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Mini-X versus G5 as backup for G3x

rapid_ascent

Well Known Member
I've been planning on having a Mini-X as a backup with my G3x system. I like the idea of the larger display as compared to the G5, being somewhat visually challenged. It seems to be a well thought out unit too. However, as I start digging into it more, it seems like it might be quite a bit more work to install (magnetometer and possibly ARINC converter) and it won't be integrated with the G3x system as well as if I used a G5 instead.

I'm wondering if others have used the Mini-x with their G3x and could provide some feedback. Plusses and minuses. Thanks.
 
I had a Mini-X as my backup for my G3X Touch because at the time the G5 was not yet out there. Since then I have replaced the Mini-X with a G5. One attraction of the Mini-X was the map/GPS capability, but in actual use, I found it not very helpful. First, managing the display with a route was way too cumbersome. Most importantly, if you are using the map page you lose the primary display, which is the most important backup function - keeping the dirty side down, and so in backup usage, the maps are not practically available. Also, the G5 battery is much better. Mine easily surpasses the 4 hour spec. And of course there is the Garmin integration - it is a wonder to behold the G5 taking over the autopilot function from a disabled G3X. Set baro on one G device, and it is set on all automatically, the flight display format, look and feel are the same on the G5 as the G3X, etc. So, I use the G5 as the backup for primary functions, and bring my iPad for map backup JIC. That said, the Mini-X is a nice device and nice display, higher resolution than the G5, but that probably is a contributor to its battery life.
 
You can do a search, and find many debates about whether a true back-up device should be (1) integrated with everything else, or (2) isolated from everything else, standing alone. There are pluses and minuses for both.
 
My $.02.

I would get a Mini with the magnetometer, backup battery and database options and have it completely disconnected from the Garmin stuff for a true standalone backup system.
 
For what it's worth, talking to Steve at G3Xpert the software in the G5 is a completely independent implementation from the G3X, OS and all. The hardware is the identical/same as the certified version of the G5. They thought about this.
 
A while back a read through some of the threads regarding backup independence. I think I agree in concept that the backup unit should be independent, but it seems Garmin has made an attempt at that. Still the G5 shares interfaces/functions with the G5 and so conceptually may not be as isolated as a Mini-X backup. However, there is the day to day usefulness of this unit and not having it integrated with the G3x means that it may be more cumbersome to setup and etc.

N49ex, Do you have a 430 or 650 connected to your backup unit?
 
Backup EFIS

Four years ago I decided to replace the old instrument panel with the G3Xt.
I told the avionics shop in Czech republic that I wanted the Dynon D10A as a back up EFIS. In late October the shop called and said the installation was finished. The system had been on ground power for 24 hours and signed of by manager.
I traveled on a regular flight to the Czech republic to pick up the plane.
Everything worked nicely so I departed late in the afternoon for the 4 h flight
to Stockholm Sweden. After 1 h 30 min red crosses started to appear on the
G3Xt, within 10 min everything was crossed out. All that was left working was the GNS430W + GTX330 + D10A EFIS. It was dark, IMC and raining over Poland, no engine instrument. I new the tank was full of 100 LL.
I got home safely and I was glad for my decision to install a separate EFIS.
As it turned out the avionics shop had installed the Can bus terminators on all parts in the system. It should have been only one at each end of the can bus.
 
A while back a read through some of the threads regarding backup independence. I think I agree in concept that the backup unit should be independent, but it seems Garmin has made an attempt at that. Still the G5 shares interfaces/functions with the G5 and so conceptually may not be as isolated as a Mini-X backup. However, there is the day to day usefulness of this unit and not having it integrated with the G3x means that it may be more cumbersome to setup and etc.

N49ex, Do you have a 430 or 650 connected to your backup unit?

I have a 750xi (which recently replaced a regular 750). I presume you mean the RS-232 link. Which BTW requires a bit of fuss - paralleling - as the 6/750s support only one link with the required protocol, and there are 2 places that need it! Goofy, but Garmin has a write up on it...)

I agree with your overall comments - I am happy with the independence (and have tested it) and really like the look and feel commonality. Pull the G3Xt breaker and you have no problem absorbing info as you shift your glance to the G5. And as said, you set baro in just one place. Same with SW updates -update the G3Xt and all other units that have updates come with it automatically, including the G5.

Reinhard Metz
 
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I agree with your overall comments - I am happy with the independence (and have tested it) ........... And as said, you set baro in just one place. Same with SW updates -update the G3Xt and all other units that have updates come with it automatically, including the G5.

You really mean "sort of independence". You're hoping no sort of crazy software error can propagate over the baro setting link. Or the software update link.

I went with RocketBob's approach: different brand for back up EFIS, absolutely no connections to main EFIS. Yes, I have to set baro settings in two places.
 
I don't think setting the Baro twice would be a big deal. That level of inconvenience is obviously not a problem for me.

Today though I was trying to figure out about hooking up the ARINC to both the G3x system through my GAD29 and the connecting to the GRT ARINC adapter to the Mini-AP. If I want to do all that, which I'm not sure I do. Then, do I need a switch for the G3x/Mini output selection to my GNS430?
 
Just like rs232, one ‘out’ can power several ‘ins’, as long as both ins can read the format that’s sent.
 
One ‘in’ can only see one ‘out’, or there will be gross confusion. Just hook up out from the main efis to the navigator’s ‘in’; nothing out of the standby efis to the navigator. If you lose the primary efis the navigator will continue to function without any efis data coming in; you’ll lose some things, like wind vectors on the gps.
 
The 430W has 2 ARINC inputs. Can those be wired one input to each EFIS and then selected via configuration or would this happen automatically or it doesn't work that way?
 
I don't know the answer. In an emergency you certainly don't want to have to go into the 430 set up menu! I'd have to read the manual (who does that?!!) to see what the 430 does if there is redundant data coming in on the 2 inputs. Or, as I said, just not hook up the standby EFIS.
I'd be curious to know what you find out.
 
You really mean "sort of independence". You're hoping no sort of crazy software error can propagate over the baro setting link. Or the software update link.

I went with RocketBob's approach: different brand for back up EFIS, absolutely no connections to main EFIS. Yes, I have to set baro settings in two places.

In that case, another option is to not connect the CAN bus to the G5 and add a GMU11 magnetometer. Then it is truly standalone. That way you still maintain the common look and feel and have a better battery life.

If you want to imagine "crazy software errors" transmitted over the CAN bus AND somehow causing the G5 to go crazy, that's a bit out there. BUT, quick story from commercial jet design - in the world of triplicated redundancy and voting, there have been approaches for ultimate independence by using separate development teams to generate the software and voting on checkpointed data, and lo and behold, they found that different teams could make the same mistakes based on common specifications, and the votes could pass, and there were still errors due to the common mistakes!

Goes to show you, there's always something!
 
Yep. I recall some years ago a major experimental avionics company got a new software upgrade thru beta test and distributed it. Everything was fine-until someone tried an alphanumeric airport ID (e.g., C83 vs KLVK). Every interconnected efis crashed.
 
The 430W has 2 ARINC inputs. Can those be wired one input to each EFIS and then selected via configuration or would this happen automatically or it doesn't work that way?

Per the manual the 430 will look first at arinc inputs, then rs232, ... There is also a hierarchy for various arinc formats. But if they are both the same, I don’t know. Maybe you can send data efis to 430 via rs232 for the backup, that would definitely be the source only if the main arinc source failed.
 
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