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G3X doesn't use GTN750 VNAV

kaa

Well Known Member
Hi all,

I recently updated our G3X Touch and 750 to the latest firmware versions, but I can't get VNAV to work. I configured GTN as described here: https://vansairforce.net/community/showthread.php?t=164885.

What seems to be happening is that the flight director (and autopilot) follows G3X's internal VNAV settings (from the flight plan page), and completely ignores altitude restrictions from GTN750. GTN correctly calculates vertical guidance as can be seen on its VNAV page. What am I missing?

Thanks,
Konstantin
 
I have seen this in installations where the GTN main board's ARINC 429 output format is not configured correctly.
 
VNAV Unavailable

Hi all,

I recently updated our G3X Touch and 750 to the latest firmware versions, but I can't get VNAV to work. I configured GTN as described here: https://vansairforce.net/community/showthread.php?t=164885.

What seems to be happening is that the flight director (and autopilot) follows G3X's internal VNAV settings (from the flight plan page), and completely ignores altitude restrictions from GTN750. GTN correctly calculates vertical guidance as can be seen on its VNAV page. What am I missing?

Thanks,
Konstantin

Hello Konstantin,

What is the Flight Plan source set to on your G3X Touch?

Thanks,

Justin
 
Hello Konstantin,

What is the Flight Plan source set to on your G3X Touch?

Thanks,

Justin

Yep, echoing this ... most likely candidate ...

Also, if you did firmware updates the 650 may have lost it's AIRINC settings, this happened to me once.
 
Thanks everyone. I didn't have time to go to the airplane, but it seems from my records that the ARINC settings on GTN are not the same as the latest G3X Touch install manual calls for. I'll try fixing this and report back.

Flight plan source is set to external, and the autopilot follows GTN's lateral guidance and approaches without a problem.
 
Symbol X out

Didn't want to start another thread for something this simple. I loaned my manual out; can someone tell me what this means?
 

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Thanks

I get it ok in the G3X's. I'll do some more research now that I know where to start.
 
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