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Posted in Uncategorized on December 31, 2012
Here’s an excerpt:
4,329 films were submitted to the 2012 Cannes Film Festival. This blog had 29,000 views in 2012. If each view were a film, this blog would power 7 Film Festivals
I read a lot of aviation blogs, on email lists and such. This particular email came from Thomas Turner of Mastery Flight Training in early November. If you would like to subscribe to his newsletter, please do so, it has some great content. He had a reader chime in which he added to his email that I wanted to quote.
This week’s FLYING LESSONS features frequent Debriefer, airline pilot and general aviation enthusiast David Heberling as a guest columnist. David sent me this email in response to last week’s discussion of angle of attack and spin awareness following an engine failure immediately after takeoff. He’s sent it to other aviation outlets also, but I think David’s comments should spark a good conversation here as well. David writes:
I realize it may be hard to believe, but I just finished reading Stick and Rudder by Wolfgang Langewiesche. I have to credit my wife for bring the book home from the library. She wants to understand flying better.
I have read many flying books and magazines during my 40 years of flying, but I have never had it presented quite like it is in this book. I actually learned something new. The primary message of the book is that the elevator directly controls Angle of Attack of the wing ONLY. My training spoke only of “pitch and power” being the totality of our flying experience. It is easy to understand why he hammers at this theme. Too many loss of control accidents occur as spins out of turns.
Langewiesche presents many examples of spins out of steep turns, the engine failure scenario being one of them. We also know about the take off and departure scenario and the base turn to final one as well. He attributed all of them to pilots cheating with the bottom rudder to quicken the turn. This cheating leads to a cross-control situation and high angle of attack. It is the attempt to raise the low wing that gets them into trouble. That the aileron can cause the section of wing ahead of it to go beyond the critical AOA is something I never thought of. The surprise and puzzlement must be extreme when the low wing goes even lower instead of rising. The spin soon follows and time is running out.
All of this cheating with the rudder was a revelation to me. I have never ever thought of doing the same thing myself. Coordinated turns were pounded into me relentlessly during my extended student pilot pre-solo period (3 years, from 13 to 16). Now, I understand why airline upset training wants us to PUSH first (unload the wing/reduce AOA), then roll level, and power as necessary. Now I understand how pilots spin out of turns. I have tried it in my aircraft at altitude. All I ever achieved was a very high pitch attitude and a turn so steep it made me dizzy. It is not the turn itself that causes the problem, it is the attempt to return to level flight when turning all cross-controlled.
This book was written in the 1940s. Everything talked about in this book is still true today. Pilots still spin out of turns. Why have I never heard about this in aviation safety circles until reading this 1940s book? Langewiesche talks about how pilots are poor judges of AOA, especially in a turn. In our airplanes, we do have a handy AOA indicator. It is the yoke. You could actually color code the shaft if you wanted to. The first half could be green, the next third could be yellow, the last couple of inches would be red. The green would be closest to the control wheel, the yellow further out, and red next to the panel when the yoke is fully extended.
I find it incredible that today we are wringing our hands over the stuck value of GA accident rates. We are all agog over scenario-based training to solve this problem. Back when this book was written, the author and Leighton Collins thought that rudderless (no rudder pedals) were the answer to this problem. This idea has never caught on in any appreciable way and I can understand why. I do think Leighton had the right idea about exposing students to this phenomenon. Yet, this never happened. Where do we go from here? How do we bring AOA back into the forefront of training? How do we inculcate students against cross controlling (except in crosswind landings) and cheating with bottom rudder in turns? How do we demonstrate this exact scenario so the student can see how you can actually stall just a portion of the wing (an extremely important portion at that) and cause a spin?
Maybe FLYING LESSONS is not the place for this kind of discussion. Do you know a suitable place? I would like to participate in it wherever it happens. – David Heberling
How many times have we disagreed on the concept of pitch control what and power controls what? My very first flight instructor taught me that pitch controls airspeed and power controls altitude and then I was handed off to a different instructor at the same flight school and he quickly learned that I was doing it wrong. For the next $1000s of dollars I spent, I had to unlearn what was primarily taught to me (remember the law of primacy) and learn the “correct” way the school wanted that concept taught. I can still hear the second instructor yelling at me that I was told incorrectly and need to get it in my head that power controls airspeed and pitch controls altitude. No exceptions.
After earning degrees specializing in advanced aerodynamics. I believe there are situations where both sayings are correct. You simply cannot adjust one variable without the other variable changing as well. This is why I like David’s comments so well. If we would simply realize that the elevator controls the angle of attack of the wings only, both of those methods will no longer matter and the training industry can move on from these arguments.
Think about it, on the backside of the power curve and holding altitude the slower you get the more power you need. The only way to increase airspeed is to lower the nose. Since we realize the airplane is at such a high angle of attack, by reducing the elevator (and angle of attack) we can regain flying speed.