SB 819 Fuselage Door Frame Corrosion

[Steve Pierce]

Here is a recent picture of a PA22/20 fuselage front door post with the sheet metal removed. The rust was blasted off of the tube exposing some pitting. A sharp awl was stuch into the deepest pit and a slight tap penetrated the tubing. All of the sheet metal was cut off IAW Service Bulletin 819. The short welds were cut off in such a way that they could all be blasted, primed with weldable primer and reinstalled.

[Gilbert Pierce]

Here is the same tube on my Clipper. Good reason to comply with SB-819

[Fred]

Those pictures are a great example of the old saying "A picture is worth a thousand words". Thanks for posting them. Congrats on the new site, it's going to be great.
Fred

[Steve Pierce]

Thanks Fred. Hopefully they will help someone else make the decision that it is a worth while service bulletin.

[Frankenpacer]

I'm sure glad this is common knowledge! It wasn't to me until I cut the sheetmetal off the tubes this weekend and found the same thing. My airplane is a desert bird so the corrosion cleans up with emery cloth, but I can only imagine how many are flying that are bad.

[Steve Pierce]

Found a spot of corrosion on the lower longerons at the tail brace wire attach fitting. Cut it off and this is how they looked underneath.

[Steve Pierce]

Here is a parts list from Univair for the door channels parts that are effected by Service Bulletin 819. The part numbers with a 16 are for the Clipper and everything else is for the Pacer/Tri-Pacer. These do have to be trimmed on the Clipper.

[Steve Pierce]

Some corrosion found on a fuselage that was flying prior to a good inspection.
3457 3458 3459

[Hillbilly]

Wow thats some lightweight tubing you found Steve!
in the second pic you posted, 100_0718 -on the starboard side diagonal tube, it looks like some "creative welding" running up the tube, what is that?

I recently got ahold of Dave Blanton's set of V6STOL Plans. He pointed out that water sometimes collects in the lower tubes and freezes solid in the winter. That certainly would explain the damage shown in Steve's last picture of the ruptured vertical tube damage near the bottom. I'll have to scan some of the info from Blanton's Builders manual. He offers several good insights on the SWP airplanes.

[Steve Pierce]

That is what it looks like happened Mark. It migrated into the next tube and corroded it also.

[Hillbilly]

Yes Mark when I read your post, I had an idea that you were on to something here.
To answer my own question Steve, applying Marks theory, I'm willing to stick my neck out
on the "creative welding" I asked about. It looks like water collected there, froze, split the tube and someone
closed it up and welded a patch over it.

[JohnW]

Being from Upstate New York (and I don't mean "Fishkill", just outside of "the City"... I mean UP NORTH!), I see this damage much more than I would like to. Often on airplanes that it's a cryin' shame to have to take the IA knife to, to fix!!! Split tubes (and "swelled up" tubes, as well). Yep. C'est la guerre. That's what that is...freeze damage.

[Steve Pierce]

Here is Service Bulletin 819.

[mjlossner]

I've been reading about the horror stories of SB 819 for years now and I think its a must do item! I have not had the opportunity to restore a short wing yet so i don't have any experience in doing the job--Yet. Question from those who have C/W SB 819. How do you reweld the door frames back on and not burn off the primer you just put on?
Thanks,Great Forum
Mikey

[Gilbert Pierce]

3M makes a weldable primer in a spray can. Welders hate it but it works. It does cause some sparking and smoking when you tig weld the sheet metal back on but it appears to work. We painted the tubing and the back side of the sheet metal with it prior to welding the sheet metal back on.

[Steve Pierce]

Another problem area I keep finding is in the wing root area of the fuselage where the wing root fairing screws to the fuselage frame. Water gets trapped in the trailing edge channel and the 3/8" channel and rusts the upper longeron. We are going to make the trailing edge piece out of a solid piece of material and fill the 3/8" channel with something. Hopefully between these fixes and a good two part epoxy primer and catalyzed polyurethane paint this will no longer be an issue on this Pacer.

Trailing edge of wing root.
100_2544 (Medium).JPG[/attachment:3c0pelcx]
3/8" Channel making the wing root fairing attach.
[ATTACH=CONFIG]3460
Top longeron repaired by inner sleeve method. The inside of this tube was like brand new. The corrosion was from the outside in.
[attachment=1:3c0pelcx]100_2553 (Medium).JPG[/attachment:3c0pelcx]

[Gilbert Pierce]

My Clipper was rotted out there as well.

[MichaelC]

Hi Folks,

Is there a downloadable copy of this service bulletin here on the site somewhere or does someone have it in PDF form that I might get a copy of?

I am (finally) beginning the restoration of my PA-22 and I want to be certain I check this one out as I've read some horror stories here on the site and others have recommended I do it, as well. I will be glass beading the fuselage, so it will be a good opportunity to check on this sort of thing.

Thanks a lot for your help and input!!

Michael

[Steve Pierce]

Second page of this thread. http://www.shortwingpipers.org/forum/showthread.php?4382-SB-819-Fuselage-Door-Frame-Corrosion&highlight=SB819

I merged the threads together.

[MichaelC]

Thanks a lot, Steve. I will be in touch soon to purchase some parts and STC's for the Tri Pacer...

Michael

[pistoncan]

As we mentioned on another SB819 thread, On the fuselage Im working on now, both upper longerons were rusted through up at the wing root and both had swell splits down by the tail. I also found the cross tube between the landing gear fittings was rusted out. (Both fuselages) I ended up replacing the all 4 longerons from the middle of the rear door to the tailpost. After seeing the pics you have posted and what I have found, I wouldn't want to fly in a plane that hadn't had it done.

[rocket]

This is not directly related to SB 819 but close enough for us short wing pilots/mechanics.


I found my favorite corrosion spot on the lower right hand longeron between the wing strut attach fitting and the forward doorpost cluster.


It seems some one or, I should say, many ones, decided the outboard edge of the belly sheet metal needed to be screwed and pop riveted and cherry maxed to this section of tubing: nine holes in all.


Needless to say the swiss cheese created an opportunity for moisture and a little dissimilar metal corrosion, you know, dogs and cats sleeping together. I noticed the paint had flaked and cracked and figured one of my copilots had kicked it in the cold. Nope.


During the next preflight I gave the wings a hearty shake to observe the main gear, I was on skis, I could see the fabric wrinkling where the tubing had broken in line with forward end of the doubler that runs inside the longeron for reinforcing the wing strut/gear attach point incurring another run on sentence of mechanical, A&P, proportions.


My shop hand mentioned a burm we had…jumped shortly after landing between the snow go race tracks at Big Lake two days before. There might have been a couple other less then smooth landings, I'll never tell the mechanic. Oh wait, I am the mechanic!


Nothing like a good shake the wings hard enough to lift your wheel off the ground preflight every once in a while.


Rocket

[Twofieros]

Last summer I posted pictures of what I found on my PA22 after sand blasting. I mentioned rewelding the old sheet metal back on. Someone else pointed out that if you read SB819 carefully it says to R&R those parts. So, to do the job right you cannot reuse the old sheet metal. It is a pain to refit everything but it must be done.

I have a feeling that SB819 will become an AD eventually. It would be easy to assume that if SB819 is done correctly then you won't have to worry about a future AD.

I can vouch for 3M's weld thru primer. It is easy to work with. Time will tell if it does it's job. At least I will have peace of mind when I'm back flying again.

Tim

[HunterJ]

Another problem area I keep finding is in the wing root area of the fuselage where the wing root fairing screws to the fuselage frame. Water gets trapped in the trailing edge channel and the 3/8" channel and rusts the upper longeron. We are going to make the trailing edge piece out of a solid piece of material and fill the 3/8" channel with something. Hopefully between these fixes and a good two part epoxy primer and catalyzed polyurethane paint this will no longer be an issue on this Pacer.

Trailing edge of wing root.
[attachment=2:3c0pelcx]100_2544 (Medium).JPG[/attachment:3c0pelcx]
3/8" Channel making the wing root fairing attach.
[attachment=0:3c0pelcx]100_4849 (Medium).JPG[/attachment:3c0pelcx]
Top longeron repaired by inner sleeve method. The inside of this tube was like brand new. The corrosion was from the outside in.
[attachment=1:3c0pelcx]100_2553 (Medium).JPG[/attachment:3c0pelcx]

Hi Steve
I know this one is from some time ago but the jpg files are no longer visible. Is it possible that you could send a copy of them as I have need to redo the channel at the wing root etc - so far longer on seems ok but gonna check real good for any cancer.
Appreciate your help if you can.
Cheers
HunterJ

[Steve Pierce]

I was gonna do that last night and ran outta time. If you are late for dinner at my house you get this scowl that goes on all night. ;)

[Steve Pierce]

I updated some of the documents and pictures. I can't find some of the wing root however. Maybe my Dad has some he can post.

[Gilbert Pierce]

I don't have any of the wing root repair. The peg that sticks out from the upper longeron that the wing/fuselage fairing wraps around was rusted almost off.

That is a folded piece of metal. After replacement I was getting water leaking in that fold and thru the fabric and into the top of the airplane in back of the head liner. I filled the slot where it went thru the fabric with RTV. That stopped the water seepage.

[HunterJ]

I was gonna do that last night and ran outta time. If you are late for dinner at my house you get this scowl that goes on all night.

We call that the wet cat look round here - you know the look that a cat gives when it's got all wet, well the female of our species knows only too well how to imitate it!
Cheers
HunterJ

[MichaelC]

Hi Guys,

Thanks to each of you for your replies and input on the frame corrosion. I will be spending some time on mine to be certain if there is any, it gets properly resolved and that the service bulletin has been properly executed. The airplane was hangared from the time it was first purchased according to the logs and other information I have on it, but that is beside the point if the fuselage decides to break in half due to corrosion!

Thanks again!

Michael

[MN_flyer1]

The comliance of this SB on a covered airplane seems pretty involved ($$$). Has anyone used other methods to check the integrity of the tubing in the critical areas? I was thinking that there should be NDT or ultrasound method (similar to what is done on struts) to at least check the areas of concern.

My plane was re-covered in 1987 (year of the SB) but there are no records that it was ever complied with. There is very little info on the recover job and to what extent the tubing was prepared for the covering. It has been a South Western US plane until 2 years ago. It appears to have been hangered fairly well since the rebuild. The visible tubing in the belly / tail looks in great condition with no signs of rust or paint flaking/peeling.

Welcome any thoughts on how to inspect or review with my IA from the experiences of others.

Thanks,

Tim

[pistoncan]

Thats the scarey part of it, The rest of the tubing looks great and then you pull the sheet metal off and go WHOAA!

I would think you could start by taking the trim off the right front door post and see what it looks like. That would give you a feel for what to expect if and/or when you pull the rest off, without having to deal with the fabric.

On both of my fuselages. The worst area was the right front door post and the longeron below the left door.

Somebody with more experience than I have might chime in with other suggestion.

Gary

[Gilbert Pierce]

All of the damage that I found was hidden by the sheet metal except for the wing fairing peg.
As Pistoncan mentioned, the worst corrosion was the verticle tube that runs from the right front gear/lift strut fitting up to the wing spar attach. There were holes rusted in the bottom of the tube.

[Twofieros]

My worst spot was on the rear door. Both the bottom of the rear post and the bottom of the front vertical post. Both had to be replaced. Neither of those are accessible without cutting into fabric.

Just like others said, mine looked fine until I removed the metal trim. Then I realized that as the metal is tapered and the gap closes as you go down, any dirt that gets in there is caught at the bottom and acts like a sponge keeping moisture against the untreated metal tubes.

I hope that helps you understand where the corrosion is. My aircraft was hangared it's entire life and lived in Ohio for 30 years then West Virginia until now. It is a 1958 Tripacer. Pacers might have different areas of corrosion.

Tim

[tim kerns]

Just finished my airframe what a mess found most of mine around left rear door

[Eagleavn]

Has anybody done this S/B on a metalized fues? Is the metal Fues better or worst?

Thanks,
LP

[Steve Pierce]

I have a fuselage here that was metalized right out of the factory and sat outside in Chicago it's entire life. The door frames etc. are as bad as fabric in my opinion but not as bad on the lower longerons.

[bndbelle]

I bought a project Colt with all the fabric off so it's a little easier and less exspensive for me to take care of SB 819. The old owner had already bought everything and gave it to me with the plane. I started removing the bottom of the right door and so far have only found surface rust. I hope the rest goes as well.:-P

[Eagleavn]

I have a fuselage here that was metalized right out of the factory and sat outside in Chicago it's entire life. The door frames etc. are as bad as fabric in my opinion but not as bad on the lower longerons.


Can you tell me the best way to inspect the metal fues(in the areas of the S/B)?

Thanks,
Lloyd

[Steve Pierce]

Slide the aluminum off and cut the door from sheet metal off the frame.

[Gilbert Pierce]

One you disconnect all of the fuselage tabs that hold the aluminum skin on it will slide off like an ice cream cone in one piece.

[JPerkins]

I'm writing up a materials list for doing the Trimmer gear conversion/seaplane door mod to get a rough estimate on what the cost would be. When I looked up the SB819 kit that Univair sells I about fell out my chair!
My questions are do you need all those with the Trimmer seaplane doors? Is it fairly easy to fabricate these pieces or is it a total pain and worth the large coin for the Univair parts?

Labor is cheap (doing it myself with my IA watching over my shoulder) so if it takes longer because I'm fabricating these parts thats not a big deal.

Thanks in advance!

[SuperPacer]

Just my opinion, but while doing the Trimmer Gear conversion and Sea Plane doors, you will have developed the skills (and collected the tools) necessary to fab any of the SB 819 pieces!! Use the saved $$ for more mods!

Enjoy the day,

John
Arizona Pacer

[JPerkins]

Yeah I figured as much. The ones I'm wondering about the most are the pieces that are channels that are only an inch or so across but several inches deep.

Actually I think I just answered my own question. I could probably form them over a piece of 1/2" or 5/8" flat stock with the corners beveled to the correct radius.

[JPerkins]

Anyone know off hand what the thickness of the 4130 the pieces are made of is?

[Jim]

Hi,

I used a Dremel rotary metal sawing blade to cut the welds on the sheet metal parts and re-used most all of them. The saw kerfs were so thin the parts went back pretty much exactly where they came from. The abrasive blades were so thin I used up or broke a lot of them though, probably forty or fifty. My only material expense was the eighty five feet of tubing I replaced. I found the trailing edges of the elevators and rudder bad too.

[PACERGUY]

I told you not to get a case of more better disease for a year or two. Mitch said you where going to stop buy and say hi last week did you make it? He just did a seaplane door mod on a Pacer did you get to see it? Hope to see you at Valdez.
DENNY

[JPerkins]

Yeah I'm trying real hard to leave things be. If I do any thing though it'll be this time next year.
I did get to meet Mitch finally. Really nice guy. He showed three or four different pacers there at birchwood and the mods he did to them. A couple of poor fellas will have to chip frozen drool off their planes.
Weather providing I'll be at the Mayday fly in, it'll be my first time I'm excited.

[JPerkins]

Jim, thanks for the advice on what you did, I'll probably go the same route instead of throwing away perfectly good pieces. Eighty five feet is a lot of pipe. Did you know it'd be that bad before you got started?

[Jim]

Hi again,

.....Did you know.....

Nope, blissfully dumb.


Back in 82 my brother and I bought a tired and duck taped together Tri-Pacer for not too many bucks. We added the droop tips and the Univair gear conversion as well as applying another coat of elasticized car paint to cover all the ring worm. Flew it until 92 that way and decided about then to repaint everything. I was using a putty knife stripping off all the coats of paint right down to the bare fabric when I found rust stains along the bottom longeron fabric. I got my AP/IA friend over for a look. He went from the tail post forward with a razor knife and found many places where you could look inside tubes. So, all of a sudden things turned into at least a recover of the fuselage.

I found a water line marking how full the fuselage got before it finally ran over the tubing at the hell hole hatch on the underside. Whoever covered the fuselage last didn't put any drain holes under the plane. When it sat outside all those years it held a lot of water and played hell with most everything down there. The drain holes on the tail surfaces were too far ahead of the rear tubes so they all held water. We usually had ice in them during the winters, being ignorant didn't know that wasn't normal. The fabric on the trailing edges of the elevators was actually close to 90% void of tubing in several places. The bottom 6 or 8 inches of the rudder posts, both fuselage and rudder, needed replacing. Even the hinge tubes on the horizontal tail planes needed attention.

I don't know how long the plane lived outside, but it leaked then held water everywhere it could. There were tubes around where the seat mounts, up around where the wing roots are, as well as bits and pieces you wouldn't think would be involved. Even the short aileron end tubes were rotted away. Like a lot of other folks here, I had more time than money and replaced and repaired my way back into airworthiness. My mechanic friend said he'd never seen a fuselage so extensively repaired.

I even made a new lower half for the curved rear window channel. Bent a piece of tubing, Skil saw slotted it, then pounded it flat with a spacer inside it so it didn't get too flat. I used to like working on my plane. I got over that about the 25th annual and 15th time punch testing and oiling my struts.

I went ahead and stripped, repainted and recovered everything else at the same time. My interior is a 2 on the ten scale, but my dog doesn't mind at all. My brother sold me his share and moved on to racing modified midgets.7912

[mmoyle]

I'm writing up a materials list for doing the Trimmer gear conversion/seaplane door mod to get a rough estimate on what the cost would be. When I looked up the SB819 kit that Univair sells I about fell out my chair!
My questions are do you need all those with the Trimmer seaplane doors? Is it fairly easy to fabricate these pieces or is it a total pain and worth the large coin for the Univair parts?

Labor is cheap (doing it myself with my IA watching over my shoulder) so if it takes longer because I'm fabricating these parts thats not a big deal.

Thanks in advance!

I bought the Univair kit/s. Could have made the parts without to much difficulty. The sheet metal is mild steel. Will get the metal thickness when I get out to the shop in a bit. The parts that will be a challenge to form are the two right side windshield door formers and the two right side front lower door formers...if doing the left side seaplane door. You'll need right side pieces for the left side. If I had a do over....I'd purchase those four parts and flow form the remainder over white oak forms. Leaf brake for a few.
Mark M.


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[pistoncan]

I used most of the pieces over. I used a 1/16 inch thick cut off wheel to cut the welds. The cuts are within the rewelded puddle so I wouldn't worry about it. One piece was bad on one side and I replaced just that side and welded it at the bend.

All my longerons are new from the rear door back. I only used the birdcage of the tri pacer.

After what I saw when I removed them, I would not get in a pacer that had not had the SB819 done.

[mmoyle]

The sheet metal is 22 gauge.


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[JPerkins]

Thanks for the info.

[Prosaria]

JPerkins, Mark sent me a bunch of the SB819 sheetmetal that he had left over. If I don't use any of the pieces, I can forward them on. It will be a couple weeks before I know what will be left, but it sounds like you are on a longer timeline than that.

[JPerkins]

I'm still in the "figure out the costs so I can see how much I need to save" stage. But I really appreciate the offer. I'm going to look at the CD tonight (finally) and see what the shapes are and how hard they'd be to fab. After everyone's great advice I'm feeling confident I can make what I cannot reuse.
Jason

[JPerkins]

Another thing I meant to ask.
What is common or typical to find under the tin? Should I anticipate replacing the tubing under all the tin or just in certain places?

[mmoyle]

Think you'll find the tubes at the rear wing mount...6-12" above the lower longeron will be pitted. Bottom longeron under the left rear door pitted. Diagonal tube at the bottom of the right door. I replaced both front tubes at the front wing mount to the lower longeron....had to on the left side...did the PA18 gar and seaplane doors. Replaced the right front tube...by accident. Fuselage was upside down in the rotisserie....some timers kicked in....I had whacked off the tube at the instrument panel cross tube before I realize how dumb I am! Specs say pitting less than 10% of the wall thickness is acceptable. Other folks use the...if I can poke through with a sharp point....the pit is to deep.
Mark


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[Steve Pierce]

You never know. Most have some tubing needing replacement. I merged threads so if you go to the first of the thread you will find pictures etc.

[Semper Fi]

The comliance of this SB on a covered airplane seems pretty involved ($$$). Has anyone used other methods to check the integrity of the tubing in the critical areas? I was thinking that there should be NDT or ultrasound method (similar to what is done on struts) to at least check the areas of concern.

My plane was re-covered in 1987 (year of the SB) but there are no records that it was ever complied with. There is very little info on the recover job and to what extent the tubing was prepared for the covering. It has been a South Western US plane until 2 years ago. It appears to have been hangered fairly well since the rebuild. The visible tubing in the belly / tail looks in great condition with no signs of rust or paint flaking/peeling.

Welcome any thoughts on how to inspect or review with my IA from the experiences of others.

Thanks,

Tim

I'm wondering the same thing.
My Clipper was completely rebuilt and recovered in 1984 by previous owners before this SB came out, here's a copy of the log, it says entire aircraft disassembled and tubing sandblasted and inspected. I'm assuming the welded parts that come off during this SB were taken off when they sand blasted the tubing, but if it wasn't than could be corrosion. It's always been hangared since being rebuilt in 1884.

[Jim]

Hi again,

.....any thoughts on how to inspect......

One thing I noticed during fabric removal was what felt like grains of sand that were fabriced over on some of the tubing. It turns out the little bumps were where rust was boiling out of pin holes in the metal.

You're only guessing what's behind the formed metal if it's not removed. I don't know if you'll find troubles behind the formers without obvious things elsewhere too, which may tell you to open more for a better look.

[Semper Fi]

Thanks Jim

[tnowak]

I haven't checked with Univair yet, but do you know if they do replacement channeling for the SB 819 check/compliance (on a PA17)?
This will be something for me to check (in detail) when I do the fuselage recover next year, however I am 99% sure I don't have any issues in this location.
TonyN

[Steve Pierce]

They sell the channels for the PA20 and 22. When I have done the SB on PA16 fuselages I have had to trim those down. I have a shear and brake and ended up making my own, less time than cutting Univair's down. The bottom of the door also tapers on the later models and doesn't on the 15, 16 and 17.

[Clayton Harper]

I can't get the Pacer in the air and do this too. What about we make up a checklist of things to do before becoming a SWP owner and after.

[Steve Pierce]

Get a Rotor Broach and drill a few holes for inspection.

[tnowak]

When the SB first came out that is what I did, but with a normal (small) drill bit.
Nice bright metal on the tubes underneath with no signs of rust or anything.
Good idea, Clayton, about the checklist, especially for first time shortwing owners (or prospective owners).
Perhaps start with a list of all ADs and SBs per shortwing type?
TonyN

[tnowak]

What about this style of checklist?
The attached is for the Vagabond and lists, I believe, all ADs, SBs and SLs etc. for the PA15 / PA17.
Feel free to edit as required.

Perhaps Steve can store this somewhere for future reference?

How about others putting together something similar for other shortwings?
TonyN

[Harold Kroeker]

Note that AD 99-01-05 has been superseded by AD 2015-08-04. I'm surprised that there are not a bunch of engine ADs as well.
Attached is the AD list for my PA-16 Clipper. Please let me know if I missed any.

[Tp109]

Note that AD 99-01-05 has been superseded by AD 2015-08-04. I'm surprised that there are not a bunch of engine ADs as well.
Attached is the AD list for my PA-16 Clipper. Please let me know if I missed any.

This is a scary thought, aluminium hinges.

[Steve Pierce]

I think it was the bracket attached to the hinge to the false spar.

[tnowak]

I have a list of some engine ADs for A65 range. Some of them are very old (1940s) so must be superseded by now.

I can try putting together a list (with what I have) and see what folks think.
TonyN

[tnowak]

Revised AD list for PA15/PA17 attached.
TonyN

[tnowak]

I took the AD/SB info that Harold Kroeker provided for a PA16 Clipper and have put it into the same checklist format as I prepared for a PA15/17 Vagabond. See attached.
Happy to do this for other shortwing types if I get given the info.
TonyN

[Steve Pierce]

Thanks Tony. When I get some time I will post these in their own seperate thread.

[Dwain]

So, I've been reading up on this service bulletin and it looks to me like it is a major PITA. I have a couple of questions so I am going to throw them out there. I read a lot of the posts on the SB, but didn't see these answers. If I missed them, point me in the right direction and I'll do more research.

1) I understand that this inspection calls for removing the metal on the doors, door frames and under the windshield. Can the inspection be done without removing any fabric (maybe the interior)?
2) For you A&P/IA Guys and Girls: How much would it cost (hours, not necessarily dollars) for you to do the inspection. I'm not talking about repairs, just look and give the owner a list of work that will be required.
3) after you do the inspection the first time, is there anything you can do to save labor on subsequent inspections (inspection ports, IDK)?
4) If this came out in 1986, it looks like roughly 30 years had gone by before the failures were occurring often enough to warrant the SB. Does that mean if you did this in the early to mid 90's you should be looking to schedule it again?
5) It looks like the Aussie version allowed x-raying (before the SB was cancelled) as a way of compliance. However, I think it says that the inspection (it doesn't differentiate between visual and x-ray) should be repeated every 5 years.

Just curious. - Dwain

[Prosaria]

1. No, I don't think so. The sheet metal has to be ground off the tubing.
2. Most of the work is removing and replacing the sheet metal, tube repairs will likely be a rounding error on the total bill.
3, 4. Do it right and it shouldn't need another one for a long time.
5. Compliance with a SB is not required. You can do as much or as little as you would like using whatever means you would like to.


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[Dwain]

Prosaria,
I understand that SBs are not required. I'm thinking of catching a problem before it becomes catastrophic - Dwain

[pistoncan]

Prosaria,
I understand that SBs are not required. I'm thinking of catching a problem before it becomes catastrophic - Dwain

Excellent choice

[Steve Pierce]

The channels cannot be removed with the fabric installed. There is nothing on the windshield, it is all retained in the boot cowl aluminum. One of those things to do at recover. The PDF of the Univair replacement channels on page 1 of this thread will give you an idea of where they are located.

[Dwain]

Sorry, bad terminology. "Under the windshield" should have been boot cowl. - Dwain

[cammons3]

Regarding paperwork, does the accomplishing of this SB require completing a FAA Form 337 (https://www.faa.gov/documentLibrary/media/Form/Form_337.pdf) for major repair (primarily) and/or alteration signed by an A&P/IA in Block 7? I'm thinking back to the shoulder harness installation thread (http://www.shortwingpipers.org/forum/showthread.php?5799-Shoulder-Harness-Installation) whereby if you welded any kind of tab onto the structure, the FAA required a 337. Since you're cutting loose the sheetmetal from the tubing, even if the tube (aka structural member) is not damaged, welding the sheetmetal back on constitutes a "major" repair...


14 CFR Appendix A to Part 43, Major Alterations, Major Repairs, and Preventive Maintenance: Paragraph (b), (1) (https://www.law.cornell.edu/cfr/text/14/appendix-A_to_part_43)

Thoughts?

[Gilbert Pierce]

SB819 was done on my Clipper along with other tubing repairs.The 43.13 and SB819 were the approved data so block 3 on the 337 did not need the FSDO/FAA approval. The 337 went direct to OKC.
Since SB819 is non structural I could be comfortable with a log book entry as long as no repairs were needed under the sheet metal. In my case there was much rotted tubing hiding behind the sheet metal so that part was a major repair hence the 337.
Stating that SB819 was completed was included in the major repair documentation.

[Steve Pierce]

Is all welding considered a major repair?

[Clayton Harper]

Is all welding considered a major repair?

I could read it, without it i being a major repair, if the sheet metal isn't structural. Call it fairing.;)

[cammons3]

I could read it, without it i being a major repair, if the sheet metal isn't structural. Call it fairing.;)

I could see that as well IF you were welding on the "fairing" itself only, and then bolting the fairing to the airframe/tube. However, the sheetmetal removed as part of SB819 is WELDED to the airframe, thus it just involved primary structure... correct?

[pistoncan]

Curt, That would be the way I would see it.

[cammons3]

I've been doing some research, and I found this thread just to confuse the matter further: https://www.askbob.aero/content/welding

So if I take some sheetmetal off of a primary structure, and then put it back on using the same methods used in original manufacturing process, does that constitute a major repair? It certainly doesn't fall under any sort of alteration, but the fact that it could possibly alter the strength of the structural member... hmmm. I'm thinking more along the lines of metal oxidation due to heating/cooling multiple times, thus altering mechanical properties. This holds truer when welding with oxyacetylene vs. GTAW (TIG).

While I'm not an avid fan of Mike Busch, he did make a pretty valid point as it relates to a Major Repair on an engine mount: https://www.avweb.com/news/savvyaviator/savvy_aviator_54_is_repair_a_lost_art_197316-1.html. AC 43.13 is always a good fall-back whenever all else fails in obtaining approved data.

I plan to discuss this with our ASI at the MEM-FSDO. He is a pretty good guy... yes, good guy and FAA used in the same sentence can be just as confusing... :cool:

[blueshortwing]

I have never seen a SB signed off on a 337. Not required for alterations because the SB is actually a revision to the Type Certificate. In thinking about this, 819 is an inspection not a repair. If you found a bad tube and had to replace during the inspection, that would require 337. Merely doing the inspection even though welding involved would not be major. Would have to be done by A&P who technically can weld.��

[Steve Pierce]

(b)Major repairs -
(1)Airframe major repairs. Repairs to the following parts of an airframe and repairs of the following types, involving the strengthening, reinforcing, splicing, and manufacturing of primary structural members or their replacement, when replacement is by fabrication such as riveting or welding, are airframe major repairs.
(i) Box beams.
(ii) Monocoque or semimonocoque wings or control surfaces.
(iii) Wing stringers or chord members.
(iv) Spars.
(v) Spar flanges.
(vi) Members of truss-type beams.
(vii) Thin sheet webs of beams.
(viii) Keel and chine members of boat hulls or floats.
(ix) Corrugated sheet compression members which act as flange material of wings or tail surfaces.
(x) Wing main ribs and compression members.
(xi) Wing or tail surface brace struts.
(xii) Engine mounts.
(xiii) Fuselage longerons.
(xiv) Members of the side truss, horizontal truss, or bulkheads.
(xv) Main seat support braces and brackets.
(xvi) Landing gear brace struts.
(xvii) Axles.
(xviii) Wheels.
(xix) Skis, and ski pedestals.
(xx) Parts of the control system such as control columns, pedals, shafts, brackets, or horns.
(xxi) Repairs involving the substitution of material.
(xxii) The repair of damaged areas in metal or plywood stressed covering exceeding six inches in any direction.
(xxiii) The repair of portions of skin sheets by making additional seams.
(xxiv) The splicing of skin sheets.
(xxv) The repair of three or more adjacent wing or control surface ribs or the leading edge of wings and control surfaces, between such adjacent ribs.
(xxvi) Repair of fabric covering involving an area greater than that required to repair two adjacent ribs.
(xxvii) Replacement of fabric on fabric covered parts such as wings, fuselages, stabilizers, and control surfaces.
(xxviii) Repairing, including rebottoming, of removable or integral fuel tanks and oil tanks.

I don't see the sheetmetal as structural. The fusleage is not heat treated so I don't see it being major to weld it back on just like Piper did. If you question it being major error on the side of caution and file a 337. No harm, no foul.

[cammons3]

Thanks for the inputs, folks. As mentioned, I did query our local FSDO. Once we got on the same page, here was his response:


There is no 337 required for welding. Welding is a process of fabrication. A 337 is required for alterations and repairs to the product itself. The welding must be done iaw industry standards. Don’t get wrapped up in the reinstallation of a channel. As long as the weld does not compromise the tubing structure, and it is done correctly, you have not done a major repair to anything. I believe people are over-thinking this issue and making it way too difficult. There is no interruption needed for this specific issue, it’s very clear...
If you do not agree with this, make a written request to the FAA. I would send it certified return receipt.

Federal Aviation Administration
Office of the Chief General Counsel
800 Independence Ave, SW
Washington DC 20591

[Clayton Harper]

Curt, It appears to me that this author, like a lot of A&Ps, is unaware of the Appendix to FAR Part 43. Do your own test. Ask a few mechanic what is in the Part 43 Appendix.

[Rick-CAS]

I think Clayton has this one. Appendix A discusses manufacturing, fabricating, and welding as major repairs. SB 819 is FAA approved data to remove, inspect, fabricate, and install. So a gray area as to just comply with the SB as a logbook entry. I would say put it on a 337 referring the SB and send it in just to cover yourself. I know Appendix A says primary structure but how do you defend what holds the windshield in. That’s a required item for flight or the front door? Secondary structure welded to primary. I’ve discussed things like this with a couple of Feds I work with. It always starts with the answer you want to hear then the “well if we were looking for something to violate you over” it would probably be a gray area subject like this.

(b) Major repairs—(1) Airframe major repairs. Repairs to the following parts of an airframe and repairs of the following types, involving the strengthening, reinforcing, splicing, and manufacturing of primary structural members or their replacement, when replacement is by fabrication such as riveting or welding, are airframe major repairs.

[blueshortwing]

I would like to discourage sending in 337's "just to be safe". I think the industry does itself a dis-service doing that and it is actually contrary to FAA policy. FAA says you should not submit a 337 for a minor. Back in the day A&P's installed radios all the time with just a logbook entry. Then somehow we started sending in 337's on them in the late 80's early 90's, then it became expected to submit even though the regs never changed. (When did Principal Avionics Inspectors become an FAA position?) Now the industry is trying to take back the authority to install radios without 337's. My method is to document my decision to declare the minor and put it in the logbook. If the FAA inspector disagrees at a later date, then we have a disagreement and find a resolution. No fraud or coverup needed. Another thing I hear from fellow IA's is "Well Ok City didn't kick back my 337, so it must be approved". Ok City only has Inspectors look at (very) random 337's to check content. Almost all 337's are only looked at by document specialists to scan into the files. They look to see if the Owner/N-number/serial is consistent with their records, but do not examine the content of the 337. It would only be looked at by an FAA Inspector if at a later date there was a problem and they went back and examined the form. The IA is the approver! My $.02

[dgapilot]

I would like to discourage sending in 337's "just to be safe". I think the industry does itself a dis-service doing that and it is actually contrary to FAA policy. FAA says you should not submit a 337 for a minor. Back in the day A&P's installed radios all the time with just a logbook entry. Then somehow we started sending in 337's on them in the late 80's early 90's, then it became expected to submit even though the regs never changed. (When did Principal Avionics Inspectors become an FAA position?) Now the industry is trying to take back the authority to install radios without 337's. My method is to document my decision to declare the minor and put it in the logbook. If the FAA inspector disagrees at a later date, then we have a disagreement and find a resolution. No fraud or coverup needed. Another thing I hear from fellow IA's is "Well Ok City didn't kick back my 337, so it must be approved". Ok City only has Inspectors look at (very) random 337's to check content. Almost all 337's are only looked at by document specialists to scan into the files. They look to see if the Owner/N-number/serial is consistent with their records, but do not examine the content of the 337. It would only be looked at by an FAA Inspector if at a later date there was a problem and they went back and examined the form. The IA is the approver! My $.02

Actually fileing a 337 for a minor repair or minor alteration is a violation of 43.9. I’ve never seen a letter of investigation or violation for it, but it is still a violation. Just as blueshortwing says, document your decision process for it being a minor in the log book entry using the decision tree FAA gives. You can’t go wrong!


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[dhillier]

Help!

Recently I started the rebuild on N5240H. I cut the sheet metal off for SB819 to reveal a fair few bits of corrosion. The tubes have all been blasted, primed and are ready for repairing. When in the USA last month I collected the SB819 kit for a PA16 from Univair.

Using drawing 11858, Pipers SB819 instructions and various photos as reference, I am still very much stuck.

I can’t figure out how many of the parts fit onto the fuselage. They appear very oversized in both length and width. Problems include

How do the 3 parts that make up the right hand entry door rear frame fit together?
How do the 4 parts that make up the front of the left hand rear passenger door fit together?
Where do parts:
16-22
16-23
16-20
16-21B
22-07B
16-21T
fit on the frame?

Does anyone have any photos or advice that may be useful please?

Regards

Dean

[Steve Pierce]

They sell the channels for the PA20 and 22. When I have done the SB on PA16 fuselages I have had to trim those down. I have a shear and brake and ended up making my own, less time than cutting Univair's down. The bottom of the door also tapers on the later models and doesn't on the 15, 16 and 17.

Merged your thread with an older one on the subject. I have some drawings and I believe some pictures I will post.

[dhillier]

Thanks - if you have some pictures that would be great.

for example on the rear door. Which way do the curved portions face and how do the 3 pieces join together?
2045120452

[Steve Pierce]

Univair has a drawing or brochure showing all the part numbers laid out like the go on the fuselage. I don't have any pictures and I haven't found the brochure yet but I do remember having to cut those channels down a lot so the next one I made my own.

[dgapilot]

Thanks - if you have some pictures that would be great.

for example on the rear door. Which way do the curved portions face and how do the 3 pieces join together?
2045120452

Dean, hope you are hanging that tube, looks like an awful lot of pitting!


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[dhillier]

Thanks. I do have a univair old univair drawing but the part number scheme doe not reflect the actual new part numbers. Also it only refers to the PA20 and the parts are different in shape and number for the PA16.

20453204542045520456

[dgapilot]

Dean, picture from my fuselage still with original door structure.2045720458204592046020461204622046320464

[dhillier]

Thanks - that really helps. I took what I though was plenty of photos but the pieces I took off just dont look the same to the new pieces. Am handing the fuselage to a approved welder and have told him just to make it better - however I wanted to save him the time of figuring out the jigsaw puzzle that is the SB.

[dgapilot]

A little late now, but if you are careful using a dremel, you can reuse the sheet metal parts that you remove (or at least most of them). If you need other pictures let me know.

[Harold Kroeker]

Univair has a drawing or brochure showing all the part numbers laid out like the go on the fuselage. I don't have any pictures and I haven't found the brochure yet but I do remember having to cut those channels down a lot so the next one I made my own.

Is this the brochure you are referring to?

20465

[Steve Pierce]

Is this the brochure you are referring to?

20465
That is it, thanks. I have a hard copy somewhere. ;)

[N2709P]

With the interior out of our TriPacer, it looks like you could use a 3/8” spot face cutter to make inspection holes in the metal trim for a boroscope inspection of the tubing called out in Piper SB 819. The inspection could be recorded, preservative injected and either closed out with a fabric patch or Wilkie button. This would save removing the metal trim and the cost of a recover job if the inspection showed no appreciable rust or corrosion was present. If all tubing could be properly inspected, an AMOC could be generated. I am sure that few aircraft have had this SB accomplished due to the labor costs to R&R the metal trim, even with the fabric removed. Does anyone see an area that they feel could not be adequately inspected by a boroscope? Maybe a spot that would require an ultrasound inspection also?
N2709P

[Jim]

Hi,

Have you read through what others have found? Mine needed 85 feet of tubing replaced, bits and long things scattered all over. Not all originate from inside the tubes, some were pretty bad under the formed metal pieces too.


https://www.shortwingpipers.org/forum/showthread.php?4382-SB-819-Fuselage-Door-Frame-Corrosion

21101211022110321104

[N2709P]

Reading and talking to Pacer/TriPacer owners and maintenance personnel, some aircraft have no rust, some have varying degrees of rust and some are just blown out everywhere. Being parked outdoors for a large part of their lives seems to be the biggest determinator. If the tubing has rust, it definitely needs to be addressed. Unless you follow the directions in SB 819 and remove the metal trim, you will never know for sure the condition of the tubing covered by the trim. If all other tubing in the aircraft looks good, having to do such an invasive inspection does not make much sense to me, if you can inspect the hidden tubing sufficiently using another method. It would be like doing open heart surgery to check your arteries rather than using an EKG and ultrasound. That is why I am asking these questions. Lots of people on this forum with lots of experience with these airframes. If someone has an observation as to why it could not be done, I would like to explore to see if there is a reasonable solution to their hesitation. A boroscope, eddy current or ultra sound inspection of the subject tubing would be vastly less costly than a strip and recover job. A recover job, even without accomplishing SB 819 by a shop would most likely exceed the value of the aircraft. Unless you are operating your aircraft for hire, you are not required by FAR’s to follow the manufactures SB’s or SL’s but it is good practice. I have known insurance companies to require that all SB’s be complied with.
N2709P

[Jim]

Hi again,

I think you're on the right track, not getting unnecessarily carried away. I don't think bore scope holes will be suitable, they will need to be welded to repair defeating the keep it simple approach. Few here would even drill a hole in an airframe without welding it closed later. I hope someone will pass through here with a suggestion on satisfying your concerns.

[N2709P]

Thanks, Jim. Just to clarify, the only inspection holes that I am contemplating are in the non-structural door and window trim sheetmetal pieces that cover and hide the tubing. These inspection holes would be covered to help keep dirt and moisture out and be easily removable for future inspections. If the tubing has not been compromised by someone drilling a hole for an attachment, ala the wing struts, I have rarely seen a Piper fuselage tube rust from the inside out. They were sloshed with boiled linseed oil and then welded closed. It would be nice if a supplier made a new fuselage structure from 4130 tubing like the J-3/Pa-18 though.
N2709P

[Steve Pierce]

I merged your thread with another on the subject. I believe the Rotabroach can be used to drill holes to inspect without removing the channels. Some pictures in this thread where I did this on some late model Super Cubs. https://www.supercub.org/forum/showthread.php?40936-Door-Frame-Rust

[N2709P]

Thank you Steve! With your experience with these airframes, do you think that all tubing described in SB 819 could be adequately inspected by a boroscope? In other words, could you place inspection ports in all areas necessary to do a proper inspection?
N2709P

[Steve Pierce]

I think you could get a good idea of what you have. I would start on the bottom of the vertical tubes and the rear door sill.

[Subsonic]

I scanned through this long thread, but am still wondering how the water gets in there in the first place. The lower rear window channel? Secondly, should there be a strategically placed drain hole(s) somewhere? Where, exactly?
Thx!

[Jim]

Hi Subsonic,

......."drain hole(s) somewhere? Where, exactly?"

When these frames were built they didn't drill holes from one to another so their innards could be oiled all at once. Since all the tubes are individual there's not much you can hope to accomplish with a few drain holes to oil in, and they couldn't be drained either. Even a small rusted through hole from the exterior will allow the humidity in and it'll never leave. A failed seal on Thermopane window turns into a humidity trapping greenhouse atmosphere.

[Steve Pierce]

I scanned through this long thread, but am still wondering how the water gets in there in the first place. The lower rear window channel? Secondly, should there be a strategically placed drain hole(s) somewhere? Where, exactly?
Thx!
Not sure how the water gets in there, maybe the atmosphere. Early J3s had holes drilled in the bottom most aft end of the lower longerons and have found them rusted many feet forward. Have cut into plenty of fuselages that were completely intact and the tubing still oily inside. The only time I find internal corrosion in a steel tube fuselage is when someone drilled a hole or the tube has been cracked for a long time, some way moisture could get in.