spite of the type certificate?

if so, why would they do that? Liability?
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Life would be simple if I could make the airplane compliant with 91.205, but the "VFR-only" limitation in the AFM probably raises an issue with respect to insurance and liability.
 
I've wondered about that with the wording in the newer manuals for ACA-built models that say "The (insert your model here) is equipped for day and night VFR operation. FAR part 91 establishes the minimum required equipment for these operations. Inoperative equipment or removal of equipment may limit operations. The references to types of operation on the operating limiting placard reflects equipment installed at the time of Airworthiness Certificate issuance."

With no "VFR only" verbiage and the references to the pt 91 equipment list plus the 'reflects equipment installed at the time of issuance' line it certainly seems to my not-a-lawyer brain that a suitably upgraded plane could be legally flown under IFR. Heck the only thing I'm missing is that pesky 23.1323 heated pitot tube requirement.
 
A real interesting subject.

Might also want to check into the ability of the weather service to predict know icing conditions at your given location as well as on your route and that of the location your headed to.

In spite of what folks think they know or experiences they have had with flying in minor icing conditions and predicted icing levels, times have changed. The accuracy of winds aloft, duration, by location are also getting harder to predict. I have been logging the ability of the weather service to predict surface wind events at my local airport. They are off a lot these days and many times the larger wind events are coming up to two to three hours later. When you have several inches of snow on the beaches of the Florida gulf coast and no snow in Alaska it's time to re-evaluate if they can still reliably predict know icing condition data. In spite of what other seasoned light aircraft pilots here in Alaska have communicated to me on flying into know icing conditions, I would say all bets are off. So that pesky 23.1323 actually means something up here, but it is also a license to be stupid when your pitot is heated but your wings have no deice capability. Food for thought and MHO.

Brian
 
Is the 23.1323 requirement applicable to CAR 4a airplanes?

just did a search - part 23 governs certification. That is, if you want to get a type certificate today 23 is your bible. I doubt that ACA has taken the time to re-certificate.

I personally do not think part 23 has anything to do with the 7 series airplanes.
 
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I have a G5 coupled to an 660 and have thought about adding the GMU11 because “everyone” does it, but what’s the value for VFR? You already know actual and desired ground track, and ground speed, why complicate things with magnetic?
 
With this instrument panel and a total lack of forward visibility, Charles Lindbergh navigated from New York to Paris. He missed his landfall in Ireland by nine miles and then located and landed at Le Bourget Field in the dark. Later, he toured 40 states in this aircraft to promote aviation. He also flew non-stop from Washington to Mexico City.

Back before I got spoiled and bought a handheld GPS, I took pride in flying 1000 mile x-countries with only sectional maps and a Rand McNally road atlas. (Flying low and reading town names on water towers was a handy nav-aid.)

"Over and Out" from the Geezer
 

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I was going to add something like that.

I believe some folks just like the extra complexity. Like those fancy engine monitors - a good Lycoming that is flown regularly will make it to TBO if the oil pressure gauge is anywhere near accurate. The rest are nice to have - temperature is required, but if you keep oil in it and have good baffles it will stay in limits all by itself.
 
Nuchatlitz said:
I have a G5 coupled to an 660 and have thought about adding the GMU11 because “everyone” does it, but what’s the value for VFR? You already know actual and desired ground track, and ground speed, why complicate things with magnetic?
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In my case, I am based at a Class C airport and have to call Approach to return. They frequently give vectors and I’d just like to have good instrument that tells me my direction, instead of trying to interpret a bouncing, swinging wet compass. If I’m putting in a G5, might as well have it giving me all the info possible, without precession.

We just bought a 7KCAB and haven’t done any of this yet, but it’s high on the list of upgrades.
 
Well, ok, but I personally never had much problem holding a heading with a whiskey compass in VFR. Unless in high winds aloft, the GPS track is very close to the magnetic heading.

If I had a 150 Citabria, I would be seriously looking at spending my bucks to make it 160 hp. Why ACA made that so difficult is beyond me - what a spectacular engine!
 
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