tonycondon
Gastons CRO (Chief Dinner Reservation Officer)
Liz so sorry to hear about this. I've got mouse issues with Leah's glider too but its chewing damage out towards the tip and will probably show OK through analysis.
While the cat's away...
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azure
Final Approach
And the worst of the bad news came today: underneath the last of the residue were more pits. My mechanic found one that he smoothed down to 0.001" above the Cessna minimum thickness, and there was still more to go. He suspects there are more just like that. So now he wants to get a DER out there to confirm that the spar is toast... I've already found a replacement spar, the only question is who is willing to do the work of taking off the wings and putting them back on again.
I've also decided to submit a claim to my insurance under the not-in-motion coverage. My agent says that according to the underwriter, whether it's covered depends on so many variables the only way to tell is to submit the claim and take it up with the adjuster.
I've also decided to submit a claim to my insurance under the not-in-motion coverage. My agent says that according to the underwriter, whether it's covered depends on so many variables the only way to tell is to submit the claim and take it up with the adjuster.
Trapper John
Ejection Handle Pulled
And the worst of the bad news came today: underneath the last of the residue were more pits. My mechanic found one that he smoothed down to 0.001" above the Cessna minimum thickness, and there was still more to go. He suspects there are more just like that. So now he wants to get a DER out there to confirm that the spar is toast... I've already found a replacement spar, the only question is who is willing to do the work of taking off the wings and putting them back on again.
I've also decided to submit a claim to my insurance under the not-in-motion coverage. My agent says that according to the underwriter, whether it's covered depends on so many variables the only way to tell is to submit the claim and take it up with the adjuster.
Very sorry to hear that. As painful as it may be now, it's much better to have caught this on the ground as opposed to possibly ending up in an NTSB report some day.
tonycondon
Gastons CRO (Chief Dinner Reservation Officer)
aw crap
Geez Liz... I'm so sad to hear about all of this. (Not nearly as sad as you, I know.) 
I understand that it might be tough to get it out of Troy, but I really hope you're able to find a good person to do the work.
I understand that it might be tough to get it out of Troy, but I really hope you're able to find a good person to do the work.
Tom-D
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And the worst of the bad news came today: underneath the last of the residue were more pits. My mechanic found one that he smoothed down to 0.001" above the Cessna minimum thickness, and there was still more to go. He suspects there are more just like that. So now he wants to get a DER out there to confirm that the spar is toast... I've already found a replacement spar, the only question is who is willing to do the work of taking off the wings and putting them back on again.
I've also decided to submit a claim to my insurance under the not-in-motion coverage. My agent says that according to the underwriter, whether it's covered depends on so many variables the only way to tell is to submit the claim and take it up with the adjuster.
Why does it require a DER to determine the condition of the Spar?
If it is that close to minimum why question it. ?
Tom-D
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They don't really have to be taken all the way off.
support them in place and pull the bolts. leave the cables and wiring alone.
Tom-D
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Geez Liz... I'm so sad to hear about all of this. (Not nearly as sad as you, I know.)
I understand that it might be tough to get it out of Troy, but I really hope you're able to find a good person to do the work.
That's what ferry permits are for.
azure
Final Approach
That was my reaction too. So I called the guru of Cardinal mechanics in Kenosha, and he agreed that was the best next move... just in case there was a field-engineered repair possible. The thing is, my mechanic doesn't think there is anything that can be done. He actually suspects the corrosion goes all the way through.
So at this point, I'm not sure whether it really makes sense to do that. I think my guy just wants a second opinion to be sure he's really seeing what he thinks he's seeing.
I don't want to have to pay a DER to confirm what we're both pretty sure of. He reaffirmed to me today that he is pretty sure the nest has been there at least 2 years, based if nothing else on the fact that some of the mouse turds have turned white. Two years of uric acid corrosion is almost certain to have eaten right through most of the metal.
I'll suggest to him your idea of supporting the wings in place, thanks.
azure
Final Approach
Thanks. My guy knows a sheet metal expert who he thinks can work on it at Troy. If not, I will probably try to get a ferry permit to fly it to Kenosha, since I know they've done this before there.Geez Liz... I'm so sad to hear about all of this. (Not nearly as sad as you, I know.)
I understand that it might be tough to get it out of Troy, but I really hope you're able to find a good person to do the work.
azure
Final Approach
Thanks. Yeah, the real drag is that it wasn't caught at pre-buy. But even a standard "annual" pre-buy might not have caught this unless they took down the headliner. If I had it to do all over again, I'd insist on removing the headliner -- it's the only way to get a good look at the spar itself.
Yellowbird
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Dang, Liz, that's not welcome news. Here's hoping for a speedy recovery.
wabower
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Send any sheet metal work here. The guy will knock it out better, faster and cheaper than you can imagine. The most recent job was a King Air spar cap (with shoring like Tom recommended so everything else could stay in place) that was completed in 60% of the time quoted by other shops.
azure
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Where is here, and who is "the guy"?
wabower
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Trapper John
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Just curious, is there anything special required to R&R 177 wings? Jigs or certain measurements? Or any 100-series Cessna for that matter? I know that for certain airframe repairs, jigs are required, but what triggers the jig requirement?
wabower
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Beats hell out of me, Bill, that's why I use Rudy. And I didn't mean to infer that Liz should schlep her airplane all the way to TX when the 177 Guru is closer. I was just echoing Henning's comments regarding the difficulty of getting good sheet metal work done quickly and properly. This guy is truly a wizard.
Interestingly, when the shop doesn't have a sheet metal job to work on, he works on the shop floor with the other guys. He's a plenty good mechanic, but nowhere near as good as with sheet metal where he's a true artist. I have wondered (and still do) if the really good sheet-metal guys are a little more right-brained than the typical wrench, as I would swear Rudy can see three-dimensional work and complex curves in his head and knows exactly what the pattern will look like.
Interestingly, when the shop doesn't have a sheet metal job to work on, he works on the shop floor with the other guys. He's a plenty good mechanic, but nowhere near as good as with sheet metal where he's a true artist. I have wondered (and still do) if the really good sheet-metal guys are a little more right-brained than the typical wrench, as I would swear Rudy can see three-dimensional work and complex curves in his head and knows exactly what the pattern will look like.
Trapper John
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I've tried to drill holes in aluminum sheet. In spite of the round bit, the holes want to end up triangular. I have a lot of admiration for good sheet metal craftsmen. You get what you pay for, no doubt about it.
wabower
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I don't even try.
azure
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I'm probably just in denial, but I keep thinking back to my conversation with cardinal guru Bob @ ENW. He pointed out that the 177 spar is shaped like an I-beam, looking through the fuselage from one wing to the other. My corrosion is on the web part, the narrow piece that connects the two flanges. By spec, Cessna's minimum thickness requirements are most stringent for the web. Yet, structurally, the web's height is its most important dimension and is not compromised by the corrosion. It even has multiple lightning holes passing through it, so it's hardly a solid piece of aluminum to begin with. It doesn't seem like it would be difficult to field engineer a reinforcement to shore up any spots that had to be thinned to stop corrosion.
This was Bob's argument for letting a DER look at it as a next step. Dunno, maybe that wasn't such a bad idea after all.
This was Bob's argument for letting a DER look at it as a next step. Dunno, maybe that wasn't such a bad idea after all.
Tom-D
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I'm probably just in denial, but I keep thinking back to my conversation with cardinal guru Bob @ ENW. He pointed out that the 177 spar is shaped like an I-beam, looking through the fuselage from one wing to the other. My corrosion is on the web part, the narrow piece that connects the two flanges. By spec, Cessna's minimum thickness requirements are most stringent for the web. Yet, structurally, the web's height is its most important dimension and is not compromised by the corrosion. It even has multiple lightning holes passing through it, so it's hardly a solid piece of aluminum to begin with. It doesn't seem like it would be difficult to field engineer a reinforcement to shore up any spots that had to be thinned to stop corrosion.
This was Bob's argument for letting a DER look at it as a next step. Dunno, maybe that wasn't such a bad idea after all.
I wouldn't allow anyone to cook the books on this. you are talking about the back bone of your aircraft. just replace it and quit wasting time.
Any DER that would declare a Spar that is out of manufacturers limits, as airworthy is crazy. he is excepting the liability of the aircraft as if it were new.
It's just too easy to do it right.
wabower
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What are your qualifications for determining that a DER is crazy for designing a simple and inexpensive fix if it is available?
If a DER provides an alternative plan that solves the problem, why wouldn't an owner be smart to use it? Why does the FAA allow DER's to exist and function in their designated roles?
I've seen ~a half-dozen DER-designed repairs during recent months. Last week's was a doubler to reinforce a hole that had been improperly made in a pair of structural components. Replacing the components would have been expensive and have required several weeks of down time. Fabricating and installing the approved patches required two days. The engineering analysis says the structure is now stronger than when the airplane was new. What's not to like?
If a DER provides an alternative plan that solves the problem, why wouldn't an owner be smart to use it? Why does the FAA allow DER's to exist and function in their designated roles?
I've seen ~a half-dozen DER-designed repairs during recent months. Last week's was a doubler to reinforce a hole that had been improperly made in a pair of structural components. Replacing the components would have been expensive and have required several weeks of down time. Fabricating and installing the approved patches required two days. The engineering analysis says the structure is now stronger than when the airplane was new. What's not to like?
azure
Final Approach
Cook the books??!
Nonono, that's NOT what Bob was talking about and I sure didn't mean to imply that in my post. He said that in most cases a DER can engineer a reinforcement to patch the thinned area and make the structure at least as strong as it was. He said that would be harder to do for the flanges because they take more stress -- but for the web, a lot would depend on exactly where the corrosion was.
I'll add that my guy didn't think it was possible and he's seen the corrosion and Bob hasn't -- but I gave him Bob's number and I'll make sure those two agree that a patch is impossible in my case before I commit to replacing the carrythru.
This is probably the heart of the matter. An isolated area of corrosion may be patchable. If the corrosion damage is widespread, follow Tom's advice.
-Skip
steingar
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New part. Don't waste time. How hard can it be to remove the wings of an airplane?
Everskyward
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Years ago I helped someone remove the wings of a C-152 so it could be towed to a mall for display. It seems like each one was only held on by two bolts.
azure
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You're kidding, right? >100 hours of work... plenty of chances to mess up and leave me in even worse shape...
steingar
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What Mari said, same experience here. Not a big deal for any other GA airplane I've ever encountered. Hey, if the 177 brains say it i I'll shut up, but it just doesn't sound right.
tonycondon
Gastons CRO (Chief Dinner Reservation Officer)
100 hrs to replace the carrythrough maybe. wings should come off pretty easy though.
really sorry that you're having to go through this. what an awful feeling
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Light and Sporty Guy
A 152 has struts so the wings are just "pinned" at the root. The Cardinal has cantilevered cantilevered so the attachments must carry the bending moment so it will be a bit more massive (and fussy).
But as Ms. Azure points out, the web of the carry through wouldn't be under much of a load - the flanges will carry the compression / tension and there isn't much shear in that point in the structure.
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It's a personal opinion just like every thing you read here.
.
In this lawyer based society, he be crazy to except the liability, it's not that they can't do it.
I'm wondering if the DER is dumb enough to tale the liability is he smart enought to design a good repair?
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Yellowbird
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Removing the wings isn't too hard, but to get the spar out, you have to remove most of the cabin interior as well as the exterior skin above the aft cabin - lot of rivets to be drilled out and replaced. Probably not hard, but time consuming.
wabower
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If it were my airplane, I'd be more concerned about the intelligence of my mechanic. If he's too stupid to understand why I'd like to save 90% of the cost of a big repair, assuming a properly-engineered and well-documented alternative were available, why the hell would I think he's smart enough to be entrusted with my airplane?
PS: A high percentage of professionals carry E&O insurance.
PS: A high percentage of professionals carry E&O insurance.
tonycondon
Gastons CRO (Chief Dinner Reservation Officer)
It looks like 2 pins in the main spar and i'm guessing one pin towards the back at a drag spar. Very similar to most gliders.
Tom-D
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100 hours equals 2 men for a week. it's a pretty safe guess.
the wings come off with 4 bolts, a cable set, a wire harness, and fuel lines, After you get all the fairings off, drain the fuel and support the fuselage to prevent it from falling on its tail.
The carry thru comes out by removing all the stuff that runs thru it, and 2 rows of rivets. To remove the rivets use a rivet shaver and remove the heads which will free the cabin skins and the spar will fall out.
Tom-D
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I'd think they will spend more time and money designing, manufacturing the repair than replacing the spar.
and no one gets to enter a major repair into the logs, which in most cases will devalue the aircraft.
Tom-D
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Not quite, the Cessna 150/2 uses the rear spar attachment point to adjust the angle of incidence. by two eccentric bushings, held in by a bolt.
flyingcheesehead
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If he's smart enough to design a good repair, then he shouldn't be worried about liability 'cuz it won't break.
In an ideal world, of course. Won't keep him from getting sued, but hopefully if the wings don't fall off he won't be found liable. And, of course, there's insurance.
Isn't there going to be a major repair entered anyway? I mean, isn't a spar carrythrough replacement a major repair?