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IFR w/ GNC420/SL30/Sport SX EFIS

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dtw_rv6

Well Known Member
Lot's of acronyms flying around in my head these days.

I currently have a GRT Sport SX with an SL30. I'm considering the addition of a GNC420 (non WAAS) for use as an IFR training platform.

The SL30 communicates via serial and works well for non-GPS approaches.

I'm not clear what an ARINC429 interface would get for me with this setup.
Will the EFIS display the full externally entered flight plan? If so, will it work with only the serial connections, or again is ARINC a requirement?

I realize that several more advanced EFIS' can do this, but I have most of the gear already installed and paid for. I'm just wondering what the limitations of the SX will be for me. Obviously I won't be able to overlay approach plates.

Thanks!
Don
 
Lot's of acronyms flying around in my head these days.

I currently have a GRT Sport SX with an SL30. I'm considering the addition of a GNC420 (non WAAS) for use as an IFR training platform.

The SL30 communicates via serial and works well for non-GPS approaches.

I'm not clear what an ARINC429 interface would get for me with this setup.
Will the EFIS display the full externally entered flight plan? If so, will it work with only the serial connections, or again is ARINC a requirement?

I realize that several more advanced EFIS' can do this, but I have most of the gear already installed and paid for. I'm just wondering what the limitations of the SX will be for me. Obviously I won't be able to overlay approach plates.

Thanks!
Don

I have a GRT HX (ARINC built in), SL30, 420W. I cannot recall exactly what you loose without the ARINC. I think ?OBS mode? (useful for holding) is lost, as the OBS communication is via ARINC. Most autopilots will use ARINC commands. I?d call GRT, see if they can give a definitive answer. I?d also put in a plug for the WAAS model (I know, more expensive) gps. Having LPV (precision) approaches to so many non-ILS airports is really nice. Also, you can legally fly ifr even if your SL30 dies. BTW, the SL30 can bring in two VORs at the same time. On the HX HSI page, one is shown as the main cdi, the other as an RMI pointer. Here?s my suggestion: get the 420 non waas if the price is right. Get your ifr rating. Then decide what panel you need, want, or can afford.
 
Will I see the Approach/Enroute/Missed approach routes on the Sport, or is it just giving me the LOC/GS needles?

WAAS just gets you down to 200' minimums, and I don't seeing doing that anytime soon in my RV. I know an ex- Harrier pilot that won't fly down that low in a GA aircraft. That's enough to tell me I'm a long way from needing LPV.

I have a bead on a GNC420 for $2700. Seems like a step up from a 300XL, but that's why I'm asking about what I'll see on the Sport.
 
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I don?t know the the answer to your first question, as I have an HX. But even so, my preference is to split the screen PFD/HSI, and look at the 420 if I want a map.
As to WAAS, don?t just think ?200? agl?; think ?lower than non-precision?. Here at LVK, if there?s a 500? overcast, LNAV is useless, but LPV easily gets me home.
For $2700 (plus database cost) I think it?s reasonable to get the non-waas, get the rating and some experience, then decide what you really want or need in a panel.
 
WAAS gets you a lot more (in the 5X0/4X0 Garmins) than just LPV ability. Additionally, in my humble opinion, an LPV to 200' is safer than an RNAV dive-and-drive to 400'. Any time you file IFR you need to be able to use all the tools you will learn. Twice I've had to shoot LPV approaches when the forecast weather was VMC. VNAV only would not have gotten me in.
 
WAAS is worth getting. For starters (IIRC), if you have WAAS, you don't care about RAIM. And although you may never *plan* to fly an approach to 200 feet (I don't), weather has sometimes been known to be worse than forecast, and sometimes to change after takeoff. And if you get a non-WAAS GPS, in a few years it may be nigh unto unsellable if you want to upgrade to WAAS.

Ed
 
I first installed a 430w without ARINC. You miss out on a LOT. Don't do it.

WAAS just gets you down to 200' minimums, and I don't seeing doing that anytime soon in my RV.

I'm going to be blunt.

That is unrealistic. Weather is not always as forcast. For example, I have flown towards an airport that was forcast not just VFR but CLEAR VFR for the whole day, only to shoot an approach to minimums because fog developed in the last 10 minutes of the flight. How are you going the use your fuel for this eventuality? 1.5 hr range so you can return home?


I know an ex- Harrier pilot that won't fly down that low in a GA aircraft.

That is just simply irrational.
 
For a non-WAAS 420 with no Nav radio, you miss out on very little without ARINC. As mentioned already, it somewhat depends on your auto pilot, because some auto pilots use ARINC for vertical steering.

I think you are missing out on most features by not being WAAS, but then you would certainly want ARINC.
 
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