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Settling with Power
Where the hell in Texas are you????
We drink beer!
El Paso,
Republic of Texas
I'm over in the humid side and beer's not always a good option when you fly for a livin.
UH-60Pilot - 9/16/2010 5:19 AM


"Vertical or Near Vertical Descent Between 200 and 300FPM, Using 20% to 100% of Available Power, With Insufficient Power to Arrest Sink Rate"

Where does insufficient power to arrest sink rate come from? Once in SWP or VRS the more power you apply the worse the situation becomes. Saying "insufficient power to arrest sink rate" seems to imply that if you had some more horse power you could get out of it by pulling more collective. I agree that early recognition is key but the proper response is to reduce collective if

Mark, could it be read like: "200FPM and not yet VRS, then power could slow you to 195FPM and you don't enter --- where over 300FPM you're toast"?

BTW,... this is the best thread on SWP/VRS I've ever read and I'm starting to feel like "... I almost really "get-it" now!!! Like VRS blows a hole in the sky that you fall through. and adding power makes the hole bigger and deeper!

No, it doesn't really work the way I think you are implying. The 200-300 fpm rate of decent is an all inclusive, one size fits all, cover every type of helicopter and atmospheric condition figure. SWP/VRS is one of those things that needs to have all the conditions met in order to get it to start. If you Keep your approach speed above ETL and into the wind all the way until you are in ground effect you can really descend as fast as you want to and never get into it. The best way to illustrate it is to have a plane try to make a downwind landing just above their stall speed and watch them fall through when they flare. Now, you probably won't get anyone to demonstrate that for you because they will probably crash and it's the same way with a helicopter. You should be keeping your airspeed up any way on approaches to stay out of the dead man's curve. If you just keep that air speed up on approaches you will be fine and will never encounter SWP. The idea is that when ever you are descending keep the rotor in clean air so that it doesn't fall through and try to recirculate it's own downwash.
UH-60Pilot - 9/16/2010 5:25 PM
I have never been in SWP and I have never had it demonstarted to me. The best way to deal with SWP is to know how to never get into it. I don't think there is much to be gained by practicing getting into SWP ...
Mark, on my 6th hour of training, with my 4th instructor, in Hawaii, R22, we did two or three SWP's. I agree with your point. But there is something really good that came from it - for me anyway -... that is, ... it's something you will NEVER forget, and something I've been wondering more and more about to this day, years later, and for some people who can't survive by rote alone, maybe it's a good thing?

Now I have to ask.... can I vertical at 100FPM????

BTW, Mark, thanks so much for the information and help!!! I'm old and crazy doing the best I can.
Pfranc - 9/23/2010 6:01 AM

UH-60Pilot - 9/16/2010 5:25 PM
I have never been in SWP and I have never had it demonstarted to me. The best way to deal with SWP is to know how to never get into it. I don't think there is much to be gained by practicing getting into SWP ...

Mark, I would take issue about not practicing SWP. Like practicing stall/spin entries in aeroplanes; they may be scary and dangerous, but a pilot needs to recognise the situation, and how to get out of it. And it can be practiced at altitude, unlike touchdown autos.
I certainly taught it, as a heli instructor, after convincing a nervous CASA examiner that I had been checked out by Robinson instructors.
Some years ago, the Australian Army lost a BlackHawk in an exercise where a pilot executed a turning, downwind quickstop, hit the ship he was intending to insert troops onto crashed into the sea and disappeared. SWP.
And even after that we had brigadiers and wing commanders harrumphing that a 'Hawk had so much power that the situation could not arise. Back to the flight line boys! They'll all do it.

Hi Rob1 .... I think Mark was talking the lone new Mosquito pilot in one seat trying this on his own without instruction... He said: "...but I don't really think it's a great idea for a pilot to go out in Mosquito and get into SWP to learn SWP recovery all on their own...."

Really good advice for someone like me with only 10 hours dual and 22 hrs in Mosquito all alone not knowing what the heck I'm doing!
Rob Hall,

Yes, you are right but within the context of the Mosquito community I would not recommend a low time pilot go out and try to get himself into SWP and try to get out of it. I would recommend the pilot practice autorotations long before SWP. In the auto the pilot need only wrap the throttle back on if it’s not going well. In SWP if they don’t successfully get out of it, they will crash and may even induce low G mast bump in the process of trying to fight their way out of it. I'm all about them doing it with an instructor in another helicopter so they can get exposure to it and learn how to get out of it. I don't think recommending full down autos and getting into SWP is a very responsible thing to do in the Mosquito community. It can be done by all but at great risk to the pilot, machine and in the broader context we need to mitigate Mosquito crashes as it seems most of them are pilot induced anyway. I'm just looking at what we would gain by advocating these guys go out and self induce these emergency procedures vice what we stand to lose. It's just a conservative approach. It's the way I have always instructed. I would never actually pull an engine off line unless I was assured I could get it on the ground or fly away. Any other time, I would announce simulated engine failure and just limit the amount of torque the pilot could pull by guarding the collective successfully simulating the reduction in power but not actually taking away the contingency power in case the reaction was not correct.

As for the Aussie Blackhawk that got into settling with power near the ship, I would say that you never do agile maneuvering around a ship. The relatives (turbulent winds) that come from the superstructures of the ship are known to destroy lift on the downwind side. I doubt that the Hawk actually got into SWP in the sense of being in VRS but rather from being in down drafting turbulent air behind the line of demarcation. I don’t know all the particulars of that situation but right off the bat it sounds like the pilot broke some of the fundamental safety rules of flying. Once again a perfect example of someone getting themselves into a bad situation. This implies to our audience here that SWP can sneak up on you at any point and BAM!... you are now in full fledged VRS, but it just doesn't happen that way.

When I was flying the Hawk in the Army I did a lot of ship landings and instructed/qualified many pilots in proper deck landing procedures and doing a downwind, turning quick stop approach is begging for trouble. In the turbulence behind the superstructures especially when the ship is underway is not a place to be playing around. That's why the deck approach is at a higher angle and the helicopter is slowed to match the speed of the ship about 400 meters out and then the final phase of the approach is at a creep so that the helicopter is at a slow rate of decent therefore keeping it out of the parameters for SWP. The same thing could happen to a Mosquito landing to a ridgeline. If the pilot got behind the line of demarcation and into downdraft it is effectively the same thing as SWP but not due to VRS and the emergency procedure may not be helped by lowering the collective at this point. Once again the best way to deal with SWP is to really understand it and know how to avoid it. In my opinion and in the context of our audience here I would leave SWP/VRS as a discussion. I don't think we have had a Mosquito crash due to SWP and I think we have bigger fish to fry in terms of emergency procedures.
Totally agree Mark. None of these maneauvres should be practiced without appropriate training. I would not advocate otherwise.
I'm sure many of you probably pooh-pooh flight sims since you can just go out and fly your Mosquito, but I've been able to get some experience with SWP/VRS and loss of translational lift in X-Plane. I'm getting better at not provoking it, and each encounter is a surprising reminder of how quickly you can go from "descending" to "falling" and how it feels to have to fight intuition in that situation. I've been very pleased with how well X-Plane simulates the effects I've read about in books.

-- Dan

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