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Garmin AOA retrofit install

- Poindexter -

Well Known Member
Bought a low time (2014) RV7A 6 months ago, and “oh boy,” it’s been wayyyy better than expected! Anyway, been doing changes/upgrades/maintenance which has been fun. The plane is an all Garmin glass panel, which includes (2) G3X non-touch (370’s); GSU 25; but with a heated Falcon pitot and only one pitot line (no AOA line).

I’d like to replace the Falcon pitot with a heated, regulated Garmin GAP 26 pitot/AOA. The only (potential) obstacle is running an AOA line from the GSU 25 to the GAP 26. There are (3) wing access panels.

Wanted to see if it’s possible and hard/easy to run the AOA line through the wing, and how to do it. Looks like the challenge is the wing-walk section with multiple ribs to navigate. And, I really, really don’t want to remove the tank.

Did lots of search on this site, but no detail for a Garmin AOA retrofit detail. Any suggestions and tips would be great. Reference pictures below. Thanks.
 

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Sounds like an interesting project. You certainly don't need to remove the fuel tank. Everything you're going to need to do will be on the aft side of the main spar. I would check AC43.13 from the FAA for acceptable methods of securing the air line in the wing sub-structure.

It's likely that someone in here has done this before.
 
Paul, I had to do this on my 7 as I wanted to add the AOA Garmin late in the build just before inspection. The most difficult part as you see is the line back too the panel. Routing on the near backside of the spar is very difficult due to drilling new holes in the ribs between the inspection hole and the fuse.

Oh - take off the intersection fairing at the wing/fuse. I chose to route the AOA tube within the 2nd lightening hole aft of the spar. I made a standoff to hold a tube (used as a conduit) that entered the side of the fuse via a drilled hole with a rubber grommet to hold the tube in place. This tube bridged several ribs inboard of the nearest inspection to the root.

You can figure the rest. Do it right, not all with materials on hand!
 
Adding AOA tubing

Yes - the wing walk area is the most difficult part. As Bill L mentioned, I removed the intersection fairing. I also removed the aileron pushrod boot and disconnected the aileron pushrod so I could move it out of the way to give me access to the wing walk area.
I used the harness clips that DeeCee/Dan57 mentioned in an older post- Mouser P/N 523-ALBCBS3045909. These clips snap onto the rib lightening holes (one way “snaps on” better than the other). These clips have a saddle on them, that I attached the AOA tubing to with zip ties. I drilled an additional hole in the fuse for the AOA tubing to pass thru (using a snap bushing). I did not drill any holes in the ribs for the tubing - I used the clips instead.
 
Clips

Tim,

I’ve been thinking about adding AOA to my -8, those Mouser clips look like just the thing for securing AOA lines. Will these clips stay in place long term or did you add a bit of epoxy to make sure they don’t slip?
 
Thanks for the credit Tim :)
I’ve installed those clips dry, more than a year ago, and up to now all is holding well. Applying some epoxy sure wouldn’t hurt.

And you guys are lucky with the -7 (and -8) having 3 access panels vs 1 on mine, should make things much easier.
 
Oly -
My clips have been in place for about 60 hours of flying, so far no issues. I thought about using a dab of glue, or drilling a hole and safety wiring to the rib, but so far have not needed too. My clips are on the bottom side of the lightening hole - with enough negative Gs, they might pull off, but I'm not acro.
 
Great feedback and thanks for the detail email Tim! Has anyone tried to drill an additional hole for the AOA line, with using extension for jumping ribs at the wing-walk area? Looks super tricky to accomplish.

Looking to do Gentlemen’s acro in the future, so want to make sure the tube stays where it should. The additional epoxy method would be great.
 
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