Airworthy?

timwinters

timwinters

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The side of the empennage on a local Ercoupe. It was initially damaged when a hangar collapsed on it and appears to have simply been "beat back out" into shape.

The damage is on one side only.

Considering the monocoque construction...is this airworthy?


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Not an engineer so not qualified to say but looks way to wrinkled for my comfort. I can picture this thing folding over.
 
timwinters said:
The side of the empennage on a local Ercoupe. It was initially damaged when a hangar collapsed on it and appears to have simply been "beat back out" into shape.

The damage is on one side only.

Considering the monocoque construction...is this airworthy?


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My initial answer would be "no".
 
You would have to look and see if the ribs or bulkheads are distorted in any way.That is just skin right?

Has it flown after the "repair"?

Any entry in the log book on the damage or repair?
 
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It would require an inspection by a DER to make that determination. Personally I would not fly it until one signed off on it, to many creases for my liking.
 
Henning said:
It would require an inspection by a DER to make that determination. Personally I would not fly it until one signed off on it, to many creases for my liking.
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No....an IA can make that determination. If he determined that a repair is required....the DER could approve the repair data if it differs from the TC data.
 
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Geico266 said:
You would have to look and see if the ribs or bulkheads are distorted in any way.That is just skin right?

Has it flown after the "repair"?

Any entry in the log book on the damage or repair?
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There is no 'just' skin in a monocoque construction, every skin, frame, and rivet is a structural component that all work in harmony to provide great strength at low weight. If there was a 4130 tube frame that had been skinned for aerodynamics, it wouldn't be a problem, but that is not the case I believe.
 
Henning said:
It would require an inspection by a DER to make that determination. Personally I would not fly it until one signed off on it, to many creases for my liking.
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couldn't you just nail a couple of 2x4's longways down the frame to add rigidity? :lol:
 
timwinters said:
The side of the empennage on a local Ercoupe. It was initially damaged when a hangar collapsed on it and appears to have simply been "beat back out" into shape.

The damage is on one side only.

Considering the monocoque construction...is this airworthy?


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Looks like the rivet heads are nearly sanded off too.
 
rbridges said:
couldn't you just nail a couple of 2x4's longways down the frame to add rigidity? :lol:
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You laugh, and the 2x4s wouldn't do it, however if I needed to brace a fuselage like that to get my sorry ass out of somewhere and back home, building an internal frame out of lumber to provide support would be my option.
 
Unless there is a specific allowance in the service manual for such damage, then it is not airworthy. And I highly doubt there is any allowable damage section in the manual for any plane from that era.

Time for a repair. And Henning is correct... it is semi-monocoque construction which means the skin is indeed structural, and must resist all kinds of applied loads, including those that would cause the skin to buckle. Skin that is wrinkled/dented like that will have far, far less resistance to buckling and that is why it must be repaired.
 
KSMooniac said:
And Henning is correct... it is semi-monocoque construction which means the skin is indeed structural, and must resist all kinds of applied loads, including those that would cause the skin to buckle. Skin that is wrinkled/dented like that will have far, far less resistance to buckling and that is why it must be repaired.
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yeah, I'm glad Henning this said it...Larry doesn't understand how the skin is important to monocoque construction? Interesting.
 
Checkout_my_Six said:
No....an IA can make that determination. If he determined that a repair is required....the DER could approve the repair data if it differs from the TC data.
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I think an IA can determine that it's not airworthy, but unless there is guidance with regards to tolerated damage, it would require a DER to determine it is airworthy.
 
Geico266 said:
You would have to look and see if the ribs or bulkheads are distorted in any way.That is just skin right?

Has it flown after the "repair"?

Any entry in the log book on the damage or repair?
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Perhaps a dictionary would be in order to learn what he meant when referring to it as "monocoque?.

[edit] ooops, I see now that Henning already beat you up about it in post #8
 
Henning said:
I think an IA can determine that it's not airworthy, but unless there is guidance with regards to tolerated damage, it would require a DER to determine it is airworthy.
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in kind....an IA can also call it good...with their signature. :yikes:

A DER is not an inspector.....they approve data.

What's missing here are additional photos. How do we know that's not a wheel fairing?
 
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Henning said:
There is no 'just' skin in a monocoque construction, every skin, frame, and rivet is a structural component that all work in harmony to provide great strength at low weight. If there was a 4130 tube frame that had been skinned for aerodynamics, it wouldn't be a problem, but that is not the case I believe.
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Wow! Ya think? :rolleyes::rolleyes::rolleyes:

A wrinkled skin doesn't mean the plane is not airworthy. Design of airplane structures also involves redundancy and engineering margins.

The question was asked is the plane airworthy, but obviously he was looking to start a ****ing match.
 
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timwinters said:
yeah, I'm glad Henning this said it...Larry doesn't understand how the skin is important to monocoque construction? Interesting.
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RotorAndWing said:
I'm not the least bit surprised about that. :rolleyes:
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Jaybird180 said:
Perhaps a dictionary would be in order to learn what he meant when referring to it as "monocoque?.

[edit] ooops, I see now that Henning already beat you up about it in post #8
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Wow, the little girls club is in full attack mode! :rolleyes:

How many airplanes have you girls built?
How many airplanes have you girls repaired?

Wow, Little Timmy I thought you were looking for advice, but I see now you just wanted to do a little "show and tell" like kindergarten. :rofl:
 
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RotorAndWing said:
About 40 years worth.

And I know what a monocoque fuselage is. :rolleyes:
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You've built 40 years worth of planes, got it. :rolleyes:

So a wrinkled skin is cause for the plane to be unairworthy ever time? No amount of damage is acceptable? :no:

I'll wait for the other girls to catch up. :lol:
 
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Geico266 said:
You've built 40 years worth of planes, got it. :rolleyes:

So a wrinkled skin is cause for the plane to be unairworthy ever time?
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In monocoque construction the aircraft skin carries part of the load. Wrinkles in a skin has weakened the structure.


And to answer your question, I've worked on aircraft for the past 40 years, earned an A&P, an IA. I've also rebuilt several airplanes as well as helicopters.
 
RotorAndWing said:
In monocoque construction the aircraft skin carries part of the load. Wrinkles in a skin has weakened the structure.
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You are ducking the question as usual.

So any wrinkle in the skin of an aircraft is cause for it to be grounded and the skin replaced is that your assertion? A simple yes or no, pretty simple really.
 
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Geico266 said:
You are ducking the question as usual.

So any wrinkle in the skin of an aircraft is cause for it to be grounded and the skin replaced is that your assertion? A simple yes or no, pretty simple really.
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I answered your question.

As an IA, if I had a question to the extent of the wrinkles, I would either consult the manufacturer or a DER for further determination.

As to the picture of the thread, with that much wrinkling I would not fly it.
 
Geico266 said:
You would have to look and see if the ribs or bulkheads are distorted in any way.That is just skin right?

Has it flown after the "repair"?

Any entry in the log book on the damage or repair?
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RotorAndWing said:
I answered your question.

As an IA, if I had a question to the extent of the wrinkles, I would either consult the manufacturer or a DER for further determination.

As to the picture of the thread, with that much wrinkling I would not fly it.
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He didn't ask if you would fly it, he asked is it "airworthy". You do know the difference right?

I asked if the plane had been flown since the repair, and was the repair in the log book.

Would you rethink your position about flying the plane knowing the "repair" was logged in the log book and approved by the manufacturer?

You based your professional opinion and 40 years of aircraft building experience on one photograph?
 
Geico266 said:
He didn't ask if you would fly it, he asked is it "airworthy". You do know the difference right?

I asked if the plane had been flown since the repair, and was the repair in the log book.

Would you rethink your position about flying the plane knowing the "repair" was logged in the log book and approved by the manufacturer?

You based your professional opinion and 40 years of aircraft building experience on one photograph?
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I know you have difficulty with reading comprehension, so please go back and read each post carefully and slowly.
 
Geico266 said:
Wow! Ya think? :rolleyes::rolleyes::rolleyes:

A wrinkled skin doesn't mean the plane is not airworthy. Design of airplane structures also involves redundancy and engineering margins.

The question was asked is the plane airworthy, but obviously he was looking to start a ****ing match.
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A wrinkle and a crease have very different physical properties, and that skin has a bunch of creases in it. You are welcome to fly it if you believe it is safe, I would not though.
 
RotorAndWing said:
I answered your question.

As an IA, if I had a question to the extent of the wrinkles, I would either consult the manufacturer or a DER for further determination.

As to the picture of the thread, with that much wrinkling I would not fly it.
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I wouldn't dismiss the wrinkles out of hand, but not being able to see if there are any damages inside the empenage I'm not going to make a determination based on an internet forum photo.
 
Geico266 said:
He didn't ask if you would fly it, he asked is it "airworthy". You do know the difference right?

I asked if the plane had been flown since the repair, and was the repair in the log book.

Would you rethink your position about flying the plane knowing the "repair" was logged in the log book and approved by the manufacturer?

You based your professional opinion and 40 years of aircraft building experience on one photograph?
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If there is no guidance from the manufacturer with regards to damage allowance, that airplane is unairworthy from a legal standpoint.
 
Norman said:
I wouldn't dismiss the wrinkles out of hand, but not being able to see if there are any damages inside the empenage I'm not going to make a determination based on an internet forum photo.
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I would, that metal is creased so it has next to no strength in the dimension required of it, it may hold through mild conditions but a good dose of turbulence could easy buckle the empennage.
 
Geico266 said:
The question was asked is the plane airworthy, but obviously he was looking to start a ****ing match.
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Not at all, people gave opinions with valid back-up. Then you gave your's, with none.

Geico266 said:
Wow, the little girls club is in full attack mode! :rolleyes:

How many airplanes have you girls built?
How many airplanes have you girls repaired?

Wow, Little Timmy I thought you were looking for advice, but I see now you just wanted to do a little "show and tell" like kindergarten. :rofl:
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And then, when proven wrong, Larry goes into full attack mode like...should I say it?...a little kindergarten girl.

Enjoy life Larry!
 
Norman said:
I wouldn't dismiss the wrinkles out of hand, but not being able to see if there are any damages inside the empenage I'm not going to make a determination based on an internet forum photo.
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I agree Norman, that's why my first post I said after looking at the picture:

My initial answer would be "no".
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Then a few post later I said:

As an IA, if I had a question to the extent of the wrinkles, I would either consult the manufacturer or a DER for further determination.

As to the picture of the thread, with that much wrinkling I would not fly it.
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I'm basing that on just basic metallurgy, knowing an aluminum skin that carries part of the structural load has creased and wrinkled, thus weakening it.

Back in the early 90's I had a ''63 Cessna 150 with a wrinkled tail boom we were working on. In order to return it to service we had to either (a) replace the tailcone or (b) get an engineering repair from a DER.

I was also involved with a wrinkled tailcone on a Bonanza. That involved replacing the tail cone.
 
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