Breath deeply and count..............................

OK..........mindfullness over.

Rotorbee - you disappoint me.

Bobakat:

When an a/c develops VRS or IVRS, 'stuff' happens inside the lift drag curve where big green arrows and vectors and angles of attack all start moaning and complaining they aren't happy and as a result of this quiet revolution going on around your rotor disc, the aircraft says F-u-*-k it, I'm outta here and goes into freefall.
No one else has come along and spoilt the party - it's all down to that nasty neighbourhood and bunch of trouble makers the "aerodynamic gang".

When an a/c develops SWP, you're in a different neighbourhood. You're in the engine neighbourhood - the hot gas clan - those nasty individuals who spend all day hitting that huge compressor at the back of the class.
The a/c needs to stop as it ends its decent to land or is approaching an obstacle and the hot gas clan come out in force until all of them that are available are hitting the compressor kid as hard as possible, to the extent where the engine says to hell with this excessive violence in my classroom, enough is enough, we cannot continue to produce the output you require from this compressor to bring the MASS of this a/c to a stop (before it hits the ground/obstacle).

Look at it another simplistic way:

You are landing your jumbo jet at Heathrow and for that given AUM you decide to apply maximum reverse thrust to prevent yourself running off the runway. But all the reverse thrust available is not sufficent to arrest the AUM in time to keep it on the runway. Your engines aren't powerful enough (IN THE REMAINING DISTANCE OFFERED) to arrest your particulr AUM.

It is an engine thang! Nothing to do with little green arrows/updraft/alpha.

Learn the difference guys and don't show your ignorance in basic helicopter theory FFS.

Calm..............close my eyes.....relax........:cool:

TC, you break my heart. Nothing could be more hurtful than your accusation that I disappoint you ...Er, why exactly?

PS: BOBAKAT and TC - don't you two mean the same thing but keep misunderstanding each other? VRS - aerodynamics, SWP - Pooooowwwweeeer

He wanted to know if anyone had anything positive to say about VRS? Well I do,...it saved my life once!,...and it was in a 44!:=

I don't know what the FAA calls it when you have insufficient power to stop your decent, but I call it FTS.
FULL THROTTLE STUPID!:eek:

"Sunshine"? HA! No one who's ever met me would ever call me that! It was a good laugh though! :ok:

Hmm, the way you are describing it here makes it sound more like a distance thang to me! Its not settling with power, its just not paying attention!:=

Its like driving in the rain or ice, if you want to stop in time, you need to start slowing down sooner!

TCoupling bare with me as you have probably noticed the English language is my second language, I am French Canadian.

No worries I see your point. Also I realized last night that there are no confusion in what VRS actually is or what it can do to you or how to recognize the first signs of it or confusion on how get out of it. The confusion/misunderstanding here is in the word itself.
Now let see if you will see my point. The text from TC pasted earlier says "incipient" you are right, but nowhere in any books or anywhere else during your initial training or annual training do they use IVRS. For us here in Canada the term incipient means you are at the beginning , first stage, the start of VRS. We have no separate or different terms to describe the different stages or the evolution of the condition from its beginning/early stage to its fully developed condition.
That you are in it at the beginning or at the end coming down 25,000ft a second it is still only called VRS. First time I heard of IVRS is here on this forum. (earlier tread)
This winter when I start giving training and if I start using the term IVRS they will all look at me and say something like, Are you sure you want to wait another 2 years before retirement. lol Now if you say that before we can call it VRS, it has to be in its full development or solidly on its way there then that might take while to get implemented in this industry.
But again I see your point.

For SuperF, yes it is a lesson or exercise 26 and part of what a student pilot should learn to get his license. But I am not not an instructor and I am not up to speed with how they teach it. I am a training pilot and give annual company training to professional pilots on Mediums (205 nowadays) and also longLine training where VRS SWP are an important part of it. 205 are notorious to get into SWP on a hot and humide day when loaded. Most of the pilots here have a good understanding on the differences of the two conditions. I do have a way of explaining both conditions if needed.

JD

fijdor,

my memory must be still working alright. it was in a 22 a long time ago, and I'm now far more comfortable in a 204 myself. totally agree that you can get all sorts of "fun" in a Bell medium if hot, high, heavy or a combination, especially sitting on top of a longline as you try to sink 200" into the "hole" in the trees!

Tabernac!

Careful boys - this is what fijdor looks like after he gets frustrated!

https://pbs.twimg.com/profile_images...ac_400x400.jpg

Ça va, JD?

The other way of considering the difference between VRS and SWP is to look at Nr.

In SWP, you have run out of power - but keep pulling anyway - the Nr will decay and you will descend - often to ground impact.

In VRS, you have run out of lift - because of the stalled roots and the vortex-ingesting tips - you can get to this stage without running out of power.

The 'lesson' given to students about VRS often involves flying downwind at 1500' or so, reducing speed below 30 kts and then allowing a slight RoD to develop - at this point the lever is raised and the ensuing vibration is described as VRS (it isn't VRS) and immediate recovery is made by increasing speed and flying out.

The student is scared by the vibration and the instructor has shown the conditions for entry - everyone goes away happy but there has been no VRS demonstrated or recovered from - only what we are now calling IVRS.

It's a bit like the difference between FW spin recovery (from a fully developed spin) and incipient spin recovery - one involves a specific series of actions to recover from the high RoD into controlled flight and the other usually just requires centralisation of the controls.

The difference between incipient spin and fully developed spin is large - in exactly the same way that the difference between IVRS and VRS is large.

Hi Crab,
Some of us got the other lesson. Climb out to about 8,000’ in a 22. Yes it took a while from memory... same start of lesson, turn down wind, pull airspeed back to zero, start a descent, shaking scary stuff, pull power, going down faster, I remember the VSI being pegged as low as it would go. After what seemed like an hour, and loosing a few thousand feet, we started a recovery and came out about 1000”.

Scared the crap out of me, but I made sure everything was done into wind after that!

Hi Super F - yes that sounds like the real deal alright - I hope everyone reads your post and realises the difference between what you experienced and what so many others get.

I wonder how confident Mr Vuichard would have been in his 'technique'...........

Last time I did SWP downwind like that I got an immediate, surprise 90° yaw,...startled the **** out of me! He had me do that new sideways recovery technique,...its pretty cool!:ok:

No butters, your trolling still doesn't have any subtlety....................:ugh:

Nope, that actully did happen!

I don't know where some of you guys are coming from. The U.S. FAA teaches now...has always taught...that "Settling With Power" is recirculation of the vortices produced by the main rotor. I won't reprint or repost the applicable section of the FAA's Helicopter Flying Handbook - you can read it yourself. But it's what I was taught when I was learning to fly in the 1970's. To recap: The FAA says that SWP *is* VRS.

But because the current generation of Robbie Rangers have to over-complicate and try to quantify EVERYTHING, some of you have invented your own definition and explanation of SWP - that of a botched approach (vertical or otherwise) in which the engine does not have enough power to stop the descent. Fine. Sounds like pilot screwupery to me. And strangely, the FAA does not address this "phenomenon" or aerodynamic condition directly. I guess they leave it up to the pilot to know the performance characteristics of his or her particular helicopter and abide by them and not land on a runway so short that full reverse won't stop you. You know, that's not the plane's fault.

In reality...in the real world of helicopter flying, it *almost* doesn't matter what you call it, or whether it's "settling without enough power to stop" or true vortex recirculation. You're probably going to crash. Yeah, yeah, if you recognize it early you might be able to employ Sr. Vuichard's technique (good luck!)...*or*...you might be able to fly out of it forward. But you usually get into it until the very bottom of a poorly-executed approach...you know, where it usually happens to those of us who don't have things dangling under our helicopters on longlines. And if it does happen at the bottom of such a messed-up approach, and you're a little slow to recognize what's happening (welcome to the club!), then you'll probably end up with smiling skids and your peers will be calling you by the nickname Bing Dang Ow from now on. (Ohhhh, just remembering that bimbo newscaster blithely reading the fake names of those Asiana Airline pilots makes me chuckle.)

I often tell the story (faithful readers of my crap have all heard it by now) of sitting in the Vibro-Massage chair attached to the Bo-105 I was flying in the Gulf of Mexico. I'd be on approach to some drilling rig which was situated in a way that the heliport was on the exact WRONG side of the rig for the winds that day. And I'd sit there, pretty much at full power as the 105 did it's notorious shake, rattle and roll coming back through ETL...I'd sit there wondering, "Is this just the 'normal' Bo-105 vibrations, or are we on the edge of SWP?" I'd be super-attentive to the collective, waiting for it to become "unhooked" from the RoD. Because you never know, right? No, you never do.

People ramble on and on about the "differences" between SWP and VRS. They say that during SWP, because you're pulling more than the engine can supply then the RPM will droop. Well...you know...aaaahhhh...most of real helicopter pilotos fly real helicopters powered by this new invention called the turbine engine. We don't pay much attention to the trials and tribulations of the unwashed, bearded riff-raff in the R-44's. I mean, really. And these modern turbines don't droop.. (At least not anymore! Anybody remember the Allison C-18 days? I do. And not fondly.)

So prattle on, boys...drone on and on about how there's such a BIG difference between SWP and VRS. The more experienced pilots among us will just chuckle and shake our heads and fly 'em the way we know how.

What difference does it make going down wind at several thousand feet? Might as well practice your VRS entry in any direction?

Easy there turbine boy! Don't blame this crackpot "SWP isn't VRS" crap on Robbie Rangers! We're the ones who still believe the textbook!:=

RVDT, you funny guy you. lol Oui ca va. Looks like they took THAT picture out of the message.

JD

Your FAA "Bible" has a lot of Fake News in it, being designed to teach the lowest common denominator, so it glosses over things and simplifies them to the point of error.

For example, it states as a fact that the air pressure increases under a rotor disk in IGE, causing less induced flow. Wrong.

On page 2.19 it shows a diagram from above with coloured part on the right saying that with forward motion, the advancing side gets more lift, and the retreating side gets less lift (IF NOTHING IS DONE ABOUT IT) and this will cause the aircraft to roll left. Garbage.

It preaches gyroscopic precession, which should only be used as a guide to understanding the delays in blade movement and the advance angles built into the swash plate to make up for them, not as the reason the disk behaves like it does.

So don't quote the FAA book as being absolute truth, it is merely a teaching aid, and not a particularly good one at that.

TC,
We hear where you coming from Mate. Your experience seems to be Mil/Police/Medevac etc. We get that.
One simple question how much time you got in the mountains, and I don't mean the Beacons, at altitude, heavy all day, single pilot doing the longline stuff we do in Canada?

I guess that was asked to me? I've got no idea, except maybe if you are doing it into wind, that when you get into the falling out of the sky part, that you are actually travelling backwards relative to the ground. I doubt if that makes any difference to the actual experience, but "maybe" it was proving the point that its best to make an approach into wind when you can.

Having never done any instructing, i would only be guessing.

Crab and Charlie are exactly correct on all counts - end of story full stop.

I love a good slanging match especially when it comes to 'us' and 'them'.

FH100: Sorry big guy - you're talking boll o cks (like the FAA do - much of the time). Europe and Canada bow to the superiority of the FAA (not).
As Ascend Charlie said - there's a lot of mischief in those FAA manuals.

And this is definitely one of them: SWP.

For the record, this clip is perfect SWP from a very well trained and probably experienced yank driver. He's done these approaches numerous times and is aware of many of the gottcha's out there, I would argue, especially vortex ring.
Which is why he wasn't expecting this:

https://www.youtube.com/watch?v=1DDDpI263qE

And do you know why he wasn't expecting this? Because it wasn't VRS it wasn't even close to VRS. The conditions for VRS were a million miles from this guys approach (into wind/ >30kts to start with / minimal RoD), I bet he wasn't even close to IVRS (vibration, increasing RoD).

This is THE perfect example of SWP and you yanks really do need to wake up and smell the coffee - the rest of the world (for once) aren't wrong with this.

[Day after day - more and more "experienced" pilots come on here and display a level of ignorance which is becoming more and more endemic as we speak. Christ, if experienced driver's are behaving like this - how, in the name of faith can we ever slag off lesser mortals???].


If helicopter pilots don't understand basic aerodynamic/ engine related phenomena like : VRS / IVRS / SWP / PS / LTE / LTA, they should be ashamed to call themselves pilots.:ugh:

Newfieboy - don't get where you are coming from? Is there a link to God - through long line - to VRS, or something? Is long line the dog's boll o x, then? Are longline pilots world experts in VRS? Keen to know more about this band of brothers gospel according to?

TC,
If that video was an example of SWP, how come there was enough power to lift off again?
Looks more like SPE (simple pilot error).

TC, sorry to break it to you, but the CH-46 accident wasn't even SWP. It was merely a misjudged approach. He probably had plenty of power. But he screwed up. His approach angle was nice and constant, but the boat was moving up and down - something obviously not taken into account. The '46 pilot came in way too shallow and caught a wheel on the fencing. Oops! Happens. It's why PHI taught us to come into oil platforms steep and slow, never shallow and fast - just for that reason. Worked for me.

To those of you who say the US FAA is wrong about this or that...well...whatever. If it makes you guys feel superior or something, that's fine.

If you guys want to narrowly define SWP as something other than VRS...well...I think y'all are wrong.

Its always the internet "pilots" bragging about how "experienced" they are who say the textbook is wrong,...always!:=

In the real world, I have never met a pilot who thinks SWP is anything other than VRS!

,...but carry on God's gifts to aviation!:D

Havent met me then !:ok:

This link provides some detailed background for the 1999 CH-46 accident:

Sea Knight off San Diego

Butters, as you admit on that other forum, your real world experiences weren't particularly successful, were they?

And what you said tells me that the pilots you have met have been poorly taught. There is a huge difference between SWP and VRS.

Ascend charlie: you are wasting your time i'm afraid.
A pilots ego is often bigger than his brain.
What a shame because so called experienced pilots have so much to offer those who look up to them. It's a big responsibility ensuring those coming up behind you do it properly.
It is literally a life saver.

Butter you meet all Helicopter pilot in the world ?

Sure if you talk only with ATPLH pilot flying from base A to baseB and back with AP on.... It's really rare for them to meet Mr SWP and VRS...
but for the utility pilot long line and many others, is the reality.. For myself i experiment both situations. In both case i finish my flight safe, but maybe have to change my pants... I teach really my studient about VRS above 1000 ft. I want they feel the vibrations and the stick dribble. I simulate the power limit for the SWP.... And i am happy when they understand what happen... ;)

Your ignorance and inexperience is showing. My memory is that we taught VRS as 'settling with power' in 68-70 US Army. I was taught to teach it in exactly the conditions of VRS, including the application of power accelerating the descent. It was hard to reliably induce the fully developed state in a TH55, as zero airspeed is hard to determine at the altitudes we did this. We, the pilots in my cohort, interchanged the terms until the late '70s early '80s when the recirculating rotor down wash was broadly taught. This I think lead to the confusion.

My memory may be wrong, but VRS signals subtly that something is happening, vibrations and uncommanded attitude changes and then when in the fully developed VRS, the aircraft feels 'sloppy', less crisp in response. SWP seemed to be more normal aircraft response in the descent, you ran out of power (or NR in the Huey) . We didn't intentionally fly into full SWP, but demonstrated it with power limitation.

Final point: In the real world, I have never had a textbook defined issue in flight. One teaches somewhat simplistic, defined issues in primary instruction to teach the most appropriate resolution clearly and emphatically. The flying part of the instruction is especially simplistic in my opinion, insisting on specific airspeed, altitude and approach procedures as though that kept hobgoblins away. It ain't that clear and easy when you're working the line...

An important point has been made here by Devil - in longline work when things don’t go to plan there’s just no time to consider if your in VRS, SWP, over pitching, or any other plethora of situations which ruin our day. You just need to react, listen to what the aircraft is telling you through your backside/eyes/ears & fix it. You need to be aware of this BEFORE the condition develops, almost subconsciously, firstly to avoid it but also to ensure you take the correct action should you fail in the avoiding part.
I think I’ve been in a VRS situation once, I say “think” deliberately as I didn’t hear a change in aircraft power train noise & couldn’t tell you what the gauges were saying (didn’t look!) as within a few seconds I had to fix it or hit the ground therefore my eyes were outside the cockpit & apparently my hands & feet were busy fixing this problem I had created. I’m happy to report I fixed it. There won’t be a second time.
There has been many comments on this thread re “here we go again” & I get that, but personally I enjoy reading all of these opinions & using the information to cross check & confirm that what I thought I knew still makes sense to me so that when my hands & feet need to react there’s no delay. Keep the discussion alive, it shouldn’t matter what our instructor said, once we have the licence it’s up to us to continue to learn, challenge what we were taught & verify, verify, verify. Theology can be debated, but physics & aerodynamics in 2017 are pretty well understood - VRS is VRS, SWP is SWP, over pitching is overpitching.
Misinformation is widespread though; despite Transport Canada differentiating between VRS & SWP I noticed yesterday that the Saskatchewan & Alberta National Aerial Pesticide Application Manuals both state that rotary pilots should pay particular attention to “vortex ring state(settling with power)”. Here we go again.

,...and you just made my point!

You call running out of power "settling with power",...even a college dropout can tell that makes no sense!:ugh:

,...but I know, keep stroking your egos and looking down your noses at the poor little, gullible, Robby guy who dares to believe the logical explanation given in the textbook!:rolleyes:

Posters may wish to peruse this thread, and note Nick Lappos's input. I'm not about to argue with Nick.

http://www.pprune.org/rotorheads/676...-settling.html

I did find this point of his a nice read!

:ok:

Dude, the point I was attempting to make was that the textbook was wrong. If that single mistake, identifying SWP and VRS as one and the same, wasn't sufficiently problematic, it added to the confusion for, what? Five decades now?

VRS is NOT SWP, even though several tens of thousands of pilots were taught to interchange the terms. Knowing the difference is the important point. It's especially important as you may expose yourself to conditions that could lead to bad outcomes from either or both in professional flying while in sanitary school settings you may not, or you may be taught by the book answers that aren't inclusive of ALL options. Example- my last several recurrent sessions did not include anything that wasn't in the FAA syllabus- until I asked for demonstration, practice. Vuichard recovery technique chief among them. The check airman was very familiar with it, he was a long line mountain pilot and an exceptional teacher...

So, I mess up my pre-flight planning and make an approach to a OGE hover a few hundred pounds above my RFM MAUM for OGE hover at that temp and pressure. I am aiming for a 70' hover to confirm my ground position before descending vertically into a smallish LS with some obstacles around it.

As I get to 70' in a level decel and start to lose translational lift, I raise the lever and pull as much power as the engine will give me but the aircraft starts to sink - I raise the lever some more but the engine has topped out and I hear the Nr start to decay and I keep going down - I am clearly going to hit the ground but why?

Is the answer

a - I have settled with power because I don't have enough to hover OGE but tried it anyway?

or b - I have entered VRS because aerodynamics weren't on my side today?

I have ended up in an overpitching state trying to arrest the descent but I am going down with full power applied and the Nr decaying. I haven't caught up with my downwash because the RoD is fairly low and I might just be saved from a hard impact by ground effect.

On a different day, I have done my pre-flight planning perfectly and I know I have OGE hover performance plus some in hand for the wife and kids. I make my approach with a slight tailwind that I didn't notice and I end up a bit steeper on finals to my OGE hover point than I intended. I have some forward speed when I look out of the window so I accept the higher rate of descent thinking that a combination of flare effect and power will sort things out near the bottom. I feel a sink and some vibration I don't much like so I grab a handful of lever - the aircraft shakes some more and sinks a bit faster so I add more collective. Suddenly I feel as though I am falling out of the sky and the ground is coming up really fast. I am clearly going to hit the ground but why?

Is the answer

a. I have run out of power and am therefore settling with it?

or b - I have entered VRS because I didn't realise I was downwind and let the external references fool me into thinking I still had forward airspeed on? I allowed a high RoD to develop with very low airspeed and tried to recover with lever. I may or may not end up with max power applied and I might even get to the point where I get Nr decay as well but that is a symptom a long way down the list and not the cause of my problem.


There may still be some who can't tell the difference and all I can say is I don't want to go flying with you.

This first one is called Full Throttle, which if you continue pulling, will lead to Low-rpm Rotor Stall, which would most likely happen before you reach settling with power (vortex ring state)!

In the second one you have clearly induced settling with power (vortex ring state) because you chose to ignore the warning signs and began settling into your own downwash!

Perhaps if we gave you all a Full Throttle Lite that would end your confusion?:ugh:

R22butters - if you don't want to learn (and possibly save your life) then carry on.

The first one is a classic for underpowered helos like the R22 - you end up with the lever under your armpit and hitting the ground hard - usually without getting anywhere near rotor stall - it is a function of poor piloting skills and only a partial decay since the engine is still pushing max power - it's not like an EOL where there is no power. It is this scenario that is often attributed to VRS when it absolutely is not the case.

The second one is where your confusion arises because you can't see that you haven't reached a power limit - it is simply VRS.

Err...TC
No there is no link to God, being a competent safe longline pilot. Just thousands of hours doing it for real.
My question was pretty simple, here I'll rephrase it. How much experience you got in the mountains,(not the UK titties) on a line doing production stuff, single pilot. If I was a betting man I would say Zero!!!
Merry Christmas and all the best for the New Year. I'm outta here going to go on a drill job, just packing my bags....ooh longline TC. Guess I'm a God. Funny that my bday is on Xmas Day....!!!