STALL RECOGNITION AND SPIN PREVENTION

(Transcript by Rod Machado)

Greetings Folks, this is Rod Machado and I’d like to welcome you to this PilotWorkshops program on Stalls and Spins. So let me begin with a question. What is the lowest altitude above ground at which you would intentionally stall an airplane? And I’m speaking about performing a power-off, full break stall in the typical general aviation airplane that you fly.

Would you stall one at 3,000 feet above ground level? Most folks I chat with would easily agree that stalling at 3,000 feet is a no-brainer, although I always recommend bringing your brain along during stall practice.

What about 1,500 feet above ground level? While some folks might think twice about stalling at this altitude, most agree that this is a safe, but minimum altitude at which to practice stalls. This is, after all, the lowest altitude at which the FAA recommends performing a stall in their Practical Test Standards.

Now here is where things get interesting. Would you stall an airplane at 1,000 feet above ground level? Most folks would say, “No.” OK, then would you stall one at 500 feet above ground level? Nearly all pilots of whom I ask this question would emphatically say no. It’s rare to find a pilot who says that he or she would intentionally stall an airplane at this altitude.

So let me witness to you that I would have absolutely no problem stalling an airplane at 500 feet above ground level. None whatsoever. It’s not even an issue with me and I wouldn’t bat an eyelash at the idea (and I mean a real eyelash, not the fake, paste-on type. I don’t wear those. That’s my story and I’m sticking to it). Just to be clear here, I’m not recommending that you or anyone else perform a stall at 500 feet above ground level. This is just a thought experiment. And no, I’m being like the Kamikaze pilot, either. He’s the type of guy who has to do all his bragging ahead of time. I’m simply making a rational and logical statement about stalls.

So why is it that most folks refuse to even think about stalling at such a low altitude? The answer is: predictability, specifically it’s a pilot’s inability to accurately predict what his or her airplane will do when it stalls.

Yep, it’s all about predictability. If I were to stall an airplane at 500 feet above ground level, I would do so knowing exactly what the airplane will do. I know exactly how it will stall and there will be no surprises, I can assure you. And I know how to recover from that stall, easily, quickly and with minimal altitude loss, too. In other words, I can predict with 100% accuracy how the airplane behaves when stalling. And this is exactly what you’ll be able to do at the end of this program (at least if you understand and practice the concepts I provide you). So let’s begin with an understanding of what it means to stall an airplane.

What Is This Thing Called a Stall? (3:16)

If you didn’t skip too many days of private pilot ground school, you no doubt learned that when the wings of an airplane exceed their critical angle of attack, they’ll stall. Last month I mentioned that the critical angle of attack is about 18 degrees for most airplanes. Once that angle is exceeded, the wings stops developing the lift they need to keep the airplane airborne. No, the wings don’t stop developing all the lift they produce. Instead, they

stop developing enough of it to match the downward acting forces on the airplane, thus the airplane begins to descend.

How do you recover from a normal stall? You must reduce the wings’ angle of attack to less than its critical value, or less than about 18 degrees and there are two ways to do this.

The first way is to reduce the angle of attack by releasing sufficient elevator back pressure or moving the elevator control forward a sufficient amount.

The second way to reduce the angle of attack is to add power. The moment you move that throttle forward, the airplane begins to move in a more forward or horizontal direction. This means that the air flowing over the wing (the relative wind) also begins blowing from a more horizontal direction. In other words, as the airplane descends steeply in a full stall, the wind blowing on the wings relative to the airplane comes from below. This is what gives the wings their large angle of attack. Add power and the airplane begins moving in a more horizontal direction, resulting in a relative wind that strikes those wings from a more horizontal direction. This, of course, helps reduce the wings’ angle of attack. Reduce the angle of attack and add power at the same time, and you’ll minimize the altitude lost during a stall.

Can you recover from a stall without adding power? I hope so, otherwise you would want to avoid doing them in a glider. Of course, there’s nothing unsafe about stalling a glider at all. But having power to add minimizes the altitude loss in a stall. In fact, it’s entirely possible to recover from a full break stall with very little altitude loss, perhaps on the order of 25 feet or less, depending on the type of stall, your recovery technique and the amount of power you pack underneath your hood.

The Six Signs of an Impending Stall (5:54)

OK, we’re going to return to stall recovery in a bit, but for now, let’s talk about how to recognize that you’re about to stall your airplane. As a general rule, if you can detect the signs that something bad is about to happen to you, you can avoid that bad thing. This is why some rollercoasters have entrance signs that read, “No pregnant women, no individuals with heart problems, and no toupees.” Recognize the sign, avoid the problem, keep your hair.

Fortunately, it’s easy to recognize an impending stall because there are six individual and very distinct signs that warn you it is coming. Let’s look closely at all six.

The first and perhaps most obvious sign that your wings are about to exceed their critical angle of attack is that (in most airplanes) you can actually feel the airflow separating from the upper cambered surface of the airplane’s wings. This is what is known as the stall buffet. As the wings reach their critical angle of attack, the airflow begins separating from the trailing edge near the wing root, then this separation moves forward and outward. Of course, the airflow separation path above the wind is dependent on several things such as wing shape, stall strips, wingtip twist and so on. But as a general rule, wings are designed to stall from the wing root outward so as to keep the ailerons effective in the stall. On most airplanes, you can feel the vibration associated with wing airflow separation in your seat as well as on the flight controls. In fact, if you’re asked to do an imminent stall instead of a full stall, then you would certainly want to recover the moment you feel this vibration. Yes, there are airplanes with very clean high performance wings that offer very little warning in terms of stall break. Fortunately, there are other means to detect an impending stall.

The second and very telling sign that you’re about to stall is a noticeable reduction in control response. As we discussed last month, the controls feel sloppy in slow flight, and they feel even sloppier as the airplane approaches the stall. The controls just aren’t as effective when you reduce the airflow

over them. One time I was performing a stall with a student in an older Cessna 150 freighter. During the full stall, the airplane entered a slight bank and my student attempted to lift the wing with aileron but it was completely ineffective. Then she did something I’ve never seen before. She released her controls and reached over and grabbed mine. Apparently she thought that I had somehow purposely unhooked her controls, because that’s what we learn to do in instructor school.

Accompanying a reduction in control response is your physical sense that the airplane is moving slower. This, of course, assumes that you’re stalling because you’re flying too slow, which isn’t always the case. But when your airspeed is low, then the airplane feels as if it’s flying slow. Consider that the vertically moving elevators found in tall buildings are purposely designed to have acceleration and deceleration that you aren’t supposed to notice. Yet, if you pay attention, you can still notice the subtle vertical accelerations even in well designed and maintained elevators. Why? Because our bodies are very sensitive to anything that might affect our balance and cause us to fall. Remember, all humans come equipped with two basic instinctual fears: a fear of falling and a fear of loud noises. And I have a fear of making loud noises as I fall. So it’s relatively easy for us to sense acceleration and deceleration in our airplanes once we learn to pay attention to them.

A fourth sign of an impending stall is the way the sound changes as your wings approach their critical angle of attack. I’m not speaking of the high pitch wining sound coming from your instructor in the right seat, either. I’m speaking of the sound the air makes as it passes through the air vents at a distinctly different from normal angle. While it’s true that it’s easier to hear this difference in sound while wearing noise reducing headsets, it can still be heard to some degree with noise cancelling headsets. Hearing is a perception and anyone can learn to perceive this sensory stimulation more accurately. This assumes, of course, that your many youthful hours spent in a punk rock mosh pit haven’t rendered your ability to hear anything less than the steam powered horn of a Royal Caribbean cruise ship. And it goes

without saying that the stall warning horn, if your airplane has one, is also a good indicator of an impending stall, too.

The fifth sign of an impending stall is one that most folks hardly every observe. The farther aft the yoke is pulled the closer the wings are to their critical angle of attack. Think about carefully. During slow flight, the control yoke is extended to nearly its full length of aft travel, which is the opposite of what you would observe in cruise flight at a very low angle of attack. In a steep turn, when the wings are closer to their critical angle of attack, the yoke is also pulled aft quite a distance. If you’re making a turn from base to final approach and the yoke is pulled aft a relatively large amount, then you’re certainly closer to the wings’ critical angle of attack.

Finally, a very significant and also underutilized sensory clue of an approaching stall is what’s happening in your pantaloons. Last month we discussed how to sense coordinated flight by the sideways loading on your derriere. But what about if your derriere appears to be gaining weight in flight and no pastries are actually involved in the process? If you sense an increase in load factor during flight, then you are moving closer to the critical angle of attack at the higher speed at which you’re flying. Said another way, if you make an airplane turn, all the mass associated with that airplane will tend to resist that turn and you’ll feel this resistance as an increase in apparent weight. You and the airplane want to keep moving in one direction while the wings are pulling you in another. The sharper the turn, the greater the resistance offered by the airplane’s mass. The result is that you are forced down in your seat by centrifugal force and feel heavier as a result. Since the airplane appears to be gaining weight, the only way to keep it flying is to increase your angle of attack or fly faster or do both. Well, we typically pull aft on the elevator in a steep turn to increase our angle of attack and in doing so, our stall speed has just increased because our wings have moved closer to their critical angle of attack. So it’s the apparent increase in weight that provides the clue that you’re now closer to stall territory. This increase in weight in your pants is one sense that most pilots don’t pay much attention to but it’s absolutely critical to learn to recognize.

If you’re already close to your stall speed and you feel that increase in weight, you should attempt to unload those wings by releasing elevator back pressure.

Just as an aside here, you might have been told that you learn then practice steep turns to demonstrate timing, proficiency, planning and so on. Well, that’s not the real reason you practice steep turns, at least I hope not. Steep turns teach you how to perceive the precursors of an accelerated stall. For instance, during the turn, your airspeed decreased, thus the reason you added power. That decrease in airspeed meant you moved closer to the critical angle of attack. The increase in load factor also meant you moved closer to the critical angle of attack. Your increasing draw on the yoke and its relatively large extension out of the panel also means you’ve moved closer to the critical angle of attack. Therefore, the steep turn teaches you one very important thing. It allows you to learn all the important clues associated with approaching the critical angle of attack at other than slow flight speeds. How’s that for a good lesson? And to think you might have been told that the practical value of a steep turn is to learn maneuvering to assist you in avoiding other airplanes or any strange assorted solid objects that might be present at your altitude. Yep, that’s what some instructors say. Go figure.

So let’s quickly review all six stall warning signs.

Airflow separation, diminished control response, the physical sense that you’re flying slower, the change in sound, the aft extension of the control yoke and the increase in load factor associated with maneuvering flight. If you understand those clues, you’ve got an understanding about stalls possessed by only a few pilots.

Why Do Pilots Stall Despite All Those Warning Signs?(16:14)

Given these six signs of an impending stall, how is possible that any pilot could accidentally stall an airplane? The answer to that question is quite

simple: Don’t pay attention to a single one of those signs. And how do you do that? That’s a simple answer, too: Find something else more interesting to hold your attention in flight.

You see, under normal conditions, human beings are actually better at tuning things out than they are at tuning things in. When I was young, my third grade teacher told my grandfather that I was having a hard time concentrating, to which my grandfather suggested that the school send me to a concentration camp. Concentrating, or tuning things in while intentionally keeping many things out, is a behavior that must be learned.

On the other hand, there are occasions where we are instinctually skilled at tuning things in and doing so on an uber-intense level. This occurs when something scares us, causing adrenaline to fill our vascular plumbing network, revealing our amazing instinctual ability to focus on the element that’s threatening us. This phenomenon is known as threat-induced tunnel vision. This should make sense to you because if you’re a cave man who goes by the name, Neal Andertall, and you see a Saber Tooth tiger who doesn’t go by the name, “Nice Kitty,” then there’s nothing more important to you at the moment than the proximity of that tiger. This is why individuals who’ve been held at gunpoint often report that the barrel of the gun pointed toward them was the biggest thing they saw in the room at the time of the holdup.

For instance, when pilots overshoot the runway centerline, that centerline often becomes the item on which they focus their attention, especially if parallel runways are involved. It becomes the element of threat for any number of different reasons, and it can cause them to completely neglect all six stall warning clues. Tunnel vision, right? This is why a NASA study once indicated that, in 75% of those stall/spin accidents where the pilot actually survived, the pilot did not recall hearing the stall horn prior to the stall. And it’s a good bet that the stall horn did actually wail prior to the accident, too. Clearly, something attracted the pilot’s attention to the exclusion of one or more of the six stall warning clues.

I’ll tell you how to cope with threat-induced tunnel vision shortly. At the moment, there’s another type of insidious, subtle yet highly maladaptive behavior that affects pilots in flight and it’s one you might not have ever read about, much less heard discussed.

The Aft Elevator Pull Reflex—Or, Getting Your Biscuit (19:21)

Believe it or not, you are actually conditioned to pull aft on the elevator control to make the airplane go up, even when the airplane doesn’t have either the energy or the power source to make that happen. That’s right. I promised you some interesting material on stalls, so let me take you to the Promised Land.

On every single flight you receive a tremendous amount of behavioral reinforcement that conditions you to pull the yoke aft to make the airplane hold or gain altitude. Let me say that one more time because it is so very important. On every single flight you make, your circumstances aloft help condition you to behave in such a way that you build the reflex of pulling aft on the yoke to hold your altitude or to gain altitude or to extend your glidepath.

Yikes! This can’t be true, can’t it? Well, it is true. This reinforcement occurs hundreds of times between takeoff and touchdown. How so? At the slightest deviation from your assigned or chosen altitude, you typically return to that altitude with a small movement of the elevator. And there’s absolutely nothing wrong with this because it’s the proper way to correct for small altitude deviations. The problem is that this behavior is the equivalent of your dog getting a biscuit every time he does something that you want him to do again under similar circumstance. Consider that every turn you make requires a slight pull on the elevator to prevent an altitude loss, and you make hundreds of turns on every flight—and if you’re a student pilot, then some of these turns are intentional. You pull aft on the elevator and the airplane remains exactly where you want it to and your brain says,

“Hmmm, very good. Do the same thing next time you want to change your altitude. And where’s my biscuit, pal?” Furthermore, you pull aft on the elevator to meet the ground at an acceptable angle during the rollout and flare. And the list of reinforcements goes on and on.

Numerically, the reinforcement for using your elevator to change or alter your flight path or altitude numerically dwarfs its reinforcement as an airspeed control. This is your brain’s way of paying for that biscuit. You develop what psychologists call reflexive habituation, otherwise known as a conditioned habit. Is it any wonder that this conditioned reflex causes pilots to attempt to stretch their glide when the engine fails or to attempt to gain altitude primarily by manipulating the elevator control? No, it’s not.

This is why one of the single biggest problems that pilots have when experiencing an engine failure is getting that nose down and keeping it down at a sufficient angle to maintain a safe flying speed. In fact, I just recently had a conversation with Jerry Gregorie, the creator of the sophisticated Redbird Flight Simulator line. He made the point that when a student first experiences a simulated engine failure in one of their machines, the person almost invariably pulls aft on the elevator back instead of releasing elevator pressure. Over the years I’ve observed the same behavior in pilots time and time again. The closer to the ground you give them a simulated engine failure the more noticeable is their aft pull on the elevator in an attempt to stretch their glide. On many an occasion as that yoke came back and the airspeed needle swung counterclockwise, I’ve had to grab their wrist and push it forward to move the yoke forward (this is far more effective than just moving my yoke forward. Of course, as I moved their wrist forward I’d always say, “Your biscuit eating days are over.”)

So what does a pilot need to do to compensate for the problems of tunnel vision and the conditioned reflex? Should he only fly while wearing a helmet? Or strictly limit his flying to the areas over mattress and marshmallow factories? Well, there’s a better way, and it involves using the same behavior that actually generates these problems in the first place.

Black Belt Stall Prevention (24:03)

The most effective way of countering a habit or instinct is by developing a stronger habit or instinct to take its place. Therefore, what we need is sufficient training to help us recognize the six stall warning clues as well a means of countering the aft elevator pull reflex. What type of training am I talking about? I’m speaking of what I call black belt stall prevention. Let me explain.

Think back to when you were in grade school and the class bully picked a fight with you. When he unleashed those two bucket-sized fists on your noggin, it’s entirely possible that the only thing you could do was cover up to defend yourself. If you didn’t have self-defense training, your natural instinct is to either run or, if you can’t run, put your hands over your head and curl up into a ball to protect yourself against a knuckle sandwich you didn’t order. I certainly remember the last time this happened to me in school. This big sixth grader came by, pushed me up against the wall and made me give him my lunch money. I coughed up the money then swore that I’d never substitute teach at that place again. The point is, without training, you’re not as likely to defend yourself properly.

So what should you do? Should you learn how to jump in a car, roll up the windows, lock the doors and enter the crane stance? Well, no. How about taking a martial arts class and earning a black belt in some type of martial arts? Ahh, now you’re making sense. Do that and no one is going to hurt you. Why? Because you’ll be packing your own Bruce Lee self defense kit in your noggin.

The next time someone attempts to hurt you, you’ll be able to rely on an assortment of conditioned reflexes to not only block blows, but return them, too. That’s what a black belt is all about. It’s about building powerful reflexes that reside in the deeper reptilian corners of your brain. The moment you feel threatened, there’s a deeper, reflexive part of you that

takes over your body and protects you. This is why the famed martial artist Bruce Lee once said that if he were ever attacked and killed his assailant, he would argue that it wasn’t him—Bruce—that did the killing. Instead, he would argue that “It” did the dirty work. With “it” being his conditioned martial arts reflex. And this is precisely what I want for you when it comes to defending yourself against stalls. I want you to have your own, “it” tucked away in the deeper corners of your mind so that “it” can assist you in avoiding all the typical stall traps. How do you get “it”? Well, there’s no big secret here. The answer is, you practice. But wait! You say that you’ve already practiced stall recognition and recoveries, so you already have it. Well, let me be clear on this one very important point. Your “it” may not be all that it’s cracked up to be.

How much stall practice have you actually had? The average private pilot probably has less than 30 minutes of actual experience being in the throes of a stall. I’m speaking of the time where they’re actually feeling the stall buffet and the stall break, assuming their instructor actually took the stall that far (unfortunately, many don’t). Yes, your instructor might have dedicated an hour to stall practice, but that doesn’t mean you acquired an hour of experience in the throes of a stall. Therefore, if you’re a newly rated private pilot, there’s a good chance that you have a half hour or less of actual stall experience, if it’s anywhere near that much. Just what do you intend to do with that? Can you imagine someone getting his or her black belt in 30 minutes? The only self defense moves they could learn in 30 minutes is running, but they already know how to do that.

As a matter of fact, martial artists usually practice at least two times a week, two hours at a time for at least three years before they’re eligible to test for their black belts. That’s a total of at least 600 hours of practice in learning to defend themselves. Six hundred hours of kicking, punching, throwing stuff and possibly biting people, depending on how authentic your martial arts studio is. How can you possibly expect to defend yourself in an airplane against stalling if you’ve only acquired 30 minutes of stall experience? Well, you can’t. And I’m pretty sure you didn’t do more than a

few stalls on your last flight review, if you did any at all. Can you imagine how good you’d be at recognizing, avoiding and recovering from stalls if you had 600 hours of actual experience doing them? Fortunately, it doesn’t take that much practice—and certainly not 600 hours worth—to counter the problems of tunnel vision and the aft elevator pull reflex. OK, so just what does it take?

Developing and Reinforcing Your Stall-Clue Recognition Habit (29:28)

Of course, I could have you go out and practice stall recovery and recognition with a competent, capable flight instructor as a means of increasing your awareness of the six stall clues. But you’d probably practice and hour and come away with, maybe a total of five minutes spent in the actual throes of the impending stall and the stall itself. While this isn’t a bad idea, I think I have a better one for you. It’s one I use on flight reviews and it gets the job done.

What I’d like you to do is to fly with a good set of eyes in the right seat during this practice session. No, I don’t mean by flying around with corneas for a transplant hospital, either. I mean that you should do this with your competent and capable flight instructor on board. That fact is that most pilots just don’t have much experience with slow flight or stalls, so having a good CFI ride along on the flight is a good choice. Then again, if you’re comfortable with slow flight at MCA (minimum controllable airspeed), then bring along a traffic observer for this session.

Head out to the practice area, level off at an altitude at least 3,000 feet above ground level then enter slow flight at minimum controllable airspeed. We talked about this in detail last month so you should be familiar with the maneuver. Now comes the fun part, I want you to reduce power to flight idle or some lower power setting, apply carb heat if appropriate then begin a descent at MCA. Keep that airplane right on the edge of a stall and don’t use any trim if you can avoid it. I want you to feel the complete and entire

message being sent to your sensory organs while on the edge of a stall. But if your biceps are so tiny that they squeak when you pinch them, then add a little trim (and, when you get the time, hit the gym to pump those squeaky little things up).

I want you to feel the wing buffet, the controls shaking, the abnormal extension of the control column, the diminished control response, the stall horn wailing or the stall light glowing in its full photonic glory. During this exercise you’re guaranteed to reach the critical angle of attack many times and the airplane will begin to stall. You’ll respond by reducing the angle of attack just enough to prevent this while keeping the airplane at MCA. This is why doing this exercise in a descent is so valuable. It provides a lot of reinforcement for inculcating the habit of reducing the angle of attack to less than the critical value. In an actual stall, you’d reduce the angle of attack further to facilitate the recovery, but this exercise helps you identify what the critical angle of attack actually feels like and how to remain just a little below it.

To increase the opportunity that you’ll remain close to the critical angle of attack and come to know it intimately, I want you to roll into and out of turns at 20 to 30 degrees of bank during the descent. This will further ensure that you’ll have practice operating near the critical angle of attack while operating at MCA. That’s right. As you roll into a turn at MCA, you’ll need to release a little elevator back pressure to change your attitude if you hope to maintain the minimum controllable airspeed. And please make sure you keep those flight controls coordinated when rolling into and out of a turn. Don’t you dare forget to use your rudders during this maneuver for reasons I’ll explain shortly. Continue the descent down to no lower than the FAA’s minimum of 1,500 feet AGL, after which you’ll return to 3,000 or higher and perform the maneuver again.

Now here’s something you might not have heard from relatively newer flight instructors. During the descent, I want you to clear the engine at least every 1,000 feet. Yes, I know that hardly anyone does this nowadays, but

that doesn’t mean it’s not a good thing to do. So how do you do it? Move that throttle forward and give it a short burst of power, moving that RPM needle at least in to the beginning of the green arc, then return the power to idle. But please don’t move that throttle quickly if you’re flying an airplane with a constant speed propeller. Remember, when you reduce power, that prop will likely move to its low pitch/high RPM position. By moving the throttle forward too fast, you might overspeed the propeller and everything else that’s connected to it. Now, why do I want you to clear the engine? Because it helps clear any carbon or lead buildup on the plugs as well as let you know that your engine is still working properly.

What does this descending maneuver at MCA do for you? It does exactly what stall entry practice does for you, but does it over a longer period of time. It lets you experience the stall clues you’ll encounter prior to entering a stall. As you are holding that elevator control aft, take the time to notice how sluggish the airplane feels. Feel the beginning of the stall buffet. Feel the yoke vibrate. Listen to those strange sounds associated with higher angles of attack and not the sounds coming from the flight instructor (they always make strange sounds), look at how far that control yoke is pulled aft. These are the stall warning clues you want to notice and remember. You simply can’t fly at MCA in a descent without having a good understanding of the clues that precede a stall. It’s simply impossible, because sooner or later you will stall.

Will this exercise really help you recognize and avoid a stall? You bet it will. Let me show you how by way of a martial arts example. In order to perfect their skill, martial artists engage in a practice known as kumijo. This is any exercise where you practice single-step throwing and blocking motions with a partner. For instance, your partner steps forward and throws a punch while you counter by moving aft, blocking and counter punching. A karate yell is also involved, especially if you didn’t block properly. This simple training exercise builds a neural pathway for reflexive martial arts behavior. In fact, the great Harvard psychologist William James once said

that the first time we respond to a stimulus is an “act,” and the second time and all subsequent times are habits.

The secret is to make your nervous system your ally by reinforcing the habit through training. Believe me when I say that it doesn’t take a lot of practice before you’ll automatically respond to an aggressive punching movement toward your face with a backstep, block and punch. There’s no thinking involved in the reaction here, either. There’s only reaction, and that means if you kept the receipt for payment on those martial arts lessons, you can throw it away because you won’t be needing a refund.

The same process applies to flight training. I want you to recognize the clues leading up to a stall and respond to them by reducing your angle of attack. In slow flight at MCA, you’ll be constantly releasing elevator back pressure just a little to keep the airplane from stalling as you roll into and out of descending turns. And that’s the habit I want you to develop. This is the aviation version of kumijo in that you are partnering with the airplane and developing the defensive and reflexive move of reducing the angle of attack slightly at the moment you feel the airplane is about to stall. I would, however, recommend that you avoid using the martial arts yell, keeee-yap during the training session. It will certainly make your instructor uncomfortable, at which point he or she will start making even more unusual noises.

More Aviation Kumijo (38:00)

While the previous slow flight exercise will help you recognize and recover from a stall, there’s another exercise that will directly counter the aft elevator pull reflex I discussed earlier.

Most pilots have Microsoft Flight simulator installed on their computer. If not, it’s an inexpensive software program (I’ve seen the Microsoft Flight Simulator “X” versions selling for $29) and it offers you a great training opportunity. How so? You can set the program to have an engine fail at a

random time during a flight. This feature is found at the menu on top the screen under Aircraft, then Failures. You’ll select the Engine tab and further select Complete Failure by clicking the Armed box followed by selecting a time interval in which the failure will occur. I suggest you put yourself in the “line up and wait” runway position then go to the program and arm the failure mode while picking a failure time interval between 5 and 10 minutes. Then you should clear yourself for takeoff and fly the traffic pattern while waiting for the simulated reality show known as, “As the Prop Turns—Or Not” to begin. Perhaps the engine will fail on the downwind or on takeoff. You don’t know. What you do know is that when it does, you want to consciously respond by moving the yoke forward as a counter to your natural instinct of pulling aft on the yoke. This action should be followed by selecting the attitude necessary to sustain the best glide speed for the machine you’re flying.

I find this feature of the program to be absolutely essential in the training of any pilot. After all, isn’t this what the airlines do with their sophisticated simulators? You bet it is. These simulators allow pilots to be thrust into the throes of harrowing emergencies that help them develop proper reflexive habits. In fact, airline simulation sessions are often so life-like that several sim instructors have told me that every once in a while one of their pilots in training has a heart attack. Now you know why you might actually hear someone yell, “Clear!” in a jet simulator rather than in a piston-powered airplane.

The fact is that once you activate this feature of Microsoft Flight sim and work the simulated pattern circuit, you’ll soon forget it’s activated. Suddenly your engine will quit and you’ll have a close representation of what an actual engine failure initially feels like. Here’s where you’ll build or reinforce the habit of releasing elevator back pressure to keep your flying machine flying.

No doubt there are other exercises you can perform to help develop these skills, but these two activities—descending slow flight at MCA and

Microsoft Flight sim in the failure mode—will definitely have you reflexively responding in the black belt mode in a short time.

Now that you have sense of an impending stall and what to do about it, let’s talk about how to ensure that every stall you make, either the ones done intentionally or even the ones done unintentionally, always result in the airplane behaving predictably. It’s time for you to become a stall psychic—that’s psychic, not psychotic—and know what your airplane will do before it does it.

Stop Stalling and Answer This Question (41:52)

OK, time for an answer to the question I posed at the beginning of this program. Remember that I said that I’d easily stall an airplane at 500 feet above ground level because I know exactly how that airplane will behave during the stall. How do I know that? Because I know how to stall the airplane so that both wings stall at the same time, which results in the airplane pitching forward in a direction from my head to my toes. Let me say that another way. If both wings stall at the same time, the airplane pitches forward in plane that’s perpendicular to the wings’ lateral or sideways axis. If the wings do this, then it’s absolutely impossible to spin an airplane. Impossible! If, however, you let one wing stall before the other, then this is the precise way to enter a spin.

Above and beyond everything else, you want to prevent an airplane from spinning. Why? Because a spin is a maneuver where you are completely out of control of your machine for a relatively long period of time. That’s why most airplanes have something known as a recommended spin recover procedure. Yes, you may be out of control the moment an airplane stalls, but by simply reducing your angle of attack to less than critical, the time interval is short enough to render the event inconsequential. This is why some skilled and competent flight instructors wouldn’t have a problem performing a stall at 500 feet above ground level (no, they don’t actually do

it, but the thought adds nary an additional blip to their EKG). No rational or reasonable pilot would ever attempt a spin at such a low altitude because it’s much more difficult to predict what an airplane will do in a spin. It shouldn’t surprise you that Bob Hoover didn’t do spins in his early—pre Shrike Commander—aerobatic routines. Why? He never puts his airplane in a condition where it’s out of control. And that’s why he’s had a long and amazing career. Smart man.

When performing a stall, how do you ensure that both wings will stall at the same time? The answer is...wait for it...you make sure they both have the same angle of attack at the moment of stall. You do that by ensuring that both wings are moving through the air at essentially the same speed and in the same direction at the moment of stall. You can make that happen by making sure that, at the moment of stall, the airplane’s nose is pointed in the direction the airplane moves through the air. Said another way, you make sure that your flight controls are coordinated when the airplane stalls.

Unless you’re flying some badly out of rig airplane, both wings will stall at the same time if the stall is coordinated. And even if they don’t stall at precisely the exact same time, the stall that does occur typically results in a relatively slight and benign rotation. Now you know why last month’s session that covered flying coordinated was so important. If you stall with the flight controls coordinated, you’ll stall predictably. Congratulations, you are an air-psychic, a real airfoil Kreskin because you can now predict how your airplane will behave in a stall.

Wing Inequality—An Easy Story to Spin (45:34)

So what happens if you stall an airplane in uncoordinated flight? The answer is that it’s likely one wing will stall before the other, possibly resulting in an entry to a spin. Let’s examine how this can happen.

You know that pushing on a rudder pedal in level flight results in the airplane yawing. To yaw means that one wing moves forward while the

other, by default, must move aft. Anytime one wing moves forward and the other moves aft, the forward moving wing develops more airspeed, thus more lift and it rises. The aft moving wing develops a little less airspeed, thus a little less lift and it moves down. Got that? Good.

Let’s continue. The wing that rises generates a slight amount of wind that blows on it from above. That means the angle of attack on the rising wing decreases ever so slightly as a result of it moving upward. The descending wing, however, generates a slight amount of wind that blows on it from below. That means the angle of attack on the descending wing must increase slightly.

If you’re having a difficult time understanding this, think of it this way. Let’s say that you and a friend hold an airplane wing above your heads then drop it. The wing isn’t moving forward, thus there’s no horizontal wind blowing on it. But the moment you drop the wing and until it hits the ground, it feels a small amount of wind that blows on it from below as a result of its downward motion. For a very short time as the wing falls, its angle of attack is about 90 degrees. Now let’s combine a wing moving horizontally at 80 knots and 12 degrees angle of attack and let that wing move downward because of a left yaw. While the wing moves aft and downward slightly, its angle of attack is now a combination of the wind blowing on it from the horizontal direction and blowing from below or in an upward direction. This has a tendency to slightly increase the downward moving wing’s angle of attack, perhaps to 12.5 or so depending on how strong the yaw was. And clearly if the downward moving wing’s angle of attack increases, then the upward moving wing’s angle of attack must decrease nearly the same amount.

Now we’re ready to see the results of inducing a yaw with your rudder pedals the moment the airplane stalls. I want you to imagine doing a power-off stall straight ahead. Go ahead, pull that throttle back and get that nose up above the horizon and hold it there. Good. Just as the airplane approaches a stall, right about when you begin to feel the wing buffet, I

want you to apply full left rudder and watch what happens. Bingo! OK, I say that word because right now you probably wish you were in a church somewhere playing this game. As you applied left rudder, the left wing moves aft and downward, and its angle of attack increased slightly while the right wing moved forward and upward, and its angle of attack decreased slightly. The result of slightly different angles of attack on each wing was that the left wing stalled first and stalled more deeply while the right wing stalled later but didn’t stall as much. You know this because the left wing falls and yaws in the aft direction while the right wing rises and yaws in the forward direction. Of course, this vertical and yawing motion induces a roll, too, which appears to result in the airplane initially banking steeply, often more than 90 degrees, followed by the nose initially pointing toward the ground. Yikes! Congratulations to you. If you don’t do anything else but hold that stick full aft, then you’ve most likely just entered your first spin.

So now you see how one wing can stall before the other, right? Simply induce a yaw at the moment of stall and you allow one wing to stall before the other. You’ve also learned something else that’s extremely important. And that is that you can’t enter a spin if you don’t stall first. That’s right. There’s no practical way to have one wing stall before the other if you didn’t stall to begin with. That’s gold in my book. Why? Because if you know the precursors to a stall and can recognize them, then you won’t stall. No stall, no spin, no get flattened.

A Neat Anti-Spin Jedi Rudder Trick (50:50)

Now that you know how and why an airplane might spin, I’m going to give you the equivalent of a Jedi Knight trick for preventing anything that even closely resembles a spin. After you hear this I know I’m going to become your new best friend, so you better call Chuck Yeager and tell him that he’s about to become number two now.

As you intentionally stall the airplane, you’ll obviously recover by releasing elevator back pressure to decrease the angle of attack while adding power to help reduce the angle of attack as well as minimize your altitude loss. In addition and simultaneous to this activity you will do one more thing. And I guarantee you that if you do it, you will never ever accidentally spin an airplane. Period. It just won’t happen.

Are you ready? Wait for it...here it comes. As the airplane stalls, if one wing drops because it has stalled first and your ship begins to yaw and roll, you step on the opposite rudder to stop the yaw. That’s right. Stop the yaw with rudder. If the left wing drops and the nose begins yawing and rolling to the left, you add right rudder and keep the nose pointing straight ahead. If the right wing drops and the nose begins to yaw and roll to the right, you add left rudder to keep the nose pointing straight ahead. No yaw, no roll, no spin. Period. And the author’s decision is final on that. A spin can’t happen if you refuse to let the nose yaw.

OK, but how much rudder should you use? You use as much as necessary. If it takes full forward deflection on the rudder pedal, then push that pedal to the floorboard. Just don’t let the airplane nose yaw. Now you don’t have to stomp on it as if it’s scariest bug you’ve ever seen. In other words, don’t yell, “Ahhh, chupacabra!!” then stomp it silly. Just push the pedal as far forward as necessary to keep that nose pointing straight ahead. And once the nose is pointed straight ahead and no longer yawing, you can release the rudder pressure and continue with the stall recovery.

Keep this very important idea in mind. While all the other control surfaces are reduced in their effectiveness as you approach a stall, the rudder is one control that remains effective throughout the stall. In other words, the rudder surface sticks up and behind the airplane into the free airstream, so it always has a fresh supply of air flowing over it. The rudder surface also doesn’t stall, because the entire tail assembly is free to move about the airplane center of mass when the rudder pedal is pushed. This

effectively keeps the rudder’s angle of attack from exceeding its critical value.

Because you’ve already begun lowering the nose and adding power for the stall recovery, applying rudder pressure to stop the yawing motion reduces any inequality in wing speed, thus makes the angle of attack of the wings equal. That means that one wing is no longer stalling before the other. That’s a good thing. A very good thing!

Up to this point, I’ve told you all the things you want to do at the moment of stall to prevent spinning an airplane. So here’s what you don’t want to do. You don’t want to try raising a dropping and yawing wing with your aileron control. Period. Why? Because to raise a falling and yawing wing with aileron, the aileron on that wing must be lowered. And you know that a lowered aileron always increase the angle of attack on that wing. The last thing you want to do on a wing that stalls, falls and yaws is to further increase its angle of attack. You want to decrease its angle of attack and you do that by moving your elevator control forward, adding power and using your rudders to stop the yaw. So your first instinct when a wings drops and the airplane begins to yaw should always—did I say “always”—be to stop the yaw with rudder and leave those ailerons alone.

Yes, it’s true that as you reduce the angle of attack to less than the critical value and add power, you can probably raise the wing with ailerons, but why do that when your rudder pedal accomplishes the same thing without any penalty involved? If the left wing drops at the moment of stall, and you simultaneously release elevator back pressure, add climb power and stop the yaw with rudder, the lowered wing will rise. Once you’re sure that your wings are no longer stalled, then you can raise one with the coordinated use of rudder and aileron if it pleases you.

Just as an aside, what happens if you stall while turning? Well, the same principle applies. There’s absolutely nothing different here in terms of stall recovery. If you’re established in a turn and one wing begins to drop and yaw beyond your present bank angle, then you stop the yaw and keep the

nose pointed in the approximate direction you were pointed at the moment of stall (or nearly so). Keep in mind that when the airplane experiences a standard stall in a turn, the turn essentially disappears and the airplane tends to fly straighter because there is no longer as much horizontal component of lift pulling it sideways. Once the angle of attack decreases and the yaw is stopped, you can return to straight flight with the coordinated use of rudder and aileron.

Now you know why I would stall an airplane at 500 feet above ground level. I know that if the airplane stalls it’s not going to spin because I will recover from the stall while working those rudders to keep the nose pointed in the direction the airplane is moving. There’s no surprise to be had here. The airplane will stall straight ahead and I’ll recover straight ahead.

Now we’re ready to look a little deeper into how an airplane might spin right or left as a result of slipping or skidding when the wings stall.

Let’s Practice Skidding and Slipping Up (57:39)

I think you’re about ready to learn something really interesting about how an airplane behaves differently when it stalls from a skid or a slip. Let’s examine the skid first.

Imagine that you are in a right hand turn during slow flight and are using too much right rudder (if such a thing is actually possible. Ha ha. I say that because in flight instructor school, you spend at least a day practicing how to say, “More right rudder,” in many different tonal inflections). Too much right rudder in a right turn means the nose yaws to the inside of the right turn, therefore you are in a skidding turn. So let’s assume that you either allow yourself to get too slow and/or you steepen the bank and, as a result of a loss of vertical lift component, you increase the angle of attack by pulling aft on the elevator. Either way, you are now closer to the critical angle of attack in a skidding turn to the right. With the nose pointing or

yawing to the inside of the turn because of your right leg ham-footedness, you reach the critical angle of attack and stall. What will happen?

You know the answer, don’t you? Ahh, don’t deny it! Since the nose yaws to the right, the airplane will spin to the right (if it enters a spin at all). The angle of attack on the aft moving right wing, the wing on the inside of the turn, increases as that wing slows down and moves down. The angle of attack on the left wing, the wing on the outside of the turn, has decreased slightly as it speeds up and moves up. If the yaw induced by this skid occurs at the moment of stall, then the airplane will further yaw and roll to the right. This is called an under the bottom stall since the names we give yaw-induced stalls are based on how the wing on the inside of the turn moves as the airplane stalls (it either goes under the bottom of the airplane or over the top of the airplane). The right inside stalled wing goes under the bottom of the airplane in this instance because it’s developing a lot less lift than the left outside wing. So this is an example of the airplane stalling then spinning in the direction it was banked, to the right in this instance.

OK, now what happens if you’re in a right turn during slow flight and you fail to use any rudder at all? Of course you should be punished, perhaps by a comprehensive reading of the FARs. But I’ll recommend you for probation this one time. During slow flight in a right turn without adding right rudder, you can bet that the airplane’s nose yaws to the outside of the turn arc, which is to the left in this instance. That means you are in a slipping turn to the right.

So what happens if the airplane stalls while the nose yaws to the outside of the turn? Since the airplane wants to spin in the direction the nose yaws, then this airplane will want to stall, yaw and roll to the left. If it does, the wing on the inside of the turn, the right wing, will stall last. That means it’s still developing a little more lift than the left wing, so it will rise up and over the top of the airplane. That’s why a stall resulting from a slip results in what is known as an over the top stall.

There is, however, something very important that you should understand about stalls that occur during a slip. Let me introduce this concept by asking you a question. Why does the FAA request that you demonstrate your ability to slip (as in slip to a landing) rather than skid when close to the ground? The answer is, there’d be fewer pilots around if the FAA wanted you to demonstrate a skid anywhere close to the ground. Why is that? Because when an airplane is about ready to stall, it’s far more likely to enter a spin when skidding that when slipping.

Let’s go back to our slow flight skidding turn to the right. As the airplane turns and the wings approach their critical angle of attack, the nose points toward the inside the turn arc. The right wing will stall first and go under the bottom of the airplane. Since the airplane is already banked to the right, this simply makes it easier for the energy of the turn to be added to the energy of the yaw and roll resulting from the stall. This is why it’s very easy to spin an airplane in the direction its turning.

Now watch what happens when we try spinning in a direction that’s completely opposite the direction we’re turning.

Going back to our right turn example, let’s enter a slipping turn to the right in slow flight. Now the nose is pointed outside the turn arc while the airplane banks to the right. At the moment of stall the left wing stalls first and the right wing wants to rise up and go over the top of the airplane. The airplane wants to yaw and roll to the left as it stalls. But the airplane’s energy is directed to the right because it’s established in a right turn. Therefore the left roll from the stall is countered (to a great degree) by the horizontal component of lift that’s pulling the airplane to the right. And this is why stalls involving slips are more benign than stalls involving skids. So much so that the FAA wants, no wait, “demands” that you demonstrate a forward slip to landing on your private pilot checkride. Do you think they’d ask you to do that if slips were as risky as skids in the slow speed, low altitude environment. No, they wouldn’t.

Now, just to be clear here, you can still enter a spin from a slipping turn, but it’s relatively more difficult to do. Over the years I’ve had students stall many different types of airplanes while both slipping and skidding. Without a doubt, the skidded stalls are almost always more aggressive and tend toward a spin compared to slipping stall entries. In most small typical training airplanes, a normal stall entry while slipping results in the typical forward pitching motion but with very little yawing and rolling motion, which makes stall recovery relatively quick and easy.

If you’ve understood how stalls are affected by slips and skids, then you’re ready to look at how pilots manage to lose control of their airplanes at low altitudes in the traffic pattern. You’re also ready to learn about how a left traffic patterns demands more stick and rudder proficiency than a right traffic pattern. What? How can that be? Well, let’s find out by taking a walk on the wild side and see something really wild.

A Turn for the Worst (1:05:27)

Let’s begin by flying a left hand traffic pattern. In this example, you’re on base leg about to begin a 30 degree banked left turn onto final approach in a typical power-on approach at approximately 40% above your present stall speed.

OK, here's the scenario that can cause you a lot of grief. As you left turn onto final approach, you might find yourself overshooting the runway centerline because of a strong left crosswind or because of a poorly planned turn. The moment you sense the over shoot, your natural tendency is to increase the bank angle, which results in a loss of vertical lift component resulting in a slight nose-down pitch. You’ll typically compensate for the nose-down pitch by pulling aft on the elevator which increases the angle of attack as well as the load factor and tightens the turn. The airplane’s stall speed has just increases while the airplane’s angle of attack has simultaneously moved closer to its critical value.

But that’s not what’s giving this scenario the patina of an, “Empire Strikes Back” movie. Two very bad things are about to happen. You might naturally use right aileron to prevent the bank angle from increasing as well as use it to roll out of the left turn back into level flight. As you rotate the yoke to the right, you might do what most pilots do in this instance and that’s fail to use any right rudder to compensate for the adverse yaw of the lowered aileron on the left wing. Hopefully, after listening to last month’s program, you won’t do this. Unfortunately, far too many pilots have feet that are DOA or dead on the airplane. As you rotate your yoke to the right to rollout, the downward moving aileron on the left wing—the wing inside the turn—creates a lot of drag and yaws the nose to the left, to the inside of the turn. Sound familiar? Now the nose yaws to the left or the inside of the turn while the airplane is still in a left turn, as the wings approach their critical angle of attack. You’re skidding and the empire is about to strike back, big time.

If this airplane actually does stall, the left wing (the wing on the inside of the turn) is likely to stall first. At the moment of stall, if you don’t reduce the angle of attack, add power and immediately push on the opposite rudder pedal to stop the nose from continuing to yaw, the left wing will stall and go under the bottom of the airplane. Yikes! You’ve just entered a spin at less than 500 feet above ground level.

The under the bottom stall is more likely in this instance because of the effects of power on the airplane. The airplane’s power-induced left turning tendency resulting from p-factor and propeller slipstream, helps yaw the nose to the inside of the turn. And the use of only right aileron and no right rudder pressure makes a skid more likely, thus an under the bottom stall more likely, too.

The fact is that stalling while making left traffic can have higher risks than when flying right traffic if you aren’t a good stick and rudder pilot (I’ll explain right traffic shortly). If you don’t use your rudder pedals properly,

then the airplane’s power induced left turning tendencies make a skid more likely when turning left.

Had you actually stalled while using rudder and aileron in coordination during the rollout from the left turn, then both wings would have stalled at the same time. That means the nose would have pitched forward directly from your nose to your toes, without the inside wing going under the bottom of the airplane. This type of stall is easy to recover from because it only requires a release of elevator back pressure to reduce the angle of attack to less than critical and the application of full power. You might have recovered in 25 to 50 feet with the airplane flying straight ahead, allowing you to go around for another, hopefully less stressful, approach.

Making a Turn Right (1:10:17)

Are you curious what happens if you stall an airplane while making right traffic? If you allow me the liberty to generalize a bit, you’ll find the following example a fairly accurate description of reality.

Let’s assume you’re making a power-on approach at 40% above you stall speed at an airport using right traffic. Let’s also assume that you sense you’ll overshoot the extended runway centerline because you, once again, failed to compensate for a strong right crosswind or poorly planned your approach (of course, I know you won’t let this happen to you, right? OK, good). As you turn right, you steepen your bank by rotating the yoke to the right but typically (especially if you’re not a good stick and rudder pilot) fail to use right rudder because your feet are on vacation. As you roll into the turn, you’ll typically pull aft on the elevator to compensate for the loss of vertical lift component. The increase in load factor along with the aft elevator pull means the stall speed has increased and the wings are closer to their critical angle of attack.

Once again, something bad is about to happen but there’s a chance that, while still being bad, it won’t be as bad as what happened when stalling

during left traffic. Once your bank is established, you’ll typically use left aileron to prevent the bank angle from increasing as well as use it to roll out of the right turn back into level flight. If you’re a poor stick and rudder pilot, then as you rotate the yoke to the left, you’ll invariably fail to use left rudder to compensate for the adverse yaw of the lowered aileron on the right wing. That’s right. As in the last example, the adverse yaw resulting from the lowered aileron on the inside wing wants to yaw the nose toward the inside of the turn. Fortunately, propeller and engine dynamics arrive to help fight off an evil empire that’s attempting to strike back. What happens is that the airplane’s left turning tendencies are neutralizing (to some degree depending on the power applied), the right yawing motion induced by the lowered right aileron. In this instance, it’s more likely that the airplane will stall with the controls being coordinated or at least more coordinated, despite your making no intentional contribution at flying coordinated. Thus, if the airplane does stall, the stall results in a head-to-toe pitching motion because both wings stall at the same time.

As a general rule, this is why accidental stalls made when flying a right hand traffic pattern tend to be less dramatic, thus less deadly (albeit still dangerous) than stalls made when making left traffic. Unfortunately, it’s difficult to make a statistical analysis of right- and left-hand traffic pattern accidents, but the point stands on its own logic, nevertheless.

The No Spin Zone (1:13:42)

So welcome to your own personal no spin zone. Give what you’ve learned about stall recognition and recovery, about the reinforcement you receive at pulling the elevator aft to change your glidepath, and about the methods you can use to counter this, you should feel a lot more comfortable at flying your airplane.

The idea of stopping the rotation of the airplane’s nose as stall recovery is initiated is an absolutely essential tool for you to keep in your mental

flight bag. The fact is that if you practice these techniques and become trained well enough to use them reflexively, then you’ve earned your black belt in stall prevention. Black belt martial artists don’t walk around fearful and timid and pilots trained in black belt stall prevention don’t fear their airplanes, either. As with all martial artists, they don’t go looking for trouble but they sure have a good idea about how to handle it if it shows up. So fly your airplane confidently by practicing these lessons.