Flying old airplanes- structural integrity

Ted DuPuis said:
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.
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I can't disagree with that statement...GA aeroplanes are remarkably well built, especially considering many of these structures were designed in the 40's and 50's and were still being built substantially the same way more than a quarter of a century later.

Having said that, my observation from working on them (and dismantling a few that were relegated to parts planes) is that these Pipers and Cessnas were never intended to still be flying so many decades after they were manufactured. They are the closest thing to a "mass market" aeroplane ever created, sort of a GA "Chevrolet", and some of the details of the way they are put together do not facilitate maintenance - one gets the feeling the airframe was not supposed to outlast things like control cables/pulleys and trim and trim indicator cables/wires, and in some cases the fuel bladders.

With enough effort (and $) anything can be repaired, replaced or rebuilt, but I really get the impression back in the heyday of GA manufacturing these things were intended to be replaced with newly manufactured aeroplanes - at the entry level and for the move up pilot (replicating the Chevrolet - Oldsmobile - Buick - Cadillac progression in the automotive world). The dramatic inflation in airplane prices starting in the 1970s raised the nominal value of the used fleet, and that probably contributed to their longevity. But there's a case to be made those days are over, maybe forever, as many of us are witnessing, with respectable airframes that are not worth the cost of overhauling the engines in them any more.
 
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Ted DuPuis said:
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.
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My instructor explained it to me in such a casual way, that it stuck with me, and probably will forever.

We were doing unusual attitude recovery under the hood. Before we started, he said something like "During recovery, remember to be smooth about everything. When people have yanked too hard, there have been reports from the ground of first seeing wings falling out of the clouds."
 
jkaduk said:
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.

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.

Please cite an accident where it was suspected that a properly maintained, certified airplane flown within it's limits "came unglued".
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Only appropriate IF the 182 has been flown correctly and inspected by reputable mechanics who know this airplane. Many aircraft this old have had ground loops, very hard landings , lousy maintence, on and on, sometimes the damage never logged. The manuf. never dreamed they would still be flown today!!America is famous for planned obsolecence. As for the B52 you should look more carefully! I immed. Recall two, one in western pa. And one in New England. Keep looking. The tail failure was due to poor design and several failed. Later corrected during rebuilds. My uncle and his son both flew them. The son flew the same s/n as his father! ( barks dale) the engines were upgraded as they were improved.(1 engines are important in flying ) No comparison with the run of the mill old Cessna, Piper, etc. the engines in these old GA aircraft are often the original with questionable " overhauls".
 
Jimmy cooper said:
Only appropriate IF the 182 has been flown correctly and inspected by reputable mechanics who know this airplane. Many aircraft this old have had ground loops...
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I want to meet the guy or gal who's ground looped a 182.

That takes a level of bad that's almost impressive enough to consider it a skill.

I want to shake their hand and get a photo.
 
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denverpilot said:
I want to meet the guy or gal who'sground looped a 182.

That takes a level of bad that's almost impressive enough to consider it a skill.

I want to shake their hand and get a photo.
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Considering the number of runway environment loss of control accidents, I'd say it isn't as hard to do as you believe... ;)
 
StevieTimes said:
My instructor explained it to me in such a casual way, that it stuck with me, and probably will forever.

We were doing unusual attitude recovery under the hood. Before we started, he said something like "During recovery, remember to be smooth about everything. When people have yanked too hard, there have been reports from the ground of first seeing wings falling out of the clouds."
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Yes. Smooth is very important when flying airplanes.

There's a video out there of a Boeing 717 stall test where they end up inverted basically straight nose down. They're well overspeed (in the video you can hear Bitchin' Betty yelling at them as such) and losing altitude very rapidly, but still make sure to execute the recovery smoothly and didn't rip the wings off.
 
Ted DuPuis said:
Yes. Smooth is very important when flying airplanes.

There's a video out there of a Boeing 717 stall test where they end up inverted basically straight nose down. They're well overspeed (in the video you can hear Bitchin' Betty yelling at them as such) and losing altitude very rapidly, but still make sure to execute the recovery smoothly and didn't rip the wings off.
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The butt puckering part of that video is watching the altitude tape wind down well into the four digit numbers rapidly. They did a good job in the recovery but the amount of altitude lost really showed they weren't expecting what happened.

The other oddity in that video I noticed and think it matches some sort of standardization after watching it a few times -- is the right seater keeps tapping the left seater on the shoulder.

But as I watched it more I realized it happens at key altitudes. Probably altitudes he's supposed to and pre-briefed to call out, but that wouldn't help the PF in the slightest when it actually happened in the real world. Tap on the shoulder passing 10,000 for example.

No point in calling it out, he's working on slowly pulling out of the dive and the trend looks like it'll be survivable but don't interrupt him. Just let him work on it. No additionally information really needed. Keep doing what you're doing over there... it looks like this airplane won't *quite* kill us today.

That's the best I can figure out. Or he just likes tapping on the other pilot's shoulder when his hands aren't busy. LOL.

Seems more likely it's his way of communicating "nothing significant to say, proceed.. concur...", and the two of them had probably flown together a lot.

One heck of an elevator ride, and there's a third pilot in the jump seat who makes an appearance near the end.

Also wondered if there were any poor ride along engineers monitoring instrumentation in the back, barfing all over the place. Hahahaha.
 
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.
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Aluminum alloys really seem unhappy with their condition and appear to strive to get back to ore condition. Be careful with corrosion on bolts, especially under tension loads. A slight amount of corrosion causes a stress riser where a crack will form. I have a nice little collection of broken bolts in my desk.
 
denverpilot said:
The butt puckering part of that video is watching the altitude tape wind down well into the four digit numbers rapidly. They did a good job in the recovery but the amount of altitude lost really showed they weren't expecting what happened.
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What I got out of the altitude loss wasn't that they weren't expecting it, it was that you need that much altitude to recover from a stall in a swept-wing jet since you end up inverted in a massively steep dive immediately. When you're basically pointed nose down and overspeeding (I'm assuming they were doing somewhere in the 350+ KIAS range to get that warning), you're going down FAST.

This is why they go through this testing - to make sure it never happens with a plane load of passengers. This is also why our planes have straight wings with much better stall characteristics unlike, say, a Lancair IV-P.
 
Ted DuPuis said:
Yes. Smooth is very important when flying airplanes.

There's a video out there of a Boeing 717 stall test where they end up inverted basically straight nose down. They're well overspeed (in the video you can hear Bitchin' Betty yelling at them as such) and losing altitude very rapidly, but still make sure to execute the recovery smoothly and didn't rip the wings off.
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A B717? As in the Boeing version of the DC-9?

Are you sure it wasn't a 727?
 
Ted DuPuis said:
What I got out of the altitude loss wasn't that they weren't expecting it, it was that you need that much altitude to recover from a stall in a swept-wing jet since you end up inverted in a massively steep dive immediately. When you're basically pointed nose down and overspeeding (I'm assuming they were doing somewhere in the 350+ KIAS range to get that warning), you're going down FAST.

This is why they go through this testing - to make sure it never happens with a plane load of passengers. This is also why our planes have straight wings with much better stall characteristics unlike, say, a Lancair IV-P.
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Seemed like a pretty low entry altitude if they were expecting an inverted upset during the stall, which is pretty likely in a swept wing.

Considering the tape seemed to bottom out around 4000 (hard to read) and most of that sort of testing would be done in the open spaces of the desert southwest where the ground is a couple to three thousand feet up, so it doesn't seem like a planned safe recovery altitude. Just whatever they ended up with and they seemed outside of the plan.

(Which is why I think the guy tapped the other on the shoulder passing 10,000. That was probably their planned hard deck for that test, but what's the point of telling the other guy much when you're blowing through it at 300+ and nearly vertical? Hahaha. He knows.)

Wherever they were, I doubt it was done over the ocean, and it didn't look like it out the window.
 
nauga said:
with more than a little schadenfreude
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LOL! Well I figured *some* of the higher risk flights they'd just set the recorders and get out, but you'd know better than I.

Quite the non-standard way to make a new Vomit Comet... and not quite the nice even parabola desired. ;)
 
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 bet you a beer you're all more likely to screw up and kill yourselves than either of those ways.
 
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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Well, there was this one...

monmouth-airport-fatal-plane-crashjpg-b0790557003f3315_large.jpg


http://www.thekathrynreport.com/2010/02/two-killed-three-missing-in-new-jersey.html

One of the pilots announced over the airport’s common traffic advisory frequency his intention to perform a low pass over the runway, and ground witnesses observed the airplane fly about 50 feet above the runway with the landing gear retracted. Global positioning system data recovered from the wreckage indicated that the airplane’s ground speed at that time was about 160 knots (kts) (184 mph). Witnesses observed the airplane’s nose pitch up just before the outboard 6-foot section of the right wing separated, and the airplane descended uncontrollably and impacted the ground.
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Gerhardt said:
Well, 6PC turns 40 today. I'd be more concerned about his structural integrity than the plane's.
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Ya, but he has the option of pulling that red handle, halting all forward momentum and staying 40 "forever"...
 
Because every AP is the very model of moral and ethical uprighteousness, structural failure is something you will never have to worry about.
Except, two years ago I was picking up a C-172A for a friend that had just been pushed out of the hanger after finishing the annual. As I taxied out to do the run-up, the right landing gear bolts sheared off.
And there was the time the strut buckled on a C-120 during preflight (I was pushing and pulling up and down on the wing tips), and the main spar on the Cherokee broke, and, the time the covering came off the entire top of both wings on a Fairchild 24 (I was in the air when that happened).
You fly enough old planes, for enough years and bad things WILL happen to structural components. I have logbooks with a bunch of incidents.
Trust no one. Learn how to take off inspection plates and look for yourself.
In the interests of full disclosure: In a former life I made money ferrying questionable airplanes, so I have way more than a fair share of incidents.
 
MAKG1 said:
I'd imagine it can be done with a flat tire.
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Trikes are commonly groundlooped by landing so fast that the nosewheel is the only thing on the runway. It therefore becomes a really nasty taildragger.
 
I fly an airplane built in 1946 and i'm guilty of looking out to the wingtips from time to time in turbulence and wonder about them staying on. To make matters worse I actually took them off and put them back on (under A&P supervision) so was that torque wrench accurate?

However the wings and everything on the plane look great on the inside, plane is in excellent overall shape. The wings are staying on.
 
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