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-   -   Unusual attitude recovery? (https://www.pprune.org/rotorheads/600332-unusual-attitude-recovery.html)

n5296s 4th Oct 2017 18:33

Unusual attitude recovery?
 
A friend of mine - who is a fixed wing and gyrocopter pilot, but not heli - sent me the following question:

I was wondering, what's the standard procedure to recover from a nose-high attitude in a helicopter (in IMC)? How do you even recognize it (without an AI)? I've googled it briefly and ended up in a hole of contrasting opinions.

So here's my reply:

Honestly I have no idea. I've never practised unusual attitudes in a heli. For sure (in a Robbo) rolling into a knife edge doesn't strike me as a great idea, which is the fixed wing answer. If it was nose-high (not vertical) I guess I'd GENTLY push the cyclic forward, and GENTLY drop the collective, and see what happens.

Someone here must know the "right" answer...

Bravo73 4th Oct 2017 20:08

Before you can answer your question, you need to answer this question: what are you doing in IMC without an AI??!?

Apate 4th Oct 2017 20:19


Originally Posted by Bravo73 (Post 9914406)
Before you can answer your question, you need to answer this question: what are you doing in IMC without an AI??!?

Suicide mission ;)

n5296s 4th Oct 2017 20:54

Well, yeah, I agree with that bit - I should have redacted that bit since he was just kidding there. But my original question remains - if for whatever reason you do find yourselves pointing skywards at 45 or 60 degrees, what do you do to recover?

MightyGem 4th Oct 2017 21:16

Move the cyclic forward to bring the nose down.

Flying Bull 4th Oct 2017 21:28

Well, helicopters don‘t like to fly nose up high anyway....
To get the nose anywhere near the horizon you need to attach horizontal stabilzers to the taiboom, which are upside down airofoils, pushing the tail down to raise the nose....
😜😜😜😜😜😜😜😜

Never flown in IMC without an AI
With modern helicopters, just press the „Maria HELP-button“, the AP will take over with IAS, ALT and HDG 😉

SASless 4th Oct 2017 21:29

Power Setting? AKA....Collective Setting? Vertical Speed?

There are a few factors that bear on the outcome of the situation....AI or no AI.

One can wind up on basic instruments with no surface reference for various reasons....besides pure dumbass.

Flying Bull 4th Oct 2017 21:35


Originally Posted by n5296s (Post 9914461)
Well, yeah, I agree with that bit - I should have redacted that bit since he was just kidding there. But my original question remains - if for whatever reason you do find yourselves pointing skywards at 45 or 60 degrees, what do you do to recover?

The bird will sink, the air catches the horizontal stab - and with nearly no Speed will push the nose down
(even if it is disigned to raise the nose normally)
Reminds me about fun in the Navy...
Was quite cool on the Lynx, flying backwards at higher speeds and then just giving a notch nose down - getting the bird into pointing vertical down 😉

Letsby Avenue 4th Oct 2017 22:01

Wings level, Attitude, Speed, Power (WASP)

FH1100 Pilot 4th Oct 2017 22:03

This is kind of a stupid scenario. Okay, so if you lower the nose, how much do you lower it and how do you know when it's enough? If you're in IMC in a helicopter without an AI you're basically dead. So don't worry about it is what I'm saying. Just freeze the controls.
It'll be over quick anyway.

n5296s 4th Oct 2017 22:24

Please guys, I did already say to ignore the bit about IMC and the AI. I'masking a serious question. In perfect day VFR conditions, you hit wake turbulence (let's say) and suddenly find yourself pointing skywards - as determined by looking out of the window. Now what do you do?

As far as fixed wing goes, when I did my unusual attitude training (VFR), yes, if you're 60 degrees nose up, roll into a knife edge, wait for the nose to drop to near horizontal, roll back out of the knife edge. Works perfectly, in any airplane (doesn't need to be aerobatic although of course to be legal you should only be practising in an aerobatic aircraft). Otherwise you're likely to run out of airspeed. That will resolve itself SOMEHOW, but could well get you into a situation where the recovery is trickier than the above.

Seems to me that a heli will thoroughly dislike that attitude anyway, since the CG will be so far displaced (horizontally) from the centre of lift. So maybe it's a non issue and (if you could figure out how to get there in the first place) it would just sort itself out.

fijdor 4th Oct 2017 23:55

Maybe you are expecting a more complicated answer to your question but it was already answered here and it is a very simple thing to do, just push the the nose forward (cyclic forward) but I would apply a little bit of power at the same time, you don't want to end up in mast bumping, keep the disk loaded in that case.
Depending on the situation, a pedal turn could be an option as well.

JD

Flying Binghi 5th Oct 2017 00:34


Originally Posted by n5296s (Post 9914544)
...In perfect day VFR conditions, you hit wake turbulence (let's say) and suddenly find yourself pointing skywards - as determined by looking out of the window. Now what do you do?...

Do we have forward speed or no ?

In my basic training, after a low run across the paddock, the instructor put the 300 somewhere past 60º and when the speed decayed applied 'rudder' (aka, pedal turn) thus giving a nice 180º turn for the next low run across the paddock. I woulda thought this were part of every heli pilot training?

Couple of years back i had a National Parks chap on board and he pointed out where that Skyhooks singer pranged. I remember thinking of the irony of the sky hook name - no hook that day. Relavence here is there were a lotta comment around pilot circles of possible unusual attitude recovery technics.






.

twinstar_ca 5th Oct 2017 00:35

Interesting video posted on YouTube on Pilot Yellow's channel... He runs a helicopter flight school in BC, Canada. He and another pilot went out in a Cabri and did some flying where the PF could not see outside. He (as the PNF) monitored and kept everything with the spinny side up but is a VERY enlightening video!!!

army_av8r 5th Oct 2017 02:54

As a military pilot, and instrument flight examiner, I suppose I had made some assumptions. Our flight task for inadvertent IMC, and unusual attitudes are very similar. They are obviously very different situations, but one can quickly become the other. The immediate action steps are, in this order... attitude, heading, torque, airspeed, trim(yaw). Attitude, set the aircraft to a level attitude in both pitch and roll. Heading, use your current heading and only induce a turn to avoid known obstacles. Torque, set the torque or power for hover, climb, or cruise (based on conditions/ airspeed). Airspeed, select and maintain an airspeed, if IMC, best endurance is a good starting point (50-80knots depending on type)... and finally Trim, verify the ball is centered. I could have an entire evening conversation on the subject, each type requires specific adjustments based on aircraft performance, but this should be enough to go in the right direction. Airplanes require certain actions to maintain airspeed energy, nose high add power, nose low reduce power. Helicopters don't needed as much focus on that energy except in the most extreme conditions.typically levelling the aircraft and applying hover power will be enough to buy me a few seconds. So, basic aircraft control is at the forefront of this task. I sincerely hope this helps

Lonewolf_50 5th Oct 2017 03:38


Originally Posted by n5296s (Post 9914325)
[I]I was wondering, what's the standard procedure to recover from a nose-high attitude in a helicopter (in IMC)? How do you even recognize it (without an AI)?

What I want you to do is this: buy a life insurance policy for this gent in the amount of about 200,000 pounds/euros/dollars. Pay the premium. You'll collect within a few years. Some people need to be kept away from the controls of aircraft. This is one such, who appears to be unable to help himself. While you are at it, do your family a favor and keep your feet on the ground, and your hands away from flight controls.

In perfect day VFR conditions, you hit wake turbulence (let's say) and suddenly find yourself pointing skywards - as determined by looking out of the window. Now what do you do?
That is the question of a passenger, not a pilot. I was almost joking in the initial response, but when I considered your follow up question, I am less joking and more interested in you living a long and fruitful life.

[email protected] 5th Oct 2017 07:15

If you are VFR and hit enough wake (or other) turbulence to suddenly put you 60 degrees nose up, you have probably overstressed the aircraft (especially something small like R22) and major structural failure is likely.

A sudden snap to 60 degrees nose up from cruise speed is about a 4 to 5g pull, perhaps more.

And, in a teetering head helo, your natural reaction will be to push forwards with the cyclic, probably inducing mast bumping as the g reduces and the probability of MR to tail boom contact.

If your chum actually wants to know how to do wingovers and pedal turns in a helicopter, that is a different conversation.

Flying Bull - with you on having fun in the Lynx:ok:

Ascend Charlie 5th Oct 2017 07:38

In every school in which I instructed, we taught the students to deal with UAs. In day VFR, turn it into a wingover, or rotorover, by rolling to whichever side is favoured, keep gentle back pressure in until the nose is almost back to the horizon, then roll wings level - but on a different heading. Once it is all stable, turn back to where you want to go.

In IMC (in an IFR aircraft) in a teetering head machine, if the wings are nearly level but nose is high, gently lower the nose while applying a small amount of collective to load the disc. If the wings are not level, or airspeed is rapidly dropping, use same as day VFR, a gentle turn with back pressure, let the nose come down, roll level.

[email protected] 5th Oct 2017 09:22

AC - I agree with everything else in your post but this

If the wings are not level, or airspeed is rapidly dropping, use same as day VFR, a gentle turn with back pressure, let the nose come down, roll level
is almost certainly likely to result in further disorientation and a worsening of the UA.

Turning and acceleration errors are what cause the leans and often lead to the UA - get the wings level first, adjust the attitude to control the speed and add/subtract power as required.

WASP - as mentioned earlier by Letsby, is the standard recovery (with some small variations in terminology) for all 3 Brit Mil services.

All of the above needs to be done positively but gently since many pilots aggravate the UA by being too 'punchy' with their recovery technique.

Arm out the window 5th Oct 2017 10:12

Pretty simple - just gently ease the nose to the closest horizon, set around hover power with collective and keep it straight with pedal.

Don't slam the cyclic forward, just go gently and mast bump won't be an issue.


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