How does a GTN and GNS combination work?

WDD

Final Approach
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Vintage Snazzy (so my adult children say)
Doing some planning, and it includes getting a new GTN 650xi. Would leave the current GNS 430 as second Nav/Com.

Would also be getting dual G275 to feed a GFC 500 auto pilot. I understand the GTN and/or GNS feeds the G275, which feeds the AP.

I had thought that one can control which one is "speaking" to the G275. But I chatted with the Garmin support line guy, and he said that if you have two Garmin navigators they are linked. What you input on one is instantly mirrored on the other. I hadn't expected that, and given he was unsure of a few other things, thought I'd put the question out and let someone who this set ups (two navigators GTN/GTN, GTN/GNS, etc.) comment.

Thanks!
 
He was correct on this one. They cross fill. I have a 750/650 stack
 
Thanks for the confirmation.

I wonder if you could also send the GTN signal to two different CDIs. But I’m fairly certain you can’t.
 
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Crossfill is a setting that can be turned on and off- have a look at the online PDF of the Pilot Guide
 
There are limitations on the crossfill between GTN and GNS. GNS must be a WAAS unit, it will not crossfill to a non-WAAS unit (your post mentions GNS430 not GNS430W). GNS needs to be at software v5.03 or later, and the cross-fill is only one way between GTN -> GNS, it will not fill the other way. I believe (GTNs certainly do) that you also need to have the same navigation database version on both units. It also requires a serial port connection between the GTN and GNS units. Between two GTNs is different in several ways.

I had thought that one can control which one is "speaking" to the G275.
You can choose which unit (source) is being displayed on the GI-275 for sure, if that was your question.
 
OK - so I can switch the navigator to which the G275 is listening, and thus driving the auto pilot. As well cross full can be turned off.

Am I correct that a navigator can’t send a signal to two separate CDIs ( an analogue and the G275 HSI) at the same time?
 
OK - so I can switch the navigator to which the G275 is listening, and thus driving the auto pilot. As well cross full can be turned off.
Yes (needs to be a ADAHRS+AP unit to have the switched outputs to the autopilot)
Am I correct that a navigator can’t send a signal to two separate CDIs ( an analogue and the G275 HSI) at the same time?
You can, but there are limitations. You can't connect an analog CDI to the main connector (GPS/VHF NAV) if there is an electronic display that sends selected course, you can only interface to the nav connector (VHF NAV only) in that case. Otherwise they would be fighting over the selected course.
 
I have 750xi and 430w with 2 gi 275’s, s-tec 20. Crossfill works from 750 to 430w, not 430w to 750. Not an issue for me - just use the 430 for NAV/com 2. Might just be a setting in the 430. Both radios show on the 275. I also have a Garmin 106 for the 430 as a backup. Can’t do GPS approaches with the 106.I can back up an RNAV approach with an ILS using the 106. Great setup for me.
 
Can GNS handle airways? I vaguely remember they couldn’t and if GTN has an airway how would GNS handle it?
 
be very careful. You will need to be at the same navigation for both the GNS and GTN units for this to work. Not sure if Garmin onepaks will include the GNS and GTN units on one subscription - though Jeppesen does NOT. So its subscriptions for the GNS and GTN units if you go that route.
But when they are on the same database - then yes, the GTN information auto-populates to the GNS.
 
I'm leaning toward leaving the old GNS connected to the current mechanical CDI as it is now, with no connection at all to the new GTN650xi and G275. It would be primarily a 2nd com, and could be a back up GPS nav if one in a million something ever happened to the to 650xi. No AP capability, but at that point it wouldn't matter.

Fairly sure the GNS isn't WAAS BTW, thus just emergency use.
 
Ditch the GNS 430. The GI 275 is probably a better backup GPS and the 430 just won’t play nicely with everything else. Database Sync/Concierge. Cross-fill. Maybe even database subscriptions. The repair options on the 430 are dwindling. Ask if there is a trade-in value that you can put toward a comm or nav-comm radio instead.
 
I’m looking at adding a GTN, I’ll keep the 430W. When it dies I’ll slide in a IFD440. The 275 is a vfr only gps.
 
Can GNS handle airways? I vaguely remember they couldn’t and if GTN has an airway how would GNS handle it?
Yes, if you program an airway into the GTN, the route and waypoints will crossfill into the GNS.

The one thing I found the GNS cannot handle is if you load a visual approach into the GTN. Not a big deal.
 
I’m looking at adding a GTN, I’ll keep the 430W. When it dies I’ll slide in a IFD440. The 275 is a vfr only gps.

Think long and hard about this. . If you go ALL avidyne - thats fine. If you have a GTN, and then add an IFD series navigator to save the 3k installation cost, you'll end up paying more with the two different database subscriptions. . . It makes no sense to have a GTN and IFD unit in the same plan.
 
I wouldn’t pay to install a GNS at this point. But right now it’s zero cost to just keep it in there, and it will work as the second com. If it lasts 3 years, great. I’ll replace it when it breaks with whatever Garmin has at that time. Maybe just a com radio, maybe a gps/com. I don’t see a need to have more than one nav radio in this VOR MON world we live in now.
 
I don’t see a need to have more than one nav radio in this VOR MON world we live in now.
Actually, VOR MON can increase your need for more than one NAV radio. If you don't have a VOT or VOR checkpoint on your field (airborne checkpoints seem to have all but disappeared), then you're left with either a dual VOR check or an airway check for performing a 91.171. And with VOR MON making airways disappear, the dual VOR check becomes more and more attractive.

Besides, doing an airway check can be a chore let alone having to do it every 30 days.
 
“Think long and hard about this. .”

Avidane $225/year for nav and obs. Just the $3K Garmin install would take over a decade to recoup. Plus it’s a backup, you don’t even need a subscription.

I’ll stick with the 430W for now with a used 440 as a quick, cheap solution when I can’t get the Garmin repaired.
 
There are some things you don't like, but put up with because overall its the best choice.

Anthem is has a great point in his previous post. Let me add to that.

Garmin is today the dominant player in avionics, similar to how Apple is with smart phones.

Garmin doesn't play well with others, even if the "other", in this case Avidyne has a nice/nicer unit.

So if you go all Garmin (with a few exceptions), all of the units get along and in total the whole panel works better.
 
be very careful. You will need to be at the same navigation for both the GNS and GTN units for this to work. Not sure if Garmin onepaks will include the GNS and GTN units on one subscription - though Jeppesen does NOT. So its subscriptions for the GNS and GTN units if you go that route.
But when they are on the same database - then yes, the GTN information auto-populates to the GNS.
One packs include bothe GNS and GTN - includes all units
 
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