Cessna 210 Potential Spar Action by FAA?

What, no alarmist level panic about "sub-par designs"? Color me shocked and chagrined. :rolleyes:

In other news. Flew my death trap last weekend for the 25th time since the release of the NPRM. Happy to report...
tenor.gif

:D
 
Here’s a description of the 210 responsible for this, according to the AOPA article.

“The accident airplane has been modified for geological survey work, including a tail boom, integral wing tanks, installation of specialized equipment in place of the rear seats, and a “non-standard engine and propeller installation.”

f85a1264bff4f24741639bf3867b63ff.jpg


But sure, the factory engineering should’ve taken all that into account when they designed that wing spar.
 
TCABM said:
Here’s a description of the 210 responsible for this, according to the AOPA article.

“The accident airplane has been modified for geological survey work, including a tail boom, integral wing tanks, installation of specialized equipment in place of the rear seats, and a “non-standard engine and propeller installation.”

f85a1264bff4f24741639bf3867b63ff.jpg


But sure, the factory engineering should’ve taken all that into account when they designed that wing spar.
Click to expand...

That's an unfortunate tail number.

I think it's reasonable to ask those in the field if they're seeing any cracking. Issuing an AD, on the other hand...

JOhnH said:
VH - SUX ???

Who is VH?
Click to expand...

And why is it that he SUX?
 
Jim Rosenow said:
Should it be considered sexist to assume that VH is a he?.....and that’s all the further down THAT road I’m going :)

Jim
Click to expand...
Didn't George Carlin have a line about that?
 
Engine and add on equipment had nothing to do with it. The wing had corrosion that caused a point stress concentrator resulting in catastrophic failure of the wing. Pretty serious stuff, easily prevented by having a look and repair if you know to do that. I'd love to see what the corrosion looked like on the failed wing.
 
FormerHangie said:
That's an unfortunate tail number.

I think it's reasonable to ask those in the field if they're seeing any cracking. Issuing an AD, on the other hand...



And why is it that he SUX?
Click to expand...

They practically need an AD to force people to do anything. Seriously, pull the damn headliner and just do it.
 
PaulS said:
Engine and add on equipment had nothing to do with it. The wing had corrosion that caused a point stress concentrator resulting in catastrophic failure of the wing. Pretty serious stuff, easily prevented by having a look and repair if you know to do that. I'd love to see what the corrosion looked like on the failed wing.
Click to expand...

There's a few pictures in this report I posted a couple of days ago on another thread:

https://www.atsb.gov.au/publications/investigation_reports/2019/aair/ao-2019-026/

Aluminum fatigues. It was a fatigue crack in the main spar carry-through that initiated this failure. Inspection and repairs can certainly be made; we've proved that amply because we aren't seeing our ancient airplanes falling out of the sky regularly. But I do believe we all have to come to accept there is some practical life limit to airframes that are being used extensively in a training or low level survey/pipeline service in particular.

Most of these airplanes were mass produced at a time when there was no expectation they would accumulate the many thousands of hours that have been put on them. I regularly see training C-172s and Cherokees with 15,000+ hours on them now.
 
Last edited:
GRG55 said:
There's a few pictures in this report I posted a couple of days ago on another thread:

https://www.atsb.gov.au/publications/investigation_reports/2019/aair/ao-2019-026/

Aluminum fatigues. It was a fatigue crack in the main spar carry-through that initiated this failure. Inspection and repairs can certainly be made; we've proved that amply because we aren't seeing our ancient airplanes falling out of the sky regularly. But I do believe we all have to come to accept there is some practical life limit to airframes that are being used extensively in a training or low level survey/pipeline service in particular.

Most of these airplanes were mass produced at a time when there was no expectation they would accumulate the many thousands of hours that have been put on them. I regularly see training C-172s and Cherokees with 15,000+ hours on them now.
Click to expand...

You would think they would post a picture of the bottom surface, nope.

I'm pretty sure a lot of those cantilever 210s had foam padding glued to that bottom surface in selected areas from the factory, hopefully everyone has removed all that junk and actually looked at it by now.

Once the headliner is out of the way it should only take the NDT tech about an hour or so to do the whole eddy current inspection prescribed in the service letter.
 
Last edited:
We're going to have the Cardinals looked at. Our birds are pretty much stock, but we do have higher times and cycles... I think one bird I fly is over 9,000 hours. The real need is for the FAA to allow us to fly some newer aircraft like the Pipistrel that are already being successfully used in Europe for things like this and make better allowances for safety stuff like parachutes. And yes, I'm being serious. Let us put a 'chute on a 177 or a 210 especially on high-utilization aircraft.
 
TCABM said:
Here’s a description of the 210 responsible for this, according to the AOPA article.

“The accident airplane has been modified for geological survey work, including a tail boom, integral wing tanks, installation of specialized equipment in place of the rear seats, and a “non-standard engine and propeller installation.”

f85a1264bff4f24741639bf3867b63ff.jpg


But sure, the factory engineering should’ve taken all that into account when they designed that wing spar.
Click to expand...
 
12,000 hours on the AF, 6,000 hrs in the last 6 years, how many G's where they pulling when the wing came off?, sounds like this bird may have been rode hard and put away wet, not mention the mods like the fuel mod and that stick hanging off the tail. I am surprised the tail did not come off, those tail brackets that look like electrical switch boxes tend to crack that tail really shakes on run ups,
Yes the spar needs to be inspected to be safe but this bird was an experimental bird at best with all the mods and who know where that plane lived in its life time,a salt water area?
 
strangebird said:
12,000 hours on the AF, 6,000 hrs in the last 6 years, how many G's where they pulling when the wing came off?, sounds like this bird may have been rode hard and put away wet, not mention the mods like the fuel mod and that stick hanging off the tail. I am surprised the tail did not come off, those tail brackets that look like electrical switch boxes tend to crack that tail really shakes on run ups,
Yes the spar needs to be inspected to be safe but this bird was an experimental bird at best with all the mods and who know where that plane lived in its life time,a salt water area?
Click to expand...
Looks like a desert area where it crashed, so it could be it spent a lot of time in the desert. That might make one lax about corrosion.
I doubt it was being used THAT hard, and I'd be shocked if it was more than 1.5 Gs. I've seen birds like that operating out in West Texas. I think generally they are flying straight grid lines down low looking for stuff - probably a magnetic imaging boom from what I can tell and I can't see a lot of hard turns down low being called for by that kind of operation. See: https://www.atsb.gov.au/publications/investigation_reports/2019/aair/ao-2019-026/ for more details. It says they were flying in a straight line as called for by their grid line plan.
Turbulence and high loadings and forgetting about maneuvering speed could be an issue, as well as low level avoidance maneuvers - I know we sometimes have to make quick maneuvers to avoid birds between 1,000-3,000' AGL especially. That terrain looks a lot like terrain I see regularly out in West Texas, so I would guess it can be pretty bumpy at times.
 
Last edited:
TCABM said:
Here’s a description of the 210 responsible for this, according to the AOPA article.

“The accident airplane has been modified for geological survey work, including a tail boom, integral wing tanks, installation of specialized equipment in place of the rear seats, and a “non-standard engine and propeller installation.”

f85a1264bff4f24741639bf3867b63ff.jpg


But sure, the factory engineering should’ve taken all that into account when they designed that wing spar.
Click to expand...

I’m pretty sure integral wing tanks became standard with the cantilever wing. Wonder if they added more and the weight was a factor.
 
luvflyin said:
I’m pretty sure integral wing tanks became standard with the cantilever wing. Wonder if they added more and the weight was a factor.
Click to expand...

You can get add-on STC tip tanks for wet wing 210s. Ones I looked at add 100# of fuel per tip tank, not including the tank weight of course (I'd guess 15 pounds per wing).
 
hindsight2020 said:
"sub-par designs"
Click to expand...
This is not the first time 210s have lost wings though, right? I seem to recall there were some other issues as well, however those were the result of flying into thunderstorms, etc.

TCABM said:
the factory engineering should’ve taken all that into account when they designed that wing spar
Click to expand...
Fair point, and you'll see issues with fire fighting aircraft too... *but* we're lead to believe that as long as the aircraft is operated within its envelope and limits it will not fail on you... putting a bigger engine and some extra equipment on there, should not, by itself, cause structural components to fail, right? Assuming you still fly within limits

bnt83 said:
foam padding glued to that bottom surface
Click to expand...
I went up in a 210 a few weeks ago to safety for a friend, the plane was a real beater and parts of the headliner were missing, and I can attest that at least from what I saw the spar had foam padding on it so you could not actually see it that well

hindsight2020 said:
"sub-par designs"
Click to expand...
I still believe that a plane built for training, and used for exactly that, should not have a wing separate on climb out. That's like pulling out of your drive way and your wheels fall off. Not a sub-par design, but it is disconcerting, at least in a club rental or plane, where you have no idea who slammed it onto the runway last and how shoddy the maintenance may be. At least in your plane you know who is flying it and you know the maintenance, and have the piece of mind that you're not dropping it onto the runway several times a day

GRG55 said:
Aluminum fatigues. It was a fatigue crack in the main spar carry-through that initiated this failure. Inspection and repairs can certainly be made; we've proved that amply because we aren't seeing our ancient airplanes falling out of the sky regularly. But I do believe we all have to come to accept there is some practical life limit to airframes that are being used extensively in a training or low level survey/pipeline service in particular.

Most of these airplanes were mass produced at a time when there was no expectation they would accumulate the many thousands of hours that have been put on them. I regularly see training C-172s and Cherokees with 15,000+ hours on them now.
Click to expand...
Metal fatigue is a scary killer, and I was always surprised that GA airplanes don't have cycle and fatigue life spans like commercial airliners do. Sure they're (mostly) not pressurized, but just surprising that there is no real life limit on these planes. Even if there is no corrosion and things "look" fine there are fatigue cracks that start accumulating and each landing event does put a higher stress level on the plane


Wings failing (or fine, carry through spars) in general is a big no-no for me. Weight savings and all that, but this is the one part of the plane that should be well over built. We've never seen a TB-20 or TB-21 lose a wing (and yes, these have been used in military applications), we've never seen a Cirrus lose a wing either.. and you know for sure of the 7,000+ built there are plenty operated by your stereotypical I'm-too-rich magenta line pilot. I'm sure there are other aircraft out there with clean wing fail records... or, if there is a wing failure (as in the case of some Mooney records I found) it was following entry into a thunderstorm, or some sort of loss of control in IMC. But just flying along, that's bonkers
 
TCABM said:
integral wing tanks
Click to expand...
luvflyin said:
I’m pretty sure integral wing tanks became standard with the cantilever wing. Wonder if they added more and the weight was a factor.
Click to expand...
bnt83 said:
add-on STC tip tanks for wet wing 210s
Click to expand...
I was told that wing tanks, and adding more weight visavie fuel to the tips of the wings, actually help make the wing stronger. This was told to me by an aircraft engineer, and a reason that large jets empty their center tanks first

I have a hard time picturing it in my mind's eye, but it had something to do with reducing the bending moment by shortening the lever arm and moving it closer to the body.. IE, the wing is now not just lifting the plane, but also fuel in the tanks and tip tanks, so it's not bending as much since the weight it is carrying is more evenly distributed, the arm is shorter. I was even given the example that a 747 flying with a missing #1 or #3 engine will have, structurally, a much weaker wing. At any rate, I don't see how that would effect the carry through spar, since that fuel weight is in the wing, and being lifted by the wing, so should be agnostic of carry through spar loads

Edit, found something online that appears to back this up: https://aviation.stackexchange.com/...wings-filled-first-and-why-are-they-used-last
 
Tantalum said:
I was told that wing tanks, and adding more weight visavie fuel to the tips of the wings, actually help make the wing stronger. This was told to me by an aircraft engineer, and a reason that large jets empty their center tanks first

I have a hard time picturing it in my mind's eye, but it had something to do with reducing the bending moment by shortening the lever arm and moving it closer to the body.. IE, the wing is now not just lifting the plane, but also fuel in the tanks and tip tanks, so it's not bending as much since the weight it is carrying is more evenly distributed, the arm is shorter. I was even given the example that a 747 flying with a missing #1 or #3 engine will have, structurally, a much weaker wing. At any rate, I don't see how that would effect the carry through spar, since that fuel weight is in the wing, and being lifted by the wing, so should be agnostic of carry through spar loads

Edit, found something online that appears to back this up: https://aviation.stackexchange.com/...wings-filled-first-and-why-are-they-used-last
Click to expand...

I'm not an engineer, so when I think of adding 115 pounds to each wingtip in turbulent rough air with fuel sloshing around and momentum of that extra weight, it doesn't make sense to me.
 
The corroding spar carrythrough is a well-known problem on the 177 and 210. On one airplane I spent more than 40 hours dressing out corrosion pits, having an NDT guy come and do ultrasonic thickness testing on hundreds of spots, and priming with the specified primer, all according to instructions from Cessna.

I wouldn't be at all surprised if the FAA proposes an AD on it. Too many shops (and owners) don't want to bother with the additional time (and cost) of pulling the headliner out and getting a better look.

There's already an AD on the wing spars: http://www.airweb.faa.gov/Regulator...cb54566186257a05004aeefa/$FILE/2012-10-04.pdf
 
bnt83 said:
I'm not an engineer, so when I think of adding 115 pounds to each wingtip in turbulent rough air with fuel sloshing around and momentum of that extra weight, it doesn't make sense to me.
Click to expand...
Me either, but apparently it has some kind of dampening effect that lessens the bending moments. I feel the same kind of "doesn't make sense" thing I learned that putting giant heavy weights at the top of a building on a pendulum actually make them safer in earthquakes by dampening the sway effect. Neither really pass the sniff test to me but I've had two different (in person, not internet folklore) mechanical engineers working in the aviation world tell me that weight out on the wings (and further out the better) actually makes the wing stronger. The aviation.stackexchange link I posted appears to validate it
 
The carry throughs themselves aren't that difficult to change IMHO, but good parts are a problem, like many things, new are not available.

Seriously, two guys could probably replace the carry through in less than a week. There is only around 60 easy access rivets in it, that hold the roof skins to it. The load carrying part is actually just bolted on. Once the wings are off and the headliner is out, you can have it out in like three hours.

Seems like a pretty good opportunity for type clubs to pursue at-cost PMA replacements.
 
Last edited:
GRG55 said:
There's a few pictures in this report I posted a couple of days ago on another thread:

https://www.atsb.gov.au/publications/investigation_reports/2019/aair/ao-2019-026/

Aluminum fatigues. It was a fatigue crack in the main spar carry-through that initiated this failure. Inspection and repairs can certainly be made; we've proved that amply because we aren't seeing our ancient airplanes falling out of the sky regularly. But I do believe we all have to come to accept there is some practical life limit to airframes that are being used extensively in a training or low level survey/pipeline service in particular.

Most of these airplanes were mass produced at a time when there was no expectation they would accumulate the many thousands of hours that have been put on them. I regularly see training C-172s and Cherokees with 15,000+ hours on them now.
Click to expand...

Thanks for posting this. That carry through looked pretty corroded to me. It also looks like it had many flights on it from the initial start of the problem until it finally let go. I would have very little tolerance for corrosion on a part like this, never mind looking for cracks. The corrosion creates stress concentration points that lead to the flaw then crack starting the remaining good metal. The dynamic loads on a wing, even in smooth air exasperate the problem. I don't think this is a time limit issue for the airframe, rather a corrosion issue and how much should be tolerated before a part is junked. I don't have those answers, but I think I could make a pretty good test.
 
bnt83 said:
I'm not an engineer, so when I think of adding 115 pounds to each wingtip in turbulent rough air with fuel sloshing around and momentum of that extra weight, it doesn't make sense to me.
Click to expand...
If you put the weight in the fuselage, the wing structure and carry through structure has to withstand the loads and transmit them to the wings. Plus the wingtip is cantilevered out there and the lift from the outer parts has a lot of leverage which loads up the center of the structure. Putting weight on the ends of the wings lets the wings carry the load without having to carry it back to the wing attach. Spar and carry through loads are reduced compared to having the weight in the fuselage.
 
Tantalum said:
I feel the same kind of "doesn't make sense" thing I learned that putting giant heavy weights at the top of a building on a pendulum actually make them safer in earthquakes by dampening the sway effect.
Click to expand...

They've certainly got a big one on the top of Taipei 101. Part of the publicly available part to see.

DSC00779.JPG
 
Last edited:
bnt83 said:
The carry throughs themselves aren't that difficult to change IMHO, but good parts are a problem, like many things, new are not available.

Seriously, two guys could probably replace the carry through in less than a week. There is only around 60 easy access rivets in it, that hold the roof skins to it. The load carrying part is actually just bolted on. Once the wings are off and the headliner is out, you can have it out in like three hours.

Seems like a pretty good opportunity for type clubs to pursue at-cost PMA replacements.
Click to expand...
To make those things you'd need the engineering info from Cessna regarding the aluminum alloy and a bunch of casting and heat-treating information, and Cessna doesn't release that sort of thing. They want to sell you a new one for something like $30K, if and when they ever get around to making more of them. It could be reverse-engineered, but that assumes a pile of liability if you get it wrong, and it will still cost a mint to make anyway. And an application for a PMA of that part would face serious scrutiny by the FAA; it's a most critical part, at the most extreme end of the risk scale.
 
Dan Thomas said:
To make those things you'd need the engineering info from Cessna regarding the aluminum alloy and a bunch of casting and heat-treating information, and Cessna doesn't release that sort of thing. They want to sell you a new one for something like $30K, if and when they ever get around to making more of them. It could be reverse-engineered, but that assumes a pile of liability if you get it wrong, and it will still cost a mint to make anyway. And an application for a PMA of that part would face serious scrutiny by the FAA; it's a most critical part, at the most extreme end of the risk scale.
Click to expand...

Agreed. That kind of component is a bona fide fleet killer if left to the devices of non-OEM support. I know folks on here make cannibalizing the salvage market part and parcel of their ownership M.O.; I just don't consider that sustainable from a resale perspective looking at the next 20 years. And yes, I have more than 20 years of flying left in me, so that matters to me. Aging/non-support of legacy fleets is a real thing, everything comes to an end in this life.

Carry-throughs would make the ruddervator skin stock issue look tenable by comparison. BL we need to find ways to re-stock the market with new entrants that can support our flying in 30 years. Maybe with enough scarcity in the 4+ seater market, EAB might finally have a non-zero role to play in offering an alternative to us non-empty nesters going forward. I continue to sit in the camp that is willing to leave performance on the table for the sake of dispatch/supportability. My monkey my circus kinda thing. Five figure lawn ornaments are not my draw to this avocation.
 
hindsight2020 said:
Agreed. That kind of component is a bona fide fleet killer if left to the devices of non-OEM support. I know folks on here make cannibalizing the salvage market part and parcel of their ownership M.O.; I just don't consider that sustainable from a resale perspective looking at the next 20 years. And yes, I have more than 20 years of flying left in me, so that matters to me. Aging/non-support of legacy fleets is a real thing, everything comes to an end in this life.
Click to expand...

I have friends who tried fitting a used carrythrough to their 210 to replace a rotten one. It's been on the ground for a number of years and may never fly. The factory didn't use drill jigs when they drilled the skins and carrythrough, so the holes don't meet any accurate pattern; the holes in the spar didn't line up with the holes in the skins. They'll likely have to replace much more than the spar.

Yes. The fleet is aging far beyond any time frame anticipated by the engineers who designed these things. Imagine trying to keep a fleet of 1970s Pontiac station wagons roadworthy and meeting original design specifications, even though many millions were built...
 
hindsight2020 said:
BL we need to find ways to re-stock the market with new entrants that can support our flying in 30 years. Maybe with enough scarcity in the 4+ seater market, EAB might finally have a non-zero role to play in offering an alternative to us non-empty nesters going forward.
Click to expand...

There is very little in the RV "universe" that you couldn't reverse engineer reasonably easily if Van's ceased existence. The composite top for the -10 comes to mind. Otherwise, all of it can be made by you in your basement with fairly basic tools, or by a good welder plus a machine shop. Besides, there are enough boutique manufactures making a living (or part of one) from the RV world, support is gonna be there for a long time.

Come to the dark side. ;-)
 
kyleb said:
There is very little in the RV "universe" that you couldn't reverse engineer reasonably easily if Van's ceased existence. The composite top for the -10 comes to mind. Otherwise, all of it can be made by you in your basement with fairly basic tools, or by a good welder plus a machine shop. Besides, there are enough boutique manufactures making a living (or part of one) from the RV world, support is gonna be there for a long time.

Come to the dark side. ;-)
Click to expand...

When my mission can legitimately fit an empty nester one, I'm 100% with ya. I am very much counting on the experimental side to keep me aloft looking at the 30 year time frame. I just don't see an environment in the certified side that inspires longevity of support without hobby-souring double digit expenses. Latter which has been the central theme behind my choice to own airplanes with much lower performance than my wallet can otherwise afford on a DOC basis. Dispatch (long term) is and has always been a non-negotiable for me.

I do wish the 4 seater market was more robust on EAB, but fully understand the economics of why they're not. My Arrow is a prime example of this. The irony is that I'd be willing to pay just a little more for the same Arrow if it was EAB, in order to gain the flexibility of operation and alternate means of airframe support available to EABs. But that's a pipedream that died with part 23 rewrite, so I'll just keep my fingers crossed and hope this ride continues to be economically supportable for the next 12 years (when the kid graduates high school) before I can grab the EAB life boat. It is a bit saddening to witness the decay of American General Aviation as a millennial looking at what the boomers had available by contrast. No crying in baseball though, it's just timing and luck in this life.
 
kyleb said:
There is very little in the RV "universe" that you couldn't reverse engineer reasonably easily if Van's ceased existence. The composite top for the -10 comes to mind. Otherwise, all of it can be made by you in your basement with fairly basic tools, or by a good welder plus a machine shop. Besides, there are enough boutique manufactures making a living (or part of one) from the RV world, support is gonna be there for a long time.

Come to the dark side. ;-)
Click to expand...

I would think the tapered main wing spars would be quite a bit more difficult to reverse engineer and make in your basement, compared to the composite cabin top on the 10. :cool:
 
GRG55 said:
I would think the tapered main wing spars would be quite a bit more difficult to reverse engineer and make in your basement, compared to the composite cabin top on the 10. :cool:
Click to expand...

Patience, jigs, and a router... It is amazing what you can do when necessity comes into play.

Alternately, a CAD file and a local CNC shop.
 
You must log in or register to reply here.
Back
Top