Garmin G5 MapMx with GNS480

Garmin gurus: I just purchased a G5 to replace a Trutrak Gemini PFD as a backup to my "other manufacturer" primary EFIS. Currently my GNS480 has a standard connection to my primary EFIS via ARINC plus a single RS232 line.

I have no interest in changing the setup of the GNS480 to my primary EFIS, nor in purchasing a GAD29 at this time. That being said, several places in the G5 installation manual reference connecting a "MapMX" format RS232 line from the GNS480 to the G5 (see the diagram on page 7-8 of the G5 installation manual). Absent the other connections to the GAD29 ARINC, is there any benefit to this single MapMX data source? What exactly does it do? Will I or could I get some nav info from the GNS480 to display on the G5?

Trying to find a list of messages transmitted by MapMX and the corresponding documentation of which ones G5 uses. Anyone know where a guy might find such a unicorn?

Nobody? Any idea what the MapMX line does for the G5, versus just installing it with nothing but pitot, static, power, and ground?

HSI

I would think it would drive the HSI page that's available on the G5.

Thanks, Dan. Perhaps that's the case, and if so I wonder if I'll also get glidepath/glideslope.

Other thoughts are that to get all that functionality usually requires an ARINC interface, which I don't plan to install - so will the single RS232 do anything at all?

Installing the unit is straightforward enough - power, ground, pitot, and static are already piped to the unit that the G5 is replacing. Opening up the connector shell to the GNS480 to get another pin installed while panel-diving is a bit more invasive. Just trying to nail down whether it'll actually do anything before going to the trouble.

krw5927 said:

Thanks, Dan. Perhaps that's the case, and if so I wonder if I'll also get glidepath/glideslope.

Other thoughts are that to get all that functionality usually requires an ARINC interface, which I don't plan to install - so will the single RS232 do anything at all? . . . . . . . .

Click to expand...

A quick look at the G5 installation manual and pilot guide suggests that the RS-232 is all that is needed. In the pilots guide, there is mention of an SL-30 NAV as a source to drive the glideslope. As far as I know, the SL-30 does not have ARINC as one of it's interfaces.

All of this would be great questions for g3xpert on this forum.

krw5927 said:

Thanks, Dan. Perhaps that's the case, and if so I wonder if I'll also get glidepath/glideslope.

Other thoughts are that to get all that functionality usually requires an ARINC interface, which I don't plan to install - so will the single RS232 do anything at all?

Installing the unit is straightforward enough - power, ground, pitot, and static are already piped to the unit that the G5 is replacing. Opening up the connector shell to the GNS480 to get another pin installed while panel-diving is a bit more invasive. Just trying to nail down whether it'll actually do anything before going to the trouble.

Click to expand...

Hello Kurt,

Sorry, hesitant to jump in since we don't normally operate the GNS 480 and G5 without both RS-232 and A429 interfaces.

The A429 interface is necessary if you want to receive roll steering and vertical guidance for approaches. The vertical deviation bar shown on LPV and ILS approaches will not be present without the GAD 29.

Your G5 will receive GPS data from your GNS 480 with the MapMX RS-232 interface (making the external GPS antenna optional, but recommended), and it should also provide lateral guidance for the CDI/HSI.

Thanks,
Steve

g3xpert said:

Hello Kurt,

Sorry, hesitant to jump in since we don't normally operate the GNS 480 and G5 without both RS-232 and A429 interfaces.

The A429 interface is necessary if you want to receive roll steering and vertical guidance for approaches. The vertical deviation bar shown on LPV and ILS approaches will not be present without the GAD 29.

Your G5 will receive GPS data from your GNS 480 with the MapMX RS-232 interface (making the external GPS antenna optional, but recommended), and it should also provide lateral guidance for the CDI/HSI.

Thanks,
Steve

Click to expand...

Hey thanks Steve! Just what I was looking for!

OK so lateral guidance on the HSI page from the GNS480 GPS flight plan, and assuming nothing from the VOR side of the GNS480. No vertical guidance.

Assuming the G5's internal GPS works well in the RV, it looks like there may not be a huge benefit to adding this wire. You've saved me some installation time!

Thanks again all.

Just to close the loop, I installed the G5 this weekend, with the MapMX line from the Garmin GNS480. Everything works just as Steve said - it provides lateral deviation from the GNS480 course on the PFD page and it drives the HSI page. If my primary EFIS fails in IMC, a non-precision RNAV approach is now possible without having to continuously divide attention between the G5 and the GNS480.

What a cool unit. As a bonus, the altitude displayed at a given altimeter setting matches my "other brand" primary EFIS perfectly, with no difference noticeable most of the time. Oddly though, the G5 thinks the RV is going 1-2kts faster (IAS) than the primary EFIS. I'll take it!