15AC ACS - Spar Intergranular Corrision

Aeronca Sedan Airplanes
deCreeft
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Re: 15AC ACS - Spar Intergranular Corrision

Post by deCreeft » Wed Apr 06, 2011 20:11

This seems to me to be shaking down to something not as bad as seemed at first...

So if there is no resulting condition to be dealt with, we are looking at $675 an airplane, to comply with something using approved parts ?

I guess I've been buying parts for de H.'s for too many years, but that seems okay with me.

I'm guessing how many inspection covers w/structure are called for...but if I have understood correctly, put me down for one airplane's worth.

I had my wings opened up when I had to put in new metal fuel tanks due to bogus parts and bogus paperwork (previous owner) so I know they are good, especially forward of the spar where it's blind...but if I can prove it once a year at annual time and get to go flying I'm cool with that...I'm 20 years older than the airplane, and I am madder about stripping down for inspection to get on am airliner because of titanium shoulder and hip!
(why can't I get an FAA approved Xray of ME signed off !?!)

Bill
Homer, AK!
Bill de Creeft

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Re: 15AC ACS - Spar Intergranular Corrision

Post by poulter1 » Thu Apr 07, 2011 18:55

All,

I had a good discussion with Burl today. One thing I want to get out is that he is not pushing this AD. The FAA has been pushing him to produce a service bulletin. He is not adverse to other methods of compliance.

By the way he is working on getting new wheels and double puck brakes approved for the Sedan and possibly 180's, 185's, and 206's. I belive parking brakes and right side brakes are also in the works. The price for a set of wheels and brakes would be around $1500. A pretty good price compared to Clevelands.

John Poulter

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Re: 15AC ACS - Spar Intergranular Corrision

Post by esandberg » Thu Apr 07, 2011 19:00

I guess everybody's seen my photos from a couple of years ago on this thread. I've looked through the factory inspection holes in the wing I haven't taken apart yet, and to some extent, the caps are visible. A quality borescope would add some to the inspection area accessible from the 4 factory covers, but the factory holes+borescope don't make the entire length of the caps accessible. I tend to agree with Brian, the option of more access covers would be nice, if somebody can convince me that the wing strength isn't being compromised. I'd hate to weaken the wings to inspect their strength.

I talked with another owner for half an hour on the phone today about this, and he asked a smart question: Based on what you can see through the factory inspection holes, what's the liklihood that you could assume the condition of the rest of the caps? For whatever it's worth, I think the liklihood is high, based on what I found. There was an exfoliation bulge at least every few feet along those caps; if you can see 1 and 2 foot sections of the caps and they look as good as the photos Matthias posted, chances are you're in good shape. My caps looked generally fair/poor everywhere, regardless of the exfoliation bulges. In my opinion.

Della Swartz at Anchorage ACO asked me back in 2008 if I'd be willing to send her a piece if she needed it and I said yes, but she never followed through on the request.

It sounds like there are some strong feelings on all sides regarding the inspection covers. I won't add to that debate, but would be willing to chop up one of the caps you see in these photos into 1' sections and mail around to owners so everybody will know better what to look for.

There's a lot of commenting going on, but Eric Wright and the Anchroage ACO isn't going to come here for the comments they incorporate into the AD proposal. If you know something about your wing that just isn't represented in the AD, please get your comments to Anchorage. Bitching about cutting up your wing here, and the reasons you think it's a pointless exercise, won't get heard by the people who need to hear it.

I, for one, am going to comment on the text that reads "...inspect the leading and trailing edges of both the upper and lower main spar cap angles...". If I'm reading this right, the instruction is impossible to comply with without unriveting the cap from the spar web, because the trailing side of both caps is riveted to the leading side of the main web. Somebody who's not familiar with the construction of this wing wrote that paragraph of the AD proposal, and if nobody fixes it, a ridiculous instruction is going to become law.

Secondly, seeing corrosion with a borescope and removing it through some 4" holes are two different things. I'm not sure exactly how I'm going to word it yet, but you'd need to be Inspector Gadget to get a Scotch-Brite pad up into some of the places you can see just fine with a flashlight and mirror. At 6'3"/310, I'm not the kind of guy who gets into small places. The access holes might let you see corrosion just fine, but getting my paw through a 4" access hole with a die grinder and Roloc disc won't happen. Including text to 'remove corrosion' from places physically inaccessible sort of becomes another silly mandate.

And third, the [proposed] AD says to "remove corrosion and treat with an inhibitor", although it does say "light corrosion" in one place. Ok, well, define corrosion then, as it applies to this AD. The powdery layer that you can rub off with your thumb? Really? You're going to make us crawl through the wing like rats removing that stuff when C-172's and Cherokees are flying around with surface corrosion all the time, passing their annual every year? If FAA wants us to deal with intergranular exfoliation, fine, but don't hold us to a higher surface corrosion standard than the spam can fleet out in General Aviation.

Those are the general comments I'm going to submit. If you can see other difficult parts of the AD, get your comments to where they'll do some good, in time to be heard.

Eric
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Re: 15AC ACS - Spar Intergranular Corrision

Post by bsafran » Thu Apr 07, 2011 23:03

I tend to think of myself as the world's biggest Sedan fan. I own several 15AC projects, help maintain some others and visit every single owner I can meet when I travel across the country for my job. Work has kept me pretty busy and off the website at probably the most important time frame for Sedan owners.

Now that I have more time to devote to the issue I just want to publicly say how proud I am of how the Sedan community has confronted this AD. Of course there was some indignant griping when this first came out, but look how it has come together recently. There have been several knowledgable people not only posting opinions of how to best move forward, but also trying to unite others into helping preserve this great plane. With all of these people working together and commenting during the short period given us, I believe that a common sense solution will be found that helps expose the planes with a corrosion problem without crippling those that don't. Even Burl has admitted on this website that while he wasn't the man pushing for this AD, he might have been mistaken about how it came about. The facts are pretty plain.

Aeronca designed and built a great plane that has lasted beyond all of their expectations. If they had any idea it would fly this long, they might have done things a little differently. Still, we are faced with the facts of today. The Sedan wing spar has an Achilles heel that can't be ignored. The airplane is far from doomed, it just needs to adjust to the 21st century. I believe by time we all gather for the 2012 Aeronca fly in at Middletown we will be satisfied with the spar cap solution we all helped form and the way we all pulled together to make it happen.

I don't think any of this would be possible without this fine website that is provided to us by Joe A. I can't imagine how we could work this all through without a common sounding board to educate us all. Thanks Joe! Now let's continue formulating the right solution to this problem and convince the FAA within the time frame provided that we have this problem licked.

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Re: 15AC ACS - Spar Intergranular Corrision

Post by seaheli » Fri Apr 08, 2011 01:57

A decision making process requires "WISDOM", listen to the older generation "AIRLINE STRUCTURES MECHANIC"!

Always get more than one view of a problem!!!

As for engineering, find an experienced aircraft structures engineer. Someone in the industry "before computers", "COMMON SENSE"!!!!!!!!!!!!!!

The FAA works for you, "OWNER-OPERATOR" NOT THE "MANUFACTURER"!!!!!!!!!


Charles
Last edited by seaheli on Fri Apr 08, 2011 11:18, edited 1 time in total.

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Re: 15AC ACS - Spar Intergranular Corrision

Post by joea » Fri Apr 08, 2011 10:04

A few comments on the current status.

First off we have started the process to work with the ANC FAA on this. The NAA is now registered with the AOPA to work with them on this.

Second an extention has been discussed with the ANC FSDO and they said that this should not be an issue. This has been requested.

Third we are working on the corrosion issue. The feds in ANC are saying that anything over ONE THOUSANDS of an inch is not acceptable and must be corrected. Well kids, its really evident that they have never worked on airplanes with a comment like that. Take a new piece of aluminum, put it out on the ramp next to an airplane and in a week it will have surface oxidation (aka corrosion) on it more than .001 that they want to use as a starting point, so we are working on this.

Burl has told me that he has no problems with the "mix and match" process, using a reduced number of inspection covers and a borescope to inspect the wing. As well we are working at removing the wording from the paperwork that the inspection covers have to be obtained from one source. We have received lots of comments from "I can make those myself" to "I have some in the hangar now, why do I have to buy them!" on this subject.

Also, anyone who has sent anything in to Della Schwartz on this subject in the last 3 years, please find your old copies of your comments. Eric Wright in ANC FAA is saying that they received NOTHING from anyone, which we find very difficult to believe, so that they had to go with what they had from the Type Certificate holder. I for one know of at least 5 people who sent in "Alternative means of complaince" comments that now evidently have gone missing.

Lastly, now have a heavy hitter on our side. The EAA's Vintage Aircraft Association unit has weighed in as the top guy there owns a Sedan and he is on our side in this. With the EAA and NAA working on this, with your help hopefully we can make a dent on this.

Joe A

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Re: 15AC ACS - Spar Intergranular Corrision

Post by esandberg » Fri Apr 08, 2011 11:51

Joe,

I commented to and corresponded with Della Swartz in late 2008 in a series of emails and photos, and have at least some of it still in my Sent Mail folder. I'll be fowarding it to you offline.

It was pointed out to me that maybe I didn't understand the text of the [proposed] AD regarding inspecting the capstrips. If 'inspect the trailing edge' means to 'inspect the underside of the trailing edge of the horizontal plane of the top capstrip', then I stand corrected.

Thanks for the time you're volunteering to help de-escalate the magnitude of this inspection.

ES

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Re: 15AC ACS - Spar Intergranular Corrision

Post by Dhelsper » Sun Apr 17, 2011 07:21

Hello All,

I did the preliminary, through-the-rear spar inspection and could see nothing like they are talking about. But then again you really can't get close except for the two factory inspection holes. I did see some light powdery surface corrosion on the ribs etc. I am not sure how much is allowable. I have owned 1152H serial #165 since 1996 and it has been in a heated hangar in IL ever since. Prior to that she lived her whole life in central IL. I would like to hear more from others on what they are finding.

Dan Helsper
(Now in) Puryear, TN

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Matt
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Re: 15AC ACS - Spar Intergranular Corrision

Post by Matt » Sun Apr 17, 2011 16:46

Thanks to everyone for their thoughts and findings, especially to Joe and the NAA for their coordination efforts!

According to the FAA records, our 1949 15AC-371 N1331H was always based in Minnesota or North Dakota. According to the logbooks, it was never on floats. The pictures that I found of it from back in the 1960s, show that the owner hangared it at his farm until 1981, when he crashed the plane. From then, it was, again, stored dismanteled in another hangar. So, most likely no real exposure to the elements, during the majority of its life.

During the restoration of our Sedan, we found that the wing spar cap angles really didn't show any signs of corrosion. Neither below nor on top of the spar caps nor on the spar web. There was some surface corrosion between a few of the overlapping sections of the wing skin sheets, though. These sheets were replaced with new ones. The ones that showed only slight deterioration were cleaned with a scotch pad, treated with corrosion stop, primed and then reused. The entire wings were treated with ACF-50, during the restoration.

We found the remains of a nest of probably rodents inside the D-section of the left wing, about 1 third the length of the wing from the root. They must have housed in there, some time between 1981 and 2002, and did create corrosion. We replaced those sheets. The nest was visible from the aileron openings. But it would literally have been impossible to physically reach that spot to remove their shit and leftovers AND get rid of the corrosion, without opening the wing skin.

Personally, I would appreciate to have inspection holes. It just makes sense and improves safety by permitting a quick and close look inside any otherwise closed section. But in my opinion, the import thing, if the AD comes into force, is that any owner is allowed enough time (at least 12 months) to comply.

Thanks again and best regards,

Matt
Aeronca 15AC Sedan – Restoring and flying the classic 4-seater: http://www.n1331h.com

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Re: 15AC ACS - Spar Intergranular Corrision

Post by joea » Mon Apr 18, 2011 11:50

Matt,

Would agree but would also personally modify your post to say "I would appreciate having some more inspection holes, but feel that 8-10 on the wing is overkill."

Another 2-3 inspection holes spaced along the wing would be nice but to have to cut 8-10 holes in the wing is far overkill, especially as we can inspect much if not all of the wing using a borescope and THEN and ONLY THEN add inspection holes IF NEEDED. Especially cutting these holes in a wing like yours that has been recently opened up and confirmed that its not needed.

As well there needs to be provisions for wings that have been recently inspected and have proof of such (photos, borescope etc) so that the addition of inspection covers can be delayed to a reasonable time frame.

Joe A

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Re: 15AC ACS - Spar Intergranular Corrision

Post by deCreeft » Mon Apr 18, 2011 12:48

I agree, Joe...
But would like to suggest that whatever the result, we keep in mind the viewpoint of a prospective buyer, as well as someone who already owns the aircraft.

What would you want to have to do to look at the wing before purchase ??

I want enough inspection holes to look at it at least once a year or on pre-purchase; not just for a signature...

Signed: Previously Burnt by "Annual"

Bill
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Re: 15AC ACS - Spar Intergranular Corrision

Post by Matt » Mon Apr 18, 2011 12:50

Joe,

I absolutely agree with you on reducing the number of holes to the absolute minimum required for a borescope inspection. And yes, after our restoration and finding no corrosion, I definitely don't want to be asked to cut holes into these wings for a couple of years, at least.

I just reread the proposed AD and am a bit shocked. If I understand correct, it would definitely require me to open both wings, again, and replacing all 4 spar caps, within only 25 hrs or 6 months, whichever is later, after the AD comes into force. Why? Because we did not replace the spar caps. Since there was no corrosion! This is definitely not acceptable.

Please, anybody correct me, if I am wrong.

Matt
Aeronca 15AC Sedan – Restoring and flying the classic 4-seater: http://www.n1331h.com

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Re: 15AC ACS - Spar Intergranular Corrision

Post by deCreeft » Mon Apr 18, 2011 14:39

Matt
I don't think you read it right.
Better brains than mine will have an opinion, but that's not what I see.

We will, when this actually goes into effect, have to put inspection holes in the wings (I agree that they are necessary, just waiting to see how many and where) but unless the wings are bad, that would be it until the next inspection ; you already know your wings are good, so all you have to do is comply with whatever method 'they' require to re-inspect them again at whatever interval 'they' require...

Meantime I went flying the other day...I'll keep doing that until the AD note comes out and the resulting time is up !
As a Service Bulletin, if that is what it is at this point; unless you are 135, you don't have to do anything.

But that's just me, and the way I read it...

Bill
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Re: 15AC ACS - Spar Intergranular Corrision

Post by deCreeft » Tue Apr 19, 2011 19:54

As a follow-up, for what it's worth:

I was in my son's hanger last night, visiting with him while he was working on the 206 on amphibs, and i counted 19 inspection covers in *each* wing...!!

Can't remember what the Beaver and the Otter had...but lots on the underside, and no problems in all those years I can remember...all seaplanes, and gratifying to be able to look and spray in there...and no lack of 'lift'.
(I like acf 50 and Fluid Film...no affiliation)

And we're talking a *Tall* stepladder on a 100 hr. Ins....easier to be using a flashlight and a mirror, than peeking through a borescope, for an old body ...

I'm not picking sides, if there are any...just offering some balance.

And a lot better than cutting holes in fabric wings and trying to keep insp. covers from sliding and fretting etc.

Ah well...It will be what it will be.

As long as we can go fly when it's over.

Bill
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Re: 15AC ACS - Spar Intergranular Corrision

Post by Matt » Wed Apr 20, 2011 11:27

Now I got it, thanks Bill!

You are confirming what Burl had already told me, when I misunderstood while rereading the proposal.

Matt
Aeronca 15AC Sedan – Restoring and flying the classic 4-seater: http://www.n1331h.com

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