HDX, IFD, External CDI

[r2brou2]

I currently have an Avidyne IFD 540 connected to an external GI-106A CDI. I'm looking at adding a Dynon HDX system.

I would connect the IFD to the HDX according to the 3rd Party Device configuration reference guide and I want to keep the GI-106A connected to the IFD. Does anyone have any experience with this? Avidyne said they have no data and they haven't tested it. They didn't say it wouldn't work, they said I'd need to test it to find out.

My main concern is when the IFD is in VLOC, where would it get the selected course/radial since there would be two sources. It would be ideal if the HDX and the GI-106A course/radials are sync'd. Since the GI-106A is mechanical, I imagine I'd always have to twist it's OBS to select a course. Would the IFD read this course and transmit that selected course to the HDX for them to stay in sync? If there is a conflict with the two sources, is there a way to disconnect just the HDX VLOC selected course/radial to the IFD so that I can get the behavior I just explained?

The whole point of this is that an ADAHRS or HDX screen failure (in a single HDX installation) will lose the course devation info. The IFD has a widget that can display a lateral GPS CDI, but there is no vertical guidance and no VLOC guidance. The D30 only backs up the flight instruments so I'm trying to figure out how to keep my mechanical CDI as a backup.

 

[r2brou2]

I figured I owed an update here. I now have the configuration I described and it works great and would recommend it to others.

When in GPS mode, both the HDX and external mechanical behave as if the other isn't present.

In VLOC mode the HDX HSI and the external mechanical CDI both get the same info from the IFD as if the other wasn't there. This means that I can dial in independent courses into the HSI and the CDI and they both act independently as if I was driving them from 2 different radios on the same frequency. The only difference here is that they are always tied to the one frequency the IFD is tied to.

If I turn off the HDX, I still have fully functional vertical and horizontal GPS and VLOC guidance available on the external CDI.

We also moved the HDX left to fit the backup D30 between the GPS and the HDX so I have a vertical column with my D30, CDI tied to my IFD, then horizontal guidance only CDI only tied to my 2nd NAVCOM. If the HDX goes dark, everything I need is right next to each other for a nice compact scan.

 

[benapilot]

Nice setup!
Completely off topic….

What is your gust lock solution? I have a 182 and I’m in the process of installing a single screen HDX. The screen blocks the gust lock hole from the top and I’m trying to figure out a solution.

Thanks!

 

[r2brou2]

Sorry I can't help you, my factory gust lock setup is a horizontal pin through the yoke collar so mine works just like before and I didn't have to modify anything.

 

[GKC Aviation]

What is your gust lock solution? I have a 182 and I’m in the process of installing a single screen HDX. The screen blocks the gust lock hole from the top and I’m trying to figure out a solution.

What model 182 do you have?
I did a 182Q, and it has a horizontal gust lock

 

[GKC Aviation]

 

[r2brou2]

Mines a Q as well with the same setup you have. The earlier models went top down, not sure what year they changed.

 

[benapilot]

Mine is an L model with a vertical gust lock. It fits upside down and there may be enough of a load on it from the elevator that it won’t slip out. I may rig some sort of Velcro strap that acts as a retainer…

 

[r2brou2]

Mine is an L model with a vertical gust lock. It fits upside down and there may be enough of a load on it from the elevator that it won’t slip out. I may rig some sort of Velcro strap that acts as a retainer…

I wouldn't want to rely on the load from the elevator and I like the velcro or similar retention idea. At least wiggle the elevator from outside with the gust lock in and see if you can release the load enough for it to fall out. The whole point is hold the control surfaces in the wind so you would want to simulate the wind loads and make sure it would stay put.

Do you have a Dynon screen on the copilot side? I'm not sure if the copilot yoke tube is drilled for a gust lock or not, but I know that the Q model originally doesn't have the collar with the hole for the lock on the copilot side like you can see in GKC Aviation's picture. I didn't like the look of the grommet retention plate that was behind the old overlays or the open hole look so I got a second collar from a junked airplane and installed that on the copilot side. Since I don't have a second Dynon, if the tube was drilled, I could put the gust lock in that side instead. I'd want to add a streamer that I'd weave between the throttle/prop/mixture to make sure I didn't forget about it doing it that way.

Would you be able to install a retention pin like this from the bottom? It doesn't protrude much out of the top and might be behind the bevel of the HDX. You could put a remove before flight streamer on this to make it obvious.