Garmin GI275 Install in a 305 Rocket

[MIm20c]

@PTK why not just move your 256 over, disconnect it, and replace it with a single 275?

[Andy95W]

5 minutes ago, MIm20c said:

@PTK why not just move your 256 over, disconnect it, and replace it with a single 275?

Or better yet, move the 256 over and install an Aspen.

[Marauder]

44 minutes ago, Andy95W said:

Or better yet, move the 256 over and install an Aspen.

Low blow... but I love it.

[PTK]

3 hours ago, MIm20c said:

@PTK why not just move your 256 over, disconnect it, and replace it with a single 275?

I have no reason to do that and would not do that! I have nothing to hide and will not pretend or somehow try to scam! And I’m not asking for any favors! My point is it’s working fine and I wish to keep it. I simply want to back it up fully to include preserving ap functionality. Is that too much to ask?

[PTK]

1 hour ago, Andy95W said:

Or better yet, move the 256 over and install an Aspen.

Andy, that would not do what I’m looking for..

[louisut]

7 hours ago, PTK said:

Thank you for your post Austin. Very nice to see these in action in a Mooney!

I have a question and it's the one major sticking point for me. I have in my panel perfectly functioning KI256, KCS55A and KFC150. So removing the vacuum is not my primary goal. What I want is simply an ADI that I can put right next to my 256 that would be a true and full backup. Not just a pretty horizon coming along for the ride. What I mean is in the event of a vacuum failure taking my primary off line, I want that back up to be ready and able to assume the full role of the primary. I want it to provide attitude reference to the KFC so it can continue on. I don’t want to be forced to also take the ap off line. There's no good reason that I’ve heard that one GI275 ADHRS+AP version cannot assume this role. And say I do go for two of them, as you did, there’s no good reason even then why the second GI275 cannot fully back up the primary by providing attitude reference to the ap! For a product touted as the 256 replacement and solution for legacy autopilots these are major shortcomings imo. I was excited when G introduced these but lost that excitement when they force us to buy 2 of them! My primary KI256 doesn't have that limitation and my electric HSI is just fine. I don’t need to replace it and don’t want to be forced to do so. There is an advantage to having a vacuum ADI and an electric HSI. All I want is to backup my 256...fully. If I decide down the road to replace the HSI and take out the KCS55A I want to cross that bridge if/when I get to it. Not forced to do so. 

The GI 275 comes in a few variants. The most expensive one is the ADAHRS+AP which can drive compatible autopilot. If you have two, then either can drive the autopilot. This isn't required; you could save about $1k by pairing an ADAHRS+AP with a ADAHRS-only unit.

I don't think the GI 275 will act as a backup for the KI 256. Is that really a reasonable use case though, for a new electric, solid-state instrument to support an older vacuum instrument made by a competitor?

Lastly, if the objective of having a backup is to improve reliability, then wouldn't you be better off installing one as a primary instead of as a backup? It has no moving parts and an independent one-hour battery; the only required maintenance is a 2000-hour connection check and nav database update every five years. In terms of reliability, that seems objectively better than the ~400 hours for an ADI and ~800 hours for a vacuum pump. What's the advantage of keeping a vacuum ADI?

 

[LANCECASPER]

4 hours ago, PTK said:

Andy, that would not do what I’m looking for..

But two Aspens would 

 

[PTK]

3 hours ago, louisut said:

The GI 275 comes in a few variants. The most expensive one is the ADAHRS+AP which can drive compatible autopilot. If you have two, then either can drive the autopilot. This isn't required; you could save about $1k by pairing an ADAHRS+AP with a ADAHRS-only unit.

I don't think the GI 275 will act as a backup for the KI 256. Is that really a reasonable use case though, for a new electric, solid-state instrument to support an older vacuum instrument made by a competitor?

Lastly, if the objective of having a backup is to improve reliability, then wouldn't you be better off installing one as a primary instead of as a backup? It has no moving parts and an independent one-hour battery; the only required maintenance is a 2000-hour connection check and nav database update every five years. In terms of reliability, that seems objectively better than the ~400 hours for an ADI and ~800 hours for a vacuum pump. What's the advantage of keeping a vacuum ADI?

Can one GI275 ADHRS+AP version be installed as primary fully replacing the 256 and utilizing it as its backup while retaining reference to ap? If it can that’s great! I didn’t think it could because it specifically calls for another GI275 for backup.

[carusoam]

Somewhere in the back of the MS files.....

Lurks these pics....

I’m not quite sure what keeps them together...

Would this be the right time to bring them out?

Are the twins in college already?

-a-

BK...

Aspen...

 

Other guys, kinda new in the neighborhood...

-a-

[J0nathan225]

I'm going on day 4 of a gi275 install as my backup ADI... They didn't know it needed a GPS source at first, then they found the gtx345 wasn't approved as said source, and now the plan is to overnighting the external VFR GPS to install, which is concerning with the whole V. F. R labeling of it... 

 

This is all being covered under a Warranty so I can't complain too much. 

[carusoam]

Seeing VFR on an instrument while flying in IMC could cause HR and/or BP to rise??? 
 

PP thoughts only, not a medical doctor...

Best regards,

-a-

 

[flyboy0681]

I scheduled the install of a -275 ADI for next month and have a question. Being that it contains a built-in air data computer, does it display wind speed and direction? Also, can the ADC be wired into the GTN 750 to display wind direction on that?

[aviatoreb]

48 minutes ago, flyboy0681 said:

I scheduled the install of a -275 ADI for next month and have a question. Being that it contains a built-in air data computer, does it display wind speed and direction? Also, can the ADC be wired into the GTN 750 to display wind direction on that?

I am getting very close to approving a 275 ADI install too.

I think as of this time (or at least as of a month ago when last I looked) they had not yet approved air data computation but I read the intention is to do so before long - just like when the G5 first came out it did not have air data computations but it became approved over time.  Garmin more than any other company has a good record of actually pushing improvements through the certification process and I am confident that this will come in time.

[louisut]

5 hours ago, flyboy0681 said:

I scheduled the install of a -275 ADI for next month and have a question. Being that it contains a built-in air data computer, does it display wind speed and direction? Also, can the ADC be wired into the GTN 750 to display wind direction on that?

With the latest software update yes, though you lose the heading tape: https://www.garmin.com/en-US/blog/aviation/gi-275-adds-gfc-500-autopilot-compatibility/. It requires the optional OAT sensor though.

[FlyingScot]

On 10/9/2020 at 10:03 AM, flyboy0681 said:

I scheduled the install of a -275 ADI for next month and have a question. Being that it contains a built-in air data computer, does it display wind speed and direction? Also, can the ADC be wired into the GTN 750 to display wind direction on that?

Yes to both - I have this combination and it works very well. You have to have the OAT sensor as well, of course.