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Vuichard again

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Vuichard again

Old 9th May 2022, 03:41
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Originally Posted by SASless View Post
Yes, I know the description mentions it. My point is that SWP has been removed from both the glossary and the indext (as well as in the Robby POH). Thus it no longer has a definition in our FAA book. Just a small blip of what it used to mean.

More importantly, there is nothing in our FAA book that says;
Settling With Power - A condition where the pilot comes in hot, waits too long to apply the brakes, then crashed as a result.
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Old 9th May 2022, 07:59
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Settling With Power - A condition where the pilot comes in hot, waits too long to apply the brakes, then crashed as a result.
No because that's not where settling with power generally causes crashes.

When you have barely enough power to achieve and maintain a steady OGE hover and then try to make very steep approaches into confined areas - for example - then you try to arrest the rate of descent, reach your maximum power available and keep going down with the RRPM decreasing (overpitching) - THAT is settling with power

Or manoeuvring in and around an OGE hover, losing ETL due to wind change or using excessive power pedal to counter crosswind for example - any scenario where you run out of power and keep pulling to try and stop the descent, drooping the Nr and hitting the ground - THAT is settling with power.

The main difference between VRS and SWP is that VRS is an aerodynamic condition whilst SWP is a performance (or lack of it) condition - the result is often the same but the cause is different.

If the FAA can't understand that then something is wrong with their system.
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Old 9th May 2022, 13:39
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Originally Posted by [email protected] View Post
No because that's not where settling with power generally causes crashes.

When you have barely enough power to achieve and maintain a steady OGE hover and then try to make very steep approaches into confined areas - for example - then you try to arrest the rate of descent, reach your maximum power available and keep going down with the RRPM decreasing (overpitching) - THAT is settling with power

Or manoeuvring in and around an OGE hover, losing ETL due to wind change or using excessive power pedal to counter crosswind for example - any scenario where you run out of power and keep pulling to try and stop the descent, drooping the Nr and hitting the ground - THAT is settling with power.

The main difference between VRS and SWP is that VRS is an aerodynamic condition whilst SWP is a performance (or lack of it) condition - the result is often the same but the cause is different.

If the FAA can't understand that then something is wrong with their system.
I have never understood why you insist on calling situations where you "run out of power" (like overpitching and being too heavy to HOGE without a headwind) Settling "with" Power? So, I'm guessing THAT'S why the FAA isn't adopting YOUR use of the term, because it doesn't make sense to them either.

Nor do I understand why YOU have to be right and THEY have to be wrong. Just like how Canada put it in their texbook that we are wrong. Such arrogance! Its just a frickin' term. Why are you so attached to it?
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Old 9th May 2022, 15:06
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To prevent a much longer debate here....perhaps a bit of ancient history being introduced might help.

A quick read of this thread done in the past right here at Rotorheads might produce a way to better frame the two competing views.

Of interest is one post made by Nick Lappos who is a very astute individual when it comes to such issues.

Vortex Ring / Settling with power (Merged)


Nick is not here to discuss the following post but it is just one of many he has contributed during other discussions of VRS and SWP.

For what it is worth....I agree with both Crab and Nick for an array of reasons.

There most certainly is a difference between SWP and VRS. and to say otherwise fails to fully consider all of the factors that affect each....and both.

I recall Nick saying in one of his posts that in some modern helicopters there is enough power in the Rotor Systems to simply climb out of VRS....although for sure I am oversimplifying what he had to say about that.




Crab and helisphere,
I can't subscribe to the updraft theory of VRS, it is just not that clean. The precise disk angle needed to enter and sustain VRS is not something that an armchair calculation is likely to prove. True VRS is a flaky thing, often needs the pilot to work at staying in the condition. I would be interested to chat with a long line pilot to see what he/she experienced in the event.
I would bet dollars to donuts that power issues are much more the issue, and I must say that few "experts" know much about the distinction between VRS and SWP to differentiate, including experienced and well intentioned government safety experts and investigators.
To my knowledge, no tests have shown anything close to a VRS case where updrafts and such have triggered any events. I believe the conditions that would create the updraft would also create enough turbulent flow to disrupt all those calculations (but that is a belief, not based on data.)
The situation is perpetuated with a thousand "VRS" demonstrations by a thousand instructors who show SWP to their sutdents. I searched youtube for VRS demos on video, and found NONE that were VRS, all were SWP.
To recap, to get VRS, you must descend at about 70% of the induced velocity, about 700 fpm, and also have about 8 knots forward velocity (straight down will not do). If you enter from lower descent rates, it is not VRS, it is SWP, and if you do nothing to correct the SWP, it can degrade to SWP.
None of the above means there is no danger, just explains what the physics of the situation is. The cure for either is about the same, once in the situation, but the cure to prevent SWP is to retain some power margin, enough to allow some vertical maneuvering while OGE. THAT is not mentioned in the typical VRS discussion, making it somewhat misleading to spin on and on about VRS, descent rates and updrafts, when most cases can be solved with adequate attention to power and weight.
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Old 9th May 2022, 15:16
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Robbie, just as a hint for the future. Crab has a huge knowledge, but also is a bit old and hard headed by now. Use the old geezers knowledge, but don't argue. Think a bit in terms of a retirement home where you try to get information from your great grandfather, where he hid all the money and jewellery.
If he does not agree with you, he will argue until the cows come home. Therefore, let it go.
Never forget, he was formed by the British military and therefore a flying god (now retired).
AFAIK, there is now no national aviation authority anymore that uses the term SWP at all. From a "do not confuse" point of view, it is better, just to let it die. End of story.
Regarding the Canadians, it's either a dig towards the US or they wanted to make a point for pilots coming from the US to fly there. Makes sense, if you have some godlike pilots from the US who argue until the cows come home (Actually, you find them in every country). Make a point in the regs and you save a lot of Canadian FI's nerves.
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Old 9th May 2022, 15:16
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I have never understood why you insist on calling situations where you "run out of power" (like overpitching and being too heavy to HOGE without a headwind) Settling "with" Power?
so what would you call it then? You are descending at a low forward speed or even straight down but at maximum available power with the RRPM gently decaying - you have the descent (which you can't arrest) so you are settling and you have max power - seems straightforward to me.

Sasless - yes I remember Nick saying it was possible to power out of VRS but you needed a huge amount of power to overcome the rotor drag caused by the vortices.
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Old 9th May 2022, 15:20
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Rotorbee - I may have retired but I am still flying, helicopters and FW.

Understanding SWP is even more important than VRS since light helicopters are often operated with minimal excess of power beyond OGE and are also flown by less experienced pilots in the main - that spells accidents to an old dinosaur like me.

One of the first things I was demonstrated on my R22 type rating back in 92 was overpitching and how to recover from it.
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Old 9th May 2022, 15:44
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Originally Posted by [email protected] View Post
so what would you call it then? You are descending at a low forward speed or even straight down but at maximum available power with the RRPM gently decaying - you have the descent (which you can't arrest) so you are settling and you have max power - seems straightforward to me.
If I were on a descent at max available power and the RRPM was decaying, I'd say I am clearly too heavy to HOGE and am overpitching.
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Old 9th May 2022, 15:57
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Rotorbee,

Just like your Grand Dad in the Old Fart's Home....do remember he got Old for a reason....especially if he was a Helicopter Pilot.

As to the FAA being the All Knowing God....that kind of thinking might prevent you from ever being that Grand Dad in the Home.

They certified a lot of Jet Rangers and later had to coin the concept of LTE as a result of the poor Tail Rotor Design....they also certified helicopters without crashworthy fuel tanks....and have issued rules and regulations that allow people to go out and kill themselves.

You did read Mr. Lappos' post I quoted....the part where he mentioned all those different experts?

Perhaps you might be a bit more kind in some of your comments as if you live long enough you may have reason to regret making them.

I have had many an argument with Crab down through the years...but have always considered his experience and knowledge to be a real asset.

This Forum is a virtual Crew Room in my view....and my experience has been a lot of learning goes on over Tea when Pilots discuss their stock and trade as much of it is art and not science....although science plays a large role. The Art is the Pilot learning to apply that science and be able to discern when and how said science is about to do him in.

Trust me....you are not young enough to make all the mistakes yourself and survive....best you learn from others....and I always tried to learn from everyone I flew with no matter their experience or license level. Sometimes it might simply be to never do what they did....usually it was a well appreciated tip or trick that worked.
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Old 9th May 2022, 16:00
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If I were on a descent at max available power and the RRPM was decaying, I'd say I am clearly too heavy to HOGE and am overpitching.
Now you have angels dancing on the head of a pin...........
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Old 9th May 2022, 16:03
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... and that's why I am really fond of your knowledge Crab. No, really. Still going strong.

I mean, it is obvious, if we keep the term SWP, the confusion will continue. Overpitching is a good term to replace it.
Isn't it ironic, that SWP/Overpitching/etc. kills way more people than VRS and we are killing a perfectly good description. Still, it's OK with me.
The paper with the graph of the blade flapping is at least for me an eye opener. I will never ever demonstrate - or trying and failing - to get deeper into VRS anymore. Incipient is good enough and no flying sideways.
Should the investigation really show, that there are now several training accidents with VRS, boy I would not want to be in Vuichard's shoes.
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Old 9th May 2022, 16:06
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Why are you so attached to it?
Because it isn't VRS but has been wrongly used to describe VRS by those who can't see the difference.

You know there is a difference so why are you so hung up on using a perfectly reasonable term to differentiate VRS conditions from SWP conditions?
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Old 9th May 2022, 16:16
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Letís agree to call it SWB (Settling Without Power)
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Old 9th May 2022, 16:42
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Originally Posted by [email protected] View Post

You know there is a difference so why are you so hung up on using a perfectly reasonable term to differentiate VRS conditions from SWP conditions?
,... because it isn't a reasonable term to describe it. You are crashing because you were simply too heavy for max power to stop your rate of descent (or in Canada because you waited too long to apply the brakes) not because of some mythical gremlin you want to call Settling with Power.

SWP (the way you use the term) just seems like a cop-out for pilots to blane external forces for why they crashed,...kinda like LTE. "Gee it wasn't my fault your expensive aircraft crashed, it was SWP."

Take responsibility for why YOU crashed their aircraft. "Sorry boss, but I was just too heavy to come in like that".
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Old 9th May 2022, 17:12
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By your logic we should do away with VRS as a term as well then - it's far more of a mythical gremlin than SWP.

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Old 9th May 2022, 17:20
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Originally Posted by [email protected] View Post
By your logic we should do away with VRS as a term as well then - it's far more of a mythical gremlin than SWP.

If that's the road you choose to follow, then knock yourself out.

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Old 9th May 2022, 17:21
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Years ago while getting my license, I listened carefully to the instructor trying to explain VRS and SWP. It seemed then, and still does, that SWP should just be amended to SWEP, and stand for "settling without enough power". No spooky and weird response to any of the control inputs. I just tried to pull pitch to stop a descent and even though more pitch helped, as I kept pulling I ran out of power and thus rpm.

The few times I tried VRS with the instructor in a 44 were plenty, and did convince me never to get there. We were in a different state, the controls didn't work, and more pitch DID NOT HELP up and until and past where I ran out of power. I like vertical ring STATE because it is like you and the machine are in some strange and bad place where controls don't work.

VRS= more pitch doesn't help
SWEP= more pitch helps until you run out of power.

That seems simple to me.

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Old 9th May 2022, 18:49
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So just to be clear - I don't care what you call SWP Robbiee - all I care about is that pilots know there is a difference between VRS and running out of power in an OGE hover.

If this whole discussion serves to highlight that difference then it was worth me banging my head against a brick wall for so many posts.

SWP/SWEP/overpitching/or whatever, causes far more accidents - as rotorbee points out - yet the reason for those accidents has often been attributed to VRS because the FAA were confusing the terminology.

That leads to pilots confusion which is always a bad thing especially if something as important as good pre-flight planning and power awareness is ignored because of that confusion.

gator2 - I agree, keep it simple. I thought it was simple since I clearly understood the difference between the two situations but I appear to be in a minority.
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Old 9th May 2022, 19:18
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Crab, please leave the brick walls alone, they haven't done anything to you.
Just to make one thing clear, the NTSB does accident investigations, the FAA doesn't. Since I tried to find those thousands of VRS accidents, I can claim, that the NTSB knows the difference between VRS and running out of power. They used the term SWP "correctly" only for VRS accidents. There are apparently only 3 in the NTSB database, since 2000 to 2015. When somebody runs out of power, it is stated as such. Just not as SWP. And there are many. About 30% of the accidents have not enough power as a factor. The whole world talks about VRS, only the US have the SWP confusion. The FAA decided correctly to not use the term SWP anymore. They fixed an old thing that started in the Navy. I don't see any reason to keep SWP as a term. It would cause just more confusion in the future, therefore SWP has to go and should under no circumstances used for something else.
I don't think that any accident investigation agency uses the term SWP for running out of power. Today, old US-pilots think in terms of VRS, when they hear SWP, younger ones talk more often about VRS, not all though, because the old still teach SWP. To change the use of the term, is much more difficult and confusing, than just dropping it. Let it die in peace.
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Old 9th May 2022, 19:33
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Originally Posted by [email protected] View Post
So just to be clear - I don't care what you call SWP Robbiee - all I care about is that pilots know there is a difference between VRS and running out of power in an OGE hover.
Fear not, I have known the difference since 2003 when I passed my PPL checkride.
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