Some observations on wing structural failures in GA aircraft.

two aircraft types have historical records of wing failures.

contrary to guesswork speculation of failure mode, the wings do not normally fail upwards (they do not clap together).

C210 wing failures generally fail downwards, not upwards, with resulting slap marks on the fuselage sides. Failure usually initiated near the flap aileron junction.
Due to washout built into the wing design to attain favourable stall progression, the wingtips on C210 in cruise have either zero to slightly negative angle of attack.

operating above Vne results in downward loads in the outer wing area.

inspection of the wing lower skin near the flap aileron junction will often show a small crease.

the wing is typically rated at around 4g positive and around 1.8g negative., I.e. not as strong with downward loads.

the above observations obviously do not apply to corrosion cracking of the carry through spar.

The other aircraft type are the Aero Commander, the typical failure is just outside the engine nacelle, again signatures with slap marks on the fuselage.

to warn C208 Caravan pilots that they are near or have exceeded Vne, a warning system (the “naughty horn”) will sound an alarm. (The flight data recorder will have a record of the exceedance)

operating aircraft within the design constraints of Va and Vne should ensure a safe operation, however, inadvertent excursions into and beyond Vne can easily happen in extreme turbulence, loss of control in upset situations.

slow down when encountering possible entry into those conditions.

It is indeed a rule

Oh dear, a chap gets slack and doesn't bother to look up and cite the rule - and gets a gentle slap over the wrist for being a bit relaxed. Thanks, Dave, and a very good new year to you, good sir.

slow down when encountering possible entry into those conditions.

..and, again, words of wisdom from a greybeard.

It never ceases to amaze me .. that old story about no old and bold pilots.

The thread is showing promise.

An area very often overlooked is an accumulation of STC for modifications.

Some years ago a C337 accident in the USA which I recall was an inflight break up; wing separation ..

The aircraft was modified with Vortex generators, and no doubt with an approved AFM supplement and STC. I recall the aircraft had modified wing tips; drooping. The airframe also has a STOL kit fitted with revised aileron and drooping ailerons when flap extended. Also in the mix was a 'speed kit' a series of revised cuffs etc at various fuselage/wing areas and the booms to the tailplane.
Each and every one of the mods was applied in accordance with the various STC's

BUT: no one had certified the COMBINATION of all the mods as one package.

In effect the aircraft was destined for another life. The aircraft was no longer a C337 but a highly modified airframe that resembled at C337.

This is precisely what I was told when I was introduced to the C210 around 33 years ago. When I read through the previous speculation in this thread I had wondered if this was (a) correct and (b) still taught.

Stay safe people.

Do we have any details about the identity of the pilot and the pax?

no one had certified the COMBINATION of all the mods as one package.

A common worry. What is supposed to happen is that the STC should be qualified as to serials applicable and compatible mods. Certainly, those of my origination in the past had words to keep things clean. This is also a responsibility of the installing agency to make sure that things are not incompatible.

The cited problem ought not to arise but, of course, it does.

This is precisely what I was told

There is plenty of information available which is useful for background and general knowledge. However, the main aim should be to remain within the AFM/POH authorised envelope and operate with a bit of commonsense. I can recall one minor battle I had in respect of operation at higher thrust. The AFM said "at pilot discretion" but didn't bother to say explicitly that this meant OEI. The operator's boss decided that the words applied across the board and I lost the argument because of the contract words.

I can't see how both VG and STOL kit could be added without both having specific approval to do so. How does one come up with performance data unless it's been tested/vetted with both options installed. The speed kit, fair enough just some fairings, account for the weight and add a few knots hopefully, but modifying the wing with lift devices you would have to have the whole thing approved, otherwise the performance data is void. Like PA-31, with VGs you get all the new data for operations with them installed and possible PUS for how many can be missing before performance penalties. If you then added a STOL kit it would have to have performance data and engineering to be used in combination with the VG. No data and no specific approval means they would not be legal to operate in unison.

If I was flying such a modified aircraft I would want to see the performance data state that it incorporates both VG and STOL modifications. That is some statement on the charts that says "STOL mod xxx with VG mod xxx installed" or such. Although most pilot's would probably assume the VGs are part of the STOL kit, that's where being familiar with these additions comes in.

That being said I'm not surprised the FAA might just rubber stamp it after seeing some mods that have been done to transport category aircraft where additional sizable holes have been cut in pressure hulls with no real mention of reduced life or such.

One of these John. ;) Snap taken when heading for the boat.


https://cimg0.ibsrv.net/gimg/pprune....b14b1988b1.jpg

Ah, not quite your routine day job, then ?

Can Mainframe & John T please list the C210 wing structural failures that they are aware of.

Being very familiar on the type, I can not see where this seeming quite often event come from - I am aware of a few strutted and non strutted events - but they can be counted on a single hand, and all penetrated very bad weather or very modified.

In short we need some proof the C210 has a reputation for structural failures (please) - wings clap up or clap down!!. We can count all the claps at this stage.

I think the fact is about ZERO have failed without a modification or a POH limit being greatly exceeded - happy to be corrected.

I don't think Cessna's engineers/designers from 60 years ago thought these aircrafts will be operational in 3rd decade of 21st century.
Everything has a "best before" date, including aircrafts, therefore they have to be treated with respect.

One aircraft I flew where you need to accelerate from normal cruise speed to reach placarded "turbulence penetration speed", Beech 50 twin bonanza.

please list the C210 wing structural failures that they are aware of.

I don't think that I made a claim regarding 210s routinely losing wings ? Any aircraft will suffer damage if loads exceed the static load limits for the aircraft (ie if they are excessively overloaded). A major problem with old aircraft is whether the fatigue life has been accounted appropriately and that depends, significantly, on usage reporting.

Beech 50 twin bonanza

No experience with that particular model. However, I think that I will continue to prefer to slow down somewhat below Va min in a light aircraft if I suspect severe turbulence. One needs to be aware of what goes into the limits and then it is a case of "you pays your money and takes your chances". I am not a fan of severe turbulence and am quite happy to trade a stall for another bite of the cherry. No guarantees, of course, I might die either way.

Bendalot.

it doesn’t take Einstein to put the two themes percolating in this thread together as a possible cause.

I‘m not saying that this is definitely the case the investigators will try and do that. Maybe this thread is the mentoring post any accident that used to happen at Rorkes, the ski club or the ‘tute when the old farts told more tales of woe learned through bitter experience. There are some valuable bits of aircraft certification and limitation that should be well understood by all.

But these discussions about a possible cause - even if not what happens to be the final cause - are valuable and needs to be mandatory reading for every pilot in the NT / Kimberley present and future. There will be two more wet seasons before the ATSB report comes out with any lessons learned. And even then it might be light on details (unlike the “probable cause” that other nations publish).

CS that is perfectly said, just be careful with the old farts and Tute comments :O!

Even company beers on a Friday night were great for a lot of ‘mentoring’ and stories. We learn from each other. Today is all in SMS however nothing beats a chat over beers.

Needless to say company culture is the base for all of this. When anyone asks me, I recommend to newbies to do their best to get into Hardy’s, ok the only company I really know but from what I do know, done right.

Many more companies that came and went and many with pros and cons on the above. Yet it appears a few with the wrong culture seem to last.

As a newbie in the Top End NEVER BE AFRAID TO ASK ANYONE FOR HELP. I’m always happy to lend my advice/ opinion, could be wrong but it will be very heavy on avoiding dem big bumpy black sparking clouds!

I’m sure there was a thread on here at some point!

It’s Interesting that some industry stalwarts recon they don’t need an SMS. Their reasoning is generally based around the same theme, that shouldn’t be to hard to work out.

It will be interesting to see if they are in business in 2 years, if CASA don’t roll over on their current implementation mandate.

‘Fly high’: Young pilot mourned after Christmas Eve tragedy

https://www.ntnews.com.au/news/north...48f2b148103ba5

You need a paid subscription to read it.

DF.

I thought JT might like this film from the CSIRO. There's a short part showing the wing come off a Hudson pulling out of a dive (1:40) that really highlights how sudden separation can occur.

https://csiropedia.csiro.au/wings-test-1947/

Can you cut and paste the article please.

The NT News one.

this film from the CSIRO

How on earth did you track this stuff down ? Re the wing - if the spar cap breaks, you end up with a hinge which doesn't work as well. At least it all happens quickly enough and violently enough for the occupants to have little recognition of what is going on .. other than for a feeling that it might not end all that well.

The section of video with the Hudson losing its wing I'd assume is the event at Bairnsdale.
Details from ADF Serials
A16-38 had seen damage to the mainplanes in combat twice and repaired. The second was being shot up by three Zeros (one shot down) at Lae resulting in repairs including main shear booms of both wings. With 915 hours on airframe (and during a filming of it in the air diving and leveling near the ground for a Cinesound film unit (Fox Movietone), disaster struck at 1500hrs on the 27/10/42 on circuit of Bairnsdale Aerodrome during a test flight following its 80 hrs service. When pulling out of high speed shallow dive at 80 feet and some 200 yards down from the camera, the starboard wing failed at wing station # 144, causing part of the outer wing (3 feet from engine) and spar to separate from the aircraft, with the aircraft then rolling inverted, causing a further failure of the tail plane, with the aircraft then crashing into the ground and exploding. The crew, Sqn Ldr P C Tampion Serv#349, Cpl H P Smith Serv#17024, LAC A P Thomas Serv#13975 and LAC N L Cheshire Serv#49572 all killed instantly. The starboard wing panel was sent to the CSIR for metallurgy inspection. The finding was that the mainplanes had been repaired per then accepted practices, but had failed in flight where numerous patched repairs were made during its overhaul at 5AD. The report stated that many Hudsons withdrawn from operational service and used in 1 OTU had been flown to the limits with resultant heavy loadings on their wings on operational service. All similar houred Hudsons were inspected some found to have similar problems, which would result in their replacement by GAF Beauforts in the near future in operational squadrons.


https://cimg4.ibsrv.net/gimg/pprune....e3d66bcce3.jpg
https://cimg5.ibsrv.net/gimg/pprune....147ba9bb21.jpg

Apologies for continuing to drift but I went down that rabbit hole too after seeing that pretty striking CSIR tape. I think that catastrophic failure was at Moruya NSW in 1945. Overloaded Anson returning to Uranquinty, attempted a farewell beat-up. Six people on board.

https://aviationmuseumwa.org.au/afcr...-james-413850/

Not an Anson Justin, twin fins. Losing a wing in a beat up is not that unusual, there is video of a Mosquito losing its wing doing the same, don't know where I saw it decades ago and repeated searches of the net over the years can't find it. Note my post says Cinesound film unit (Fox Movietone) filmed the Hudson crash and the wing went to CSIR for inspection, the film above was produced by C.S.I.R.’s Division of Aeronautics. I'm sure you will join the dots.

There's still a lot of old films around, hard to find many that have been converted to digital to post unfortunately. There seems to be a lot of accidents filmed around Australia, whether staged for what was about to be attempted (and went wrong) or they just recorded a lot of aviation activity in the 40s/50s. Lots of reels of Boomerangs and Beauforts.

Just catching up with this thread. Would be interested in some expansion on JT’s comment in response to the passage I quoted from FAA SAIB CE-11-17, so I have a better understanding of the intersecting variables. For convenience, here’s the SAIB passage I quoted, followed by a quote of JT’s comment:[Bolding in SAIB CE-11-17.]When you say: “if Va is above Va min”, are you talking about cases in which the designer has chosen to nominate a Va above Vs*sqrt(n)?

Is your point that because of what Va is actually only about – design of the empennage and ailerons – there are cases in which full deflection of a single flight control (particularly for pitch) may not be a problem for the empennage or ailerons in isolation if that happens at or below Va, but may still be a problem from the limit load factor of the ‘main airframe structure’? (That’s presumably why AC 23-19A says, among other things: “Va should not be interpreted as a speed that would permit the pilot unrestricted flight-control movement without exceeding airplane structural limits, nor should it be interpreted as a gust penetration speed.”) Thus: “without risk of damage to the airplane” is an overstatement in the passage quoted from SAIB CE-11-17?

Right you are Megan. At least it’s pretty quick.

are you talking about cases

That's my take on reading the FARs. Pitching loads need to be cognizant of limit load factor potential to cause raised eyebrows.

It therefore seems to me that this statement from AC 23-19A is a good 'takeaway' for us gumbies with hands on the controls:

is a good 'takeaway'

djpil's observations in #160 are pertinent. See, also, Federal Aviation Regulation Sec. 23.349 - Rolling conditions. (risingup.com).

I'm quite happy, for strong turbulence and/or manoeuvring, to sit around a reasonable amount under Va min. Sure I might get into a stall problem, but I get to have another go at living. Do have another look at the old video linked at 43inches's #179. The boys didn't get anything beyond a few more seconds prior to their unfortunate demise.

What is "Va min" and where do I find that in a POH?

What is "Va min"

Just my relaxed terminology for the lowest Va available to the OEM, viz, Vs√n.

The problem is that Va is an engineering design requirement, where it is limited to a minimum of Vs√n. Due to a disconnect between certification and operations, years ago, pilots have come to believe that Va is this minimum value which is not necessarily the case. The minimum value is nice because it provides some measure of protection against exceeding the limit load factor used in the aircraft's structural design by stalling - albeit only for simple pitching manoeuvres and for MTOW.

Some years ago, the FAA introduced a more useful (to pilots) speed, Vo. Progressively, Vo will come into general usage. Vo is a maximum of Vs√n and of much more relevance to pilots than Va.

So you won't see Va min anywhere other than here. I don't know how many aircraft have Vo specified as yet but it will be comparatively few. As new designs come into the marketplace, we will see Vo included in their POH information.

Makes it a bit tough for us gumbies with our hands on the controls...

Makes it a bit tough for us gumbies with our hands on the controls...

Not really. The discussion earlier with djpil provides a clue.

For the normal category aircraft, the limit load factor, typically, but not always, is 3.8g.

Vo is going to be near to 1.95 x Vs.

If you want to give yourself a bit for mum and the kids in turbulence or manoeuvring, perhaps aim for something closer to 1.6 x Vs.

The only caveat is that you need to apply the PEC to the Vs numbers so that the sums are in KCAS and then convert the answers back to KIAS via the PEC. Use the Vs values for whatever gross weight might be of interest and it all should work out fine and dandy.

So simple!

One wonders why anyone could ever be confused...

The problem is that the standard of theory instruction is pretty average in many areas, this being one. That, also, has to do with the syllabus, the exams, and the fact that many students are endeavouring to get through their exams with the absolute minimum level and standard of theoretical knowledge. Flight instructors beget like theory knowledge impoverished flight instructors. In many cases, the only theory instruction up and coming pilots get is from those instructors so the cycle remains viciously feeding upon itself.

I have some background in theory instruction and, I have to say, there are some documents out there which claim to be texts which are, themselves, a bit average.

At least, those of us with an engineering background and who are involved in the theory side of things can pass on this sort of stuff to our students.

It is nice to have a bit of an idea what the rules are, where they are, and what might be involved. At the end of the day, it is nicer to have useful bits of take away stuff to note in the shirt pocket notebook. I can recall my first training captain in the airlines taking out his voluminous pocket notebook on day one. It had all sorts of useful stuff in it that he had laboured to acquire and he periodically pulled it out to check if he wasn't sure that his memory was spot on for any particular item.

I learnt a lot from my training captains and checkies. Also, I was fortunate that all my PPL and CPL instructors were rather experienced and knowledgeable A grade instructors who knew their stuff pretty well.

That was back in the day when political correctness didn't come into it at all and the student was expected to learn. If he didn't, the pressure ramped up appropriately to get the message across. My first PPL instructor took along a rolled up newspaper. First time mistakes were addressed patiently and gently. Do it again and the student error correction newspaper would be applied, patiently and gently, to the back of the skull. I don't recall that anyone made all that many mistakes along the way. My group all soloed in short order (4-8 hours) and PPL tests all came up pretty much on minimum times (scratching the memory here - 35 hours to unrestricted ?)

Dreadful ? Of course, by current standards. Effective ? You bet.

One basic stat that highlights the issue is average solo times. When I started 5-8 hours was normal, if you took more than 10 the CFI got involved, now it seems 15+ is normal. A lot is the distractions from basics in the syllabus, lack of practical knowledge by the instructors and so on. Sometimes I think of the phrase "the road to hell is paved with good intentions", which sums up the regulations that have been implemented to improve standards, but has had the opposite effect in that it over complicates something that is very basic.

Aviation is something that has simple rules of survival but over complicated regulation, the two don't match. The problem is getting back to understanding those basics again in the early stages. Faulty foundations and the whole thing eventually fails, no different in teaching techniques to building a tower.

SIDS from CESSNA are not 60 years old.

"Best Before " is listed in the SID's program.

So not 1 (ONE) single example of a wing clap given (up or down) from the beast you all say has a history of wing failure.

Mine was a simple question for you all to show the "problem" with the C210 wing. "FAILURES"

Not even JT will show an example - yet you all still believe in the tooth fairy.

"perhaps aim for something closer to"?

"should work out fine and dandy"?

"convert the answers back to KIAS via the PEC"?

Meanwhile, if any of this discussion is going to translate into something halfway useful in the world of a young pilot/student pilot in the cockpit of an 'average GA aircraft', there must be a quick 'rule of thumb' calculation of IAS Vo for the range of weights of the aircraft.