Garmin G5 or Overhual AI Indicator (artificial horizon)?

[corn_flake]

My AI Indicator has been acting up lately.  First at altitude and now even at below 10k feet.  Thoughts on overhual the gauge or upgrade to Garmin G5?  By the way, I have no intention of removing the vacuums pump.  I like my wing leveler as poor man's auto pilot.  .   I think overhual should cost around $400.  I think a new Garmin G5 is around 2.5k plus install.  

[BrianWilkins]

It all depends on your wallet. Personally, I would not install a G5. While the G5 is nice, I would personally either just overhaul your AI or spend the extra money and get a GI275 because you get a ton of extra functionality with the 275 that you don't get with the G5.

[EricJ]

A G5 is a very good instrument and a good addition if you have a GPS navigator.     My G5 HSI was installed not long after my DG failed, and later after several AI failures I punted and put in a second G5 to replace the AI.   I highly recommend them.

I've flown with GI-275s as well, and while they certainly have their place, I think the display space on the G5 is used much more efficiently and is more readable than the 275.    I'd suggest getting a good look at both before making a decision. 

 

[Vance Harral]

I have specific experience with this.  We did exactly what you're proposing, about 4 years ago: installed a single G5 configured as an ADI to replace our failing vacuum AI.  We retained our vacuum system to drive the vacuum DG and the Brittain autopilot.

The ADI installation is relatively simple compared to an HSI installation, and any A&P can likely do it competently.  All you need is the G5 itself, a connector kit, and pneumatic couplings for the pitot/static lines (collectively the cost of all this is a bit more than the G5 unit by itself, but not much).  No integration with nav radios is required, though you do have to either connect to the RS-232 GPS output from a GPS, or connect an external antenna to the GPS receiver in the G5 itself.  Any competent shop will have done a bunch of G5 installations, and should be able to give you reliable quotes for various options with reasonable labor charges.  Make sure any quotes you get include the connector kits, so as not to be surprised by a small-but-non-zero additional charges over what you might see vs. online advertised prices for the G5 unit alone.

One thing to be aware of is that if you have a standard 6-pack panel with the DG directly below the AI, and you do not pay extra for the equipment and labor to flush mount the G5 ADI, the outer bezel of the G5 unit may impinge on your view of the very top of the DG.  The very top of the DG is of course the most important part, so that's a concern.  I didn't think this would be a big deal, but it did moderately annoy me for a year or so until we bit the bullet and installed a second G5 as an HSI.  Whether you'll have this problem depends on the particulars of your panel, seat position, and height.  You should make yourself a little mock-up of the outer bezel of the G5 to see how things would look in your airplane.

I disagree that a GI-275 is a no-brainer preference over the G5, though it's a complicated decision.  I've flown both, and yes, for about $2K more the GI-275 has more features, a higher resolution display, and it won't have the non-flush-mount problem I discuss above with the G5.  It's a wonderful instrument.  But it's also a physically smaller instrument, despite its higher display resolution.  So if you really take advantage of all the extra EFIS features (synthetic vision, airspeed and altitude tapes, VSI indications, GPS track, flight path marker, slip/skid indicator), you wind up with a very busy display on a very small screen.  This would have been fine with me in my 20s and 30s when my eyes were great.  Now that I require optical assistance, I prefer simpler and larger displays, and to some degree a GI-275 ADI feels more like a win in the bragging rights department than it does in actual utility.  The display can be simplified by disabling features, but then you of course wind up asking yourself why you paid more for them in the first place.   So... it's a big cost/benefit personal preference issue, and you shouldn't choose something on the basis of pictures on the internet or what others argue here.  Make the effort to go see some actual installations in actual airplanes, ideally in a Mooney similar to yours.

Finally, consider how likely you are to install a second electronic gizmo when your vacuum DG/HSI eventually fails.  HSI installations are complicated by interfaces to magnetometers, radios, and autopilots, and the GI-275 has some advantages in that department due to native interfaces it supports, which require an extra converter box (GAD29) in a G5 installation.  Those advantages mitigate some of the additional cost of the GI-275 unit itself vs. a G5.  Hard to say how much without a specific quote, so you might want to get quotes on dual ADI/HSI installations even if you intend to retain your vacuum-powered DG/HSI for now, just to understand the future cost implications.

[corn_flake]

I appreciate the responses!

How about uAvionix AV-30-C?  It seems to do just about the same as G5 at a lower price point.  

[Vance Harral]

21 minutes ago, corn_flake said:

How about uAvionix AV-30-C? 

The physical size of the display in the AV-30 is even smaller than that of the GI-275 due to the bezel knobs and buttons, and it has a lower resolution.  That makes it a non-starter for me in an IFR aircraft, but again, this has more to do with the quality of my eyeballs than anything else.

The AV-30 backup battery is advertised at 2 hours typical.  That's considerably less than a G5, but comparable to a GI-275, and most people agree that 2 hours is plenty of backup time.

My opinion of the AV-30 is negatively skewed by the teething problems uAvionix had bringing the product to market, but those seem to now be solved, and as of 2025 lots of people seem to be happy with it.  Do note that if you eventually install a second AV-30 as a DG/HSI, it's critical to pay extra for the Av-mag external magnetometer even though it's "optional".  Without the magentometer, precession of the instrument is worse than a mechanical DG, arguably unusable in IMC.

Overall, I'd be perfectly happy to fly behind an AV-30 in an aircraft intended primarily for VFR.  But I wouldn't put one in an airplane I really intended to fly in the clouds, except as a backup to something else.  Just my $0.02 of course.

[Andy95W]

1 hour ago, corn_flake said:

I appreciate the responses!

How about uAvionix AV-30-C?  It seems to do just about the same as G5 at a lower price point.  

It’s probably a fine instrument. But if you ever decide to install a Garmin HSI (either G5 or 275) you’re going to wish you’d gone all Garmin. They end up talking to each other and backing each other up.

The AV-30 HSI doesn’t have glideslope capability, which is a shame, because otherwise it’s probably a nice unit. 

[rbmaze]

I love my G5s. When I started instrument training a couple years ago I routinely flew in aircraft both with and without them. I quickly decided I would not purchase a plane with a steam AI or DG if I was ever going to fly IFR, even in VMC.

For the AI, my favorite feature may be the digital barometric-pressure setting. I always adjust my digital first followed by analog. When I get updates on pressure it is so easy to know if I'm at the correct setting.

I also use the altitude bug all the time which is a great feature.

Having v-speeds visualized is another useful thing to have.

This month I am installing a GAD13 and temp probe to display OAT and TAS on my AI, in addition to winds aloft on my HSI. I haven't used a GI 275 and it could be a case of not knowing what I am missing, but I am very satisfied with the G5.

By the way I also have a vacuum pump to run my PC system.

[Bartman]

I have an Aidyne 440 driving a King HSI and a nice audio panel and that’s about it. My Century IIb requires the vacuum AI so even if I added the G5 in that position I would have to keep the vacuum, but I have never found a justification to get a new autopilot. 

If my Century IIb augmented by the STEC Alt 30 for altitude hold ever dies, it will be the start of a whole new panel.

[Vance Harral]

2 hours ago, Andy95W said:

The AV-30 HSI doesn’t have glideslope capability

It's my understanding this is no long true, with the release of the AV-HSI converter unit.  See https://aviationconsumer.com/avionics/uavionix-av-30-efis-glideslope-arinc-ap/

This is part of the teething pains I talked about.  I think uAvionix felt like they had to get "something" out on the market ASAP a few years back to stay relevant in the face of competition from Garmin and Aspen.  But the original AV-30 implementation lacked features, and had issues like excessive DG drift.  I feel like uAvionics essentially sold beta units to customers, then fixed the issues and missing features later, but I guess I don't begrudge them that strategy too much - it's used a lot in the tech industry.  Anyway, that's all history now.  Seems like most of that stuff has been addressed, and is arguably not relevant to potential new customers.

[Matthew P]

buy for the future, get the GI-275 as an ADI, then down the road the GI-275 for the HSI/backup ADIm get rid of all of your vacume system, and if you ever get the GFC-500 you won't be wishing you would have bought the GI-275s..

[McMooney]

Get the G5, it really is that much better.  Gi275 if you're feeling spicy.

I replaced my ai after it decided to ping pong around while in a cloud, i NEVER want that experience again.

 

 i chose the G5s as i figured i'd eventually go g3x but after flying with them for the last year,  I think i'm good,

Only feature i feel i still want / need is synthetic vision.

 

[IvanP]

I prefer G5 to GI-275. The latter is too crowded in my opinion. While the unit has good functionality, the display seems to be too small for the amount of data it is showing. Maybe it can be decluttered in config. I flew couple of planes with dual GI275 but did not like it much. 

My old plane had dual G5s and S-Tec autopilot and I miss them dearly. My current bird has King HSI/AI/AP combo and I am stuck with it for foreseeable future as I cannot justify the cost of new autopilot, etc., just for kicks and giggles. Unfortunately, G-5 will not drive KFC 150 AP. Overhauling vacuum instruments can be expensive proposition. Do not know what AI do you have, but MidContiinent quoted me $4,500 for overhaul of KI 256 gyro. Aerolab did it for about $1,600 or so.     

[donkaye, MCFI]

One thing I particularly like about the G5 is its ability to display Density Altitude when on the Ground.  It also has a 4 hour battery instead of the 1 hour battery of the GI 275.  To display the DA a Gad 13 and OAT probe is required.

[PeteMc]

I'll toss my vote in for the GI-275 if the budget will allow.  Much better instrument in my opinion.

You may also look at what the G5 options are down the road (auto pilot, etc.) and what the GI275 is capable of.  When you consider the wiring, etc. will the G5 lock you into limitations that you'll end up spending much more down the road replacing it (even if there is some resale value) and then having to rewire for the GI275.

 

[ProtoFly]

I had the uAvionix AV-30C's in my Cherokee.  Install was easy - no need for a Garmin dealer.  Added the AV-MAG, which completely resolved any issues with the DG drift.  Single serial input from the GPS gave a very nice magenta line.  The AV-30 has a higher resolution than the G5's (which I have in my M20F), and you can easily customize the display from a very basic DG or AI, or, add other bits of information.  Now that they have the Auto-pilot and HSI functionality, it's a complete solution.

If my Mooney hadn't already had a G5 installed as an HSI, I'd have absolutely gone with the AV-30's again.  Displays were very nice, and having flown behind the AV-30, G5, and GI-275, my order of preference for aesthetics is:  AV-30, G5, GI-275.  

My G5's are OK, but really should be 'flush mounted', as they look horrible sticking up from the panel.  The GI-275 and AV-30's have that all over the G5 - you get to keep the 'steam gauge look'.

Also for consideration is the Aspen E5.  It's upgradeable, but you would probably want to have a secondary AI, since the Aspen is a single unit.

[Pinecone]

If you were to go Aspen, you need a two panel system to get rid of the secondary AI.

When I purchased my plane it had an Aspen 1000 Pro (not MAX, one panel with AI and HSI) and a G-5 as secondary AI.   I almost went to a upgraded Aspen 2000 Pro MAX as they had some aggressive Oshkosh deals for trade in.

The Aspen was nice and I was fine with it.  The synthetic vision was not really useful with the small screen, but the same with the G-5 or GI-275.

The GPSS steering worked great with the KAP-150 that was in the plane.

I decided to bite the bullet and do the full on G3X based panel, keeping the G-5 as the backup.  I prefer the straight up and down tapes and the longer battery life.

[M20F]

Go G5, as others have said the 275 is too small and too cluttered. 

[midlifeflyer]

One other thing in favor of the G5 I’m not sure was mentioned, is its simplicity. From what I’m seeing with various pilots, the learning curve transitioning from analog is significantly smaller than with more complex glass. 

[natdm]

Is it possible that Garmin is releasing something new at Oshkosh that you may want to wait for?

[DCarlton]

On 6/16/2025 at 12:56 PM, corn_flake said:

I appreciate the responses!

How about uAvionix AV-30-C?  It seems to do just about the same as G5 at a lower price point.  

I went with the AV30 about a year ago in my F.  I’m keeping my vacuum system.  I just added an external magnetometer.  It fits easy in the panel.  I’m satisfied.  

[DCarlton]

On 6/16/2025 at 10:58 PM, donkaye, MCFI said:

One thing I particularly like about the G5 is its ability to display Density Altitude when on the Ground.  

The AV30 does too.   I have DA configured on my “takeoff screen”.  

[Jakes Simmons]

I’ll throw a quick 0.02 cents in. I LOVE my ver. 2 AV30…as a standby AI. I tried 2 of them as primary instruments and in cross country IMC conditions the representations were a little too course. E5 now as primary. However UAvionix as a company is fantastic. Every dealing I had with them was excellent as well as general support. They pack a lot in those little units at a fair price point, and even my early AV30’s never failed…the E5 has red screened on me twice,  both IMC. AV30 got me down. Support from Aspen has been solid but I’m always leery of the single E5.

[natdm]

What else do you have on your dash? If you have more Garmin, a GI275 allows wireless database updates (and other features), since it has Connext.

I've had a G5 and a 275 in the plane and both are nice. The G5 is 10 years old (almost) and the 275 is half that. My mechanic actually sold and shipped me a G5 when my AI died and I was out of town, which I had installed. Then when he got the plane to work on it for other squawks, noticed the JPI secondary EIS was hooked up incorrectly and had to redo or remove it. He pitched selling the G5 and getting a 275 AI and EIS, and I love both. 

The 275 does make you look ever so slightly harder to see the same information that the G5 shows since it shows more, but it also has a better screen with more pixels. Other than spending the money to install the G5 then installing the 275 a few months after (ouch), I don't regret it.

[Will.iam]

I wonder if you put a magnifying glass mounted over the 275 that would allow you to see all the detail but in a much bigger size if that wouldn’t be worth the effort to try. Build a little slot bracket around the bottom of the gi275 and you just slide the glass dome in place making it removable / temporary so you don’t have to deal with stc and only if you went inverted could the glass fall out. Something like this: