My SB 14-12-06 experience

[Piper J3]

Originally Posted by AirHound

Anybody, do the wings have to come out or off, and flaperons and push-rods disconnected to take out the original and install the new SB bracket?
__________________
Doug

Look here for SB 14-12-06... https://www.vansaircraft.com/service...12&doctype=all

[Strappe]

The original SB 14-12-06 advises to remove both wings, and the fuel tank. Some have written that they were able to do it without removing the fuel tank. Not sure how, however, unless you can get out the blind rivets on the R side by going at it under the fuel tank from aft of it.

The engineers at Van's are convinced there was a direct impact on the brace, and assured me that load forces on the airplane would not affect it that way, and would have done damage elsewhere that would be obvious.

[rvbuilder2002]

Originally Posted by Strappe

The engineers at Van's are convinced there was a direct impact on the brace, and assured me that load forces on the airplane would not affect it that way, and would have done damage elsewhere that would be obvious.

The damage visable in the photo could have occurred from a direct impact on the flapperon torque tube. Such as a hard hit during wing installation when a flapperon wasn't properly aligned.
Please do a thorough inspection of the flapperons and related systems.

[rvbuilder2002]

Originally Posted by Strappe

So, #rvbuilder2002, do you think this was related to unusual load on the fuselage rather than to a direct impact on the brace instead? I ask, because last year during the CI, I was trying to get better placement of pads on a saw horse by lifting the aircraft with my back in the bulkhead line of rivets and hear a long pop at one point. I was afraid I had damaged something, but I did not find anything after lookin it over carefully inside the fuselage. I did not see any rivet parts anywhere.

This year, however, I noted the missing rivets and I saw a single rivet head lying on the fuselage floor in the tail section between the bulkhead I had lifted on and the next one aft. That's when I also noticed the 4 missing rivets, all of which I replaced. I don't know if I looked behind the flaperon tubes at that point. The bulkheads and all fuselage metal is not distorted or bent anywhere on the inside or outside of the airplane, and it never flew any differently after the CI last year (for what that's worth).

There is a rivet intact in the lowest hole.

Here is a wider view of what I found this past fall.

That is the exact type of scenario I was thinking of.
The pop you heard was likely the rivets letting go.
The last one didn't because once the others shear, it just became a pivot point that the two parts rotated on.

[bobg56]

Yes, the wings come off so you can remove the flapperon linkage to get access to repair area, I also removed fuel tank, it's pretty tight if your a big guy.

[Strappe]

Originally Posted by rvbuilder2002

The damage visable in the photo could have occurred from a direct impact on the flapperon torque tube. Such as a hard hit during wing installation when a flapperon wasn't properly aligned.
Please do a thorough inspection of the flapperons and related systems.

Will do. I will ask some other RV-12 owners to take a look as well.

This is the only time I have ever removed the wings, and I have yet to install them. I removed them to install the AOA kit.

[bjdecker]

Originally Posted by Strappe

Yesterday, while routing 1/4" tubing during the installation of the AOA Retrofit Kit, I discovered the crack (complete break) in the bearing brace Part# F-1206F affected by SB 14-12-06. We bought the plane from its builders in 2017 and have put about 200 hours on it. The aircraft documents reflect compliance with the SB via replacement of the brace. I have done two condition inspections, most recently in September, and never noticed this crack, though I admit I was not looking for it. I had checked the torque seal on each occasion, but I believe the crack would have been hidden behind the flaperon push rods.

This break looks to me to be the result of a rather violent force. The support tech at Van's thought it the result of a direct blow of some sort. He shared the photos with their engineers, and they arrived at the same conclusion.

That seems very odd. That's not a place where it would be easy to strike the brace with enough force to break it. Even so, the dent in the brace away from the crack and what looks like a scrape in the metal are hard to dismiss.

(I have also posted an image of a problem I found at the last inspection in September where 3 of 4 rivets were missing from a rib.)

Anyone have other thoughts?

The AN3-?A bolts through the rod ends looked a little long to me, then I noticed that the nuts are AN364 instead of (probably) AN365 -- might want to check those. Also, I think the servo arm angle looks a little much, could be the washer stack-up? Usually it's bolt head, Big 5702 washer, Small 5702 washer, rod end bearing, small 5702 washer, arm, AN960 washer, AN365/MS21042 nut.

[jrtens]

The nut is correct. The 12 KAI 32 specifies an MS21083-N3 which is similar to the AN 364. Saving weight wherever they can.

[Strappe]

Originally Posted by bjdecker

The AN3-?A bolts through the rod ends looked a little long to me, then I noticed that the nuts are AN364 instead of (probably) AN365 -- might want to check those. Also, I think the servo arm angle looks a little much, could be the washer stack-up? Usually it's bolt head, Big 5702 washer, Small 5702 washer, rod end bearing, small 5702 washer, arm, AN960 washer, AN365/MS21042 nut.

[pilotyoung]

I'm in the process of my condition inspection right now. When inspecting for this service bulletin, I noticed a crack on the pilot's side of the bracket. I called and ordered the fix and today was able to remove the fuel tank. I don't see how you could possibly do this repair without removing the fuel tank. My airplane has 575 hours on it.