Single GI-275 and G5 stack

[CA182R]

I don't understand the requirements of the GI 275 for replacing the primary airspeed indicator, attitude indicator, and altimeter. Here are two passages from the GI 275 AFMS:

AFMS section 1 - GENERAL:
"The ADI and HSI can be installed as stand-alone primary flight instruments as long as there are other equivalent source(s) of primary flight information that are independently powered."

AFMS section 1.2 - Standby Instruments and the GI 275 ADI:
"Except for installations that are limited to VFR, GI 275 systems require standby attitude, altitude, and airspeed instruments. Several types of standby instruments might be installed, including a standby GI 275 ADI, other ADI, or individual analog instruments."

So... the primary GI 275 requires another set of primary instruments, or standby instruments, or both, or ..?

What I'm really wondering is can I add a GI 275 ADI to my Garmin G5 stack and remove the airspeed indicator, attitude indicator, and altimeter? The G5 documentation indicates that the G5 can be secondary for these instruments. Not sure if "secondary" and "standby" mean the same thing.

And while we're at it, would the GI 275 and G5 sync settings like baro, presumably through the CAN bus?

Perhaps one (expensive) way to achieve this is to use a GI 275 primary ADI + GI 275 standby MFD...

I doubt I'm the first to think about this combination. Any thoughts or information?

 

[GRG55]

Some time back I noticed on the Garmin website the photo on the GI 275 blog page (below) shows the airspeed indicator and altimeter replaced with other instruments. Not sure if that is indicative.

 

[Mtns2Skies]

I'm not sure about the G5 combo, but two GI275 AHRS are legal to eliminate the Altimeter/airspeed/VSI. That being said even my avionics shop said they don't think that's a good idea. But your mileage may vary.

 

[GRG55]

I'm not sure about the G5 combo, but two GI275 AHRS are legal to eliminate the Altimeter/airspeed/VSI. That being said even my avionics shop said they don't think that's a good idea. But your mileage may vary.

I would say if one does eliminate them and loses that lovely color display in IMC, one would be truly screwed.

 

[asicer]

I would say if one does eliminate them and loses that lovely color display in IMC, one would be truly screwed.

I believe that the idea is that the odds of losing both of them at the same time should be at least as low or lower than the odds of losing simultaneously both the vacuum pump and the electrical system.

 

[GRG55]

I believe that the idea is that the odds of losing both of them at the same time should be at least as low or lower than the odds of losing simultaneously both the vacuum pump and the electrical system.

The title of the tread suggests the OP intends to install only one.

 

[asicer]

The title of the tread suggests the OP intends to install only one.

Alongside two G5's... so that's 3 devices that need to fail before you're screwed.

 

[Salty]

I asked the garmin guys during their 275 presentation if they play well with G5’s, and they said no, they don’t play together at all.

 

[CA182R]

I like my G5s but I don't like the things around them as much. I was hoping to kill 3 or 4 birds with one stone, so to speak. But the more I think about it the more I think it would take 2x GI 275s to accomplish this.

I think Garmin should consider the install base of dual G5s that could be tempted into adding a GI 275 to replace the remaining flight instruments, if this was properly supported (at least transfer altimeter setting) and STCd..

 

[WannFly]

Down the road I am sure it’s doable by garmin. As on today it’s not.

 

[Bill]

We are scheduled to go into the shop in January to replace the AI and HSI with two GI 275s. We are keeping the rest of the traditional six pack as is.

 

[Mtns2Skies]

Because I can't resist bragging about how I spent 19 AMU's...

 

[Bill]

Because I can't resist bragging about how I spent 19 AMU's...
View attachment 91415

nice, which Garmin navcoms are those?

 

[Mtns2Skies]

nice, which Garmin navcoms are those?

Radio stack as follows:
Aera 660
GMA342
GNC255
GTR225
GTX327

GDL82
GDL50

None of the above were included in the 19AMU's... that was just for the 275's + misc cleanup.

 

[Bill]

Radio stack as follows:
Aera 660
GMA342
GNC255
GTR225
GTX327

GDL82
GDL50

None of the above were included in the 19AMU's... that was just for the 275's + misc cleanup.

We’re getting two 275s and replacing the King 197 and KNS80 with a 255, and of course the associated cleanup of removing the old slaved HSI, vac system, etc.

 

[GRG55]

Radio stack as follows:
Aera 660
GMA342
GNC255
GTR225
GTX327

GDL82
GDL50

None of the above were included in the 19AMU's... that was just for the 275's + misc cleanup.

What did you do for ADS-B out?

Disregard...missed the '82

 

[asicer]

We’re getting two 275s and replacing the King 197 and KNS80 with a 255, and of course the associated cleanup of removing the old slaved HSI, vac system, etc.

For the around the same $19k?

 

[Bill]

For the around the same $19k?

our local shop quoted us $16k for all of the above. I personally think that quote is BS as all other shops were $20-23k. But, my partners want to go with the low bidder. Will it really be only $16k? Will it all go together properly? Only the shadow knows.

Partnerships, there are pluses and minuses....

 

[WannFly]

Dual 275 out here is about 15k installed, for me at least (no I am not doing it), already have a magnetometer and the OAT stuff in the plane. Don’t have vac system either

 

[NordicDave]

I like this panel from a Cessna 150. Doesn’t get much cleaner than this.

 

[asicer]

our local shop quoted us $16k for all of the above. I personally think that quote is BS as all other shops were $20-23k. But, my partners want to go with the low bidder. Will it really be only $16k? Will it all go together properly? Only the shadow knows.

Partnerships, there are pluses and minuses....

Thanks for the info.

At around $20k installed, one has to wonder how much more it would be to go to a 10" G3x Touch/G5 combo.

 

[Groundpounder]

I was going to replace the ADI in my airplane with a GI-275, paired with a G5 HSI which I already had. I was told that I would still need a separate ADI in that config even though I could swap the G5 from an HSI to and ADI with two button pushes.

 

[Bill]

Thanks for the info.

At around $20k installed, one has to wonder how much more it would be to go to a 10" G3x Touch/G5 combo.

Our problem is we’re keeping the perfectly functional KFC-200 autopilot, and only the GI275 can provide attitude information to the King. Also, do know that the G3x touch is just a dumb display. You still have to buy all of the electronic boxes that are behind the panel to provide data to the G3x.

Going G3x would have nearly doubled the budget of the upgrade.

 

[Ryan F.]

You're dealing with some of the same decisions/thought processes I encountered on my current upgrade path. The GI275 and G5 are in different worlds; they don't talk to each other in any way. What they can do on their own, and what they're certified to do, is different as well.

With two GI275s (which back each other up) it is possible to do away with your legacy instruments, i.e. airspeed, altitude, and heading indicator. Whether this is advisable from a UI standpoint is another matter. In my view they're far too miniscule to rely upon for that purpose; the airspeed and altitude indications are not substantially larger than a 14-point typeface on a piece of paper held out at arm's length. Legible, but hardly ideal flying single pilot IFR bouncing around in light to moderate turbulence. Frankly I'm a little surprised this was considered suitable from a certification perspective, but they got it, so that's that. If I were to install a pair of GI275s I'd leave my legacy steam gauges even though it would not be legally required.

As a result, that sent me back to the G5s while leaving the altitude and airspeed indicators in their normal locations. Much easier to scan/interpret in the same scenario as mentioned previously.

Just to further reinforce the "size" issue, I still have my legacy VSI although the G5 features a very accurate version. It's the same problem -- just too small. I can pick up the tiny G5 VSI in my scan if I concentrate but it's not natural and it fades into the clutter of the background all too easily. My little piston bird is old and I still use FPM for all kinds of things. It'd be great to ditch the VSI as I could really use the panel space for other things but it just doesn't work for me. If I won't ditch optional equipment such as a VSI I'm sure not going to ditch the primaries.

Autopilot is the big consideration for a lot of us. Unfortunately the G5s won't communicate with my old Altimatic III, but the GI275 would. I'm leaving open the possibility of installing a GI275 in the place of my mechanical standby attitude indicator at some point in the future, if it's possible... it's not yet clear if this mix-and-match will be permissible. My avionics tech believes it is possible but not yet legal. I haven't dived into the depth of the legalities surrounding this. For now the shop, mine anyway, won't mix and match the two units in any way.

I agree with Bill re: the G3X. That unit was out of reach in terms of making a responsible financial choice about the panel of my 54 year old airplane. Would be nice, though.

 

[Bill]

As a result, that sent me back to the G5s while leaving the altitude and airspeed indicators in their normal locations. Much easier to scan/interpret in the same scenario as mentioned previously.

Autopilot is the big consideration for a lot of us. Unfortunately the G5s won't communicate with my old Altimatic III, but the GI275 would.

I agree with Bill re: the G3X. That unit was out of reach in terms of making a responsible financial choice about the panel of my 54 year old airplane. Would be nice, though.

Basically the same conclusions. Our KCS55A is dying, it sometimes will not slave to the proper heading, and even unslaved it sometimes does not track with the heading of the plane and match the whiskey compass. No bueno in IMC. So, two 275's for us, and our KNS80 only works about half the time, so out it goes along with the King 197. So this is stage one, we will end up with the two 275's, the 430W as N/C1, and a new 255 as N/C2, and keep using the legacy KFC-200 AP. Stage two in a year or two will be to upgrade the 430W for a 650 or whatever else is out that makes sense. We will then be poised to migrate to the GFC500 if/when the KFC-200 dies.

 

[Mtns2Skies]

I like this panel from a Cessna 150. Doesn’t get much cleaner than this.

View attachment 91420

Panel is probably worth 2x what the airplane is... Is the plane owned by an avionics shop?

 

[Salty]

I like this panel from a Cessna 150. Doesn’t get much cleaner than this.

View attachment 91420

Clean yes, but less usable than steam gauges. Lots of information packed into tiny little screens with half the panel space being totally wasted. Then on the other extreme, putting a 750 into a 150 is completely silly. I guess with an autopilot (making it TAA) you could use this to do all your training through commercial? I don't see it being practical for anything else.

 

[David Megginson]

Right now, if my AI and DG failed and weren't worth repairing, I'd probably go for two GI-275s. In the future, if the AV-30 gets certified as an IFR CDI and adds a lot of other missing features, I'd add it to my shortlist as well. I declined to install a G5 when I had my GTN 650 installed in 2017, because I thought it looked hideously ugly on a panel of round gauges (beauty is in the eye of the beholder, I know).

 

[NordicDave]

Thanks for the info.

At around $20k installed, one has to wonder how much more it would be to go to a 10" G3x Touch/G5 combo.

The question is very sound. It appears the GI-275 Product line makes more sense if the panel strategy is either:

1. Scale into the full capability over time as a pilot can afford it display by display
2. Just needs 1-2 displays without the cost of any panel surgery
3. G3X won't fit

Other than than that, the G3X makes greater economic sense when considering a full panel of GI-275's. Also the benefit of full sized screens for small sized content.

Panel is probably worth 2x what the airplane is... Is the plane owned by an avionics shop?

This was conventional wisdom for a long time. Recent aircraft sales are demonstrating many new buyers want a robust avionics solution. I cited an example in earlier threads of a good friend who sold his Warrior the a market record price with all new avionics; Twin G5's, G5 Engine monitor, new GPS nav/comm, etc.

This particular plane has a used GTN-750 bought due to a GTN0750TXi upgrade, and 3 new GI-275's bought with the recent rebates.

A complete panel upgrade is premiere in many buyers minds. Not only are dramatically new & modernized flight instruments desirable, but knowing 50 year old wiring with who knows how many hacks for prior work just goes away. An all new panel is an important safety and reliability change that must happen sooner than later in the eye's of many buyers.

Most people who can afford an airplane are buying cars for $55K-$100K. Buying a Cessna 150 or Warrior for $60K-$70K is no big deal to many.

 

[CA182R]

I'm surprised by the high install cost of the GI 275. It uses GMU 11, GTP 59, same as G5 except minus the possible surgery to the panel. Maybe the cost is high only when interfacing to non-Garmin avionics. The GI 275 battery also has a pretty high replacement cost compared to the G5. Too early to tell how frequently it needs to be changed.

I'm still thinking the GI 275 can have a place in a G5 panel as MFD/CDI and TC/AI replacement. Could be a way to ease into it...

 

[Jdm]

I have 2 G5’s and 1 GI-275. Very happy with this set up, and they all work very well together. Not getting rid of the the 4 pack though. It’s too handy for backup situations. I’ve already had one dual G5 major malfunction (different airplane) in flight. It was hard IMC when it happened. I was so thankful to have good backups. Resulted in an air turn back using the magnetic compass to join a localizer to get back in. Unfortunately, poor installation by an authorized garmin shop in SC caused the malfunction.

 

[CA182R]

I have 2 G5’s and 1 GI-275. Very happy with this set up, and they all work very well together.

What is the role of the GI 275 in that setup?

 

[David Megginson]

The question is very sound. It appears the GI-275 Product line makes more sense if the panel strategy is either:

1. Scale into the full capability over time as a pilot can afford it display by display
2. Just needs 1-2 displays without the cost of any panel surgery
3. G3X won't fit

Other than than that, the G3X makes greater economic sense when considering a full panel of GI-275's. Also the benefit of full sized screens for small sized content.



This was conventional wisdom for a long time. Recent aircraft sales are demonstrating many new buyers want a robust avionics solution. I cited an example in earlier threads of a good friend who sold his Warrior the a market record price with all new avionics; Twin G5's, G5 Engine monitor, new GPS nav/comm, etc.

This particular plane has a used GTN-750 bought due to a GTN0750TXi upgrade, and 3 new GI-275's bought with the recent rebates.

A complete panel upgrade is premiere in many buyers minds. Not only are dramatically new & modernized flight instruments desirable, but knowing 50 year old wiring with who knows how many hacks for prior work just goes away. An all new panel is an important safety and reliability change that must happen sooner than later in the eye's of many buyers.

Most people who can afford an airplane are buying cars for $55K-$100K. Buying a Cessna 150 or Warrior for $60K-$70K is no big deal to many.

That is a good point. As a thought experiment, try going window shopping for a plane that has a fairly up-to-date avionics panel. They're hard to find, and the buyers can demand fairly high prices. So I agree that some of the old conventional wisdom about avionics upgrades no longer seems to apply.

 

[NordicDave]

That is a good point. As a thought experiment, try going window shopping for a plane that has a fairly up-to-date avionics panel. They're hard to find, and the buyers can demand fairly high prices. So I agree that some of the old conventional wisdom about avionics upgrades no longer seems to apply.

My hangar neighbor considered selling his late 60's 206 that has been in family since 1972. The plane is nice, but no log books other then past 5 years. The plane had a new $11K interior and $125K G500 panel. He had to a steady stream of buyers at $225K. One buyer sent him a cashiers check sight unseen. He returned the check and decided not to sell as his personal situation changed. The premium panel was a key attraction. G500, GTN-750, GNC-255A, STEC 55X fully coupled, PSE-450, Mid-Continent back-up.

 

[Jdm]

What is the role of the GI 275 in that setup?

Provides multiple roles. Primary, I use it as a CDI. It works parallel to the G5’s if desired, or can be used to monitor an entirely different source. It can be coupled to nav 1 (gps, lpv, loc, g/s, vor) or nav 2 source (Loc,ILS,vor, etc). Switchable on screen as desired. It offers CDI, HSI, moving map, route data, terrain, weather, traffic, and backup gps source.
My favorite setup yet!

 

[flyingcheesehead]

Thanks for the info.

At around $20k installed, one has to wonder how much more it would be to go to a 10" G3x Touch/G5 combo.

I would expect that combo to run high 20s/low 30s installed.

I have 2 G5’s and 1 GI-275. Very happy with this set up, and they all work very well together.

Do things like the baro setting, altitude/heading/airspeed bugs, etc transfer between them or do you need to set those things in both places?

What version of the GI 275 do you have, and what is it configured for?

Got pictures? Sounds like a cool setup!

 

[Jdm]

Do things like the baro setting, altitude/heading/airspeed bugs, etc transfer between them or do you need to set those things in both places?

It’s independent. Not slaved to G5’s

What version of the GI 275 do you have, and what is it configured for?

Not sue about the version, but installation was complete around March if that helps. It’s set up as an MFD with page 1 default to CDI as my preference.


I’ll try to send a few pics.

 

[Jdm]

So many configurations. Here’s a few pics of what I have..

 

[Jdm]

Here we are with G5’s coupled to #1 ILS while the 275 is coupled to #2. Much larger and brilliant presentation on the 275.

 

[GRG55]

Panel is probably worth 2x what the airplane is... Is the plane owned by an avionics shop?

It is until the owner writes that big check...

More seriously, I'm guessing it's an IFR trainer now.