A different take on Vuichard
 

So, normally whenever an instructor and I have done VRS recovery (both techniques) its always been at like 2,000' agl. Well recently, an instructor had me do it at 100'.

Now (of course) we didn't actually enter VRS at just 100', but he did have me do the side step recovery maneuver at that altitude while on a decently fast approach, saying that (in reality) that's more likely where this technique shines, as (of course) 100' is waaaay to low for the traditional one.

Anyway, it was a lot of fun, and I'm glad I finally got to experience a more practical way to practice this maneuver.:cool:

That would be a firm no thanks from me.

Instructing VRS, one thing I learnt is how unpredictable it is sometimes you couldn’t find it sometime you flirt with it and other times you got a hell of a ride.

I wouldn’t be messing with the incipient states at that height lest they become fully developed.

In my opinion VRS is quiet easily avoided and recovery is chasing the horse after it’s bolted.

So the Vuichard myth is still being taught.......and believed......

Is it a myth? I understood it was a valid technique, although not one which the CAA allow to be taught.

Surely this is a couple of days early for April Fool’s? Or is it Darwinism in waiting?

here is the previous discussion

https://www.pprune.org/rotorheads/62...ard-again.html

Hargreaves99 - it is a valid technique only as far as getting away from IVRS is concerned and is no more efficient or effective than either just pulling power or just putting the nose forward a bit to gain speed.

If you remove either the low speed or RoD from the VRS equation then you won't go from IVRS to VRS and any sensible action is likely to achieve that.

Vuichard's 'technique' takes the RoD out by pulling max power - the rest of the manoeuvre , rolling and yawing isn't necessary.

It works for early IVRS only and will not save you from full VRS.

That's why the CAA think it shouldn't be taught.

So on a decently fast approach you are nowhere IVRS or VRS - what, pray tell, is the point in the sidestep manoeuvre?

Did he pull max power and then add a boot-full of pedal? What did the Tqmeter say (or MAP gauge indicate).

My experience is that the 'add full power" -part of the sideways exit method is not necessary for the exit of VRS. It's there to have all the power in use at the moment the rotor exits the VRS. The exit itself can be accomplished with SOME power applied. I guess that different helicopters react quite differently to VRS, the R44 beeing quite stabel in 1500-2000 ft/min descend where adding max power even for extended period of time does not help. The R44 stays responsive to the cyclic and, here my experience ends, would probably come out of VRS with any long term cyclic input even regardless of collective position. With other helicopters your milage may vary, especially if the cyclic authority is compromised.

Interesting reactions. Some of you think we entered VRS at that height, some of you don't see the point of demonstrating without entering VRS, and some of you don't believe the maneuver is even legit, lol.

Anyway, the instructor was one of these old guys, who's been flying/teaching for years, if that makes any difference, lol.

So am I and I see no point in pretending to be in IVRS to show a fairly basic manoeuvre to get you out of IVRS

In my humble opinion i dont think Claude has ever been in VRS ! Having been there once I can assure you adding power to step out made it worse not better !!!!

So, I guess you feel the same way about, pretending to be in IIMC, just to show a fairly basic maneuver to get out, or pretending to have partial power loss, to show the fairly basic maneuver to get down with it, or pretending to have a 100' foot obstacle in front of you, to show the fairly basic maneuver to get over it?
:ok:

Or pretending to be a professional helicopter pilot just to create arguments on a website..............

And as it happens, in those three situations you are putting the aircraft at the height and speed of the scenario you are simulating - your Vuichard demo had the height but not the speed so please tell me what you learned from it.

Well, given that the most likely scenario for getting into VRS on approach when you think your airspeed is sufficient, is because you're in a tailwind, doing this simulation with a good amount of forward speed was correct for that type of situation.

Anyway, I learned what it would look like to perform that maneuver at low altitude with forward motion, intead of the usual OGE hover at 2,000' agl.

Sorry if this offends your sensibilities, pal, but I haven't done anything new in a helicopter in a very long time, so it was a nice break in the monotony.

I would not say it's a different take on Vuichard, it's more so the reverse. For instance, when longlining and moving your bucket into a dip site, if you feel any early stages of onset coming in, your natural reaction is to move the aircraft sideways. You have your head out of the door and that it the natural way to go - sideways. It's probably been used ever since we started lifting things on lines with our heads out the door.

Whether you believe in the Vuichard technique or not, learn how not to get in the situation and learn to identify the early stages of onset. It is good that you got exposure at a low height.

There is a video around somewhere of an incident where a Md900 fell off the top of a building in the Gold Coast in Australia whilst lifting air conditioning parts and got into VRS. The pilot used the side slip technique to gain control at the bottom of the 'fall'. He was/is a high time longline pilot from NZ/BC and would have no idea who Vuichard is, let alone how to spell it.

Don't quote me on this, but I've been under the impression that the idea of this Vuichard thing was to adapt the long-line technique for those of us who don't do long-lining.

Anyway, until this recent experience I'd never seen a practical reason for this technique, since I never really spend any time in the OGE hover environment.

Now I never claimed to be the sharpest knife in the drawer but I always wondered about this accelerate forward to escape from IVRS/VRS as I was led to believe it was caused by descending into. a descending column of air caused usually be being slightly downwind and that pulling power only added to that problem.

Last time I checked most helicopters (smaller lighter aircraft as compared to the strongly powered behemoths that according to some can use power alone to escape....lowering the nose to accelerate gives a negative effective for ROC and demands more power which would add to the downward velocity of the air column.

The goal is to get out of the downward flow of air....and it seems intuitively obvious that the shortest direction to do that would be to either side rather than forward as in my mind the shape of that downward moving column of air is not going to be circular but rather more of an elliptical shape (longer fore and aft and narrower side to side).

Also...a turn into wind rather than extending your down wind approach with a higher ground speed close to the ground has undone many a helicopter and pilot.

I suppose the nice folks at the CAA don't care much for teaching Tail Rotor Emergency procedures using rotor rpm and collective when the pedals are not working as advertised either.

Does it matter what labels are affixed to the situation or recovery techniques or can we just talk about the effect of flight controls and applications of power, etc and not get hung up on the labels?

I can almost hear the near Gregorian Chant of Vulchard, Vulchard, .....GO!

The thing about pushing forward to get out of VRS, is that we're always practicing it with a vertical fall from an OGE hover, where pushing forward does move you clear.

In reality though, it'd probably be more like that video they show at the Robby Course where the R44 is on a downwind approach to a rooftop, gets into VRS, hits hard, slides across the roof, then gets dynamic rollover and falls to his death.

He had forward movement, so probably didn't realize he was in it until too low, but thing is, with his already forward momentum, would pushing the nose forward even get him out of VRS?

Seems no one ever talks about this when it comes to the "traditional" recovery technique.

Doesn't anybody fly an approach by maintaining an apparent walking pace over your toes? Positive forward motion (visually over toes and IAS), controlled rate of descent, aim point steady in the window. From 300' and 60kt, the decreasing airspeed makes the walking pace looks constant all the way to the hover where you have a REAL walking pace.

A downwind approach will have groundspeed apparently higher than indicated airspeed, something which should be detected well before losing translational lift. But people still fall out of the sky, and run out of left pedal, and do silly stuff. Like "Pretend" VRS at 100', and practising bleeding.

You are confusing groundspeed with airspeed chum. If you fly a downwind approach without realising it (unless the wind is very light and variable) you shouldn't be in the cockpit. If you know you are downwind you take extra care to avoid letting a high RoD develop.

Prevention is always better than cure.

That is a horrible accident Robbie. The pilot made a bad decision to continue for the rooftop, when they had space and height ahead to recover. The commital point was much much later than than the clear acceleration into VRS. The aircraft was also stable in VRS and not pitching, yawing and rolling, so really good conditions to recover.

Having reached the roof, the pilot slid long from one side to the other and then hit a small barrier tipping the aircraft over the edge and death. It seemed to me that the pilot and pax could still have survived the initial bad decision to go for the roof if:

1) they had lowered the collective progressively and promptly and got the weight square down on the roof.

2) running out of roof, lift the collective and hop over the barrier, at which point they would already have been out of VRS because there was no sink rate - but possibly out of the performance envelope, so it might have happened again…

It was a pinnacle approach SE. If the pilot had recce’d and done a power check they might have realised that the approach was a NO GO.

And was there any performance planning pre-flight? I’d hazard not.

I’ve said it before - he’s a travelling snake oil salesman

The Vuichard video I have seen shows the aircraft in a stable state sinking through in its vortices. Lovely and stable, apart from the increasing ROD. But as you say, the aircraft can be all over the shop and it seems to me that the idea of an effective controlled cyclic sidestep and effective yaw input in that condition is a little fanciful.

And as one of the biggest risk factors is running out of power to control the accelerating sink rate, overpitching followed by proper ugly VRS renders the idea of adding of collective somewhat redundant. It is surely a way to get yourself killed in an aircraft that is at its performance limit or beyond.

One problem with discussing IVRS and recovery techniques is that the incipient stage is very variable and not binary - you can go from having the right figures on the dials to believe you are at the onset of IVRS, where pretty much any recovery works, to being much deeper into the void where application of power takes you from IVRS to VRS very quickly (as Hughes 500 alludes to).

The Vuichard 'technique' works at the very early stage simply because doing pretty much anything would remove you from the parameters of IVRS - he has just made a song and dance out of it.

Exactly! A FW analogy would be to say that the way to recover from a spin is to add some power and lower the nose.

You seem to be assuming the pilot knew he was in VRS. He may not have, hence the decision to "continue yo the rooftop".

Anyway, the flight was intentionally flown downwind to get the required angle for the photo shoot, so I'm guessing they did their performance calculations.

Thing is though, Robby pilots are generally only shown VRS recovery from an OGE hover, so we don't know what it looks like when we have forward movement, thus the pilot may not have even realized it, until the very end when he went to pull power to land.

The aircraft was next to a building. We see the acceleration in the video, taken at some distance and from above. I find it a stretch that the pilot was unaware that they were in a downward acceleration. In fact, I’d guess that the collective was pulled to check the acceleration and the low RRPM alarm went off. Then the pilot went for the roof to land asap. Not a good decision or IVRS response and pretty much locking in a bleak outcome.

Lot’s of supposition? Yes. But there is plenty of evidence to support that take
in the video, and you say it was a downwind approach. If that is true, then going for the rooftop with a big sink rate was extremely dangerous and perhaps indicative of poor training and certainly poor airmanship. Not trying to be down on the pilot, but they did also kill their passengers.

Perhaps the pilot did performance planning for that shoot and found… what?
WAT chart - check
HOGE power - I sincerely doubt it.

And without the latter, the approach should not have been attempted downwind.

Maybe it is also useful to separate out utility versus other kinds of flying. Moving out of the vortices sideways may be a trick that is up any low level utility pilot’s bag of tricks to catch IVRS. But I doubt it has much application for public transport. And may be a method that invites false confidence and risk-taking by hour-building photoshoots.

If the pilot really was unaware of the high sink rate, then they really should not have been doing what they were doing.

And when it started to go South, just follow the training: lower the collective a little and attitude at the horizon until airspeed is indicated.The escape route forward seemed fine.


Did IVRS in the sim for the first time in many years a while back. The TRE wanted to see more airspeed before recovery, but I saw 35 knots and that was good enough for me. It took several seconds. But surely that’s the point? See it developing and fix it. Apply the basic training and don‘t impede what should be an intuitive response.

As you no doubt know, training for VRS is done into wind on light or no wind days. Doing it downwind with a fair wind component is a different matter altogether. And may result in aircraft and occupants in a smelly heap.

The pilot was on a photo shoot with pax, so its not unreasonable to think that he just got distracted and didn't notice his increasing rate of decent. I mean sure, its easily evident from our perspective watching the video, but from his point of view,...?

Aa for false confidence promoting risk taking? Lol, we already have plenty of that with all these VFR jobs in VFR only helicopters requiring an instrument rating.

As I said, he was next to a building - a nice lateral reference, had a variometer - on which the eyes needed to be scanning IN, together with remaining power in hand.

At the end of the day, the pilot got into IVRS and responded badly. And everyone died. I think it is a fair critique to say an avoidable event was caused by poor procedures and decision-making. The pilot was just another passenger along for the ride.

And most importantly for this thread: Vuichard would not have helped this pilot one bit.

I thought this practice ended in the late 90's. I have NEVER taught VRS from a hover. I always do a traffic pattern with a simulated floor of 1500' and on final tell the pilot to just pull the nose up to a decell and hold it, nothing else.

Never heard of this way.

I got my PPL in 2003, and CPL in 2006, and throughout my training, insurance/rental checks, subsequent BFRs and six trips to the Robby Course, these past twenty some odd years, its always been done from a HOGE at around 2,000'.

Wouldn't mind trying your method though.

Gordy makes an interesting point.....as probably it is far more likely to encounter this horrid life threatening aerodynamic situation during a landing approach of some kind where the descending column of air catches up to the helicopter and begins to move forward of it.

At which point the floor falls out from under you and down you go.

It can happen while hovering OGE as well.

How many ways is there to encounter it....count them best you can.

How about hovering IGE on a pinnacle and drift too close to the down wind side....might that be a way?

Mustering.....might also provide some opportunities for it to kick off.

I taught it much like Gordy....but put the aircraft into a known downwind situation at 3,000 feet AGL and then asked the Student to do as Gordy described except I asked for the victim to achieve a OGE hover as best possible on the desired heading (down wind) and indicated altitude.

Nature, the laws of aerodyamics and gravity took care of the rest.

Sorry....but no undies got soiled doing these maneuvers as sometimes it was very tame and others not so tame but the concern was more of realizing the controls did not have their full normal authority although they were still working in normal sense but not as one is used to them doing.

One thing I did sense is that fully lowering the collective in a accelerating attitude (pitched down a bit) added stability to the rotor system.

In helicopter flying I am of the opinion there is more than one right answer sometimes and that is always contingent to the many different variations of conditions affecting the situation.

For instance, that is why in Test Flying....achieving the data points as set forth on the Test Card often take many repetitive attempts to get all of them accomplished in a satisfactory manner.

I’ve not seen the R44 crash video that many have discussed on this thread. However, I’m not so sure that many of the so called ‘Vortex Ring’ crash videos are actually Vortex Ring at all.

I was always taught that Vortex Ring was a combination of Root Stall on the inner portion of the disc and loss of lift on the outboard portion of the disc due to increased induced flow caused by the vortex. As Rate of Descent increases into fully developed Vortex Ring State, the stalled portion and the vortex section have expanded laterally, potentially to meet each other, rendering the rotor system ineffective at producing lift and hence control. Please feel free to correct me if I’ve got this wrong!

My reasoning is that if a Rotor disc, or more accurately a rotor blade, is experiencing Vortex Ring State, it is effectively no longer producing lift. If that’s the case, the coning angle would surely reduce? Most of the crash videos I’ve seen that are passed off as Vortex Ring State actually show an increase in coning angle, often just before impact. More a case of HTG (as a result of poor energy management and over-pitching) than VRS in my opinion.

I’d be interested to see the R44 video discussed earlier if anyone can point me to a link.

JJ

JJ,

that video is very elusive! If Robbie has a copy it would be great to post it in the thread. I have also seen it whilst doing the Robinson factory safety course.

It really would be a good basis for this discussion on IVRS/VRS and Vichaurd. I can‘t see how it could be used without making the situation worse. A snake oil test perhaps?

This has been discussed many times before, and yes, an awful lot of accidents that people/reports say are VRS are in fact overpitching, or simply the aircraft running out of power (too heavy, downwind etc)

Sadly, the only place I've ever seen that video is at the Robby Course (been there six times), and (even sadder) since they've doubled the price of that course I doubt I'll ever see it again,...unless you've got $1,500 bucks I can have, lol.

Only the middle section is producing lift but you make a good point about the coning angle, I hadn't really considered it with regard to VRS.

I certainly agree about the cause of many accidents not being VRS - underpowered helicopters are far more likely to run out of puff trying to manoeuvre in and around HOGE and end up overpitching as a result.

Granted, the end game in each case is usually a broken helicopter.

Exactly, when doing buckets on a 100’ line into the dip sites on cloudy days, you are on the edge of it all the way in the latter portions of the approach. I need pilots to recognize the incipient nature and make a cyclic adjustment without losing more than 20’ of altitude. It can be done, we sit right on the edge in training and go in and out of the start of it multiple times on one training event.