Adding GNC 255 Nav/Com - going off script

Nathan Miller

Nathan Miller

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Nathan
Going off script = It's not in the blivin' Install Manual :confused:

Existing:
G5 (HSI)
GNX 375 (GPS / Transponder)
GTR 225 (Com #1)
Dual Collins VIR-350 (Nav receivers)
Collins VHF 250 (Com #2)

(See image below)

I can forsee a day when I pull one of the Nav receivers and the Com #2. In their place, a GNC 255 nav/com would go. I'd love to get a VOR indication on my G5 :)

However, in the G5 install manual and the GNC install manual, I can't find a scenario that details how such a wiring interconnect would take place (GNX 375 and GNC 255 simultaneously wired to G5).

In the G5 experimental install manual, they show it plain as day.

In the G5 STC install manual, while I see interconnection diagrams that show a GTN 650 and GNC 255 feeding a G5, it is not shown with the GNX 375 and GNC 255.

Is there a reason why Garmin wouldn't include 375/255 in the G5 STC? Do I need to have a little bit of patience for them to finish testing the setup out and release an updated G5 install manual?

20200416_175905_4MP.jpg

BTW - still recovering from the latest round of upgrades. Between that and the flipping pandemic, it likely wouldn't be until 2022 where I could embark on such an endeavor. So, long story short - I've got the time to wait on Garmin :p

(Edited for readability)
 
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I think we learnt today that STC and TSO are just suggestions.. just plug em in :p

sorry couldnt resist. I couldnt find it in the install manual either. I will ask my avionics guy next week and see if he has access to some super secret stuff that we mere mortals dont have access to
 
Too hilarious. BTW - you're officially my new favorite hero on POA. Whereas I just shrugged off the pompous attitude, you came back punching with *shudder* actual facts and solid logic without pulling out Johnson Bar measuring devices. Kudos.
 
Also - shot in the dark - does anyone have (or discussed with their shop the possibility of) one of Garmin's 2" GPS Navigators (GPS 175 / GNC 355 / GNX 375) and GNC 255 Nav/Com wired up to a G5 as an LPV / ILS indicator?
 
This is a totally supported interface, so long as you don’t have an autopilot, or you have a garmin autopilot, otherwise it’s not approved (G5 can’t switch the analog outputs that a legacy autopilot requires, so AP might be following what you don’t have selected). You just wire the 2” navigator according to that part and the gnc as to the vhf navigator on the second set of 429 input. The reason it’s not drawn out specifically is due to the combination matrix just starts to get out of hand, just read the notes in the drawings about interfacing with dual navigators.
 
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I am in the exact same boat... I am having the GFC500 AP installed in June and currently have the GNX375 and an old KX155.. I wanted to take out my 155 and have a 255 installed so I can get ILS/VOR on my G5... It looks like it can be done but even though it's not in the STC manual (it shows only a serial connection and not ARINC) is this okay for certified aircraft? I am guessing it is..
 
Indiana_Pilot said:
I am in the exact same boat... I am having the GFC500 AP installed in June and currently have the GNX375 and an old KX155.. I wanted to take out my 155 and have a 255 installed so I can get ILS/VOR on my G5... It looks like it can be done but even though it's not in the STC manual (it shows only a serial connection and not ARINC) is this okay for certified aircraft? I am guessing it is..
Click to expand...

The VHF Navigator install pages (covers the GNC255) shows both the ARINC 429 connection and a serial connection, with a note (#6) about interfacing when doing dual navigators.
 
Ryan Klems said:
The VHF Navigator install pages (covers the GNC255) shows both the ARINC 429 connection and a serial connection, with a note (#6) about interfacing when doing dual navigators.
Click to expand...
I only see that in the Experimental manual though.. did they update the certified one? I only have Rev14.. Do you have the latest revision?

Thanks!
 
WannFly said:
Rev 22 is here - http://static.garmin.com/pumac/190-01112-10_22.pdf
Click to expand...

Thanks! I tried to look on Garmin's site but I could not find a newer version.. They defiantly updated it to allow the ARINC connection.

Does anyone know if or have a picture of the G5 showing both a VOR and a GPS course? Can it display an ILS along with GPS course? I am curious if it's one or the other with having 2 separate units.
 
Indiana_Pilot said:
Thanks! I tried to look on Garmin's site but I could not find a newer version.. They defiantly updated it to allow the ARINC connection.

Does anyone know if or have a picture of the G5 showing both a VOR and a GPS course? Can it display an ILS along with GPS course? I am curious if it's one or the other with having 2 separate units.
Click to expand...

Not sure what you mean by showing "both a VOR and a GPS course" .... you have to select one or the other for navigating (what is going to show the deviation indications) at a time (just select the nav source from the menu on the G5). However, you can turn on the bearing pointers so you could have GPS course up for navigating and have the VOR bearing pointer displaying at the same time. But you can only navigate one at a time, and the nav selection on the G5 is also what the GFC500 would be following.
 
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Ryan Klems said:
Not sure what you mean by showing "both a VOR and a GPS course" .... you have to select one or the other for navigating (what is going to show the deviation indications) at a time (just select the nav source from the menu on the G5). However, you can turn on the bearing pointers so you could have GPS course up for navigating and have the VOR bearing pointer displaying at the same time. But you can only navigate one at a time, and the nav selection on the G5 is also what the GFC500 would be following.
Click to expand...

That's what I meant.. I wasn't sure how you could display data from both.. The bearing pointer was my answer. So if I am navigating with GPS using my 375 but load the loc freq in my 255 to shoot an ILS do I have to switch the nav source on the G5? (It sounds like I do according to your statement above)
 
Indiana_Pilot said:
That's what I meant.. I wasn't sure how you could display data from both.. The bearing pointer was my answer. So if I am navigating with GPS using my 375 but load the loc freq in my 255 to shoot an ILS do I have to switch the nav source on the G5? (It sounds like I do according to your statement above)
Click to expand...

Yep, you'll have to manually switch by pushing the knob on the G5 and then rotating the knob to move the selection over to the nav source field and then press the knob. That'll switch you between the two nav sources.
 
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