Proper procedure for touch up paint on control surfaces?

Fearless Tower

Fearless Tower

Touchdown! Greaser!
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Fearless Tower
Noticing some paint failure on the trailing edge of my elevator trim tab. I'd like to get it touched up to prevent it from getting worse.

Any restrictions or recommended procedure on touching up a trim tab? With proper masking, I should be able to do the application without needing to remove the trim tab.
 
Someone with more mechanic knowledge than I may want to comment on when the requirement to rebalance the control surface kicks in after painting. I know there is one, but not the triggering criteria. But I am certain that an A&P has to be involved in that when it is required.
 
Is it an older Barron is the part aluminum ?
 
To me that's new,the older beech aircraft used magnesium for the trim tabs,they where constantly rotting from the inside out. I changed the tabs to aluminum and the problem went away.
 
Remove any corrosion and old piant on the surface and then touch up. The removal of the old paint and adding new paint has no effect on the surface balance. If it were that critical it would had never be approved. The flutter range is explored during the GVT and flight test. On most planes the control surface linkage is enough to dampen flutter conditions.

José
 
Piloto said:
Remove any corrosion and old piant on the surface and then touch up. The removal of the old paint and adding new paint has no effect on the surface balance. If it were that critical it would had never be approved. The flutter range is explored during the GVT and flight test. On most planes the control surface linkage is enough to dampen flutter conditions.

José
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Can you tell us which FAA document says this is OK? The one thing I know for sure is that repainting balanced control surfaces is not preventive maintenance and thus requires an A&P's involvement.
 
Ron Levy said:
Can you tell us which FAA document says this is OK? The one thing I know for sure is that repainting balanced control surfaces is not preventive maintenance and thus requires an A&P's involvement.
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How many FAA inspectors can dance on the head of a pin?

Jim

.
 
Ron Levy said:
Someone with more mechanic knowledge than I may want to comment on when the requirement to rebalance the control surface kicks in after painting. I know there is one, but not the triggering criteria. But I am certain that an A&P has to be involved in that when it is required.
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Do you really think removing a layer of paint and then replacing it will change any thing?

Yes, rebalancing a flight control is an A&P function.

but paint touch up is not.
 
I wouldn't swear to this, but legally speaking, I think any time a control surface is painted at all, it has to be check balanced, unless the manufacturer's manual says otherwise. The acceptable range for static moment on an aileron usually is pretty narrow.

Practically speaking, I doubt removing old paint and replacing it with new paint would make a difference. But it it were my airplane, I would check balance it, anyway.

-Rich
 
Ron Levy said:
Can you tell us which FAA document says this is OK? The one thing I know for sure is that repainting balanced control surfaces is not preventive maintenance and thus requires an A&P's involvement.
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FAR 43, Apendix A Para (c ) item ( 9 )

(9) Refinishing decorative coating of fuselage, balloon baskets, wings tail group surfaces (excluding balanced control surfaces), fairings, cowlings, landing gear, cabin, or cockpit interior when removal or disassembly of any primary structure or operating system is not required.

Trim tabs are not balanced.
 
RJM62 said:
I wouldn't swear to this, but legally speaking, I think any time a control surface is painted at all, it has to be check balanced, unless the manufacturer's manual says otherwise. The acceptable range for static moment on an aileron usually is pretty narrow.

Practically speaking, I doubt removing old paint and replacing it with new paint would make a difference. But it it were my airplane, I would check balance it, anyway.

-Rich
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The parameter of the elevator on a 170/172 is plus (0) minus 22 inch pounds maximum.

IOWs when you attach it to the fixture as described in the 100 service manual, when you let go, it will go trailing edge down and require no more 22 inch pounds to lift it.
 
Tom-D said:
The parameter of the elevator on a 170/172 is plus (0) minus 22 inch pounds maximum.

IOWs when you attach it to the fixture as described in the 100 service manual, when you let go, it will go trailing edge down and require no more 22 inch pounds to lift it.
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Thanks, Tom. I actually understand how it works and how it's done. But it's been too long since I studied or used that information to remember the legalities.

As I recall, however (and I could be wrong about this, too), ailerons are check balanced with the trim tabs attached, so I'm curious why you say they're not balanced. They're not separately balanced, but wouldn't they be considered part of the aileron for balance purposes?

Again, I'm talking legally, not for practical purposes. I doubt it would make any difference in this specific case.

-Rich
 
RJM62 said:
Thanks, Tom. I actually understand how it works and how it's done. But it's been too long since I studied or used that information to remember the legalities.

As I recall, however (and I could be wrong about this, too), ailerons are check balanced with the trim tabs attached, so I'm curious why you say they're not balanced. They're not separately balanced, but wouldn't they be considered part of the aileron for balance purposes?

Again, I'm talking legally, not for practical purposes. I doubt it would make any difference in this specific case.

-Rich
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The Cessna 100 series ailerons were not manufactured with tabs. They are weighted in the leading edge and must meet their criteria in the MM, by adding or removing the weight to make the aileron stay neutral. They have a pretty loose balance allowance. When anyone adds a tab to make the aircraft fly right, the tab must be in place when the balancing is done.
 
Tom-D said:
Trim tabs are not balanced.
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Yeah, but the elevator they're attached to frequently is. The trim tab on the Navion after you install the PA Tail STC is a substantial amount of surface.

Of course, the amount of grime on my elevator usually exceeds the amount of anything that could be considered a touch-up to the paint.
 
I was unable to look into the Baron Service manual, but I would start there and see what it says. The 100 series manual that Tom has mentioned has a section for paint touch up in Section 19 I believe (but that doesn't help you). Either way, If you have access to the manual it will most likely give you some kind of guidance.
 
Don't a lot of Baron's have magnesium control surfaces in the tails? Further isn't paint damage often an indicator of underlying corrosion?
 
Alexb2000 said:
Don't a lot of Baron's have magnesium control surfaces in the tails? Further isn't paint damage often an indicator of underlying corrosion?
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Older barons do. I don't believe mine does not have magnesium but I am looking.

As far as underlying issues, the paint is at least 10 years old and you can see quite clearly that there is no corrosion at the trailing edge where it is chipping. It isn't a large area, but I want to address it before it gets worse.
 
Tom-D said:
FAR 43, Apendix A Para (c ) item ( 9 )

(9) Refinishing decorative coating of fuselage, balloon baskets, wings tail group surfaces (excluding balanced control surfaces), fairings, cowlings, landing gear, cabin, or cockpit interior when removal or disassembly of any primary structure or operating system is not required.

Trim tabs are not balanced.
Click to expand...

But they are on the high leverage side of a balanced surface. IIRC any time you painted a Beech tail feather, checking balance was a requirement. That said, I don't think touching up the paint is going to be a mass critical situation.
 
Fearless Tower said:
Older barons do. I don't believe mine does not have magnesium but I am looking.

As far as underlying issues, the paint is at least 10 years old and you can see quite clearly that there is no corrosion at the trailing edge where it is chipping. It isn't a large area, but I want to address it before it gets worse.
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Clean the surface with toothpaste and a brush, wash it thoroughly with vinegar and use a brush to touch up the paint.
 
Tom-D said:
FAR 43, Apendix A Para (c ) item ( 9 )

(9) Refinishing decorative coating of fuselage, balloon baskets, wings tail group surfaces (excluding balanced control surfaces), fairings, cowlings, landing gear, cabin, or cockpit interior when removal or disassembly of any primary structure or operating system is not required.

Trim tabs are not balanced.
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True, but they are attached to a control surface which is balanced after the trim tab is attached.
 
Ron Levy said:
True, but they are attached to a control surface which is balanced after the trim tab is attached.
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Do you have the MM to declare what procedure is to be followed?
 
Ted DuPuis said:
The person who chipped it off must make sure that nobody calls the FSDO.
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Right,,,,, because it is a major alteration to use a small brush and replace the paint.
 
So when the paint flaked off, it changed the balance already. So one must balance the control surface to account for the missing paint then re-balance it to account for the touch-up???

I'm out of balance, Crap!
 
What is the permissible weight of bird droppings on a control surface before you need to check the balance? :rolleyes:

Seriously, if you're so close to the limit that a few small brush strokes will trigger a flutter condition, you have other, more pressing problems to address.
 
Tom-D said:
Right,,,,, because it is a major alteration to use a small brush and replace the paint.
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What brush? I didn't see a brush.
 
Jeff Oslick said:
What is the permissible weight of bird droppings on a control surface before you need to check the balance? :rolleyes:

Seriously, if you're so close to the limit that a few small brush strokes will trigger a flutter condition, you have other, more pressing problems to address.
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For sure.


I did watch a guy several years ago sand his control surfaces (ruddervator) and then skim them with bondo (hail damage) and repaint, then reinstall. :nonod:
 
Ron Levy said:
Can you tell us which FAA document says this is OK? The one thing I know for sure is that repainting balanced control surfaces is not preventive maintenance and thus requires an A&P's involvement.
Click to expand...

Can anyone find the FAA document that allows nature to remove paint from an aileron? Did the Chief Counsel approve said removal by dirt, air molecules, and perhaps ice?

I believe these elements are in violation of the FARs and should be fined heavily until they stop removing paint from aircraft without following FAA approved methods!

Let's write a letter to the Chief Counsel and see if her Highness can provide some lawyerly guidance to these rogue elements. They are exhibiting a disdain for her Eric Cartman-esque, author-I-tahhhhh!!!
 
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