FWIW... I'm in the middle of wiring my dual G5s now. I have a GNS430, GTX345, and an Stec30. Currently I view weather and traffic from the 345 on the 430 (and 796)
To interface the G5 with the autopilot, the install requires a box called the GAD 29.
To wire the system, the GNS430 needs to ingest EFIS/Air Data streams from the GAD29 into BOTH the available AIRINC 429 ports (pins 48/49 and 50/51) (Fig 5-12 in the install manual)
Why does this matter? To get WX/Traffic from the 345, the 430 uses one of the 429 streams (pins 48/49.) Apparently, Garmin F'd up and there is not enough space. Soooo... Garmin just told me I had to choose. If I wanted to use the 2nd G5 as and HSI w/ my autopilot and GPS/VHF Navigator, I will NOT be able to get WX/Traffic on the 430.
BTW, this is the same for the GTN6XX/7XX, 5XX, and 480.
WTF!?!?!?
That said... There is a glimmer of hope. Garmin knows this SNAFU and says they are working on it. They wouldn't give me a time frame, but the next software REV is suppose to fix this. They have already done the programming, they just need the approval. The new update will allow for all EFIS/Air Data junk to talk to the 430 via one 429 channel rather than two, allowing for the 2nd to be used for the traffic from the 345.
Ugh.....
If anyone wants to look at the install, it is here: http://static.garmin.com/pumac/190-01112-10_11.pdf


