PPRuNe Forums - Practice Recovery from VRS lately?

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Practice Recovery from VRS lately?

FWIW, Airbus Helicopters has published a new Safety Information Notice (No. 3463-S-00) that says they do not recommend placing a helicopter into fully developed VRS. Leave that to the simulator.

There is additional information about the “classical” and “Vuichard” recovery techniques.

Got in got out a few times recently with a 407 bucketing a long line, if you want to call that practise.

Not a regime to linger in, except maybe for training purposes. I didn’t find it easy to teach.

I get plenty of practice of trying not to get into it. Yes we know, avoid tailwinds at all costs, but in the real world, sometimes you have to accept a tailwind component to get the job done. There's no substitute for knowing your machine and its nuances but always stay alert and ready for that surprise. I tend to test the decent half way down on approach and start to pull power gradually to avoid a large pull at the bottom. If it doesn't feel right as you close in, you still have the go around option to try another angle or switch drivers.

Quote:

Originally Posted by malabo (Post 10683430)

Not a regime to linger in, except maybe for training purposes.

That's exactly what the AH Safety Information Notice cautions against due to significant increases in dynamic loads on rotor components. According to AH, the resulting stresses were not accounted for in component service lives. That's scary.

I'm curious what Airbus' definition of a "fully developed" VRS is. I doubt very many instructors would let it get all the way to the 6000 fpm descent rate, which would be a fully developed VRS according to the books. The ones I have done were all recovered at the onset of the shutter/increased vibration and a continuously increasing rate of descent despite collective pull. So are they concerned with the increased vibrations that develop at the onset or the actual full blown thing with a 6k fpm drop rate?

Just shows that Airbus is well removed as to what happens in the real world. I am happy to put an aircraft into incipient vortex ring, but not full VRS, been in it once and lucky still to be here. The things I have seen written by people just confirms the lack of understanding of the difference between IVRS and fully developed VRS. Those who think they have been in VRS have been no where close

When I went through my CPLH training in the US it was common practice to go up to 5000 ft + and intentionally bring the aircraft into VRS up to the state where you could watch the sinkrate increase dramatically when slightly adding collective and only little effectiveness on pedals and cyclic left. I never really felt comfortable practicing that manoeuvre as unlike to e.g. a simulated engine failure it just didn‘t feel like having control over the aircraft.
Returning to Europe and converting my FAA license into a European one we only practiced VRS up to the entry stage (vibrations and shaky controls) followed by immediate recovery until positive rate of climb.
When I told the instructor about what we did in the US he looked at me and said:“Well, I guess you‘re lucky you are still here“ followed by a story about bended pitch links as a result of extensive VRS training.
Reading the AH Safety Information Notice

Quote:

the resulting stresses were not accounted for in component service lives

the following question arises. What exactl would cause those resulting stresses?

Quote:

Originally Posted by verticalspin (Post 10683586)

AH doesn't give a definition, and probably due to the fact the SIN covers their entire fleet. However, I think it misleading to classify “fully developed VRS” just by a potentially extreme achievable RoD. The FAA says, "A fully developed vortex ring state is characterized by an unstable condition in which the helicopter experiences uncommanded pitch and roll oscillations, has little or no collective authority, and achieves a descent rate that may approach 6,000 feet per minute (fpm).”

Quote:

Originally Posted by Spunk (Post 10683616)

Quote:

the resulting stresses were not accounted for in component service lives

the following question arises. What exactl would cause those resulting stresses?

I am really surprised to read about your experience. As a TCE, it is always stressed to me by the FAA that we are not to teach by letting it get to a fully-developed state. The principle is early recognition & recovery action. Makes sense - the longer you leave it, the less control response you get, and the more difficult it is to recover.