AOPA Pilot Magazine - November 2010 - 32

LICENSETOLEARN

BY ROD MACHADO

Stall commandments

re you nervous about stall practice? You have copious company. One student I inherited from another instructor became so nervous during the

would stall simultaneously, and the airplane would pitch from your nose to your toes. Unless you are a professional prizefighter, that means the airplane will pitch straight ahead of you in a very predictable manner. No yaw and roll. Recovery from this type of stall is easy—reduce the angle of attack by releasing elevator backpressure and apply maximum allowable power to help further reduce the angle of attack and minimize altitude loss. Now what happens if you have happy feet and stall sequence that he developed a peculiar habit accidentally stall an airplane in uncoordinated of humming along with the stall horn. I’m not kidflight? Your stall becomes a hummer and a bummer. Longtime CFI Rod Machado ding. This airplane had a two-tone stall horn and It’s time to follow the second stall commandment. has recently he’d hum right along, changing pitch with the horn. Stall commandment number two: Thou shalt not published his During the stall, his tunnel vision was so intense that lift a falling wing with thy ailerons, but instead thou newest instruction you could put a moving finger up to his lips and have shalt simultaneously reduce the angle of attack and manual. him make the “boo, boo, boo” sound that’s perfectly stop the yawing motion with rudder. That’s right. If you stall an airplane in uncoordinormal—for an infant. Why do some pilots get nervous when the wings of their nated flight, it’s likely that your nose (actually, the one on the airplane go on an aerodynamic strike? One word: predictabil- airplane) will begin to yaw at the moment of stall. You may be ity. Specifically—the lack of it. If an airplane stalled and always in a tizzy, but you’re not yet in a spin, so you don’t apply full pitched only forward along a plane perpendicular to the lateral spin recovery technique (more on this momentarily). You’re in axis of the airplane (from the student’s nose to his feet), then a normal stall with one wing stalling a bit more than the other. stalls would be a ball, and most people’s discomfort would be That’s why you’re yawing (and perhaps hearing a slight hum in tamed. The problem is that during the stall one wing can reach your headset). its critical angle of attack before the other. Once that happens, Reduce the angle of attack and simultaneously stop the yaw the airplane begins to yaw and roll in the direction of the most by applying rudder in the direction opposite the yaw (whatever stalled wing. You know where that can lead, right? I’m talking you do, don’t lift the falling wing with the aileron until you’re about the “cardinal spin” of aviation—the unanticipated spin. sure it’s no longer stalled). How much rudder do you use? Push Here are the two stall commandments you need to know to the pedal to the metal until the yaw stops. You aren’t going to make stalls more predictable and much more fun: hurt the rudder. Your rudders don’t have feelings. Keep in mind Stall commandment number one: Thou shalt not stall an that your rudder is the last flight control forfeited in the stall. airplane in uncoordinated flight. To some this may be a revela- That means it works well during the stall, mainly because it’s tion, but it’s actually sound stall theory and one of the most poking up behind the airplane into the free airstream. If the important rules about making stalls more predictable. It’s also airplane doesn’t yaw it won’t spin. Period. the single biggest reason you always want to fly coordinated. Of course, if you dilly instead of dally, and let the airplane When an airplane approaches the stall with the inclinom- enter a full spin, then you’ll want to do what my friend and eter’s ball displaced even slightly, one wing may have a slightly spin expert Rich Stowell recommends in his ultimate stall book, larger angle of attack than the other. The result? One wing stalls Stall/Spin Awareness. You’d use the PARE technique—reduce before the other, and the airplane begins to yaw and roll in the Power, neutralize the Ailerons, apply opposite Rudder to stop direction of that wing. Why does this happen? Imagine you’re in the yaw, and then use the Elevator to break the stall (but don’t a skidding left turn, meaning that the nose points inside the turn break anything else, even if it’s a rental). Do you see the pattern and the ball deflects to the outside of the here? It’s your rudder that either stops the turn (think too much left rudder for the yaw before the spin, or stops it in the spin. Join the fun bank angle used). Excessive left rudder Rudders rule. Rod Machado will be a featured yaws the airplane’s nose to the left, resultSo there you have a low-hum, twospeaker at AOPA Aviation Summit ing in the left wing moving rearward (the commandment plan of action that allows 2010 in Long Beach, California. He wing slows down slightly) and downward you to have a ball with stalls. But do try will offer three different forums this year. He is also a co-host for a “Dine (increasing its angle of attack slightly). and keep that ball centered. Around” event on Thursday, NovemThe result is that the left wing stalls first ber 11. For more information, visit in the left skidding turn. Had you been on Visit the author’s blog (www.rodmachado. the website (www.aopa.org/summit). the ball and kept it centered, both wings com). 32 • NOVEMBER
2010

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AOPA Pilot Magazine - November 2010

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