stall recovery in turns

[woodstock]

Hi all

I am nearly done with Stick n Rudder. The last few chapters are devoted to air safety/Dangers of the Air.

The writer states that one of the most (or the most?) common fatal accident involves spinning out of a turn - more specifically tight ones.

In reading this I'm trying to visualize all that you'd do in a climbing turn (his main example) and I think my one question is - how do you realize ahead of time you are in danger of stalling/setting yourself up for a spin? we've practiced the normal straight/level flight stalls, not turning, yet. what sort of things do you look for (or try to avoid doing in the first place) and how do you recognize it in time?

I know you are first supposed to get the nose down at all costs, and if the wing is dropping you don't pick it up with aileron, you are supposed to pick it up with high rudder (opposite rudder) but I also know in a quick panic situation you may not think of that and do what is instinctual but also wrong.

I'll likely come up with more questions along these lines but this is a start.

thanks.

 

[Brian Austin]

...how do you realize ahead of time you are in danger of stalling/setting yourself up for a spin?

Airspeed, airspeed, airspeed. If your airspeed is high enough, you can't stall. No stall, no spin. Keep in mind that Vso changes as your attitude changes, too. And, if it's coordinated, your stall will be no different than a straight stall, aside from your attitude.

we've practiced the normal straight/level flight stalls, not turning, yet. what sort of things do you look for (or try to avoid doing in the first place) and how do you recognize it in time?

Depending on the plane, you MIGHT hear the stall horn but I don't count on it, especially in a turn. You will feel the buffet, sluggish controls, etc., of a straight stall. Otherwise, back to airspeed and coordination. You can't spin if it's coordinated and you can't spin if it doesn't stall.

I know you are first supposed to get the nose down at all costs, and if the wing is dropping you don't pick it up with aileron, you are supposed to pick it up with high rudder (opposite rudder) but I also know in a quick panic situation you may not think of that and do what is instinctual but also wrong.

Don't worry about the instincts. It becomes a learned reaction, especially if your CFI makes you practice turning power-on stalls for five flippin' hours before your checkride because you're nervous about them.

 

[VFR Flyer]

Airspeed, airspeed, airspeed. If your airspeed is high enough, you can't stall. No stall, no spin. Keep in mind that Vso changes as your attitude changes, too. And, if it's coordinated, your stall will be no different than a straight stall, aside from your attitude.
snip

I don't think that is correct!! I thought you can stall an airplane at ANY airspeed. The thing to worry about is angle of attack.

 

[Toby]

Brian's right, but I'd say think coordination first, rather than airspeed. The mantra goes no yaw, no spin. I've stalled at some pretty high airspeeds.

Don't mean to pick apart your answer, Brian. You talked about coordination, too. Lately I've found it helpful to stop thinking in terms of airspeed, because it's tempting to fill your head with numbers, and really there are many stall speeds, an infinite number of stall speeds, depending on circumstances. You bank the plane a little more, you load the wing a little more, no longer is XXmph going to hold you up.

 

[Brian Austin]

I don't think that is correct!! I thought you can stall an airplane at ANY airspeed. The thing to worry about is angle of attack.

With no AOA indicators in 99% of GA aircraft, one has to look at airspeed as the indication on how close Vso is.

 

[Brian Austin]

Lately I've found it helpful to stop thinking in terms of airspeed, because it's tempting to fill your head with numbers, and really there are many stall speeds, an infinite number of stall speeds, depending on circumstances. You bank the plane a little more, you load the wing a little more, no longer is XXmph going to hold you up.

Let's consider how the basic student is taught here. Yes, there are infinite number of stall speeds and I mentioned Vso changes with attitude. Bank 30deg and Vso is different than straight and level. Bank 60deg and it's even higher.

With no AOA indicators and a basic, pre-PPL student, she's going to be taught airspeed and coordination. You can crosscontrol the plane and not spin IF your airspeed is above Vso for that particular condition (pitch/attitude). So coordination, while important, is less of a factor than airspeed. If the airspeed across the wings is above Vso for that condition, it won't stall. No stall, no spin.

 

[woodstock]

Hi all,

thanks - still thinking this through. two things come to mind (don't have the book in front of me). when you are turning, you can't use the "where is the nose on the horizon" in the same way as you would in level flight (right?). he said a big mistake people make is to see the nose going UP, so they think, well, correct it by hitting the DOWN rudder (which confuses me as to why this is wrong, because the down rudder would be the one you would want to use to coordinate it - turn left, use left rudder, etc.) when instead they should put the nose down first.

also: let's say I am in the traffic pattern, just doing touch and goes. I'm in a climbing turn, after I take off, to go cross-wind. since I am still climbing, I'd still want some right rudder (despite turning left) or at minimum ease off the rudder, and do not use left, correct? since there is still a lot of left turning tendency (high power, low airspeed) you don't want to use left rudder at this point. I KNOW this intellectually but am not at the point where I can spot it.

still absorbing the replies, thanks...

 

[Ken Ibold]

I KNOW this intellectually but am not at the point where I can spot it.

Here's something that might help. When you practice any kind of turning maneuver, take a few seconds during the turn to focus on the seat-of-the-pants feel. Is your body sliding toward the outside of the turn? Are you feeling like you're going to fall inside the turn? Put your butt to work! Eventually you will develop a feel for turn coordination, and that is really the dynamic when it comes to spins. No yaw, no spin.

Now, that doesn't really address the problem of stall recovery in turns, which was your original question, but it does address the primary safety aspect presented by stalls in turns. A coordinated stall, even while turning, is just a stall. If you're putting yourself in the initial climb scenario, you've got lots of power on, so the stall recovery is almost instant in most light planes, simply remember to level the wings and it'll fly out of it just by reducing back pressure (assuming you're not grossly mistrimmed or out of cg).

 

[RotaryWingBob]

Airspeed, airspeed, airspeed. If your airspeed is high enough, you can't stall. No stall, no spin. Keep in mind that Vso changes as your attitude changes, too. And, if it's coordinated, your stall will be no different than a straight stall, aside from your attitude.

I have to disagree (nitpick). Vso is measured under specific conditions. Once it's measured it cannot change unless the definition of Vso changes.

Stall speed does indeed change with attitude, but Vso cannot. It's also important that stall speeds vary with weight as well (or with the square root of weight, to be precise).

As someone else pointed out, you can stall a wing at any airspeed. Consider a dive at Vne, then pull out of it abruptly. If the wings don't fall off, they'll stall.

I do agree with the importance of staying coordinated -- that's really the key, isn't it?

 

[woodstock]

yaw is when your nose goes the other direction from your turn? you are turning left using ailerons, nose goes right - yaw? (i.e. same thing as adverse yaw?)

is there a list of all the V speeds/shorthands? Vne - never exceed. Vso - stall speed (clean?) etc.

 

[n741dm]

All the input you're receiving is good, any nits aside... For me, the main comfort/safety factor is remaining coordinated throughout the turn. If the plane is coordinated, even if I should miss the pre-stall warning signs of buffet or mushy control feel, the plane will drop off pretty much straight ahead - a "non-event" on the pucker meter.

An important thing to remember when reading Stick and Rudder is that it was written when aircraft displayed much less benign handling characteristics. Airplanes from that era were nasty handling little devils!

It sounds to me like you have a pretty good understanding of the dynamics, Elizabeth... now you just have to go out and experience one of those extended practice sessions (not really fun) that will gain you the comfort level you desire.

You go, girl!

 

[spiderweb]

Hi all

I am nearly done with Stick n Rudder. The last few chapters are devoted to air safety/Dangers of the Air.

The writer states that one of the most (or the most?) common fatal accident involves spinning out of a turn - more specifically tight ones.

In reading this I'm trying to visualize all that you'd do in a climbing turn (his main example) and I think my one question is - how do you realize ahead of time you are in danger of stalling/setting yourself up for a spin? we've practiced the normal straight/level flight stalls, not turning, yet. what sort of things do you look for (or try to avoid doing in the first place) and how do you recognize it in time?

Elizabeth, Wolfie is very good in this book about wanting to arrive at a solution that works ALL of the time. The airspeed idea works almost all of the time, but not all of the time because, as we've seen in the posts above, you can stall at any airspeed. The answer is AOA.

Now, you can refer to your POH to find the airspeed at which you will stall at a given angle of bank (it will be higher than straight and level), but this doesn't help with how you feel, which is what I think you're really getting at.

The most important thing is to keep your airspeed well above stall for the angle of bank AND keep the turn coordinated. An incipient stall while turning (whether climbing or descending) will feel similar to one straight and level. You will feel the controls start to mush on you, you may feel a shudder, etc. And you've already pointed out that you need to lower the AOA, i.e. lower the nose and straighten the wings.

What Stick and Rudder is going on about, though, is the classic cross-controlled turn from base to final with a tailwind on base. What happens is a pilot doesn't take the tailwind into account on base, and so turns late for final. After rolling out, she sees that she's way over to the side, and needs to get back on the centerline, so she tightens the turn to get back to centerline. Now, though, she doesn't like the big bank, so she adds some opposite rudder, and pulls back on the yoke to keep the nose up (without adding power). She's already slow, because she's at approach speed, so the steep bank (which already increased the stall speed) combined with the cross-controlling of the rudder, combined with the slower airspeed and higher AOA pushed it over the edge, and she will flip over and spin in. The moral is that if you need to do heavy maneuvering in the pattern, and especially from base to final, just go around and set yourself up better the next time.

Now, I would advocate going up with your CFI and practicing slow flight with full flaps. Practice at very slow airspeeds, at a very high and safe altitude, and practice gentle turns, at first. Even at 10 degrees of bank, you will really feel the mush. Now, if you're CFI is up on his or her spin training, go ahead and practice stalling out of those shallow turns.

OK, now If you practice the classic power-off, highly-banked, cross-controlled turning stall, you will be practicing spins. Do not do this unless your CFI is very adept at spin recovery. (Many CFI's get just a quick signoff on this.) But this is exactly what happens in the fatal base-to-final spin-ins. I have practiced spins at a safe altitude with my CFI, and it is another world. My take is that you would definitely notice it, but then again, the very few people who have spun one in and survived said that they never saw it coming.

 

[n741dm]

Elizabeth, Wolfie is very good in this book about wanting to arrive at a solution that works ALL of the time.

Wolfie...WOLFIE...WOLFIE? My God, Ben... that's like calling Mahatma Gandhi, "Matty"! ! !

There go your style points again...

Excellent description though.

 

[gismo]

Elizabeth, while there's a lot of good stuff in Stick and Rudder, it's a bit out of date WRT spinning out of a turn being one of the most common causes of airplane accidents.

A stall in a reasonably coordinated turn in most modern GA aircraft will not depart into a spin and is actually one of the easiest stalls to recover from. All you have to do is release a little back pressure since you probably haven't trimmed for the increased AOA required for the turn.

Turning by itself doesn't increase the likelihood of a spin if you stall, but it does make the detection of a spin a bit more difficult since you are already turning.

Something to remember is that if you stop any yaw rotation with the rudder the plane will not spin and this is easy and natural. The unnatural part of spin recovery (vs prevention) is that once a spin develops beyond the initial stages you must make and hold control inputs that are somewhat counterintuitive.

Also worth noting is that stalling in a turn almost always produces very obvious buffeting due to the higher airspeed at the stalling AOA in an accelerated stall.

 

[BruceAir]

I've made several videos that show the effects of stalls in turns while coordinated and with top and bottom rudder applied. You cand find them in Windows Media Player format at:

http://www.bruceair.com/ShortVideo.htm

A longer demonstration of stalls (straight-ahead and from a turn) is at:

http://www.bruceair.com/video.htm

Scroll down to the "Stall Demonstrations" video.

Please note that you should download these videos to your local hard drive--don't try to view them directly from the Web page.

Another excellent source of information, including videos, is Fighter Combat International. Check out the Training Articles and Training Videos available at: http://www.fcitraining.com/newsletterlist.htm.

A specific example is at: http://www.fcitraining.com/clips/skidded_turn_high.wmv

-Bruce
www.BruceAir.com

 

[fgcason]

I've made several videos that show the effects of stalls in turns while coordinated and with top and bottom rudder applied.

Where's the one for bottom rudder?
Or am I just blind?

 

[BruceAir]

You'll find examples with both top and bottom rudder at:

http://www.bruceair.com/LongVideo.htm

Scroll to the last video in the left column, "Stalls and Incipient Spins."

 

[fgcason]

You'll find examples with both top and bottom rudder at:

http://www.bruceair.com/LongVideo.htm

Scroll to the last video in the left column, "Stalls and Incipient Spins."

Ah. Thanks.
I was looking for it in the short videos for a fast load since I have the wonderful wonders of dialup. The USB port and T1 connection is at work but it's not prohibitive here at home.

I like your site. I loaded a few of the short video's. They're very well done, visually and narrative.

 

[woodstock]

wow, those were great (woohooo!)

ok, so I'm clear... you cross controlled, and nose up - stalled. you released back pressure... since you already spun (once?) you'd also want to right it with opposite rudder, right?

what if you are turning left, and really give it too much left rudder - what then? you'll spin off to the left? and use right (after releasing pressure) to correct?

when you are doing practice stalls - straight and level... up up up you go... high power, low airspeed... you gotta give it enough right rudder. too much, you can break right. too little, you break left. and use opposite rudder to correct. (check).

 

[BruceAir]

The basic recovery from any incipient or developed spin involves counteracting the elements that caused the phenomenon in the first place, viz., yaw and a stall.

You also want to reduce power to idle, because power usually aggravates spins (e.g., flattening and accelerating them) and, of course, power drives you closer to the ground, since that's where you're headed.

Although recovery techniques may differ among aircraft types, many experts in spin training advocate the[size=-1] mnemonic PARE:

Power: Idle
Ailerons: Neutral
Rudder: Full opposite direction of rotation until rotation stops
Elevator: Through neutral to reduce angle of attack

An excellent guide is available from FCI at:

http://www.fcitraining.com/article15_fci_training_jul04_2.htm

You can download a PDF version at:

http://www.fcitraining.com/Docs/FCI_Spin_Recovery_Procedure_Guide_Jul2004.pdf

And a set of links to other references and guides is on my Web site at:

http://www.bruceair.com/spins.htm

-Bruce
[/size]

 

[gismo]

wow, those were great (woohooo!)

ok, so I'm clear... you cross controlled, and nose up - stalled. you released back pressure... since you already spun (once?) you'd also want to right it with opposite rudder, right?

Right, except that "opposite" rudder is soley to cancel the yaw, not because "you already spun". Regardless of how you got into a spin or what your attitude is during any part of the spin, you always push on the pedal that causes the plane to turn the opposite way it's turning in the spin. Forget which wing is lower, just determine which way the nose (or wing for that matter) is moving across whatever you can see (ground, clouds etc) and step on the side the nose/wing is moving from. During a stall break and/or incipient spin, the same thing will prevent the stall from becoming a spin. IOW stop the yaw and there will be no spin.

what if you are turning left, and really give it too much left rudder - what then? you'll spin off to the left? and use right (after releasing pressure) to correct?

Yes, but typically the airplane will roll pretty rapidly into the down wing (past vertical) in that case, and the nose is likely to pitch way down as well. It's quite likely you will go inverted temporarily although the end result will still be an upright spin.

when you are doing practice stalls - straight and level... up up up you go... high power, low airspeed... you gotta give it enough right rudder. too much, you can break right. too little, you break left. and use opposite rudder to correct. (check).

Correct, but again I want to caution you to think in terms of stopping the yaw rather than pushing on a particular rudder that's dependent on how the spin started. If you were skidding down a wide icy runway and the plane started to yaw (point) to the left, you would naturally push on the right rudder to bring the nose back. In a spin or spin entry, it's the same thing except you must pay attention to the direction the nose is moving rather than the direction it's pointing.

 

[woodstock]

ok, thanks! got it.

 

[woodstock]

by the way I am really focusing on this b/c the thought of doing something stupid scares the crap out of me - and this seems like one of the easiest stupid things to do.

 

[Brian Austin]

by the way I am really focusing on this b/c the thought of doing something stupid scares the crap out of me - and this seems like one of the easiest stupid things to do.

Well, to me at least, it was kinda scary...but you'll be surprised at how fast it becomes second nature to hit opposite rudder and begin recovery FAST.

 

[grattonja]

by the way I am really focusing on this b/c the thought of doing something stupid scares the crap out of me - and this seems like one of the easiest stupid things to do.

I don't remember what you are training in (I know you told the collective board in an earlier post) but, based on my somewhat limited experience with skyhawks and archers, I recommend that you take up your CFI and do accelerated stalls. You know, basic, turning, 30 degrees or so of bank, stalls. My CFIs have always been reluctant to do these with me for some reason, but our chief pilot at the flight school ALWAYS insists on testing on them, despite the fact that the local DEs do NOT do accelerated stalls. Frankly, I was afraid of them at first. What I found was, for the most part, they are as benign as the straight ahead stalls in the trainer type planes. I am pretty confident with them now. Fear of the unknown and all that on my part gone.

Jim G

 

[Brian Austin]

I don't remember what you are training in (I know you told the collective board in an earlier post) but, based on my somewhat limited experience with skyhawks and archers, I recommend that you take up your CFI and do accelerated stalls. You know, basic, turning, 30 degrees or so of bank, stalls. My CFIs have always been reluctant to do these with me for some reason, but our chief pilot at the flight school ALWAYS insists on testing on them, despite the fact that the local DEs do NOT do accelerated stalls. Frankly, I was afraid of them at first. What I found was, for the most part, they are as benign as the straight ahead stalls in the trainer type planes. I am pretty confident with them now. Fear of the unknown and all that on my part gone.

Jim G

My CFI and I worked on these for a long time. He insisted on going through a full break for recovery, which I had a tendency to let get uncoordinated at the last second (too much anticipation). I always recovered within 100 feet but it still scared the crap out of me. Day before the checkride, we did over a dozen of them while logging 5.6 on the Hobbs because the DE specifically had it on her itinerary. I was sweating big time by the end of that ride.

Uncoordinated even a little and the C172 can get a little squirrelly.

Next day, checkride....didn't do them. Sigh.

 

[grattonja]

My CFI and I worked on these for a long time. He insisted on going through a full break for recovery, which I had a tendency to let get uncoordinated at the last second (too much anticipation). I always recovered within 100 feet but it still scared the crap out of me. Day before the checkride, we did over a dozen of them while logging 5.6 on the Hobbs because the DE specifically had it on her itinerary. I was sweating big time by the end of that ride.

Uncoordinated even a little and the C172 can get a little squirrelly.

Next day, checkride....didn't do them. Sigh.

I have gotten the sense that the DEs, in my local area anyway, simply don't do them. The Cessna Pilot Center material does not even demonstrate accelerated stalls. The PTS does allow for them, but certainly doesn't mandate them.

Jim G

 

[Brian Austin]

I have gotten the sense that the DEs, in my local area anyway, simply don't do them. The Cessna Pilot Center material does not even demonstrate accelerated stalls. The PTS does allow for them, but certainly doesn't mandate them.

Jim G

Oh, we did accelerated stalls, just not turning. She also didn't make me go full throttle, making it almost a non-event. I recovered at the first sign of a shudder (horn never went off, either), said "whoops, too soon" and re-established the set up but she said that was enough, she was satisfied that I recognized it and recovered.

I can't imagine NOT doing them and understanding what is happening, let alone how to recover!

 

[MSmith]

When I had my checkride, we did a straight-ahead accelerated stall. No problem, though the wing dropped a smidge (and I snapped it back to level with the right reactions - no extra altitude loss).

What was weird is that we didn't do a power-off stall - just a partial power stall. We went from slow flight to "leave the power there and pull up" to a stall. I had never done those before, but it was no problem at all - nice and gentle.

 

[BruceAir]

When introducing students to stalls (and when reviewing stalls with certificated pilots), I distinguish between the stall maneuvers required for the various PTSs and learning about and understanding stalls. Let me explain:

It's obviously important to learn to peform the stall demonstrations required for the private and commercial practical tests. These maneuvers emphasize recognition of the onset of a stall and prompt recovery either as the stall approaches or after a break. Recovery involves counteracting yaw, reducing angle of attack, adding power, and resuming normal flight with minimum loss of altitude.

But performing those maneuvers often doesn't promote a thorough understanding of and comfort with stalls.

We often spend time on slow flight, flying down the runway at low altitude, and other exercises related to landings to help students who don't get to spend much time in the critical phase from approach to roundout to touchdown. I have found that adopting a similar approach to teaching and demonstrating stalls frequently enhances understanding and ultimately helps students perform the required maneuvers more precisely and with greater confidence and comfort.

Regardless of whether the maneuver is an approach, departure, or accelerated (i.e., turning) stall, I stall the wing and hold the stall long enough for the student to feel the buffet and experience the other symptoms of a stall. I then recover just by reducing angle of attack. Having begun the demonstration at a safe altitude, I then smoothly bring the airplane back into another stall, repeating the process 3 or more times to give the student more experience with the aerodynamic phenomena associated with a stall.

When demonstrating accelerated stalls, I "bounce the airplane" through 180 or more degress of turn, showing that if you apply rudder to keep the ball in the center, there's little tendency for a wing to drop--the nose just falls back through the horizon. As soon as the wings are flying again, the buffet disappers and the controls respond normally. Increase the angle of attack back to the critical angle, and the stall develops again. And so on.

The process is much like having a student fly down a long runway while never touching down. It gives the pilot more time to develop the visual cues, the feel of the airplane, and the control inputs required to make better landings.

Having demonstrated a series of these manuevers, I coach the student through flying some him or herself. It's remarkable how much their anxiety drops and their confidence increases. Recovering without power elminates the confusing effects of so-called torque and emphasizes that a stall is all about the wing and angle of attack, not airspeed, power setting, etc.

When we return to the "by-the-book" PTS stalls, students are familiar with all the signs of an impending stall, they're more comfortable in the transition from normal flight to the stall regime, and much more competent in making prompt, accurate, and effective stall recoveries that meet the goals of the PTS.

 

[Henning]

Hi all

I am nearly done with Stick n Rudder. The last few chapters are devoted to air safety/Dangers of the Air.

The writer states that one of the most (or the most?) common fatal accident involves spinning out of a turn - more specifically tight ones.

In reading this I'm trying to visualize all that you'd do in a climbing turn (his main example) and I think my one question is - how do you realize ahead of time you are in danger of stalling/setting yourself up for a spin? we've practiced the normal straight/level flight stalls, not turning, yet. what sort of things do you look for (or try to avoid doing in the first place) and how do you recognize it in time?

I know you are first supposed to get the nose down at all costs, and if the wing is dropping you don't pick it up with aileron, you are supposed to pick it up with high rudder (opposite rudder) but I also know in a quick panic situation you may not think of that and do what is instinctual but also wrong.
thanks.

Practice spins (and other acro if possible) until it becomes instinctual as to what you need to do when you see & feel whatever combinations of inputs.

 

[BruceAir]

Fighter Combat International has posted a new article/video about recovering from incipient spins caused by a stall out of an uncoordinated turn.

You can find the article and video at:

http://www.fcitraining.com/vid_clip9_incipient_spin.htm

 

[Bill]

Fighter Combat International has posted a new article/video about recovering from incipient spins caused by a stall out of an uncoordinated turn.

You can find the article and video at:

http://www.fcitraining.com/vid_clip9_incipient_spin.htm

Bruce, that is great. I'm going to ask my instructor to do that in the Citabria. Good to know what happens and how to get out.