I can't make sense of this crash

mscard88 said:
One is accomplished annually, the other every 100 hours. But then you know that. ;):)
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Well......

There’s a bit more to it than that. :rofl:

Besides that fact.
Annual requires IA, 100 hr only needs A&P.

But what I was hoping the OP knew was that an annual and 100 hr are no different in scope or detail.
 
Stuff happens to airplanes.
Sometimes it's bad stuff.
Sometimes you get lucky and find the bad stuff before you get off the ground.
Sometimes you don't find the bad stuff until it's too late.

Two weeks ago on July 19, I was out doing stalls and spins in one of the Cubs.
Two other guys flew it in the intervening time after I did and didn't report any problems.
On Monday, July 30, I grabbed the left wing to give it a shake (to test the bungee cords on the landing gear) and the wing went "POP"!
Pure, unadulterated luck because I ALWAYS grab the right wing as I go past to put my gear inside.
It appears a bunch of wood parts in the left wing came unglued. It's 77 years old, so It shouldn't be a surprise.

Stuff happens to airplanes.
Sometimes it's bad stuff.
Sometimes you get lucky and find the bad stuff before you get off the ground.
Sometimes you don't find the bad stuff until it's too late.
 
woodchucker said:
Total speculation: the student was climbing to an assigned altitude, possibly in a turn, and inadvertently stalled, panicked and wouldn’t release the controls.

That’s about the only scenario where I could see this happening outside of a control system failure or suicide.

What’s the plausibility on that? It’s late and I’m bored. I really hope to see the case study on this. OP is right, it’s a strange one. A 172 will fight to keep you alive. This is .... bizarre.
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Don’t think that would cause an inflight break up.
 
GreatLakesFlying said:
As renters, how do we know that the airplanes we are flying are not compromised by corrosion, prior Va violations, etc? These failures may be discovered during annual inspections, but this may be too long. Can they be caught during the 100-hour inspection?
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That's my biggest fear as a renter. That I will be given a broken plane that I have no shot to get back on the ground safely. At times, it has made me question my participation in this hobby.

And what's worse is that the school may not even know that a previous renter did something dumb to stress the plane to its limits or whatever. Not sure some people would volunteer that info to be held financially responsible for repair costs.
 
sarangan said:
It would be interesting to know if the airplane had its wings removed for any reason in the past, like say, an off field landing. May be it wasn't put back together properly.
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If it shed the outer wing panels first, assembly wasn't the issue. That's overstressing.
 
I would also think that corrosion or maintenance error wouldn't tend to cause both wings to suddenly depart at once while an overstress would be more likely to. Just spit balling here. I'm just a mechanic, not an engineer.
 
Shepherd said:
Stuff happens to airplanes.
Sometimes it's bad stuff.
Sometimes you get lucky and find the bad stuff before you get off the ground.
Sometimes you don't find the bad stuff until it's too late.

Two weeks ago on July 19, I was out doing stalls and spins in one of the Cubs.
Two other guys flew it in the intervening time after I did and didn't report any problems.
On Monday, July 30, I grabbed the left wing to give it a shake (to test the bungee cords on the landing gear) and the wing went "POP"!
Pure, unadulterated luck because I ALWAYS grab the right wing as I go past to put my gear inside.
It appears a bunch of wood parts in the left wing came unglued. It's 77 years old, so It shouldn't be a surprise.

Stuff happens to airplanes.
Sometimes it's bad stuff.
Sometimes you get lucky and find the bad stuff before you get off the ground.
Sometimes you don't find the bad stuff until it's too late.
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Wait, explain this shaking the wings in a cub. Never seen this done.
 
SkyDog58 said:
Regulatory wise, what is the difference between an annual and a 100 hr?
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Nothing, they are pretty much the same. 100 hr is required of aircraft used for commercial operations. And yes flight instruction counts. Of course certain ADs will come due at different times but that’s pretty much it.
 
There used to be a pretty good magazine, Private Pilot. And a pretty good columnist, Tropical Ed. One of Ed's columns was about how pilots, especially helicopter pilots, should fess up about accidental misdeeds. Engine overspeed, rotor overspeed, etc. Just fess up so the next guy can fly safe.
 
Lindberg said:
Wait, explain this shaking the wings in a cub. Never seen this done.
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One of the "issues" with the J3 is the landing gear. It's got metal hinge\attach points on the fuselage, and bungees cords as shock absorbers.
The 2 main issues:
The attach points on the fuselage can break and not be easily visible
The bungee cords wear out, break or come loose, but they are inside leather bags, so you can't see them.
The test:
Grab the wing tip and yank it up and down. If you can hear metal noises the hinge\attach points on the fuselage are suspect, and should be checked. If the plane sits with one wing higher than the other, chances are the bungees are no good, or you finally broke the metal parts.
 
Shepherd said:
Pure, unadulterated luck because I ALWAYS grab the right wing as I go past to put my gear inside.
It appears a bunch of wood parts in the left wing came unglued. It's 77 years old, so It shouldn't be a surprise.
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Go buy a lottery ticket quick...
 
MassPilot said:
I remember reading years ago that there has never been a C172 structural failure when flown within airspeed and G limits. I'm not sure if this is true or just an urban legend.
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I had read that somewhere as well. I also saw a YouTube video of Rod Machado talking about it as well. I am not sure how to validate it without a bunch of research. It will be interesting to see the outcome from this accident.
 
Major structural issue somewhere or suicide?

You would REALLY have to work at tearing the wings off a 172
 
Jim_CAK said:
I had read that somewhere as well. I also saw a YouTube video of Rod Machado talking about it as well. I am not sure how to validate it without a bunch of research. It will be interesting to see the outcome from this accident.
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As mentioned before, you have to include maintenance issues. There has been at least one 172 wing fall off due to the loss of a strut bolt.

https://www.ntsb.gov/_layouts/ntsb....ev_id=20021230X05642&ntsbno=FTW03FA053&akey=1

But, once you exclude all the causes of wings falling off, then, yea, no wings are going to fall off.
 
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benyflyguy said:
Once again I find it amazing that this stuff happens with a CFI on board not to mention a seasoned one it seems. I look back at the CFI’s I’ve had over the years and can’t imagine one of them suggesting or wanting to do something like this. Shocking really In my experience.
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You make it sound like it was the CFI's responsibility. When I was actively instructing, I would look forward to students who liked doing spins. It was all perfectly legal. Now I wonder if that was a smart thing. Despite being in the utility category, and at a safe altitude, I had no idea of the damage history on the airframe or how it had been flown before.
 
sarangan said:
You make it sound like it was the CFI's responsibility. When I was actively instructing, I would look forward to students who liked doing spins. It was all perfectly legal. Now I wonder if that was a smart thing. Despite being in the utility category, and at a safe altitude, I had no idea of the damage history on the airframe or how it had been flown before.
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Report finding were overstress fractures without mention of corrision or wear and tear. Diving planes to the point of ripping a wing off started off as plan but didn’t end the way they wanted it to. Without “being there” we all will never know what really happened.
I just think if there is a CFI on board there is an extra added veil of safety. Am I wrong??? Someone saying “we shouldnt be doing this..” Just like the recent Las Vegas Cherokee 6 going down. CFI and DPE midair in Fl. It sucks.
 
benyflyguy said:
Report finding were overstress fractures without mention of corrision or wear and tear. Diving planes to the point of ripping a wing off started off as plan but didn’t end the way they wanted it to. Without “being there” we all will never know what really happened.
I just think if there is a CFI on board there is an extra added veil of safety. Am I wrong??? Someone saying “we shouldnt be doing this..” Just like the recent Las Vegas Cherokee 6 going down. CFI and DPE midair in Fl. It sucks.
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People have been debating for a long time whether spin training is doing more harm than good. During the recovery, the airframe will get stressed. There is no way around it. The question is whether it is getting over-stressed. The assumption is, if you are below Va, then all is good. But we rarely account for weight, or the time delay in the pitot sensor. Repeated excursions beyond Va even for a couple of seconds could lead to cumulative airframe stresses. Additionally, with a CFI on board, one is more likely to push the limits and let it spin a little bit longer. I am not saying I know what happened here, but it seems to me that catastrophic mechanical failures are more likely to occur when you push the airplane to its limits, which happens more during a training flight than during a routine trip.
 
sarangan said:
Additionally, with a CFI on board, one is more likely to push the limits and let it spin a little bit longer.
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A fully developed spin is a stalled maneuver. There’s really not much stress during the spin itself and nothing about making it two, three, or twenty turns adds any additional stress.
 
orange said:
That's my biggest fear as a renter. That I will be given a broken plane that I have no shot to get back on the ground safely. At times, it has made me question my participation in this hobby.

And what's worse is that the school may not even know that a previous renter did something dumb to stress the plane to its limits or whatever. Not sure some people would volunteer that info to be held financially responsible for repair costs.
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Pre-flighting a military aero club airplane long ago, I found multiple rivets missing on a flap attachment bracket. Just popped out. . .gonna happen, sometimes.
 
SkyDog58 said:
Regulatory wise, what is the difference between an annual and a 100 hr?
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They have similar scope. An annual must be performed by an IA, whereas the 100 hr can be performed by a non-IA A&P.

When you're flying passengers for money, they don't want you to wait to the end of the year before checking things, hence the 100 hour requirement.
 
sarangan said:
People have been debating for a long time whether spin training is doing more harm than good. During the recovery, the airframe will get stressed. There is no way around it. The question is whether it is getting over-stressed. The assumption is, if you are below Va, then all is good. But we rarely account for weight, or the time delay in the pitot sensor. Repeated excursions beyond Va even for a couple of seconds could lead to cumulative airframe stresses. Additionally, with a CFI on board, one is more likely to push the limits and let it spin a little bit longer. I am not saying I know what happened here, but it seems to me that catastrophic mechanical failures are more likely to occur when you push the airplane to its limits, which happens more during a training flight than during a routine trip.
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Spin training is mandatory in Canada, and Canadian airplanes are not falling apart in flight.

That airframe is designed to 3.8G, with a 150% safety factor beyond that to cover variations in materials and workmanship. Unless the airplane is badly corroded, or someone else was doing unauthorized and unskilled aerobatics and overstressed the airplane so that it failed on a subsequent flight, it's hard to imagine anyone pulling the wings off a 172 in a spin maneuver. 172s don't even want to spin, and tend to fall into a spiral after a turn or two. If that spiral is let go until the airplane gets too fast, yes, you might break something.

We had G meters in the Citabrias. Even 3G is a LOT of pull, not at all what we usually encountered in a 172 spin recovery. Most pilots have probably never experienced it.
 
What instructor would spin a plane, or allow the maneuver with a first flight trainee in the left seat? That makes little sense.
 
A properly done spin isnt exactly a stressful maneuver on the plane or pilot.
 
Shepherd said:
Grab the wing tip and yank it up and down.
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My first few plane rides were in gliders, my brother in law flew them back in Canada, and I remember he always shook the wings hard before climbing in. I thought it was comical at the time, but learned that since the wings are detachable it's a good last minute check to ensure the wing is on right, etc. I still do this on any plane I fly. Granted on the Cirrus it will flex a bit, but it's good peace of mind for me at least if nothing else

Dave Arata said:
What instructor would spin a plane, or allow the maneuver with a first flight trainee in the left seat? That makes little sense.
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So my brother went to Embry Riddle. Didn't fly, but became an engineer later working for Pratt, etc. Anyway, he went up with a friend on an instruction flight (he was backseat) and vowed never again after that. He's not a wuss by any stretch of the term, but his recollection of the events (this was many years ago, he's my senior by a good margin) was that they slowed, the nose was high, a beeping went off, and then the wing dropped straight down, then the nose, and the next thing he knew they were starting at the ground spinning round and round for what felt like an eternity. All the time his buddy sat frozen on the left seat and the instructor didn't say much.. so it sounds like at least in that example the instructor let the 172 develop pretty heavily into a spin before recovering

I've also heard rumors of people horsing around in Archers, and other planes not certified for those types of maneuvers.. it's absolutely crazy to me but it happens. Like others have said, this is why I hate renting planes. Who knows what the last person did in that plane that may have fatigued that metal just a little bit more, or just a little beyond what the engineers designed for. Especially on a 1970s era trainer... 50 years of abuse will have its toll
 
Tantalum said:
So my brother went to Embry Riddle. Didn't fly, but became an engineer later working for Pratt, etc. Anyway, he went up with a friend on an instruction flight (he was backseat) and vowed never again after that. He's not a wuss by any stretch of the term, but his recollection of the events (this was many years ago, he's my senior by a good margin) was that they slowed, the nose was high, a beeping went off, and then the wing dropped straight down, then the nose, and the next thing he knew they were starting at the ground spinning round and round for what felt like an eternity. All the time his buddy sat frozen on the left seat and the instructor didn't say much.. so it sounds like at least in that example the instructor let the 172 develop pretty heavily into a spin before recovering
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We really need to get ya up for a spin. That’s a very common emotional reaction to the first one. The second one, it doesn’t look quite as dramatic. The third, the instructor can ask you to stop it on a specific heading and you can hit it within about ten to twenty degrees.

They WILL go nose down fairly significantly if the entry is done a certain way, but the whole maneuver from inside is really docile and very little G load or side loads or any kind of kinetics after the entry is done and that just feels like entering a turn.

Where people get caught is after recovery in the resulting dive. They pull too much trying to hurry the nose back to the horizon where their brain wants it to be. Sometimes folks taught “power for altitude” will forget the nose is down and cram the throttle forward in the dive, too. “Throttle is not helpful in this case...” LOL.
 
Dave Arata said:
What instructor would spin a plane, or allow the maneuver with a first flight trainee in the left seat? That makes little sense.
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Why not?

Not a first flight thing, but I do spins pre solo.

I don’t have a 172 POH infront of me, but spins with a rear pax seems like it wouldn’t be in utility catagory
 
I'm more considering the possible jitters of a first training flight. Many first timers don't even like to experience a stall let alone a spin. Just food for thought.
 
I do know that a 172 will gain speed rapidly coming out of a spin, at a rate much greater than simply pushing on the yoke (of course, I never shoved the yoke so hard as to hit minus two g's or anything like that.)
 
Kenny Phillips said:
I do know that a 172 will gain speed rapidly coming out of a spin, at a rate much greater than simply pushing on the yoke (of course, I never shoved the yoke so hard as to hit minus two g's or anything like that.)
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Gravity is the same in both dives. You don’t need a 2G push over to get the same dive with the elevator as a dive after a spin recovery. Just push LONGER. The aerodynamics are the same.

The feel of increasing speed in the spin recovery is the quick transition from stalled to flying again. That’s just during the transition. The airplane will hit whatever speed it would have hit if you made the exact same dive with elevator.

It just has a feel like it “came on suddenly” as the wind noise and engine RPM increases quickly and the controls become effective and you have to push to keep the nose from coming up too quickly if it was trimmed nose up before the spin.

But it’s a completely normal dive. The nose is just down further than you would normally push it down against the pressure of an effectively flying elevator and horizontal stab. Trim it all the way nose down, it’ll do the same thing as the dive after the spin recovery but you’ll be pulling hard to recover.
 
Dave Arata said:
I'm more considering the possible jitters of a first training flight. Many first timers don't even like to experience a stall let alone a spin. Just food for thought.
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I almost quit flying after my instructor let me get a C150 into a spin (unintentionally on my end) on my second ever flight. Scared the hell out of me as I didn't know any better. Instead I ended up switching schools, instructors, and into PA28's.

In hindsight, that C150 had to be near/over max gross with he and I in there to begin with, so playing spin games was definitely a bad idea.
 
You guys know more about this stuff than I, but if both wings came off at the same time, couldn't that be sabotage?

Don't mean to get all spooky and Twilight Zone here, but I could understand if *one* wing came off, the plane gyrated wildly, and the other one came off shortly thereafter. But both at the same time? Or can eyewitnesses really tell on something like this?

Just curious.
 
denverpilot said:
A fully developed spin is a stalled maneuver. There’s really not much stress during the spin itself and nothing about making it two, three, or twenty turns adds any additional stress.
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It is not the spin itself, but the recovery that causes stress. As soon as you stop the rotation with opposite rudder, the aircraft is in a straight-down dive (actually slightly more than straight down), and will build up speed extremely quickly. That's the difference between a one-rotation spin and a five-rotation spin. Once autorotation has developed, it will take more time to stop the rotation, during which time the airplane will build up a high forward speed. A one-rotation spin can be stopped quickly, so less speed will be built during recovery. I agree that in any case the airplane should withstand 3.8G up to maneuvering speed, but that is for an airframe that has not been previously abused. I have yet to see a spin that did not cause a substantial g-force during recovery. I don't have numbers because I never flew with a g-meter. But if the wings or elevator were going to give out, that would be the time.
 
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