Vuichard technique for settling with power?

[Thomas coupling]

Going back to the OP who begins with a quote for a techinque to address settling with power:

Another recovery technique is called the Vuichard Recovery Technique: initiate the recovery by increasing the collective to takeoff power, then simultaneously applying power pedal to maintain heading and opposite cyclic (15-20 degree bank) cross controls to get lateral movement. As soon as the rotor disc reaches the upwind part of the vortex the recovery is completed. Average loss of altitude during the recovery is 20-50 ft depending on the duration of the recovery procedure.

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The message that needs to be out there is that IT IS THE WRONG TECHNIQUE for recovering from either IVRS or VRS.
It is bad enough trying to pronounce this guys name never mind trying to remember whether to PULL power or LOWER the lever.
[Although - technically in VERY powerful turbine engined helos - there is a case for removing oneself from VRS using 'application of power'].
In MOST cases, when in VRS, the following is observed:
Vibration.
Sloppy feedback response in the controls.
Pitching, rolling and yawing to some extent.
Blade slapping.

Recovery technique for VRS:
Select smooth (do not "ram") and progressive nose fwd using cyclic to around 20 degrees n/d.
As the a/c departs the turbulent VR, controls become more responsive.
Feed in collective power to minimise height loss. (Usually >8kt fwd speed).

VRS requires most helo's to be in a RoD of around 800 - 2500 feet per minute. Anything greater than this is due to the a/c simply 'falling' out of the sky. In fact, >2500fpm pushes the descending helo out of the VR.

WHILST IN A VRS DO NOT RAISE THE COLLECTIVE -it will aggravate the VRS.

http://www.pprune.org/rotorheads/116...-merged-3.html
refers (post 51+)

Quote from N Lappos:

During VRS, typical modern helicopters retain some cyclic control. The rate of descent will make the horizontal tail try to pitch the nose down, which will help you recover. Reduced collective and nose down will produce a fast exit from VRS. Increased collective will only help if the aircraft has a great deal of excess power, not at all likely in anything but an empty machine with powerful turbine engines.

Note from the data on the web site that VRS is unlikely in a purely vertical descent, some forward speed is needed, maybe 8 knots. In practice, it is difficult to attain and hold VRS, as the condition is unsteady and tends to break of its own if any disturbence is induced. That does not mean it can't do harm, since the first 1000 feet of drop might be several hundred feet too many!

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Please make sure you are 100% certain you know how to avoid VRS in the first instance (IE: Identify IVRS early and recover with N/d and power ).
IF you are unfortunate to find yourself in fully developed VRS (and you have the height beneath you to recover) - select >20 degrees n/d, check down on collective, clear the VR, then and only then pull power.

[[email protected]]

So Monsieur Vuichard, whoever and wherever you may be, it seems your 'technique' has been sent to room 101, never to see the light of day again.

It might have been an interesting idea if it wasn't for the 'apply full power' part which, as TC has highlighted will just make things worse in VRS and, since the definition of SWP is that you don't have any power left, is pointless when dealing with SWP.

Since modern rotor systems with bigger hinge offsets retain control power much better than teetering heads, it is possible that the lateral cyclic might help, but no more than forward cyclic will.

Application of pedal may or may not be effective but not as effective as pushing the nose down.

Short answer - stick to the basics as described by TC and others.

[jymil]

This recovery technique has been proven to be working during official test flights for the Swiss CAA. You can inquire more information from Mr Vuichard directly if you want, his contact data are available in the Swiss CAAs helicopter examiner list:
FOCA - Examiners for pilot examinations


The whole point is: this technique can save lives, e.g. the 4 people which got killed by the CHC crash in 2013. And it is counter-intuitive, because we were all taught pulling collective up during VRS is wrong, as Thomas coupling reiterated. However, it does work because you can get out quickly of the vortex column into undisturbed air left or right of you by applying a 20 degree bank.

[[email protected]]

This recovery technique has been proven to be working during official test flights for the Swiss CAA

Any data to support this? test configuration, aircraft type, AUM, IAS, RoD?

Seems strange that only the Swiss advocate this method or is it wider spread than that?

The CHC crash would not have been avoided using this technique - you have to recognise you are in VRS first. There were a whole lot of other factors which could have prevented it.

[mdovey]

It certainly isn't described in the R44 POH, which I have at home.

The wikipedia article says it is in the (2013 edition) R22\R44 Flight Training Guide (FTG), which is the fifth manual listed at Robinson Helicopter Co.

Whilst, I can find html versions of all the POH's Robinson website (and it isn't in those), there doesn't appear to be a html version of the FTG and I don't have access to a hard copy.

[n5296s]

Seems strange that only the Swiss advocate this method or is it wider spread than that?

Maybe it's because they have a different relationship with the holes in the cheese?

(Sorry, couldn't help it. And thanks for all the contributions to this thread, it's all quite amazing actually - and also the reference to the ancient (by Internet standards) contributions by Nick Lappos et al).

There seem to be a lot of parallels between FDVRS and fully developed fixed-wing spins. They both have a fairly simple aerodynamic explanation, on the face of it. They both behave predictably about 95% of the time, so you're not really prepared for the 20th time when it turns around and bites. And it's only when you get into deeper analysis of exactly what is going on that you realise just how complex the whole thing it is.

From a pilot training pov, there's no reason ever to be in either, just to know what causes it and to recognise the onset so you can NEVER go there. (That said, I've done a lot more spins than I ever intend to do FDVRS, for which my target is zero unless one day I'm lucky enough to fly with one of the handful of people who could safely demonstrate one).

Thanks again for all the quality input and reflection on here...

John

[Peter-RB]

A random Question Not an excuse to Take me out at Dawn.!!

Would VRS and or Ivrs be the fixed wing equivalent of a Full stall ?

Now moved away from the screen, to watch from a safe distance..!

Peter-RB

[FH1100 Pilot]

It's all well and good to talk about theoreticals like how many thousands of feet it takes to recover from FDVRS. But it doesn't really matter. Conditions like VRS and SWP do not typically occur up at altitude where the hapless pilot has plenty of time and altitude to figure out what's happening. No, these things usually happen down low, at the bottom of a mucked-up approach. And then it's over pretty quickly. BAM! as Emeril Lagasse would say.

Using the Sr. Vuichard's method might work for a VRS encounter (although I personally have not yet tried it). But what would happen if you were just running out of power to stop an increasing rate of descent? You feed in a bunch of right cyclic and push the left pedal...and...you hit the ground sideways.

Remember, there's not a lot of time to sort things out. Either way, it'll probably be over before you know it.

Then there's the feelings of panic, denial and the resultant "this can't be happening" inaction. Even just a couple of seconds of that can mean the difference between saving the day and crashing. Oh, we all like to think we're some magic combination of the Chucks: Yeager and Aaron, but sadly we pilots can sometimes be very, very human. I know I can. And my name ain't Chuck.

And anyway, why are we even discussing this? Are helicopters still crashing due to VRS?

[jymil]

Any data to support this? test configuration, aircraft type, AUM, IAS, RoD?

Aircraft was an AS350, that's all I know. But again: feel free to contact Mr Vuichard directly yourself, I'm pretty sure he can give you all those details.

The CHC crash would not have been avoided using this technique - you have to recognise you are in VRS first. There were a whole lot of other factors which could have prevented it.

Sure, this is all speculation at the end. But from what I read, it kind of fits the scenario in my opinion:

There was then a second automated call of "check height" followed by a "100 feet" automated call. The report stated: "At some point the commander saw the sea, but he was unable to arrest the helicopter's descent and it struck the water shortly thereafter.

So the pilots didn't have much altitude left, certainly not enough for doing a standard vortex recovery.

[Thomas coupling]

Why should Britain tremble..............................................

[busdriver02]

Well between TC's rather definitive response, FH's astute point about altitude and rolling the aircraft while crashing, and I totally missed the increase in collective part of the original post; I'm done exploring this on an academic level. It was fun gents, thanks for letting me play.

[dammyneckhurts]

I have spent most of my 11,000 ish hours looking down a longline, flying in the mountains in Western Canada. In my world we work upwind, downwind, uphill, downhill and nasty combinations of downwind and downhill. We work in a "Production based" environment and we get very accustomed to working in conditions that are conducive VRS.

When VRS happens close to the ground it's usually immediately following a power increase and the first thing you will feel is that you ass gets lighter in the seat. You will feel lightness in the seat way before you feel rotor vibration or sloppiness in the controls. Usually when you add power your ass gets heavier in the seat... if you pull the collective and you get lighter you need to take corrective action immediately.

[MightyGem]

The last thing one would want to do during VRS is to pull FULL collective power."

Obviously not for "normal" helicopters, but can't those with excessive amounts of power(an unladen UH60, for example), power themselves out of VR?

[ShyTorque]

MG, I wouldn't rely on trying to power out of VRS. When I experienced it, albeit in a Puma rather than a Blackhawk, we were just about at max continuous power when the aircraft entered (the HP was trying to achieve an OGE hover at high altitude in the dark). The rate of descent was very impressive and we lost a lot of altitude during the event.

Thinking about this, an analogy is having a powerful car at full throttle but having wheel spin and little traction.

[Vertical Freedom]

Bollocks

Tried the Vuichard technique & it's complete bollocks firstly in settling with power (SWP) there is no emergency & recovery is to pull more power (if You have extra) or just pole forward.......end of story If in IVRS or VRS, in my humble opinion; simply pole forward, as the shake/rattle/roll dissipates apply more power to climb away

If it ain't broke...............don't try & fix it!!!

[MightyGem]

MG, I wouldn't rely on trying to power out of VRS.

I wouldn't, but I'm pretty sure that Nick Lappos mentioned it in one of his posts on the subject.

[jymil]

can't those with excessive amounts of power(an unladen UH60, for example), power themselves out of VR?

No, because power is actually a factor causing the problem. In the vortex ring state, the helicopter is trapped in a recirulation of its own wake. The more power you apply, the faster the recirulation goes and the faster you sink.

However, the point many people seem to miss here is that the vortex ring does not only consist of a downdraft, but also an updraft and the core idea of the Vuichard recovery technique is to use the updraft to get out of the vortex as quickly as possible.

It this wouldn't work, then Tim Tucker wouldn't have put it in the Robinson Flight Training guide.

If it ain't broke... don't try & fix it

Well, it is "broke" as long as we see unnecessary VRS accidents happen, the latest just being the Rega A109 crash last month.

[Vertical Freedom]

If it ain't broke... don't try & fix it

Hey jymil

I meant the recovery technique, works no need to reinvent the wheel. If someone is (still) getting into VRS & crashing then they don't understand the causes of entering VRS & blindly bumbling on oblivious It's there flying technique that needs adjustment & not the recovery technique

Happy Happy avoid VRS

[Nigel Osborn]

With older type helicopters with limited max power, in VRS pulling more power did increase the ROD. However when the Wessex 5 came on line, especially at low weights, by pulling max power it would blast its way our of VRS & climb. Do that in a Whirlwind & big trouble!

A few years ago a Puma 330 made a steep slow night descent to a ship & got into VRS. From 500 feet to splash was about 15 seconds & that's with 2 experienced Puma instructors on board! Luckily both survived.

[n5296s]

I flew the R44 again today (a different one, no floats or glass panel). My instructor hadn't heard of the Vuichard technique by name, but when I explained it, he said, "we've just started teaching something very similar". Just using right cyclic to slide out of the VRS, no pedal. We tried it, it certainly works (for incipient VRS, not the fully developed beast) - whether it works faster/better than forward cyclic is hard to say.