Dual Garmin G5's install question

[Jim Peace]

First off an apology I tried to search this on mooneyspace but you know how that goes.....I know it has been covered before.

I just flew a J model that just had an install of two G5's.  The ADI turns on when the master switch is turned on and the HSI does not come on unless the avionics master is on.  

In my C model it is hooked up so that both are on when the master is on.

I thought we discussed in the prior thread it can only be one way or the other and it should be with the master switch only.

What was the final answer and a link if someone can do a better search than me, I am sure the STC reads like stereo instructions.......

Thank you,

Also is there a way for the end user to adjust the pitch offset and change to "duel cue?" or is this only done by the shop? In cruise flight level altitude the pitch was 4 degrees nose down.

Asking for a friend..

Than you

[Ragsf15e]

15 minutes ago, Jim Peace said:

First off an apology I tried to search this on mooneyspace but you know how that goes.....I know it has been covered before.

I just flew a J model that just had an install of two G5's.  The ADI turns on when the master switch is turned on and the HSI does not come on unless the avionics master is on.  

In my C model it is hooked up so that both are on when the master is on.

I thought we discussed in the prior thread it can only be one way or the other and it should be with the master switch only.

What was he final answer and a link if someone can do a better search than me, I am sure the STC reads like stereo instructions.......

Thank you,

Also is there a way for the end user to adjust the pitch offset and change to "duel cue?" or is this only done by the shop? In cruise flight level altitude the pitch was 4 degrees nose down.

Asking for a friend..

Than you

I’ll be interested as well.  Mine is getting 2 installed right now.  I do know the primary AI is supposed to be on the master so you can turn off the avionics master and still have power to it.  Not sure about the HSI.

The leveling procedure is in the stc.  Supposed to level the airplane on the ground, adjust G5 to level and then it’s set.  It’s not adjustable after that, at least not easily by the user.  Even if you level it in “cruise”, you’ll find that it’s off when you cruise at different indicated airspeeds - ROP, LOP, or even at different altitudes as that will change the aoa a bit.  I wonder if the shop leveled his properly? 4 degrees seems like a lot.

[Jim Peace]

Just now, Ragsf15e said:

It’s not adjustable after that, at least not easily by the user.  Even if you level it in “cruise”, you’ll find that it’s off when you cruise at different indicated airspeeds - ROP, LOP, or even at different altitudes as that will change the aoa a bit.  

Mine was way off after install and I had it adjusted by the install shop for 0 pitch during normal cruise.  It has actually been very good this way, very intuitive to fly. 

[Ragsf15e]

Just now, Jim Peace said:

Mine was way off after install and I had it adjusted by the install shop for 0 pitch during normal cruise.  It has actually been very good this way, very intuitive to fly. 

Any idea if they had followed the leveling procedure in the stc the first time?  I wonder how close that will get it or if, like yours, it could still be way off?

[7.Mooney.Driver.0]

First off an apology I tried to search this on mooneyspace but you know how that goes.....I know it has been covered before.
I just flew a J model that just had an install of two G5's.  The ADI turns on when the master switch is turned on and the HSI does not come on unless the avionics master is on.  
In my C model it is hooked up so that both are on when the master is on.
I thought we discussed in the prior thread it can only be one way or the other and it should be with the master switch only.
What was the final answer and a link if someone can do a better search than me, I am sure the STC reads like stereo instructions.......
Thank you,
Also is there a way for the end user to adjust the pitch offset and change to "duel cue?" or is this only done by the shop? In cruise flight level altitude the pitch was 4 degrees nose down.
Asking for a friend..
Than you

Per Garmin STC when installing dual G5’s the one use as ADI needs to be power from the battery bus and the one use as an HSI powered from the Avionics bus.. As far as calibration of pitch/roll offset i would take it to a garmin dealer shop to get it fixed. But someone who knows what they are doing and won’t mess your configurations up can also do it..

Hope this helps.




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[ragedracer1977]

Interesting, mine were installed under a previous revision and both are connected to the battery bus

[Jim Peace]

5 hours ago, ragedracer1977 said:

Interesting, mine were installed under a previous revision and both are connected to the battery bus

same here.....does that mean they must be rewired at some point in my airplane?

[Andy95W]

18 minutes ago, Jim Peace said:

same here.....does that mean they must be rewired at some point in my airplane?

Not really.  Technically, our old M20Cs didn't have avionics buses.  But if you're having other work done, it would be a pretty easy swap to put the HSI on the avionics switch.

[ragedracer1977]

2 hours ago, Jim Peace said:

same here.....does that mean they must be rewired at some point in my airplane?

No. And I can't fathom a good reason to do so

[EricJ]

9 hours ago, ragedracer1977 said:

No. And I can't fathom a good reason to do so

It's just whether you want the load of both of them even when the avionics master is off.   It also isolates at least one of them during engine start when there are a lot of transients on the master bus (which is one of the reasons why there's an avionics master in the first place).   During an in-flight problem if you need to start isolating things you can kill power to at least one of them without affecting lighting, etc., and it'll keep running on its own battery, anyway. 

So there are some advantages to having one on each bus, but it's not all that horrible to have them both on the master, especially if you can isolate with a breaker or two to take them off the main battery if you have an alt failure or something.

 

[Baker Avionics]

17 hours ago, ragedracer1977 said:

Interesting, mine were installed under a previous revision and both are connected to the battery bus

They just jumpered everything most likely and did a "Chinese blueprint" installation.  

[ragedracer1977]

3 hours ago, Baker Avionics said:

They just jumpered everything most likely and did a "Chinese blueprint" installation.  

No. There was an entirely new bus bar installed off the battery bus for all the G5s and accoutrements

[ragedracer1977]

3 hours ago, EricJ said:

It's just whether you want the load of both of them even when the avionics master is off.   It also isolates at least one of them during engine start when there are a lot of transients on the master bus (which is one of the reasons why there's an avionics master in the first place).   During an in-flight problem if you need to start isolating things you can kill power to at least one of them without affecting lighting, etc., and it'll keep running on its own battery, anyway. 

So there are some advantages to having one on each bus, but it's not all that horrible to have them both on the master, especially if you can isolate with a breaker or two to take them off the main battery if you have an alt failure or something.

 

I was surprised the manual didn't have them both on the avionics bus.  When installing, I thought about that.  I came to the conclusion that Garmin or the FAA decided that they were more akin to flight instruments than avionics, and should be powered like they were.  

 

[Baker Avionics]

25 minutes ago, ragedracer1977 said:

I was surprised the manual didn't have them both on the avionics bus.  When installing, I thought about that.  I came to the conclusion that Garmin or the FAA decided that they were more akin to flight instruments than avionics, and should be powered like they were.  

 

I like the way you think

[bradp]

On 12/31/2019 at 6:59 PM, ragedracer1977 said:

Interesting, mine were installed under a previous revision and both are connected to the battery bus

Yes it changed at some point in the revision history IIRC 

[bradp]

On 1/1/2020 at 12:51 AM, Jim Peace said:

same here.....does that mean they must be rewired at some point in my airplane?

Jim the level reference for Mooney is taken off the river line above the battery compartment / empennage access.  It’s pretty easy to redo your pitch offset for your friend.  There’s a formula in the config / calibration step sections of the reference manual.  In a nutshell measure your nose deg up with a digital protractor along that rivet line.  Plug that into the equation and re enter the pitch offset.  The experimental software version allows you to change it in flight.  Mine is within a degree or two of zero - sometimes a little ANU or AND depending on the speed / config - but that’s the way it’s supposed to be.   
 

What dual cue do you reference.  No such thing. ;-)   It’s in one of the display submenus 

 

[Marauder]

Heavens forbid you need to put your Mooney in a river to get to the correct river line.

Jim,

There is a nice seam where the rivet line overlaps on the fuselage. I was able to use level the Mooney using no jacks and just the lip drop-off from the hangar and letting out some air from the nose wheel.




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[Bob - S50]

Here's what I did.

I assume the shop followed the correct procedure (they told me they did) to set the pitch.  When we got the plane I noticed that in cruise, the AI showed me to be about 3 degrees nose low.  After flight I went into the setup mode and selected the pitch attitude settings.  It showed an offset of -4.5 degrees.  I changed it to -1.5 degrees.  Now it's perfect.  Shows us 3 degrees nose high on the ground and just about spot on perfectly level at normal cruise speed.

[Bob - S50]

3 hours ago, Bob - S50 said:

Here's what I did.

I assume the shop followed the correct procedure (they told me they did) to set the pitch.  When we got the plane I noticed that in cruise, the AI showed me to be about 3 degrees nose low.  After flight I went into the setup mode and selected the pitch attitude settings.  It showed an offset of -4.5 degrees.  I changed it to -1.5 degrees.  Now it's perfect.  Shows us 3 degrees nose high on the ground and just about spot on perfectly level at normal cruise speed.

There is a chance I had the signs wrong on that statement.  At any rate, make a change and reboot.  If you don't like what you see, make another change in the appropriate direction and try again.

[bradp]

Bob makes sense as the mid body /J attitude is about 2 degrees nose high on the ground- depending on your biscuits and tire inflation :-)

[Baker Avionics]

On 12/31/2019 at 2:58 PM, Jim Peace said:

First off an apology I tried to search this on mooneyspace but you know how that goes.....I know it has been covered before.

I just flew a J model that just had an install of two G5's.  The ADI turns on when the master switch is turned on and the HSI does not come on unless the avionics master is on.  

In my C model it is hooked up so that both are on when the master is on.

I thought we discussed in the prior thread it can only be one way or the other and it should be with the master switch only.

What was the final answer and a link if someone can do a better search than me, I am sure the STC reads like stereo instructions.......

Thank you,

Also is there a way for the end user to adjust the pitch offset and change to "duel cue?" or is this only done by the shop? In cruise flight level altitude the pitch was 4 degrees nose down.

Asking for a friend..

Than you

Well, you can tell "Your friend" that there is a way and generally Garmin will not allow Certified installations to do it though you can do it in the Maintenance pages.  It should've been done at the shop, but we show the owners where to do it in case of minor adjustments are needed at a later time....Ahem....I hope this helps.  

[vorlon1]

On 1/1/2020 at 4:28 PM, ragedracer1977 said:

No. There was an entirely new bus bar installed off the battery bus for all the G5s and accoutrements

How much did it cost to install the new bus?

Like it has been pointed out here before, the older C models don't have an avionics bus...

[ragedracer1977]

31 minutes ago, vorlon1 said:

How much did it cost to install the new bus?

Like it has been pointed out here before, the older C models don't have an avionics bus...

Mine had an avionics bus.  Installed when the panel was updated to a standard 6 pack.  Before I owned it. 

Adding a bus for the G5s and accessories was just part of the install.  It was attached to the master bus.

[bradp]

My G5 HSI and GAD are on an auxiliary bus that I wired to the pilots footwell.  I don’t have a picture but I believe Byron has the same thing. IA didn’t have an issue with that location.