AV-30-C vs regular vacuum DG

MRC01 said:
My local shop finally had an open time slot and installed the magnetometer for me. They said it took 25 hours of labor?! That seems high to me. What do you all think? When I pick it up tomorrow I plan to ask them why it took so much labor.
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Seems excessive to me also. However, if they were unfamiliar with the AV-30, the first time would involve figuring things out. They would have to fabricate a new harness for the AV-30, as well as a firmware update harness. Everything is multiple conductor shielded cable, which can be time consuming to work with. Downloading and installing the firmware utility and flashing it is another task. Takes 15 minutes, but could easily consume half a day to figure out what to do the first time.

Actually installing the magnetometer itself is easy. Find a spot, fish the cable, attach male and female mini molex connectors, fabricate a bracket, mount and connect.

The bracket shouldn't take more than an hour max. Just cut a rectangular piece of aluminum, bend the end to a right angle tab, drill 4 holes, and mount with machine screws.
 
Yeah, seems high to me too.

That said, airplanes can bring some unexpected drama. Stripped screws, things liked that. Removing the vacuum system is also not too hard but things like fishing out the old vacuum lines and removing the old gauge is time too.

If it was the shops first time, there is a learning curve. Shops I've delt with will share some of that time if asked (respectfully)

I think I'd ask just for some explanation.
 
jbarrass said:
That said, airplanes can bring some unexpected drama. Stripped screws, things liked that. Removing the vacuum system is also not too hard but things like fishing out the old vacuum lines and removing the old gauge is time too..
I think I'd ask just for some explanation.
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This was only to add the magnetometer to an existing AV-30C installation! And they said they had done one before, estimated 1 day of work.
Yes, I will ask them why more than 3 times the normal amount of labor.
 
I picked up the plane this morning. The verdict is they didn't run into any problems, they just work methodically and slow and "do it the right way, the first time". They say they've done these before and they always take about 24 hours of labor, even when the airplane is clean with no issues (as mine was). And when they estimated it at "1 day" they meant 24 hours not 8 hours. I paid them for their work but I'm never going back. That's my lesson and reminder to get the estimate in writing like I always have done before - even when it is just a "one day" job.
 
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Did you have one AV-30 or two?

If you have two, the magnetometer can be connected so that both units receive the input. However, that would also mean double the harness fabrication, and more monkeying around under the panel. If the rear of the instruments is difficult to access, that could be slow and aggravating. Also, were either of the units connecting to GPS or OAT?

I still think 25 hours is quite a lot. I installed mine and it wasn't anywhere near that. But I have easy access to the back of the AV-30, and it was a single unit with no GPS input.
 
This is the firmware update harness. It's not complicated, but if they didn't have one, it might take a few hours to read through the documentation and make it. Then each AV-30 would be disconnected, the update harness inserted between the main harness and the instrument, and firmware flashed from a laptop.

PXL_20240204_192713736.jpgIMG_20240206_195125.jpgPXL_20240204_192654308.jpg

Oh yeah, I forgot about calibration. That is procedurally the same as swinging a compass card. Point the aircraft in each of 8 directions, start it, read the indication, then enter the correction. That's another hour or two.

Point being, unless the original installer wired the harness up for the magnetometer and for updates, there's a lot more to it than just installing the magnetometer. D-subs can be time consuming, especially with shielded cable.
 
Ed Haywood said:
Did you have one AV-30 or two?

If you have two, the magnetometer can be connected so that both units receive the input. However, that would also mean double the harness fabrication, and more monkeying around under the panel. If the rear of the instruments is difficult to access, that could be slow and aggravating. Also, were either of the units connecting to GPS or OAT?

I still think 25 hours is quite a lot. I installed mine and it wasn't anywhere near that. But I have easy access to the back of the AV-30, and it was a single unit with no GPS input.
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I have two AV-30Cs with the vac system entirely removed. The OAT was already installed and connected to the upper AV-30 in AI mode. There is no GPS. The work they did was to install the magnetometer and connect it to the lower AV-30 in DG mode.

They did spend time finding the best spot in the airplane free of EMI, mounting it with proper physical alignment, properly routing & tieing down cables, etc. But even so, 25 hours is a lot.
 
I installed an AV30E in my experimental. Power, ground, two OAT wires and a serial wire from the GPS (pitot & static of course). No magetometer as of yet so, for now, I'll use GPS guidance along with the wet compass hanging above it. Still tweaking and playing with the unit but so far it seems to be really cool ...
 
Daleandee said:
I installed an AV30E in my experimental. Power, ground, two OAT wires and a serial wire from the GPS (pitot & static of course). No magetometer as of yet so, for now, I'll use GPS guidance along with the wet compass hanging above it. Still tweaking and playing with the unit but so far it seems to be really cool ...
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People have varying experiences with how well the AV-30C works in DG/HI mode without the magnetometer. Mine was barely as good as an old mechanical DG, it would drift on average 5* every 10 minutes. It could drift better or worse depending on turbulence, temperature and maneuvering.

Overall I'm happy with the AV-30C, great to eliminate the vacuum system and mechanical gyros. I've had them for just over 2 years now. But this is a VFR airplane with no panel GPS. Those who want an IFR system with panel GPS would be better off spending a few extra bucks for Garmin.
 
I think it's important to know which SW/FW version is on the AV-30 when trying to compare its performance. I have 2. OAT connected to the AI, GPS, Magnetometer and WiFi adapter to both. It's an amazing unit. I think earlier versions of FW weren't as robust. The AV-30 website calls it SW but it seems more like FW to me, but clearly I am incorrect as it's their product. Current version is 2.5.0 prior to the upgrade they were 1.0.8. I didn't fly with 1.0.8 so I'm not sure the differences but from what I've read I think there were a lot of stability improvements including DG precession.
 
szwinger said:
... I didn't fly with 1.0.8 so I'm not sure the differences but from what I've read I think there were a lot of stability improvements including DG precession.
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That's true, the AV-30C DG started out unusably bad in early firmware versions and gradually got a little better in later versions. Mine has recent 2.X firmware, with the internal hardware magnetometer (which I don't use). When I reported the lackluster performance of the DG to uAvionics, drifting about 5* every 10 minutes, they said this was "normal".
 
True. Back when I installed mine the magnetometer wasn't available. A couple of years ago when I was speaking with uAvionix about how to improve performance of the DG without the magnetometer, they gave me the impression that they gave up on trying to improve it with software updates (such as Kalman filtering) and instead they doubled down on getting the magnetometer certified.

The basic message is, if the DG works well enough in your installation without the magnetometer, then you're lucky, be happy. Otherwise, don't waste time trying to improve it, but just install the magnetometer.
 
25 hours seems like a lot for installing the mag. I'm thinking I did the AV-30, tailBeaconX, AV-Mag, and OAT in not much more than 25 hours.
 
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