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Dealing with old antenna holes

bill.hutchison

Well Known Member
Rude awakening time.

My 6A had an old Levil Beacon ADS-B Out system; apparently one of the few that worked reliably - seriously, Levil was shocked that it worked fine when I called them and asked for a manual.

Anyway - it used a Rami 180 antenna on the turtledeck for the GPS source, and there was a belly-mounted antenna for the OUT.

The new stuff won't use the same holes - footprint is different for the turtledeck antenna, and the belly antenna just won't be used.

What's the best way to deal with it? Fab up some aluminum and just cover the holes up? Do it from the inside and then glass it? Just leave the old antennas in place?

I figure there are lots of ways to deal with it but I'm new to this and wondering how to cover/plug and get a nice-looking finish. I dislike the idea of leaving the old antennas because....well...just because. I'd like to delete if I can.


Thanks in advance.
 
A dime-dollar patch is a common way to fix something like this. It's a common repair for holes in sheet metal panels that has been around since God was a kid and a version of it is in the 43.13.

Basically, it's an internal doubler without any antenna holes in it then a small plug the same shape and thickness as the hole you want to fill riveted to the doubler. You can then fill and paint to match if you want, but there are millions of airplanes flying around with dime-dollar patches perfectly visible and the smallish ones tend to blend right in once they're painted to match the base color.

It gets it's name from the idea of a sliver dollar with a dime stacked on top.
 
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A dime-dollar patch is a common way to fix something like this. It's a common repair for holes in sheet metal panels that has been around since God was a kid and a version of it is in the 43.13.

Basically, it's an internal doubler without any antenna holes in it then a small plug the same shape and thickness as the hole you want to fill riveted to the doubler. You can then fill and paint to match if you want, but there are millions of airplanes flying around with dime-dollar patches perfectly visible and the smallish ones tend to blend right in once they're painted to match the base color.

It gets it's name from the idea of a sliver dollar with a dime stacked on top.

Neat idea - makes a lot of sense for the antenna holes. I'm guessing the doubler is riveted to the skin? Or is it glued or something?

For the screw holes, they're quite small - #6 or #8, I think. Filled the same way?
 
Doubler/dollar riveted to the skin, plug/dime riveted to the doubler. FYI- they don't have to be round, that's just a way to visualize it and the name stuck.

AC43.13 has guidance for rivet spacing and pitch for all this.

For the antenna mounting screw holes, you have several options;

They are likely sized for a #6 so you could dimple and install a -6 rivet to fill the hole, but it takes a lot of grunt to set a -6 rivet, especially is something as thin as a skin. Unless you're using soft non-structural rivets that are easy to set, the chances of an oopsie are higher than with a smaller rivet that requires a lighter touch.

You can just fill them with filler and hope it doesn't pop out. You could also fill them with fiberglass flox.

Personally, I would just match drill the doubler, dimple the holes then reinstall flush screws. note- I'm not talking about using filler over the screw heads, I'd install the screws after any sand and fill operations and and just leave them exposed like a fairing screw. If you didn't want to dimple all that stuff you could also just install pan head screws. Either way, a screws that looks like it's intended for something isn't nearly as ugly as a screw hole that the filler has popped out of. Who knows, it might be a handy place for a future go pro mount or something.
 
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Rude awakening time.

My 6A had an old Levil Beacon ADS-B Out system; apparently one of the few that worked reliably - seriously, Levil was shocked that it worked fine when I called them and asked for a manual.

Anyway - it used a Rami 180 antenna on the turtledeck for the GPS source, and there was a belly-mounted antenna for the OUT.

The new stuff won't use the same holes - footprint is different for the turtledeck antenna, and the belly antenna just won't be used.

What's the best way to deal with it? Fab up some aluminum and just cover the holes up? Do it from the inside and then glass it? Just leave the old antennas in place?

I figure there are lots of ways to deal with it but I'm new to this and wondering how to cover/plug and get a nice-looking finish. I dislike the idea of leaving the old antennas because....well...just because. I'd like to delete if I can.


Thanks in advance.

You could just make a nice patch the shape of the base of the new antenna that will cover all of the old holes. Taper the edges of the patch for a nice transition from the skin. Seal it down with a thin layer of pro seal. Place a backup plate on the under side.
 
Download the AC43.13-1B document for free from the FAA website.

Go down to Figure 4-16 on page 173 of the PDF and you will see some typical skin repairs.

Thank you for this. It's a fascinating document.

What I *think* I'm going to do is fabricate a doubler using the old ADS-B OUT antenna base as a template, but make a hole that I can mount the new UAT antenna to so that I don't have to drill an extra hole in the airplane's belly.

For the turtledeck antenna, it would end up being just two #6-sized holes. Filling them seems simpler, but while I mull that over, I'm going to put the old antenna in place and probably mount the SV-2020 antenna on the glareshield. That will give a decent weather seal while I decide what to do there.
 
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