Would get a better honest answer from interviewing those who’ve left KA recently, as they would not be in fear of their jobs.

RAAF Bristol Freighter that lost its port wing at Mallala while on an instrument flight, previous crew had done aerobatics, three fatal.Why so? Both are designed to the requirements of FAR 23.What is your point if I might ask, as I said above, both are built to FAR 23 standards.Easy to fall apart in any airframe if you are ignorant of the limitations. 210M top of green is 168KIAS, Va, is depending on weight 96 - 119KIAS. The 210 is no different to any other aircraft in handling turbulence.

to the extent a second pilot seated at the Navigator position blacked out

I did quite a bit of engineering work for an operator of Bristol Frighteners at EN back in ancient days. I must say that this tale is both eye-opening and salutory.

About as bright as the lad on the B707 which provided a massive cultural wakeup call for the military's airworthiness system ?

Seasons Greetings to you, good sir, and the good lady wife.

Seasons Greeting John, and your good lady Sal of course. And a Happy New Year, don't kick the heels too high tonight, we old folk have to watch out for each other. :ok:

If the above is indeed correct, I would suggest that certain Government Authorities would find such arrangements somewhat 'dodgy!':hmm:

I'm sure that AFAP could give the appropriate advice.

we old folk have to watch out for each other.

It will require some VERY loud fire crackers and such to wake us up, I fear.

I’m sure the AFAP’s advice would be that perhaps a pilot or two might benefit from joining the union in the first place.

Historic: VH-HWY & VH-KUZ
 

.
These Pprune links cover two accidents mentioned in this thread. They are both worth reading.

2017, C210 VH-HWY, en route Darwin to Elcho near Howard Springs

NT C210


1999, C441 VH-KUZ, en route Groote to Darwin
Scroll down to #15 for photos.
The aircraft was evidently rebuilt and is still flying as VH-JLT

Request details for Cessna Conquest Storm encounter and severe damage after U/A recov

.

Entirely agree.

I perhaps should have been a tad clearer in my original post. I have since downloaded a C210M (1977) manual. All any pilot can do is apply the limitations and definitions as they appear in the POH which is supplied to the vintage of aircraft they are flying.

This particular one defines Va as “Manoeuvring Speed is the maximum speed you may use abrupt control travel”. (Curiously, no mention of full control deflection at this point)

Further down, on Page 2-4 it lists Va as a variable of weight. Between 96 and 119 KIAS. With the admonition to not make full or abrupt control travel above those speeds..

And yet further down they recommend turbulence penetration speeds in accordance with the variable Va. I’m not sure when Vo was defined, I assume it was sometime after 1977?

I’d be curious to learn how many fresh 200 hour C210 pilots are aware of these limitations. It’s a slippery aircraft with a surprisingly low turbulence penetration speed. This was my only point.

And finally, are there any other aircraft with Va or Vo limitations which vary with weight? My somewhat fuzzy memory can’t recall any other.

And indeed, any structural failure is usually from the accumulation of stresses accrued over a hard working lifetime.

Anyhow, here’s wishing everyone a Happy New Year.

defines Va as “Manoeuvring Speed is the maximum speed you may use abrupt control travel”

Some of the AFM/POH descriptions can present interpretative difficulties unless you know the background. However, the important takeaway is that Va has little to do with the idea of structural protection by stall before break. If the OEM's choice of Va is the minimum value, that may well be a useful outcome so far as pitch input is concerned. Without having undertaken an extensive research exercise, I can only presume that the majority of aircraft are designed on the Va min basis. Va is concerned with the structural design of the controls and related fittings.

Vo was introduced in an attempt to un-confuse the issue for pilots. Vo is defined as Va min. Progressively, with the introduction of newer certifications, we will see Va being the province of the OEM designers and pilots being interested in Vo rather than Va.

it lists Va as a variable of weight

That concern has been discussed earlier in the thread. If we are looking at Va min, then to maintain any value of Va for the pilot, the value on the day needs to reduce as weight reduces from MTOW so that the speed still gives the intersection of the stall line with the limit load factor ie some level of stall before break.

recommend turbulence penetration speeds in accordance with the variable Va

Sounds good to me. If I get into unexpected super severe turbulence, I want to be well below Va min (or Vo). Why ? Pretty simple. If the wings depart company with the aircraft, I'm dead. If I stall, I get to have a second bite at the cherry.

The problem, though, is that it is NO GOOD flying along at Vc and then observing that one should really be a lot slower - you are, very likely, dead before you get the chance to slow down, particularly in a higher performance, slippery machine. It is IMPERATIVE that the pilot be a thinking sort of person, anticipate the possibility of severe turbulence and slow down BEFORE the problem presents itself.

I’m not sure when Vo was defined, I assume it was sometime after 1977?

I'd have to look it up but, as I recall, it came in with an amendment in 2007.

I’d be curious to learn how many fresh 200 hour C210 pilots are aware of these limitations.

Probably, very few. Certainly, that has been my observation in theory instruction and such simulator instruction as I have done in previous years. The pilot text books don't talk about it (although I'm writing several such books and they, most certainly, will), the very great majority of instructors have no idea about it, and so the "blind leading the blind" syndrome just rolls on. There has been an ongoing effort by the Industry to fix this problem but it is going to take a LONG time to achieve that.

And finally, are there any other aircraft with Va or Vo limitations which vary with weight?

Without doing the research, I can only speculate that the majority of light aircraft will have Va based on Va min and, so, need to consider the weight variation thing. Keep in mind that Vo is a relatively new limit and will progressively (and slowly) come into the routine lexicon for pilots. Va will still remain as it is an engineering design limitation. Vo, one hopes, will give the pilot folks a more useful (and simple) limitation. However, the basics of the Va rules will apply. One control input at a time, to the stop (or checked) and then released, and no rocking and rolling on the controls - one input. For this reason, I prefer being quite below Va if things get frighteningly rough.

And indeed, any structural failure is usually from the accumulation of stresses accrued over a hard working lifetime.

Ah, yes and no. If you overload a structure excessively, it will break, even if the aircraft has only just entered service. As the aircraft ages, the reality is that the "fatigue bucket of life" progressively gets emptied. The result is that we need to do structural maintenance stuff to balance this - if a fatigue problem is not detected, for whatever reason, the aircraft can break, progressively at lower and lower applied loads.

One key point is what is "severe". As pilots it's usually the top level of something bad, however nature does not have a rheostat dial that works on 1-10, with 8,9,10 being the severe setting, rather anything above severe becomes infinite. So the dial can be turned up infinitely beyond the severe setting and what could happen is just purely unknown.

Severe turbulence is the point you lose control of the aircraft either momentarily or totally or it simply just falls apart as the loading is so 'severe' it exceeds all limits, picture flying into a tornado. Which is what a CB can generate given the right conditions, and anywhere, not just the midwest USA.

Severe Ice is another thing, it starts at a point your ice protection starts to be overwhelmed slowly to an aircraft becoming an ice block in a few seconds. I have seen the few second thing and it should scare the hell out of any pilot, get out quickly or more importantly avoid.

Point is no aircraft is certified for flight into "severe" conditions, because it is a place that has no limits.

One key point is what is "severe".

For me, if it causes me to raise my eyebrows and think or say naughty words, that's enough to qualify as "severe". Dying is so permanent. Apart from that consideration, there is the matter of conditions necessary to permit one to drink one's coffee. If that makes me a wuss, so be it.

Keep in mind that we are talking (structural) design standards here, not AIP definitions. The design standards specify minimum required gust levels for which the design must comply and they are, I suggest, reasonable in the overall scheme of things.

So far as the pilot is concerned, if it is rough beyond a bit, then why not just be conservative ? You may have a g-meter, which doesn't help all that much and, apart from that, it is just fear and feel in the tail.

If it is rough, or likely to get rough, slow down. The flight isn't going to take all that much longer to complete. If you pull the wings off, you don't get to the destination.

I can recall super rough conditions where no-one died but it wasn't fun. For example, back on the Fokker, there was an Easter where the Melbourne and Bass Strait weather was horrific. The jets were doing emergency descents, left, right, and centre. We eventually gave up trying to get into Melbourne and ended up in Mildura. We had a brand new hostie on board and she spent most of the trip in the jumpseat, terrified. When we eventually got back to Melbourne, she went off and looked for another job. You don't really need to expose yourself to that sort of stuff.

One of the TAA mates, paralleling us on the day, observed that, during the ILS into Melbourne, the aircraft tried to turn upside down and, generally, was out of control. When it started to go up, they took that as a sign from the Gods that they probably ought to go somewhere else ....

It is an interesting question. I've flown with pilots through sustained moderate turbulence and they have called it severe, I then asked, "did you feel out of control at any point, and were loose object flying around the cabin" in all circumstances but one I could answer no, however I've had one turbulence encounter that was like hitting a brick wall in a car and stuff on the aircraft broke instantly without any warning, landed and wrote the aircraft up as having a severe turbulence encounter. Luckily no main structure was damaged in that encounter, but a number of ancillary items dislodged, including instruments and fittings. I even had a hand full of parts from inside the cabin that had shaken loose during the single shock encounter to give to the engineers to repair.

As far as machines surviving these encounters, as pilots we have very little insight into how the craft was assembled. There's the minimum certified requirements, then there's what the manufacturer actually put together, which may be stronger or even weaker than designed based on competence and quality of materials, workmanship etc... then there is age and abuse, exposure. I mean one company could choose to make the spar double thickness and weight as they never want a wing to fold, the other guy makes it as light as possible with new untested materials to make the craft light and nimble. Who knows what you are flying on the day other than the limitations imposed during certification and knowledge of how aircraft are built and fly. A good place to get an insight is the ATR saga, where initial certification created a latent icing issue because they were band aiding minimalist design. They found a nasty issue with control reversal during normal stall testing in clear air, fixed it with some VGs to delay separation, but never tested for the same issues in icing conditions. Then certified it for icing, with no limits, which the EASA to FAA crossover lost in translation certified for all icing (including severe) and then numerous accidents occurred which after much pilot angst led back to initial certification.

The problem with Va is actually too much science/physics/philosophy when it comes to explanation, hence confusion and lack of knowledge.
​​​​​​
With all due respect, regular Joe Bloke pilot won't go reading any scientific material if not understood within 1 or 2 paragraphs. For many, flying in green band on ASI is assumed safe, although Va is closer to the beginning of the green.

The simple rule should be taught: When in turbulence or approaching turbulent weather, slow down to Va and your survival chances will improve.

​​​​​​

Va has nothing to do with turbulence penetration, at least not in a Part 23 aircraft. I’ll shortly post some info from someone who’s an expert on the FAA certification system and also a link to an FAA document produced as a consequence of pilots labouring under misconceptions about what Va means.

Operating at or below Va won’t make operations in turbulence ‘safe’.

How far is Va from Vb, and how far are both of them from Vno ?
C210 data:
Va=117kt
Vb=119kt
Vno=165kt

Whether they are related or not is irrelevant. They are close to each other and many of POH's actually don't have Vb listed.

Nobody ever said Va (or Vb) are safe speeds. They are speeds which will increase survival chances in turbulent weather.

Note, Vb is not listed in C210 POH, but there is a reference in vh-sjw report:

https://www.atsb.gov.au/sites/defaul...-069_final.pdf

Doesn't mean jack Pinky. Pilots that take these jobs KNOW they aren't being paid correctly, but they still take them, you know why of course.

Join the union? How can you when you're being paid as above?

The airworthiness design regulations specify Va so anything contrary to those regulations is incorrect. A pity that there has been a disconnect between certification and operations people on this subject for so long (it is not the only issue where such a disconnect exists). The guidance from the FAA per LB's post is quite clear.

Most Pitts aircraft have Va> Vs.√n - something for aerobatic pilots to think about. Aircraft certified some years ago will continue to have Va in their AFM/POH, the exception being the Seminole which has introduced Vo.

From FAA SAIB CE-11-17. The bolding is in the Bulletin:Note: If you’re not in smooth air, VA ain’t very relevant. And, as noted earlier, VA is a number chosen by the designer for the purposes of design. The only constraint is that VA may not be less than Vs x sqrt(load factor). The loads resulting from full control surface deflections at VA are used to design the empennage and ailerons.