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Issues with GTN 750/650 NAV2 integration in X-Plan - Printable Version

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Issues with GTN 750/650 NAV2 integration in X-Plan - fritz.vogel - 08-19-2025

I am currently running a simulator based on X-Plane 12 and using the TDS GTN 750Xi and GTN 650Xi plugin together with RealSimGear hardware for the GTN 750, GTN 650, G500, and G5.
In my setup, the GTN 750 is configured as NAV1/COM1 (Pilot side) and the GTN 650 as NAV2/COM2 (Copilot side), with crossfill enabled. The G500 and G5 displays are used to show the NAV sources.
Problem description
When flying approaches, I encounter the following issues:
  1. ILS approaches via GTN650/NAV2
    • G500 on NAV2: LOC + GS correct (green).
    • G5 on NAV2: GS appears and is valid, but the lateral needle is magenta (GPS-like) and points to the wrong direction.
  2. VOR approaches via GTN650/NAV2
    • G500 on NAV2: correct behavior.
    • G5 on NAV2: magenta GPS-like needle and a frozen glideslope indication (which should not exist for a VOR).
  3. LPV approaches
    • Via GTN750/NAV1: glidepath sometimes does not appear or is inconsistent.
    • Via GTN650/NAV2: before UNSUSPEND, the GS is shown but frozen; after UNSUSPEND it becomes correct, and both G500 and G5 show proper indications.
  4. General observation
    • The G500 behaves correctly on NAV1 and NAV2.
    • The G5 shows wrong colors (magenta instead of green) and “GPS-like” indications on NAV2 sources.
I also tested with the RealityXP GTN plugin: in that case, almost everything works as expected, except for VOR on NAV2, where the G5 also shows a magenta GPS-like needle with a frozen GS. This makes me think the issue could be related to how NAV2 outputs are mapped.
Current settings
  • GTN750Xi: NAV1/COM1, GPS1/VLOC1, “Connect GPS to HSI” enabled
  • GTN650Xi: NAV2/COM2, GPS2/VLOC2
  • Crossfill enabled
  • Legacy VC Integration: tested on and off, same behavior
  • “Connect GPS to VOR”: disabled
  • “Connect GPS to Autopilot”: enabled
  • “HSI Auto-Slew”: enabled
Question
Could you please confirm if my settings are correct for this kind of dual GTN750/650 + G500 + G5 setup?
And is the described NAV2/G5 behavior a known limitation, or are there adjustments I can make to the configuration files to solve this?
Thank you very much for your help,
Best regards

RE: Issues with GTN 750/650 NAV2 integration in X-Plan - adminOwner2 - 08-19-2025

Hello,

We will start by stating that RSG G500/G5 do not offer official TDS GTNXi support, because of this, behavior as stated above will occur.

If you are in GPS mode in the respective GTNXi unit, then the TDS GTNXi will not overwrite the NAV source, as stated above, since you have "Connect GPS to VOR" disabled, which is correct. We merely write to the appropriate GPS1/GPS2 datarefs.

RE: Issues with GTN 750/650 NAV2 integration in X-Plan - fritz.vogel - 08-26-2025

(08-19-2025, 09:14 PM)adminOwner2 Wrote: Hello,

We will start by stating that RSG G500/G5 do not offer official TDS GTNXi support, because of this, behavior as stated above will occur.

If you are in GPS mode in the respective GTNXi unit, then the TDS GTNXi will not overwrite the NAV source, as stated above, since you have "Connect GPS to VOR" disabled, which is correct. We merely write to the appropriate GPS1/GPS2 datarefs.
Hello,

thank you very much for your reply. I have now performed a complete series of tests and organized everything into PDF files in order to keep the upload size manageable. Each PDF shows the GTN units, the G500, the G5 and the relevant datarefs for one scenario. I also included a separate PDF with my current settings.
Unfortunately the forum only allows five files per post, so I will split the results into two parts.
Here are the first documents:
  • Settings.pdf – shows my current TDS GTN plugin configuration
  • ILS NAV1.pdf – everything correct, both G500 and G5 show green LOC and GS
  • ILS NAV2.pdf – G500 shows correct LOC+GS in green, G5 shows a magenta lateral needle pointing in the wrong direction and a magenta GS that follows correctly
  • LPV NAV1.pdf – both G500 and G5 show correct lateral guidance, but only the G5 shows a glidepath, the G500 does not
  • LPV NAV2.pdf – G500 shows the approach correctly, on the G5 the lateral and vertical needles appear but remain frozen
(08-19-2025, 09:14 PM)adminOwner2 Wrote: Hello,

We will start by stating that RSG G500/G5 do not offer official TDS GTNXi support, because of this, behavior as stated above will occur.

If you are in GPS mode in the respective GTNXi unit, then the TDS GTNXi will not overwrite the NAV source, as stated above, since you have "Connect GPS to VOR" disabled, which is correct. We merely write to the appropriate GPS1/GPS2 datarefs.
Continuing with the remaining scenarios:
  • VOR NAV1.pdf – G500 shows the correct VOR needle, the G5 interprets it as a localizer, shows a green GS which should not exist, and the GS is frozen
  • VOR NAV2.pdf – G500 shows the VOR needle correctly, but the G5 shows a magenta needle pointing in the wrong direction and also a magenta frozen GS

I hope these PDFs give you a clear picture of the situation. The datarefs shown in the screenshots do change as expected, but I am not completely sure if they are always the correct ones or if they reflect exactly what should be seen for each case. At least they help to illustrate the behavior.
Could you please confirm whether this is simply because the RSG G500 and G5 are not officially supported, or if there are adjustments that could make this work more reliably. And are there any plans to add proper support for the G500 and G5 in the future.

Thank you again for your time and support.
Best regards,
Fritz

RE: Issues with GTN 750/650 NAV2 integration in X-Plan - adminOwner2 - 08-26-2025

Hello Fritz,

Thank you for the information.

Unfortunately we do not know when there will be official support from RealSimGear for the G500/G5 gauges coded by them, this question needs to be addressed to RealSimGear.

What we can state is that we see a mismatch in screenshot ILS NAV2.pdf where both GTNXi units are in VLOC mode, yet the G5 is in GPS mode. The G5 should be tied/configured to match the TDS GTNXi, Copilot unit:
sim/cockpit2/radios/actuators/HSI_source_select_copilot (GTNXi Unit 2; 650 in your example)
and of course the _pilot for the Unit 1 GTNXi (750 in your example)

The only item that we are looking into is this, which could be a TDS bug, pending analysis:
http://forum.tdssim.com/thread-1596.html

If this is the case, then it will solve VOR NAV1.pdf from your post.

Let's recheck the VLOC mode when we release the new version, if this is a TDS issue, then for the GPS mode, we would direct you to RealSimGear.

Best regards.