GI275 Installation Questions

[MisfitSELF]

Reference Original configuration 1984 M20J with KI 256 Attitude, KI525, and KAP150 autopilot.  I'm installing two GI275's to replace my ADI and HSI and getting a 750Txi to replace my GNS-80 RNAV and my KNX or whatever radio.

First:  Does anybody have an electronic copy of the installation manual?  Specifically the:  GI 275 Part 23 AML STC Installation Manual (P/N 190-02246-10)?  I wanted to double check some of the installation assumptions my avionics shop is making.

Baring not getting the install manual myself...

Second:  I'm getting two GI275's to replace my ADI and HSI.  Which power buses are the preferred solutions?  I think I'd want the ADI on the master switch and the HSI on the radio switch.  Analogous to how it is with the "steam gage" installation where the heading gyro isn't powered until the radio switch is on.  The shop currently has this the other way around (ADI on Radio switch, HSI on Master)

Third:  They (my avionics shop) has the magnetometer going through the ADI, not the HSI.  Given the block diagram of my old school set up, this seems weird.  However, the tech doing the job assures me that Garmin told him specifically to do it this way.  But this would seem all the more reason to have the ADI on the Master Switch -- if for instance I have to shut off the radio switch due to a failure, then I'd still get heading information into my ADI without needing the back up battery.  They both have backup batteries, so there is that redundancy.

I can find the maintenance manual but I wanted to double check the installation assumptions made by my avionics shop.  They are fairly new at installing these on aircraft.  I think I'm their second customer.  Of course, before everybody jumps on my case, they have the installation manual as a Garmin dealer and have been working directly with Garmin for some of these questions, but there's only so much clarity you can get through a phone.  It would be good to put my finger directly on the recommended way this should go as the guy is paying for it and has to live with it.

Bruce J. Wilder

[PT20J]

I’ve found Garmin tech support very knowledgeable and helpful.

Skip

[Andy95W]

Bruce- for your third question, don't worry about it.  It's CAN bus architecture. Every component talks TO every other component THRU every other component. Seems weird, but it works.

[carusoam]

Best description of CANbus ever, Andy!

Best regards,

-a-

[RobertGary1]

I don’t think it’s legal for the attitude to be on the avionics bus. Mine is attitude on master and HSI on the avionics master. 
 

-Robert 

[carusoam]

Is the device rated to handle the voltage atrocities of engine start-up?

As many engine monitors are now...

-a-

[59Moonster]

My dual G5’s are setup to the master. Looks like the 275’s would be as well, otherwise you won’t have the backup capability (I think). 
 

from Garmin: 

DUAL ADVANTAGES 

With dual GI 275 displays³ as your primary flight instrumentation, reversionary backup capability retains attitude and heading data⁴ on the remaining HSI or MFD if an outage should occur.

[Ragsf15e]

3 hours ago, 59Moonster said:

My dual G5’s are setup to the master. Looks like the 275’s would be as well, otherwise you won’t have the backup capability (I think). 
 

from Garmin: 

DUAL ADVANTAGES 

With dual GI 275 displays³ as your primary flight instrumentation, reversionary backup capability retains attitude and heading data⁴ on the remaining HSI or MFD if an outage should occur.

Seems these are wired “iaw installation manual” in all sort of ways. My G5s are wired with ADI on master and HSI on avionics bus.  They do backup each other just fine.  If the ADI dies, the HSI becomes an ADI.  If the avionics bus loses power, the HSI goes on battery, but it’s still backing up the primary ADI that still has power on the master.

[carusoam]

Keep in mind, also...

How Mooney avionics busses are wired... with their fail safe mechanism...

Even when their relays fail (get de-powered), they fail on...   

It only seems magical...

Best regards,

-a-

[jetdriven]

I have the manual, send me an email I’ll give it to you. The GI75 do not use canbus for inter-device communication, they use HDSB, which is like ethernet, but without the RJ45 plugs on it. 
I have installed one of these already.. You want the GMU11 heading sensor  going to the ADI, and then you want the ADI on the master switch, that way if you gang bar the airplane you still have independent heading through the attitude all the ADI, but it comes on and aligns  while you’re starting..

[flyboy0681]

Question about a G-275 install. I put some feelers out to local shops and wrote to them that I want to add a GI 275 ADI with the A/P interface. Additionally, I stated that I wanted to get rid of the existing AI along with the vacuum pump. The response from one shop was that in in order to get rid of the vacuum driven instrument and pump, two G 275's would need to be installed, one for the AI, the other functioning as a backup and would be installed and configured as an HSI.  They said this is what the STC requires.

Is this correct?

 

 

 

 

[RobertGary1]

1 hour ago, flyboy0681 said:

Question about a G-275 install. I put some feelers out to local shops and wrote to them that I want to add a GI 275 ADI with the A/P interface. Additionally, I stated that I wanted to get rid of the existing AI along with the vacuum pump. The response from one shop was that in in order to get rid of the vacuum driven instrument and pump, two G 275's would need to be installed, one for the AI, the other functioning as a backup and would be installed and configured as an HSI.  They said this is what the STC requires.

Is this correct?

 

 

 

 

Sounds right. Not sure why you want to get rid of the vacuum unless his broken. I have two gi-275 and the vacuum attitude. When did anyone cry because they had too many indications of life saving attitude. 
 

 -Robert 

[flyboy0681]

32 minutes ago, RobertGary1 said:

Sounds right. Not sure why you want to get rid of the vacuum unless his broken. I have two gi-275 and the vacuum attitude. When did anyone cry because they had too many indications of life saving attitude. 
 

 -Robert 

Several reasons. The existing KI-256 has had issues in the past and required a couple of overhauls. In addition, we are having a new panel cut and the 256 does not fit in the standard 3" hole, which means once it eventually comes out there will be a gaping hole. And of course it would be nice to shed the pump.

[Ragsf15e]

2 hours ago, flyboy0681 said:

Question about a G-275 install. I put some feelers out to local shops and wrote to them that I want to add a GI 275 ADI with the A/P interface. Additionally, I stated that I wanted to get rid of the existing AI along with the vacuum pump. The response from one shop was that in in order to get rid of the vacuum driven instrument and pump, two G 275's would need to be installed, one for the AI, the other functioning as a backup and would be installed and configured as an HSI.  They said this is what the STC requires.

Is this correct?

 

 

 

 

I would definitely be skeptical of that answer.  The G5 can replace an ADI without doing 2.  The thinking is that it’s way more reliable than the vacuum instrument already and you have to keep the backup “partial panel” instruments so you do have a legitimate backup.  Maybe the GI275 required 2 of them since you can get rid of the other instruments?

Personally, I wanted 2 G5s before pulling my vacuum, but I’m with you, the vacuum and it’s ADI were not kept in the airplane once I had a good, redundant electronic system.

[carusoam]

For ADDITIONAL interesting insight installing Garmin GI275s...

A couple of MSers have posted some informative videos...

I’m not adept at YouTube enough to copy the link...

I put in the key words garmin gi 275 mooney, and look who I found there...   Austin, ChrisK Koppel, and Rmag videos...

Best regards,

-a-

[MaggieL]

In a Garmin GI-275 webinar I specifically asked if you could replace  vacuum AI with one GI-275 and was told "yes, as long as you keep your TC" 

I'd love to get my hands on the GI-275 install manual...haven't seen a leak of it yet. 

[carusoam]

Welcome aboard Maggie!

Unfortunately, The Garmin company likes to keep some documents close to the vest...

I have an AI and a TC...  if I replaced one with the GI275 wouldn’t I have to keep the other?

Keeping a TC for back-up is silly financial logic... worn TCs fail in bumpy weather, it is much better to have two AIs....

But....

I know a few guys around here that have some close contact with that afore mentioned vest...  

If you can add some additional detail about your question... this would help me shake the right MS tree...

Best regards,

-a-

 

[N201MKTurbo]

9 hours ago, MaggieL said:

In a Garmin GI-275 webinar I specifically asked if you could replace  vacuum AI with one GI-275 and was told "yes, as long as you keep your TC" 

I'd love to get my hands on the GI-275 install manual...haven't seen a leak of it yet. 

I have the install manual. Not sure if Garmin would get mad if I posted it, or mad at the dealer I got it from. I can look up specific things if you like.

[flyboy0681]

15 hours ago, MaggieL said:

In a Garmin GI-275 webinar I specifically asked if you could replace  vacuum AI with one GI-275 and was told "yes, as long as you keep your TC" 

I'd love to get my hands on the GI-275 install manual...haven't seen a leak of it yet. 

I got rid of the pump with one -275 and kept the TC.

[N201MKTurbo]

So this is on the first page of the install manual.

I don't want to PO the Big G.

© 2020
Garmin Ltd. or its subsidiaries
All Rights Reserved
Except as expressly provided herein, no part of this manual may be reproduced, copied,
transmitted, disseminated, downloaded or stored in any storage medium, for any purpose without
the express prior written consent of Garmin. Garmin hereby grants permission to download a single
copy of this manual and of any revision to this manual onto a hard drive or other electronic storage
medium to be viewed and to print one copy of this manual or of any revision hereto, provided that
such electronic or printed copy of this manual or revision must contain the complete text of this
copyright notice and provided further that any unauthorized commercial distribution of this manual
or any revision hereto is strictly prohibited.
Garmin International, Inc.
1200 E. 151st Street
Olathe, KS 66062 USA
Garmin (Europe) Ltd.
Liberty House, Hounsdown Business Park
Southampton, Hampshire SO40 9LR U.K.
Garmin aviation support and warranty information is available at garmin.com/aviationwarranty.

Edited December 19, 2020 by N201MKTurbo

[Hank]

2 minutes ago, N201MKTurbo said:

So this is on the first page of the install manual.

I don't want to PO the Big G.

© 2020
Garmin Ltd. or its subsidiaries
All Rights Reserved
Except as expressly provided herein, no part of this manual may be reproduced, copied,
transmitted, disseminated, downloaded or stored in any storage medium, for any purpose without
the express prior written consent of Garmin. Garmin hereby grants permission to download a single
copy of this manual and of any revision to this manual onto a hard drive or other electronic storage
medium to be viewed and to print one copy of this manual or of any revision hereto, provided that
such electronic or printed copy of this manual or revision must contain the complete text of this
copyright notice and provided further that any unauthorized commercial distribution of this manual
or any revision hereto is strictly prohibited.
Garmin International, Inc.
1200 E. 151st Street
Olathe, KS 66062 USA
Garmin (Europe) Ltd.
Liberty House, Hounsdown Business Park
Southampton, Hampshire SO40 9LR U.K.
Garmin aviation support and warranty information is available at garmin.com/aviationwarranty.

Are you making commercial distribution? Argument could be made that non-commercial distribution here (i.e., no compensation in return) could be a sales aid for Big G . . . . Because it let's prospective purchasers see what it will and won't interface with, and what other requirements are.

[N201MKTurbo]

1 minute ago, Hank said:

Are you making commercial distribution? Argument could be made that non-commercial distribution here (i.e., no compensation in return) could be a sales aid for Big G . . . . Because it let's prospective purchasers see what it will and won't interface with, and what other requirements are.

If you can get written permission from Garmin, I'll upload it.

[MaggieL]

On 12/19/2020 at 6:22 AM, N201MKTurbo said:

I have the install manual. Not sure if Garmin would get mad if I posted it, or mad at the dealer I got it from. I can look up specific things if you like.

Presumably they restrict the distribution to make sure only their dealers can do installations.

I maintain a library of avionics documentation for equipment our flying club either has installed or might install, and the install manuals are useful reading for background, and in planning future upgrades. I'm guessing somebody will leak it online eventually (that's how I got the ones I have now); I don't have specific questions and understand your desire not to piss off Garmin or get your dealer in trouble. 

[Vance Harral]

For those of you who recently installed or plan to install GI-275s, what specific features or differences led you to prefer that unit over the less expensive G5?  Our mechanical AI is going south, we'll be replacing with an electronic ADI, and we're considering both options.  I've read the marketing blurbs, I think I understand the differences (form factor, touch screen, interface capabilities, etc.) and I can see why the GI-275 has more "value".  But between the price difference of the hardware itself, and the considerably more expensive installation quotes we're getting, I'm having a hard time feeling the additional features are worth the premium cost vs. the G5, especially after having seen them side-by-side.  Would love to hear other Mooneyspacers' opinions, just to make sure I'm not missing something.

[flyboy0681]

3 minutes ago, Vance Harral said:

For those of you who recently installed or plan to install GI-275s, what specific features or differences led you to prefer that unit over the less expensive G5?  Our mechanical AI is going south, we'll be replacing with an electronic ADI, and we're considering both options.  I've read the marketing blurbs, I think I understand the differences (form factor, touch screen, interface capabilities, etc.) and I can see why the GI-275 has more "value".  But between the price difference of the hardware itself, and the considerably more expensive installation quotes we're getting, I'm having a hard time feeling the additional features are worth the premium cost vs. the G5, especially after having seen them side-by-side.  Would love to hear other Mooneyspacers' opinions, just to make sure I'm not missing something.

The G5 AI cannot drive the King autopilots while the GI-275 can. Nuff said.