Tom-D
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Tom-D
While the cat's away...
- Thread starter azure
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Thanks for the link, but it really doesn't tell us the composition of the coating. I honestly haven't found anything to show which of us is correct.
Back on topic, I did see something that suggests that the paint has a vastly different coefficient of expansion compared to the metal, causing the paint to crack under temperature extremes, an alodine coating doesn't have this problem.
I suspect BS- I think if the surface is prepped properly, the paint should work fine but I don't paint (or alodine) plane parts for a living.
azure
Final Approach
That's not the only reason it's bad news. The more important reason is that the part is generally not available except as a salvage item. There is no old stock available anywhere, and no third-party source.
Steve
En-Route
$7,500/wing plus labor, for a ball park figure on salvaged wings
http://www.aircraftpartsandsalvage.com/cessna-cardinal-wing-p-6091.html
http://www.aircraftpartsandsalvage.com/cessna-cardinal-wing-p-6092.html
several years ago one of the early victims of the cardinal spar corrision malady actually paid Cessna to build him new wings for around $12,000 as I recall. I can only imagine what the price would be today for new ones.
http://www.aircraftpartsandsalvage.com/cessna-cardinal-wing-p-6091.html
http://www.aircraftpartsandsalvage.com/cessna-cardinal-wing-p-6092.html
several years ago one of the early victims of the cardinal spar corrision malady actually paid Cessna to build him new wings for around $12,000 as I recall. I can only imagine what the price would be today for new ones.
azure
Final Approach
The ballpark figure I've read is $4 amu for the spar, ~6 amu labor. For the carrythrough (not the wings).
I say again -- the issue is availability, not so much expense. They are NOT a stocked item, you cannot order them. A few Cardinal owners have managed to score one through contact with an owner who kept one from a salvaged aircraft. It takes a long time and a lot of legwork to find one. Many give up.
I say again -- the issue is availability, not so much expense. They are NOT a stocked item, you cannot order them. A few Cardinal owners have managed to score one through contact with an owner who kept one from a salvaged aircraft. It takes a long time and a lot of legwork to find one. Many give up.
Tom-D
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The part we are talking about is the spar carry thru in the fuselage, the wings will be OK. they attach to the outboard ends of the carry thru.
It's the piece you bump your head on getting into the back seat of the 177.
It's a large casting that must be very strong, and have no stress risers in it.
Large aluminum casting are very susceptible to inter-granular corrosion, due to improper heat treatment processes.
Tom-D
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I didn't realize that a carry thru would be that hard to find, Cessna usually supports their aircraft better than that.
Salvage yards here we come.
Your mech might be really care full and blend the corrosion out and see if it still meets the requirement.
I'd really like to see pictures.
Tom-D
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I have never seen Zincromate primer crack or fall off when the surface was prepared properly. there are Cessnas that were protected as seaplanes way back in the 50s that are very nice inside yet today.
azure
Final Approach
IF he can be sure that there's no deeper corrosion that can't be seen. But yes, I'm holding out a little hope there.
He is also sending pictures out to a Cessna tech rep, but I don't have copies yet. We have the service limits from Cessna via CFO.
Tom-D
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very interesting discrepancy, I'd be grateful to know what Cessna has to say.
azure
Final Approach
I tried to upload a copy of the Cessna document but I only have it as a TIFF, and the BB says "invalid file".
But here is what it says, verbatim:
"Remove all corrosion on Carry Through Spar web. The rework is serviceable if after blending and smoothing the minimum thickness is 0.22 inches or greater."
It does not say what the original thickness is. 0.25 is my guy's guess.
But here is what it says, verbatim:
"Remove all corrosion on Carry Through Spar web. The rework is serviceable if after blending and smoothing the minimum thickness is 0.22 inches or greater."
It does not say what the original thickness is. 0.25 is my guy's guess.
Tom-D
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OK I misunderstood the .220" it is the total thickness of the material after all corrosion is removed.
now all we need to know it the thickness of the material to start, to know how much we can take off.
I would form a buffer pad from 400 grit wet and dry sand paper for my dremel tool and start buffing away the corrosion, when I thought it was all removed, I would dye check it, then I'd measure it to see what I have left.
220 or less I'd start calling the salvage yards. 221 or more I treat it and fly.
Yellowbird
Pre-takeoff checklist
If worse comes to worse, here's a spar at a salvage outfit in Texas: http://www.texasairsalvage.com/main_view.php?editid1=31696
Attachments
Yellowbird
Pre-takeoff checklist
CFO has it as a jpeg also:
Attachments
azure
Final Approach
Can the dye test be done on a vertical surface? Or for that matter, do you have to remove the spar and immerse it?
Scott -- yeah I know they had a jpg too but it looked like a worse quality image than the tif.
Tom-D
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the dye is applied by a spray can, and it makes a mess, but it can be applied to the bottom of most any thing.
bbchien
Touchdown! Greaser!
Oooh Liz. This is a nightmare and I hope it works out..... 
Ted
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iFlyNothing
I do hope it works out.
But remember: You found out on the ground. Finding out about problems in the air is, well, less fun. Especially when they involve major structural components of the airplane.
But remember: You found out on the ground. Finding out about problems in the air is, well, less fun. Especially when they involve major structural components of the airplane.
azure
Final Approach
Well yeah, but I've been flying it for almost a year. This is not a new problem, it's been developing for a while. Maybe quite a while.
Why didn't my pre-buy mechanic find it? That is a rhetorical question: he didn't find it because he didn't really look. He opened the inspection panel and examined what was right in front of his nose. That's not good enough. I didn't know any better at the time, but he should have. Actually he did, he was an experienced Cardinal owner and had dealt with minor corrosion on his own spar ct.
He just wasn't doing his job.
According to my mechanic, the chunky, discolored insulation was a dead giveaway that something was amiss. There is no way the pre-buy guy could have missed it unless he was sleepwalking.
Based on what I know today, I would not buy a Cardinal without a pre-buy in which the headliner was actually removed and the spar thoroughly examined. Although my problem should have been found, it's more common to have corrosion on the front side of the spar where it's impossible to see it through the inspection panel.
Why didn't my pre-buy mechanic find it? That is a rhetorical question: he didn't find it because he didn't really look. He opened the inspection panel and examined what was right in front of his nose. That's not good enough. I didn't know any better at the time, but he should have. Actually he did, he was an experienced Cardinal owner and had dealt with minor corrosion on his own spar ct.
He just wasn't doing his job.
According to my mechanic, the chunky, discolored insulation was a dead giveaway that something was amiss. There is no way the pre-buy guy could have missed it unless he was sleepwalking.
Based on what I know today, I would not buy a Cardinal without a pre-buy in which the headliner was actually removed and the spar thoroughly examined. Although my problem should have been found, it's more common to have corrosion on the front side of the spar where it's impossible to see it through the inspection panel.
Gary
En-Route
That is indeed one ugly problem. I do hope you can get it cleared up without a new spar.
Gary
azure
Final Approach
I had a long talk today (long distance) with the mechanic who annualed my plane the past two years, the last annual in 2010 being less than a month before I bought it. He says he borescoped the spar through the inspection panel at the last annual and certainly handled the insulation. My mechanic says that most of the soiled insulation was aft of the spar -- actually the worst of it was even aft of the inspection panel, but there was some on either side too that should have been apparent. But the mechanic in NY saw no evidence of mice up there.
If it's true, that changes the picture a little (I say "if" because though I don't think he has any legal incentive to CYA, embarrassment and injured pride can help to fog a person's memory) and makes this a bit of a, if not a "whodunit", then a "howdidit". When were them critters in there? And where did poor 8JT pick them up? The more recently, the better the chances the spar will be fixable. Yet my mechanic says he's never before seen any evidence of mice in the metal hangars at VLL, and he's worked on a lot of airplanes here over quite a few years.
There's one place my plane has sat overnight where the cabin was definitely left open to intruders, and that's when the windshield was being replaced early last summer. That was in a concrete hangar at a rural field. The plane would have sat in there, maybe for days, with no windshield. Were there mice in the hangar? I have no idea, but the crew who worked on my plane spent long hours there and I'm pretty sure I saw food being eaten there.
Working against this theory is that my guy is fairly confident that the rodent infestation is at least 2-3 years old. There were a LOT of droppings up there, and a large fraction of the insulation had been thoroughly messed up and mixed with bits of chewed paper. It looked like my ceiling had been home to several generations of mice, and very unlikely that it was a one-time invasion that began last summer; though he couldn't rule out that I could've flown with some New York rodents that stowed away on the delivery flight.
Just thinking out loud here...
If it's true, that changes the picture a little (I say "if" because though I don't think he has any legal incentive to CYA, embarrassment and injured pride can help to fog a person's memory) and makes this a bit of a, if not a "whodunit", then a "howdidit". When were them critters in there? And where did poor 8JT pick them up? The more recently, the better the chances the spar will be fixable. Yet my mechanic says he's never before seen any evidence of mice in the metal hangars at VLL, and he's worked on a lot of airplanes here over quite a few years.
There's one place my plane has sat overnight where the cabin was definitely left open to intruders, and that's when the windshield was being replaced early last summer. That was in a concrete hangar at a rural field. The plane would have sat in there, maybe for days, with no windshield. Were there mice in the hangar? I have no idea, but the crew who worked on my plane spent long hours there and I'm pretty sure I saw food being eaten there.
Working against this theory is that my guy is fairly confident that the rodent infestation is at least 2-3 years old. There were a LOT of droppings up there, and a large fraction of the insulation had been thoroughly messed up and mixed with bits of chewed paper. It looked like my ceiling had been home to several generations of mice, and very unlikely that it was a one-time invasion that began last summer; though he couldn't rule out that I could've flown with some New York rodents that stowed away on the delivery flight.
Just thinking out loud here...
Last edited:
Yellowbird
Pre-takeoff checklist
I've had two hangars where I saw the occasional mouse. And in one of them, the occasional frog and even a crawdad.
I had Yellowbird's interior gutted for a few months when I replaced the interior and windows. From seeing the cabin innards, I'd guess that the most liklely mouse path to the cabin overhead would be up one of the main gear legs, into the gear well and then into the space under the cabin floor. From there, up through the vertical structure behind the doors to the point where the spar is attached. There are some holes in the horizontal stringers where the fuel lines and some wiring pass through, and a clever mouse could probably find a way up. What attracted him to go that far up is a good question.
If your mechanic hasn't done so already, it would be a good idea to remove the upholstery panels from the aft cabin to see if there are other mouse nests.
d.grimm
Pre-takeoff checklist
Not that it helps, I had the inspection plates off a Cub overnight, a mouse got in there and chewed all the rib stitching off. I had looked in there the day before and everything was fine. Can you say wing recover? Yuck!
Dave
Dave
Tom-D
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Tom-D
Pull the tapes, and re-stitch it.
d.grimm
Pre-takeoff checklist
That's what I ended up doing. Hindsight, recover would have been faster.
Dave
Dave
You use all three. Alumiprep cleans the oxidation, the Alodine reacts with the new oxidation and the zinc chromate provides a paint type barrier coat between the aluminium and the environment.
azure
Final Approach
Yep, that's the plan now (hopefully). Now if I can just get my mechanic back to work on my plane... he seems to have an endless stream of distractions keeping him from it.
Ted
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Yep, that's the plan now (hopefully). Now if I can just get my mechanic back to work on my plane... he seems to have an endless stream of distractions keeping him from it.
I find this is frequently the case when an aircraft has an ailment the mechanic is not particularly interested in working on.
The part I don't get is that the typical reward (money) is frequently insufficient incentive.
Allow me to try to explain. Some jobs we don't like doing for whatever reason. If we don't like doing them, we probably never got real good at doing them so when we do them, it probably takes more time than it should, and more time than we'll bill for. Given this, we end up with a double whammy situation, we're doing a job we don't like doing and we're "losing money" at it. This is quite frequent with sheet metal work.
azure
Final Approach
I doubt if this has anything to do with that. It took him over a week to get started on my annual, before anyone suspected this problem. It's a character trait with him: anytime someone has an airplane with a problem, he will drop whatever he's doing to look at it and then chat with the owner for a couple of hours. He's about the nicest guy you've ever met, but he has twice as much work as he needs to keep him occupied, and lots of commitments that have nothing to do with working on planes.
Ted
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That's a management problem.
We all have things we don't like to do. If I don't want to do something, I'll bill substantially more for it to discourage the person from asking me to do it. If that person chooses to have me do it anyway, I'll come out enough ahead to make it worthwhile.
Tom-D
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In many case I evaluate the repair and order the supplies to do it, and set the aircraft aside until they arrive. If Lisa is trying to find a new/different carry thru it may take a while, and he is continuing to service his other customers.
It may be a case where the A&P can't dedicate his whole shop to one project.
Tom-D
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I'm a bit more Frank with folks than that, I tell them that I'm not the guy they want, I am not that great at doing this type of work, here is the number for the guy who has the equipment and talent to do it right.
See........... Ya Bye.......
Ted
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That is a good way of doing it, and one that more people should employ.
That's different and how most all shorthanded shops operate especially if it's a busy field. It's also why you use specialty shops when you run into specialty problems which is where ferry permits come into play.
azure
Final Approach
Oh sure, he didn't have the sanding wheel he needed at first, so he ordered it and had to wait until it came in. But then, once it was in, he turned to annual another plane, saying the owner had flown up from Florida.
I'm not waiting for a new spar, I'm waiting for him to smooth out the corrosion so we'll know IF I need a new spar. That's something that has to be done to Cessna's spec, so it's not something I'd think of tackling myself even if I had the tools and the time.
azure
Final Approach
Unfortunately the airplane isn't even in any condition right now for a ferry flight. It's still disassembled for annual. He promised to start putting it back together while waiting for the sanding wheel to come it, but of course he never did. The way he works, it would take him a week just to get the airplane flyable.
The club I belong to doesn't use him for annuals and most maintenance because he's so slow. They have their own mechanic, fortunately, but he doesn't know a thing about Cardinals, and charges well over the going A&P rate for non-club planes.
Tom-D
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Sounds like he has you over the proverbial barrel.
tell him you are going to hire another A&P to finish the work. see what he does.
Of course be ready to hire the A&P just in case he says to go ahead.
azure
Final Approach
There's the rub, he'll know it's a bluff. He knows there aren't any other mechanics on the field who would tackle the job. Next year I probably should take it somewhere for annual. I just didn't have the time this year to make the arrangements.
I've been told that the only way to keep him working on your plane is to keep the pressure on. I'm at a disadvantage there since I work full time (actually more than full time) and the phone is just not as effective as in person.
steingar
Taxi to Parking
Liz, either you go find another part yourself, or wait. You have no other choice. BTDT. Good luck. If it makes you feel any better, this is a long way from the worst maintenance nightmare of which I've heard.