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G5 Navigating with only RS232 data

birddog486

Well Known Member
When tied to a WAAS Navigator, Is there a way to get the correct lateral scaling displayed on the G5 using RS232 data without a GAD29?
 
Well we're missing some specifics.

However, I found that my Garmin 4xxW series - which outputs both RS232 and ARINC 429 - ONLY outputs the necessary data for auto scaling on the ARINC 429 output.

So in the dynon world, you need to have the HS34 interface so you can wire up ARINC 429. That also then gave me turn anticipation for the autopilot. Nice to have flying approaches.
 
No

Short answer is no, no scaling information is sent via RS-232. When hooked to a 4xx via RS232, it functions pretty well as a “GPS” HSI though, which is how I have mine right now until I get the GAD29 in there. With the GAD29, it translate ARINC data to canbus data, and you get full CDI functionality, including vertical and lateral guidance. What I have noticed though, is if you drive an autopilot from the G5, even without the scaling, it is so accurate anyway that the lateral deviation will keep you well within 1 dot of CDI deflection from a standard “needles” indicator. Since I don’t have a GAD29 yet, I let the autopilot fly the lateral course, while I hand fly the vertical glide slope or step down, when you “break” out, your dead center on the approach. Gonna get around to that GAD29 one of these days…
 
The scaling issue is for approaches and not used for other tracking. Not sure on the legalities, but keep in mind that in enroute mode, full deflection is 5 miles off course and when scaled for the approach segment, full deflection is 1 mile off course (2 miles within 30 miles of approach airport). I don't think I would fly an approach to minimums with enroute deflection outside of an emergency. In emergencies, the 430 has a CDI screen that scales.

Larry
 
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RS-232 Information

The RS-232 datastream contains crosstrack information, but we do not know what full scale deflection represents from that information, so the deviation is not scaled properly. As mentioned, depending on the phase of flight, full scale deflection will represent different values, so the RS-232 information is not reliable for IFR Flight. You would only want to use that information for VFR navigation.

Thanks,

Justin
 
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