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GMU-11?

Depends on what functionality you want. I believe if you want the DG/HSI function the answer is "Needs". It's optional otherwise.
 
Hello,

The G5 does not need a GMU 11 for the standard Attitude Indicator. It is nice to have if you would like to enable the magnetic heading on the AI page.

For the DG/HSI version, a GMU 11 would be required for magnetic heading. Add a GAD13+GTP59 (Temperature Probe to CAN Converter) along with the GMU11 Magnetometer, then you will have the full suite of Magnetic Heading, OAT, TAS, Winds Aloft, and Density Altitude. All very useful pieces of information.

In the event of no GMU 11, the internal GPS receiver of the G5 can display GPS TRK.

BR,

Brad
 
very very nice to have ;)

Dual G5, GNX375, with GAD13 + 29, and GMU11 on my ship: for my taste and wallet, a perfect and affordable combination. Density alt on ground, TAS and wind data when airborne :cool:
 
Uh, no. Do not need heading input to a G5, mostly... especially if the G5 is a backup.

What you really care about (almost all the time) is your course. Heading is used to help you achieve that course, but heading is subject to magnetic errors in the airplane, and winds can add an additional difference between heading and course. If there's no heading source, the G5 will display GPS course -- which is what you really want, and you don't have to keep trying different headings to get your desired course.

With a fast turn rate, GPS course may lag more than a heading source, but that's really a so what. And if you're on vectors, ATC will give headings but unless there is a significant crosswind, the difference between heading and course will not be significant. And ATC will adjust your assigned heading as required if you're flying course. Yes, there are possible legalities here, but operationally, it's like a DG that has drifted significantly.

Adding a GMU11 can be a real pain, especially when you consider running all the wires, etc. If the G5 is your only displayed heading source, yeh, makes sense. Otherwise...
 
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Doug,

I suggest you first figure out what you want the G5 to do. At one end it is a basic airspeed, altitude, AI displaying GPS heading. At the other end it is a back up to your EFIS for IFR doing full HSI duty for both GPS and VOR/LOC/GS inputs.

For the latter, a quick look at the ACS catalog indicates (to me at least) the following list of “must have” stuff:
- G5, $1289
- GMU-11, $275
- GAD 13/GTP59, $470
- GAD 29, $475
Total: $2509

What I don’t know is if the GAD 29 is needed if you have some other ARINC interface.

I also note that at $2509, you are now at a price with other EFIS options.

So, defining the mission would be my suggestion as next step.

Carl
 
My G5 is a backup for my EFIS. It gets its GPS from my 430W via a spare serial port, so I get track instead of heading. I find that to be quite a bit more useful than magnetic heading. No GMU11 for me.
 
One more consideration with a GMU 11 - if the G5 is intended as EFIS backup, and the EFIS is a G3X, you will still get magnetic heading if the G3X fails. But - if you are relying on the G5 (with its battery) as a backup for a total power failure, then you will lose the GMU 11, as it is not powered from the G5 and its battery.
 
We Don't Have a GMU-11. Yet.

1. Minor point...When ATC gives you a heading, they want you to steer that heading, not a ground track. And actually, there's usually so little difference between heading and track, it shouldn't matter.
2. I find that if I'm doing a lot of turns, the G5 loses track of the ground track. I'll briefly get a note on the G5 screen something like "No GPS Signal" and the track on the display will go blank. More of a nuisance than a Big Deal. I 'spect this is because we don't have an external antenna hooked up to the G5 and the internal antenna doesn't always have a good, clear view of the sky.
Upshot of all this, I plan to add a GMU-11 when finances and time allow. Not urgent.
 
On a stand-alone G5 install you will like the GMU 11 and GAD 13 combo with the G5 as it gives wind speed and vectors at your altitude, and the GAD 13 will also provide density altitude and TAS. If you are interfacing with the G3X then those features are provided from the G3X LRUs via the CAN Bus (one of which LRU is the GMU 11). You would only use the GAD 13 for a stand-alone G5 install although it could be left in place if upgrading to a G3X later. The GAD 29 is only needed to interface the G5 to a panel navigator or give heading bug or navigation commands to a third-party autopilot. I did a dual G5 with a GNC 355 talking to an S-Tec 40 autopilot through a GAD 29B in a Comanche this way.
 
1. Minor point...When ATC gives you a heading, they want you to steer that heading, not a ground track. And actually, there's usually so little difference between heading and track, it shouldn't matter.
2. I find that if I'm doing a lot of turns, the G5 loses track of the ground track. I'll briefly get a note on the G5 screen something like "No GPS Signal" and the track on the display will go blank. More of a nuisance than a Big Deal. I 'spect this is because we don't have an external antenna hooked up to the G5 and the internal antenna doesn't always have a good, clear view of the sky.
Upshot of all this, I plan to add a GMU-11 when finances and time allow. Not urgent.

The internal antenna on the G5 appears to rather hit-or-miss relative to a reliable GPS signal. I bought a GA-26C antenna from ebay for $45. I never installed it because I opted for the 430W as a source, but I think I'll soon be selling the 430W for an IFD440 and I may run the G5 on its own.
 
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