Flying old airplanes- structural integrity

James331 said:
I'd wager a beer that you're more likely to get killed by gunshot from a over zealous DHS Rambo encounter on the ramp, than a major structural failure while operating per the POH.
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I'll go with that. :)
 
When was the last time you heard of major parts falling off of an airplane that was not being flown through a thunderstorm? Every time I see this question I think of the B-52. The newest ones were built in 1962. They fly low level where they get hammered by turbulence. They have wrinkles in the skin that looks down right scary. Ever hear of one falling apart? Me neither.
 
Dan Thomas said:
Those little bolts are of little concern. What's more important is the condition of the aluminum structure; it corrodes much more easily than the bolts. There are some areas where corrosion starts, and unless the airplane is inspected thoroughly by someone who knows what to expect, it can progress to dangerous levels. The Cessna SIDs mentioned by StewartB are the right idea. For example, there's a laminated joint in the wing front spars that can corrode between the laminations and rot away.

The tail is also something to watch. The tail is often what fails first in a high-G pull-up, anyway.

That said, I don't hear of Cessnas falling out of the air due to inflight structural failure. But that will change as the fleet gets older.
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Spot on.. speciality the early Cessna 170/ 172 front spar Carry thru. we see more and more impending failures in this area.
 
jkaduk said:
When was the last time you heard of major parts falling off of an airplane that was not being flown through a thunderstorm? Every time I see this question I think of the B-52. The newest ones were built in 1962. They fly low level where they get hammered by turbulence. They have wrinkles in the skin that looks down right scary. Ever hear of one falling apart? Me neither.
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Your Cessna and Piper should be built so stout and inspected so often.
 
jkaduk said:
When was the last time you heard of major parts falling off of an airplane that was not being flown through a thunderstorm? Every time I see this question I think of the B-52. The newest ones were built in 1962. They fly low level where they get hammered by turbulence. They have wrinkles in the skin that looks down right scary. Ever hear of one falling apart? Me neither.
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I sure have heard of B52s coming apart in midair and you can educate yourself simply by googling B52 accident history. I recall one where the whole tail fell off in turbulence. It's important to note that every B52 has been completely gone over several times since inception at the factory including structural updates, engines, on and on. If your currently flying a light aircraft built fifty, sixty years old remember it's not been back to the factory and anything could come unglued and probably has many times but unproven by what little was left of it and what could be determined.
 
pigpenracing said:
I am still flying my 1940 J-3 and the wings have not fallen off yet :)
Parts back in 1940 were not made in China.
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If your 1940 cub was rebuilt, and it probably was more than once , and if the restorer did it correctly , it could be better than factory new. They are taken down to the frame, checked carefully, wings stripped, spars, checked inspected carefully , on and on. Impossible to say on an old 172, 182' etc. etc. I've owned a cub and a champ plus two t crafts that were all redone in the late 90s.mtheyvwere done correctly by excellent restorers. Several were trophy winners.
 
flight2000 said:
Worried about the wings falling off, not so much. I'm more worried about control wires snapping in flight. Mis-rig one and you can snap the wire or saw through other critical items. :eek:

https://www.pilotsofamerica.com/community/threads/elevator-trim-wire-snaps-mid-flight.51397/

Brian
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This, I know every pre-flight I'm looking at those contol cables, moving control surfaces listening for any weird binding or rubbing noises. I'm looking at safety wires and piano hinges, I'm looking at push-rod linkages.

That's the stuff that's going to ruin your day outside of a pilot f-up or your spinner quitting on you. I worry about those control cables because you can't see what they're rubbing up against. I sometimes have dreams about my elevator cable failing. Those aren't good dreams...
 
There has been some interesting banter over this topic. I didn't want to start one of "those" threads but it was just a thought I had the other day flying in some turbulence through the Columbia Gorge.

I always thought the "Cessna Whistle" was caused by the air vents either getting some blockage or excess moisture. When I hear it in the clouds I start watching for ice. Great safety feature.
 
Did those firefighting tanker a/c wreck because of age and deterioration, or because of the demands of their work?
 
Tom-D said:
[snip] Some so called mechanics could fail a steel ball with a rubber hammer.
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OK, that made me laugh out loud. And I've seen folks like that. :)
 
Has the Cessna spar carry-through corrosion resulted in an accident?

Thinking about normal loads applied to it in flight, how would it fail - ie in which direction?
 
Jimmy cooper said:
I sure have heard of B52s coming apart in midair and you can educate yourself simply by googling B52 accident history. I recall one where the whole tail fell off in turbulence. It's important to note that every B52 has been completely gone over several times since inception at the factory including structural updates, engines, on and on. If your currently flying a light aircraft built fifty, sixty years old remember it's not been back to the factory and anything could come unglued and probably has many times but unproven by what little was left of it and what could be determined.
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You're comparing the life and stress of a B52 to a C150?
 
Let'sgoflying! said:
Has the Cessna spar carry-through corrosion resulted in an accident?

Thinking about normal loads applied to it in flight, how would it fail - ie in which direction?
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Don't know if... but the carry through in most high wing strut aircraft are loaded primarily in compression so it would collapse inward.
 
We found a cracked wing strut on a 180 last year. Tiny crack in the spar tube running through one of the big rivets that hold the lugs at the ends of the strut. It was an eddy-current NDT that found it, and we were looking for it because it was a Cessna SID and the airplane was a floatplane, which gets banged around on rough water. Cessna issues those SIDs based on Service Difficulty Reports sent in by mechanics.

Spent 40 hours blending out corrosion pits and taking ultrasonic thickness measurements on a 177's (Cardinal) spar carrythrough. They're famous for corrosion, and they're carrying the entire airplane. No struts to direct some of the load elsewhere.

We regularly find worn or fraying control cables. If the annual inspection is being done right (which costs more money, btw) they will get caught long before they're any safety risk. But the owner has to be willing to pay for decent maintenance, and many aren't. Their sense of security is often based on wishful thinking.

I see enough stuff to make me real careful about flying old junk, and experiencing two engine failures due to poor maintenance had a hand in that caution. Found a cracked spar (a longstanding crack) in another that I had flown for over 60 hours. A broken stab spar in another that handled all funny in flight, and that had the lower strut bolt nuts missing, tend to make one cynical. That last one had just had an "annual."
 
James331 said:
You're comparing the life and stress of a B52 to a C150?
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I certainly am not. Simply replying to the fellow who said ....."I've never heard of a b 52 coming apart". They most certainly have, not to mention B47s which were relatively new. On two of the old t crafts I bought ,then rebuilt , frayed cables were found, and an old 150 could easily have some.,
 
Let'sgoflying! said:
Did those firefighting tanker a/c wreck because of age and deterioration, or because of the demands of their work?
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I'm no expert on the subject, but my recollection was metal fatigue from years of loading. Like the early model C130 that folded up in flight while doing the same thing.
 
denverpilot said:
People who haven't seen a Cessna with the little cover strip off to get at the fuel lines or whatever, often don't realize there's very little attaching the wing to the fuselage and you can just look between both and see mostly daylight. Heh.

But the scarier Jesus Bolts are in helicopter rotor heads and blade attachments. ;)
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65,000 lbs of centrifugal force on Black Hawk blades. Two metal pins are all that's keeping those blades from being let loose.
 
dmspilot said:
I have read that there has never been an inflight structural failure of a strut-braced Cessna. Not sure if still true.
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Scott Crossfield's 210 was an early, strut braced version. It came apart in a T-storm about 20 miles from where I'm sitting right now.
 
Let'sgoflying! said:
Has the Cessna spar carry-through corrosion resulted in an accident?

Thinking about normal loads applied to it in flight, how would it fail - ie in which direction?
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Not that I know of.
 
Velocity173 said:
65,000 lbs of centrifugal force on Black Hawk blades. Two metal pins are all that's keeping those blades from being let loose.
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The next time you have one of those pins in your hand, try to cut it. :)
 
ChemGuy said:
I'm no expert on the subject, but my recollection was metal fatigue from years of loading. Like the early model C130 that folded up in flight while doing the same thing.
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That C-130 had an unauthorized wing beam repair. I know Greg the previous pilot that had quit a week prior to this accident.
 
Jimmy cooper said:
On two of the old t crafts I bought ,then rebuilt , frayed cables were found, and an old 150 could easily have some.,
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I've found several Cessna's with corroded cables, specially the elevator trim cables where they round the corner in the Horizontal stabilizer.
 
Tom-D said:
The next time you have one of those pins in your hand, try to cut it. :)
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They actually found cracks in them years ago. The contractor was cutting corners and not heat treating per spec. They obviously don't get their blade pins from them anymore. They're pretty darn stout though. There have been blade failures in the 60 but I know of none that were caused by actual pin failure.
 
Velocity173 said:
65,000 lbs of centrifugal force on Black Hawk blades. Two metal pins are all that's keeping those blades from being let loose.
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I'd be very surprised if it's that simple. Components like that usually have a failsafe design with multiple failures required for complete failure, usually a solid bolt or pin inside a hollow one, and sometimes more.
 
Capt. Geoffrey Thorpe said:
Don't know if... but the carry through in most high wing strut aircraft are loaded primarily in compression so it would collapse inward.
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The first one was found during taxing over rough ground, making the wings wag up and down, the pilot noticed the flexing of the wing root vents. disassembly found that the hat section and wing root attachment were nothing but white powder. the replacement & repair is about $2500. Now it is a pretty common inspection during annual.
This is where the type clubs are a big deal, someone in the club knows these soft spots
 
kyleb said:
Scott Crossfield's 210 was an early, strut braced version. It came apart in a T-storm about 20 miles from where I'm sitting right now.
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A couple of Skymasters have shed wings as well.
Skip Miller said:
OK, how about the spar carry through on the C177 Cardinal?
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The primary load on those is bending. Compression on the top edge, tension along the bottom. Whole different animal. Dunno if any have failed or not.
 
Jimmy cooper said:
I sure have heard of B52s coming apart in midair and you can educate yourself simply by googling B52 accident history. I recall one where the whole tail fell off in turbulence.
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Don't need to educate myself. My father flew them. But I did do a real quick google and only found one or two a very long time ago.
Jimmy cooper said:
It's important to note that every B52 has been completely gone over several times since inception at the factory including structural updates, engines, on and on.
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Okay structural updates I'll give you. The engines and on and on don't contribute to the longevity of the structure. Sure it's been gone over several times. It's a war plane flown a lot, in harsh conditions so that's appropriate. Just as the inspection of a C-182 according to the maintenance manual is appropriate for it, and thus far has proven to prevent them from falling apart.
Jimmy cooper said:
If your currently flying a light aircraft built fifty, sixty years old remember it's not been back to the factory and anything could come unglued and probably has many times but unproven by what little was left of it and what could be determined.
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Please cite an accident where it was suspected that a properly maintained, certified airplane flown within it's limits "came unglued".
 
Velocity173 said:
They actually found cracks in them years ago. The contractor was cutting corners and not heat treating per spec. They obviously don't get their blade pins from them anymore. They're pretty darn stout though. There have been blade failures in the 60 but I know of none that were caused by actual pin failure.
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I instituted a 25 landing inspection on E2A tail hook stinger attachment pins, because we found a cracked one. that's a 2.25" pin that is hardened steel. yeah things crack.
 
GlennAB1 said:
I'd be very surprised if it's that simple. Components like that usually have a failsafe design with multiple failures required for complete failure, usually a solid bolt or pin inside a hollow one, and sometimes more.
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Well sure, I'm not talking about a simple bolt or something. I'm just saying two pins are what hold back all that force. I should say the entire spindle module is what keeps the blades from flying off but they're attached to it by two pins.
 

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Structural failure is a frightening thing. While it has happened in rare cases, it is important to know that it's very rare.

A few years ago, I went and searched through the NTSB reports for Cessna 310 crashes that involved structural failures. Virtually all of them were night IMC, and the remaining ones were day IMC (usually flying into a thunderstorm). The reports concluded that the pilots got spatial disorientation ended up inverted or in a spin, and then yanked too hard trying to get out of it, resulting in parts (usually the tail) falling off the plane. That significantly eased my concerns.

I would imagine if you searched for the 182 you'd find much the same. These planes are old, but they were built well from the factory.
 
The tail nutplate AD in 150's, has that ever caused an inflight breakup?
 
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