Dump the CDI?!?!

Hi All,

Going to be installing a SV-D700 Skyview soon and want to be able to shoot VOR/ILS approaches using the built-in HSI. The question is to keep a seperate CDI or not? Obviously, redundancy is always good, but then so is a clean panel and a lighter airplane.

My thinking is that in the unlikely event that the screen goes dark in the middle of an approach, I have enough redundency (handheld GPS, altimeter, airspeed, turn coordinator) to abort and get vectored to VFR conditions. Or, in the case of a VOR approach, I have a back-up handheld with VOR capabilities. The reality of my IFR flying is usually punching in to our out of a layer.

Anyone faced or facing this decision?

Thanks!

Lose it...Most GPS/VOR/LOC/GS nav sources have a built in CDI of some sort you can use as a backup.

If you keep the mechanical one and use it in parallel with the Skyview, there might be issues with who owns the OBS setting.....

I agree with Brian but...

...I'd be more concerned about staying right side up in IMC. To that end, I have an ADI II that has a horizon that shows pitch and bank.

The CDI inside the Dynon is easier to use, IMO.

Best,

I'd say use the one in the EFIS. Now that it appears Dynon is making the CDI a realistic and usable size it's the way to go.

On top of that, you can't easily "share" analog type CDI's with EFISes and there are more reasons than just the plain HSI/CDI to have the NAV source interfaced with your EFIS - especially if you plan on using the autopilot. Lastly, the price of the little CDI's (2 or 3 inch) will pay for a lot of Dynon equipment!

Cheers,
Stein

By not installing the CFI, you've covered the cost to go with the 10" too.

Looks like 4 votes to None!

Thanks for all the great feedback guys. I agree with prioritizing maintaining orientation in IMC so a TC and altimeter are included as backups in case the screen goes dark (as well as ASI).

This simplifies the wiring, shaves some weight, and means I can sell my CDI to pay for other upgrades!

When we re-did :Louise's panel a few years ago, we had the digital CDI that she had used with he SL-30, and we had the panel space, so we installed it along with the two Dynon screens. Yes, it is extra redundancy,m but it was free, and I find that I like setting the OBS with that knob far better than with the push-buttons on the D10A or the D180. I have never run in to a "contention" problem with it (between units).

I doubt I'd buy a CDI as a backup if I didn't already have one on the bench (I haven't for the -8, or the -3), but since it was there, it works well.

Paul

I'd keep it, I had the experience of one going dead on a low approach and it's no fun. For me redundancy is king.