Would now somebody please post what the CAA in its endless wisdom has to say about it. Just to get everybody on the same page here.
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Originally Posted by Rotorbee
(Post 9972786)
Would now somebody please post what the CAA in its endless wisdom has to say about it. Just to get everybody on the same page here.
JD |
Well dear fijodor, how about you doing some research work? Bit lazy aren't we?
Seriously, don't you think I tried? Unfortunately the CAA of UK does not provide this information easily. If you search on the aforementioned site for SWP, it does not find anything and suggests to try "setting wing paper" which makes no sense at all to me and surprisingly does not find anything useful either. Therefore we need somebody who has at least an idea, where the CAA does hide this information or the books latest issue. Satisfied? BTW: Being closer to the UK than to Canada does not mean, that we understand their way of thinking better than yours. The Brits way of thinking is puzzling to the rest of the world. |
I don't think the CAA actually address this issue with a 'handbook' or 'flying guide'.
There may be an advisory notice or a circular somewhere but I couldn't find it easily. The British Helicopter Association have some guidance documents but nothing detailed on VRS or SWP. |
SWP in the UK is partly a misnomer. SQUEP pilots (suitably qualified and experienced persons) know that SWP is a construct which is drilled into anyone who operates machinery over here: (Buses, cars, lawn mowers, planes, boats, helicopters). F = MA.
If you don't have sufficent F in your engine(s) to equal MA, you will crash! Simples. Basic law of physics. There is no need to exagerate or obfuscate over it. VRS, I would suspect is more akin to being discussed in aerodynamics/flying manuals/teaching aids, not a CAP from the regulator. TC is leaving the building.........................shall I switch the lights off now. Are we all done? |
Pst ... is he gone?
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Originally Posted by Rotorbee
(Post 9973929)
Well dear fijodor, how about you doing some research work? Bit lazy aren't we?
Seriously, don't you think I tried? Unfortunately the CAA of UK does not provide this information easily. If you search on the aforementioned site for SWP, it does not find anything and suggests to try "setting wing paper" which makes no sense at all to me and surprisingly does not find anything useful either. Therefore we need somebody who has at least an idea, where the CAA does hide this information or the books latest issue. Satisfied? BTW: Being closer to the UK than to Canada does not mean, that we understand their way of thinking better than yours. The Brits way of thinking is puzzling to the rest of the world. |
Originally Posted by Rotorbee
(Post 9973929)
Well dear fijodor, how about you doing some research work? Bit lazy aren't we?
Seriously, don't you think I tried? Unfortunately the CAA of UK does not provide this information easily. If you search on the aforementioned site for SWP, it does not find anything and suggests to try "setting wing paper" which makes no sense at all to me and surprisingly does not find anything useful either. Therefore we need somebody who has at least an idea, where the CAA does hide this information or the books latest issue. Satisfied? BTW: Being closer to the UK than to Canada does not mean, that we understand their way of thinking better than yours. The Brits way of thinking is puzzling to the rest of the world. So far you seem to be the only one being insulted about it. Little sensitive aren't we? Now you may not have noticed but i did research the subject in Canada and posted what TC had to say about it in this tread and I am thinking that you probably copied and pasted what I put here already instead of researching it.. Again Rotorbee why don't you put some effort in looking up VRS and SWP and telling us what YOUR Aviation Authority in YOUR country has to say about it, unless it is too complicated to get to it. PPRune being an International Aviation forum why not get what other Aviation Authorities have to say about it. So far only Canada and the US has something to say on VRS/SWP (and they are being criticized about it) I thought Canadians were so nice and polite? JD |
Shy - I just got a link to a CAA safety Sense leaflet which mentioned VRS but only briefly.
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But that does provide a link to this
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So far only Canada and the US has something to say on VRS/SWP But seriously... why do people get so het up about the finer distinctions? As a low time heli pilot (but I think I'd feel exactly the same if I had 10,000 hours) I know what I need to: don't go there. Keep your descent rate low when flying slow, and if you're HOGE and don't have the power to hold altitude, get the h*ll out. As for true fully developed VRS - why would anyone ever, ever, ever go there? From what I've read here, it sounds truly terrifying, far worse than a FW spin, which does even have its uses. I wonder for every person who writes a tale of "I started at 10,000 feet, and when I recovered I could count the flies on the cows" how many people didn't recover in time and ended up splatted on the ground? For sure I don't want to find out first hand. So is there more we need to know than Just Don't? (I know it's different for long line and mountain rescue and such, but that's a whole separate speciality. I guess just easing in a bit of forward cyclic isn't such a great idea if the effect is to knock half a dozen people off the roof of the building with the A/C unit you're supposed to be putting there). |
96S, it's because most helicopter pilots are pedantic morons who love to argue over the stupidest of things. Get two helicopter pilots together in a room, and (if you're not one of them) you might come away not knowing exactly *what* colour the sky is - because the other two will argue about it interminably. Ho-lee crap.
"It's cyan!" "It's azure!" It's friggin' BLUE, boys. As I've said...as I've always said...these issues with descending vertically into your own downwash only happen down low at the bottom of a f'ed-up approach. It probably won't matter what technique you use to get out of it, but if you've waited too long to figure it out then it's not going to matter and you're probably going to crash the ship. The stupidest of the stupid are the ones who claim that you can, in your heavy helicopter, make a fast approach, do a big flare at the bottom, then fall through and hit the ground hard and then call it SWP. Oh. My. God. But yet there they are. There is an infamous video of a U.S. Navy CH-46 doing a very shallow, very fast approach to the aft landing pad of some helicopter carrier/boat/ship. The pilot misjudges things a bit and gets one wheel stuck in the fencing just short of the deck. The helicopter stops, but the ship keeps moving forward. Guess what? Before you know it, over she goes! Backwards into the water. And somebody in this very thread called it a "settling with power" accident. Yeah. Uh-huh. Right. You, 96S will find, as you go through your career, that some people who claim to know a lot about how helicopters fly really do not. They'll quote you textbook upon textbook as proof. (There are even those who claim that the advancing blade of a rotor in forward flight flaps *up*! Amazing. But that's a different subject.) Everybody is an expert on the internet! Am I? Pfft, hell no. But I do know not to come in vertically (or even below ETL). On a no-wind day. In a heavy helicopter. |
The stupidest of the stupid are the ones who claim that you can, in your heavy helicopter, make a fast approach, do a big flare at the bottom, then fall through and hit the ground hard and then call it SWP. Oh. My. God. But yet there they are. I agree that CH46 isn't SWP, it is just a punchy arrival gone wrong when the wheel gets caught - sadly people died in that one. (There are even those who claim that the advancing blade of a rotor in forward flight flaps *up*! Amazing. But that's a different subject.) Everybody is an expert on the internet! |
Originally Posted by FH1100 Pilot
(Post 9974650)
...these issues with descending vertically into your own downwash only happen down low at the bottom of a f'ed-up approach.
It's more than f... up aproaches that might lead You into that (vrs) |
Shy,
the results of a search depends of a lot of things, search engine, localisation, cockies, browsing history and many more. My search results are certainly different than yours and I can not find anything useful on the CAA site. Robbo Jock, the link is dead for me (server not available) and points to an eurocontrol site for registered users. That would not be the UK CAA then. Fijodor: Sensitive? Not at all. I think it is funny. I just find the wording amazing, as if the author was really annoyed with the rest of world not understanding the difference between VRS and SWP. But I believe, that this is inappropriate for a training manual. Just imagine a class where one student came from the US and uses SWP. For the rest of the class he would be the uninformed one. That's counter-productive in a training environment. Here they call it VRS with a hint that SWP is a synonym. That's what EASA land does. But if you haven't realised by now, I am FAA trained. I am one of the "uniformed" ones, but do understand the difference between VRS and SWP as the Canadians use it. I just don't think that insisting stubbornly on one definition is constructive, when the rest of world sees it (due to practical reasons, not logic) as a synonym. And I believe, this is also the FAA's view. What it boils down to is, that everybody understand the term VRS, no problem there (even the uninformed ones, after all it is in the FAA training manual). What all the fuss is about is, that SWP is either used as the "not enough power left" or as a synonym for VRS. Apart from the Canadians, it looks like no aviation authority uses SWP other than as the synonym. Therefore no official training manual will contain it. To the big dismay of the Canadians and some Brits, this will result in a lot of young pilots trained as half uninformed ones (half wits if you want). Does it matter? I don't think so, as long as they know, what is going on, how to avoid it and how to get out. I personally find the thread highly entertaining. It started on how to get into SWP/VRS and instead of being an aerodynamic or power availability discussion, we can't even agree on the terms to use. Nick Lappos tried it years ago, suggesting that we on PPRuNe just agree on one term - VRS preferably - and move on. Well ... |
But if it makes just one pilot think about hover performance or operating conditions and what he is trying to do with the helicopter and prevents a mishap (or worse) then it makes all the discussion (most of it quite civilised) worthwhile.:ok:
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Sorry about the broken link. After a bit of experimentation, I think the page is generated when clicking through to it, so won't exist for anyone else. Strange way of going about things, but there y'go.
Try this link then scroll down to Vortex Ring (under 2010). It's a UK Aeronautical Information Circular, Pink 020/2010 |
Rotorbee, one thing is for certain, I'm sure my "cockie" is different to yours. But from your last reply I'm not sure if you're uniformed or uninformed. :)
I have no axe to grind either way on this subject (life's too short to get my undies in a bunch about it) which is why I wrote my initial post (#2) on this thread. But my thoughts; how about: The approaching IGE situation. 1: "Under pitching" = not pulling enough power early enough to arrest a high ROD at very low IAS near the ground. 2: SWP= following situation 1, you pull to all the power you've got, too late - you keep on going down! 3: Over pitching = what follows from 2. No more engine power, but you can't stop your left hand from pulling pitch! The OGE situation. 1: Under pitching = as per 1 above, but OGE. 2: SWP / IVRS. As per 2 above, but you don't have the visual cues and the ROD builds. The airflow through the disc begins to recirculate but you could fly away because you still have good cyclic response (Vuichard technique might work here). Call it IVRS if you prefer. 3: Fully developed VRS. Use whatever technique you like to regain some forward speed to stop the recirculation, but you are going to lose a lot of altitude because you no longer have good cyclic response, the aircraft will be pitching and rolling all by itself and your ROD will be higher than you've ever seen before. You can forget all about a recovery in "20 to 30 feet" as I read in an article about the Vuichard technique! Most helicopters are rigged with more pitch control than roll control. We Brits prefer to use forward cyclic, and lots of it. I'm off to work very soon (late shift today) so can't participate further. Obviously, as usual I'll be avoiding situation 1 above so the subject won't crop up in practice. |
I could not agree more, but we have also to think about the common student pilot who does not have (yet) the background needed to understand the fine differences.
We as FIs can not prepare them for every possible situation they will find themselves in. We provide them with a limited set of tools to manage the most common types of problems. We use tons of "Lies to children" in the teaching process, just not to overwhelm the learner. For example: Everybody learns about Bernoulli for their PPL, but this is just part of the equation. But do we want student pilots to solve the Navier-Stokes-Equations? Hell, no! Just conservation of momentum, mass and energy will be too much for many, FI's included. While we all agree that VRS is the right word and SWP should be used in another context, reality is unfortunately different. During the teaching process we can use one tool to get out of both of it. In both cases reaching ETL will solve the problem. If we now use Vuichard (we have thread for that, don't start it, it is just the example closest to it) in on situation where you have enough space to the side to use it and forward stick in a case if not and forward stick in a not enough power situation but only if ... - you probably get my point by now - we probably do more harm then good. Too many "if's" are bad. While I absolutely love the banter here and chip in whenever I can, the really fruitless discussion about who uses the right words does not provide any insight for the newbie. I see no harm in using both terms, as long as everybody knows what we are talking about. Or we just should set SWP on the list of forbidden words. That's a thought. |
http://www.ead.eurocontrol.int/eadba...2010-05-20.pdf
1. UNITED KINGDOM AERONAUTICAL INFORMATION CIRCULAR AIC: P 020/2010 20-MAY-2010 Safety VORTEX RING. NATS Ltd UK Aeronautical Information Service Heathrow House Bath Road Hounslow, Middlesex TW5 9AT 1.1 Introduction The following paragraphs are a reminder to helicopter pilots of the ever present danger and insidious nature of vortex ring. The usual American term for this condition is 'power settling', a description that sums up the potential predicament for the unwary pilot. 2 The Vortex Ring State 2.1 Vortex ring state is a phenomenon that occurs when the main rotor tip vortices are recycled into the induced airflow. This state can exist when the vertical rate of descent is greater than half the air velocity induced by the rotor and is normally experienced at low forward speeds and significant rates of descent. The effect of this is to produce severe instability of the airflow around the rotor disk with subsequent aerodynamic inefficiencies and loss of rotor thrust. 2.2 Many modern helicopters with high disc loading (high induced flow) will require a relatively high rate of descent before the possibility of vortex ring exists and it may be this factor, combined with greater amounts of power generally available today, that has led to a view that modern helicopters do not develop vortex ring. This is not the case and whilst it can be difficult to induce vortex ring deliberately, the possibility of a vortex ring occurrence always exists if the helicopter is operated in the relevant flight conditions. 3 Conditions for Entry 3.1 Vortex ring becomes a possibility when the airspeed is below about 30 kts, with a rate of descent greater than 300 fpm and with power applied. This can be a very unpredictable process so there may be occasions when, operating beyond these conditions, vortex ring is not encountered. However, the greater the time spent within these conditions, the greater is the chance of encountering the problem. The inaccuracy of helicopter airspeed indications at low airspeeds should also be considered and allowed for, particularly when operating out of wind or with a rate of descent. 4 Symptoms 4.1 The symptoms of vortex ring are typically: (a). The Incipient Stage: i. Increased vibration and buffet; ii. The onset of small amplitude 'twitches' in roll and yaw; iii. Longitudinal, lateral and directional instability. (b). The Established Stage: i. A very rapid build up in rate of descent which can exceed 3000 fpm; ii. Reduced effectiveness of cyclic inputs in roll or pitch; and iii. Application of collective pitch having no effect in reducing the rate of descent (possibly increasing it). 4.2 It is possible to pass through the incipient stage very quickly; the warning cues for the pilot may not be obvious. A fully developed vortex ring state may therefore result with very little warning; especially at night, in poor visibility or at high altitude when visual cues are absent. Even when the vortex ring state is fully developed the flight can be very smooth with little or no increase in vibration; the only real clue being the sudden indication of a very high rate of descent. 5 Recovery 5.1 The Incipient Stage 5.1.1 As soon as the incipient stage is recognised, immediate recovery action must be taken. This is best attempted by maintaining the collective position and applying forward cyclic to achieve a nose down attitude, in order to increase airspeed without delay. More power can be applied if required as soon as steadily increasing airspeed is indicated - it is not necessary to wait for the best rate of climb speed. The effectiveness of the incipient stage recovery must be carefully monitored and more positive action taken, as described below, if any signs of slow recovery or established vortex ring become apparent. 5.2 The Established Stage 5.2.1 In order to recover from established vortex ring, the flow state around the rotor must be changed in some way. Application of forward cyclic should increase airspeed but it must be borne in mind that a large amount of cyclic may be required and held for several seconds before a significant pitch attitude and speed change is achieved. It may be necessary to reach a large nose down attitude to obtain positive airspeed. Lowering the collective to reduce power towards auto-rotation is also effective, but forward airspeed must be gained before power is reapplied during recovery. Both methods will result in an inevitably large height loss. The best technique for recovery is to combine both actions positively, then reapply power when steadily increasing airspeed indications are regained. It is not necessary to wait for best rate of climb speed before adding power. 6 Applicability 6.1 All helicopters are susceptible to vortex ring and all helicopters suffer from unreliable airspeed indications when operating below about 30 kts. Flight at low airspeeds, particularly with poor visual cues, must be treated with caution because it only requires a relatively small increase in the rate of descent for there to be a significant probability of vortex ring development. 6.2 Vortex ring can occur at any height above the ground cushion. 6.3 At typical helicopter operating heights, particularly during photographic and surveillance tasks or during steep or vertical approaches, the conditions referred to in paragraph 3 must be avoided since lack of height will make recovery from the condition uncertain. Pilots should therefore always maintain airspeed when turning or descending in high wind conditions. Pilots should therefore always maintain airspeed when turning or descending and especially when downwind in high wind conditions http://www.ead.eurocontrol.int/eadba...2010-05-20.pdf |
From the Chief Instructor - Robinson Helicopters.
“Settling With Power” In the U.S., there seems to be a great deal of confusion on whether the vortex ring state should be properly or improperly referred to as “settling with power.” The controversy stems from a condition completely different from the vortex ring state, in which engine power required exceeds engine power available. Over the years, various aviation organizations have used conflicting terminology in discussing these very different conditions. In the 1950s, the U.S. Navy referred to the vortex ring state as “power settling” and used the term “settling with power” for the power-available-vs.-power-required situation. Not wanting to let the Navy set the standard, the U.S. Army reversed the terminology in the 1960s. Army pilots in Vietnam used the term “settling with power” to refer to the vortex ring state and “power settling” when they were trying to get out of a tight landing zone with too many troops onboard. The FAA uses “settling with power” in its discussion of vortex ring state in both the Rotorcraft Flying Handbook and the Practical Test Standards (probably because there are more former Army pilots in the FAA than former Navy pilots). Outside the U.S., the picture is much clearer; for the most part, the term used is “vortex ring state.” I say, let’s call it what it is—the “vortex ring state,” not some vague term that has different meanings to different pilots.—Tim Tucker Unfortunately he then spoils it all by supporting the Vuichard technique. |
TC your UK source is simply wrong.
The usual American term for this condition is 'power settling', a description that sums up the potential predicament for the unwary pilot. Mr Tucker provided a nice summary, however to correct his little anecdote, since I was trained by the Navy (and Marines) in the early 80's, by the early 1980's the Navy was teaching the same terms that Mr Tucker attributes to the Army. Not wanting to let the Navy set the standard, the U.S. Army reversed the terminology in the 1960s. Army pilots in Vietnam used the term “settling with power” to refer to the vortex ring state and “power settling” when they were trying to get out of a tight landing zone with too many troops onboard. The FAA uses “settling with power” in its discussion of vortex ring state in both the Rotorcraft Flying Handbook and the Practical Test Standards (probably because there are more former Army pilots in the FAA than former Navy pilots). For example: 2. Do not let the helicopter hover on the glide slope prior to the intended point of landing, as the risk of entering the vortex ring state will be greatly increased. a waveoff shall be initiated to avoid the possibility of entering the vortex ring state. See Vortex Ring State, TH-57 NATOPS, Part IV or Chapter 11. NAVAL AIR TRAINING COMMAND NAS CORPUS CHRISTI, TEXAS CNATRA P-457 Rev (01-15) Pages 4-30 and 4-31. The TH-57 NATOPS manual addresses vortex ring state, as does the ground training in basic helicopter aero. You and quite a few others are simply wrong, due to being about 30 years out of date in what you think is true about what someone else teaches. I wish to salute crab, and completely agree that in getting people to think about this, regardless of these bun fights over terms, we hope that rotary wing aviatiors will know the difference and know what to do about:
On that we can all surely agree. |
I agree. There is a similar situation in the fixed wing world, albeit not about the terminology used. The PPL syllabus no longer includes fully developed spinning and recovery, but concentrates on how to avoid spinning in the first place.
That argument has been going on for about thirty years and rumbles on just like this one. |
All throughout flight school as well as with my twelve flight reviews so far, I have never heard the term "power settling"! The only place I have ever heard that term is on the internet from old military pilots.
As for the condition of "power required exceeding power available", that is brought up during the SFAR 73 discussion of rotor decay, low-rpm rotor stall, low-rpm recovery, and power management, but has no name for itself. |
To the big dismay of the Canadians and some Brits, this will result in a lot of young pilots trained as half uninformed ones (half wits if you want). But just for you I will inform Transport Canada that they could be responsible for the stupefying of future generations of pilots by using words (actually, just one) not appropriate to certain persons (actually, just one) and defining certain conditions (VRS, SWP) that do not fit certain individuals. Rotorbe, just keep flying circuits around the airport and be careful not to hurt yourself. JD |
How about this for a univeral term that everyone can enjoy?
"Too Heavy To Hover" Its even fun to say, "Oh' ****, we're about to TOOTOO! :ok: |
Butters
All throughout flight school as well as with my twelve flight reviews so far, I have never heard the term "power settling"! The only place I have ever heard that term is on the internet from old military pilots. As for the condition of "power required exceeding power available", that is brought up during the SFAR 73 discussion of rotor decay, low-rpm rotor stall, low-rpm recovery, and power management, but has no name for itself. |
My dear Fijdor I am so sorry, that I have offended you. I can not deny the fact, that English is not my mother tongue. You should hear me speak, my accent is truly horrible. In all the three languages I have to deal with day in day out, I have an accent. Even in German. My French teachers gave up on me early and then I married a francophone woman. Imagine what she has to endure.
What makes you think I don't like the Canadians or the Brits? I do apologise, if I hurt you, while it was meant as a mere joke. A bad one probably. Sorry about that, but that happens when one is not capable of mastering a single language. I do not like a word? Sorry to hear that, but I think you got that wrong. SWP or VRS, I don't care, as long as I know what we are all talking about. I like the TOOTOO. That goes perfectly with big eyes and a light panic. While I do like a nice educational flight around the circuit, I cherish more the time I had in the bush, despite having realised not being on the top of the food chain. It is a revelation that all the racket one does, the common grizzly sees you as tinned food. I am all for the silent helicopter, at least then bears don't react like children to the bell of an ice cream truck. Lately I have discovered that aerobatics is my thing. My stomach tends to disagree and any selfie would require quite a bit of photoshopping to get the face colours partly human. But my instructor says this will get better with time ... with most pilots ... not always ... I might be a rare exception. Despite that, I do understand that you are well beyond my experience level and I can not apologise enough, if I have offended you with my presence on PPRuNe. You know, Fijdor, in the future, you might want just to ignore my posts. The time you loose while reading my sorry attempts of explaining my thinking, you will not get back. But allow me to read your posts. I find them most interesting. Since this will be the last post you read from me, I wish you all the best and a the most satisfying time for the rest of your career. |
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