The Not-So-Noble Lie

On Friday, I was flying with Chris, who’s been working on his private pilot's certificate on-and-off for years, in four or five different kinds of airplanes, with I don’t know how many instructors. I’ve finished up his program, and we’re getting his checkride done this week. Chris is a thoughtful guy, and I always enjoy talking with him. He’s one of the most inquisitive and introspective students I’ve ever had. And something came up that turned into one of those “Aha!” moments for my students that I absolutely live for.

Every so often, I’m able to make professional use of my degree in Philosophy. It’s very very rare, but it happens. Yesterday, while I was a thousand feet in the air, doing something that would have been unthinkable 2400 years ago, Plato once again makes himself relevant to me.

In the Republic, Plato has Socrates describe a “Noble Lie,” which he presents as a myth necessary for (or at least greatly beneficial to) society. Its falsehood is supposed to be outweighed by the harmony and social justice that would result if it were to be taken as the truth. It wasn’t an allegory, or a parable, but was meant to be used as an article of faith.

When I was in college, that occurred to me as a total cop-out. At best, it’s just cheap trick, but at worst, it’s an unforgivable compromise of Plato’s reverence for Truth. I mean, we’d just gotten done with that whole “shadows on the wall of the cave” analogy, so tossing "Truth" out the window in favor of “Justice” seemed…icky. I know that’s a juvenile reaction, and I understand that a mature and scholarly reflection of the entire work casts Plato’s myth-of-the-metals in a different light, but that’s not the point here.

The point is that I didn’t like it, and I still don’t.

And, while Plato’s own Noble Lie isn’t relevant to flying airplanes, the concept of a “Noble Lie” applies to a lot of stuff in flight training. Teaching people things that aren’t strictly true, but which are intended to produce good results if they’re understood as true, is everywhere in my field of work. And I like that even less.

Now, I have philosophical reasons for disliking it, but I can suck that up. I mostly have to deal with the problems that arise when flight training’s “Noble Lies” fail to produce their intended good results…which happens a lot. Then, you have a real lack of understanding, and a practical inability to accomplish or explain a task, and usually, a lot of confusion surrounding it.

This happened with Chris, downwind in the pattern at Orlando Executive airport. We’re a little too high and a little too fast coming abeam the aiming point.  I pointed this out to him.  Faced with the need to descend and slow down, Chris wiggled the stick a bit, then asked me: “Okay… so is it ‘pitch-for-airspeed’ now?”

The next 1500 words you’re about to read occurred all at once in my head, prefaced by a big “Oh, Dear.” Chris was struggling with a Noble Lie he’d been taught, and it was getting in the way of flying the plane. Of course, I couldn’t just spit it all out right then- timing was critical at that moment, so I said:

“Just fly it.  The plane isn’t behaving any differently just because we’re in the pattern. We’ll talk more when we’re done with this approach. Just fly the way you usually do.” And then he did.

The Noble Lie he’d been taught goes something like this: 

Normally, when you fly an airplane, use the power as your primary control for airspeed (more power = go faster, less power = go slower) and you use pitch as your primary control for altitude (pull up = climb, push down = descend).

However, when operating at speeds below minimum drag, the airplane is operating on the “back side of the power curve” and controls enter the “region of reverse command” in which that relationship is reversed.

This is the case during “slow flight” and during an approach to land. Pitch attitude becomes the primary control for airspeed (pull up = go slower, push down = go faster) and power is the primary control for altitude (more power = climb, less power = descend).

This confusing wad of jargon has befuddled more student pilots (including me) than I can even count. If you haven't learned to fly, you're probably blinking and saying "huh?"  If you have learned to fly, you're probably groaning and thinking "Oh God. That... stuff."  And if you're Johnny Expert and have come to peace with it, you're probably pretty darn proud of yourself for thinking "oh yes, that's not so hard."  But it is hard. This generates thousands upon thousands of student pilot questions, and many hours of double-talk by CFIs and mentor pilots who may not be too sure about it themselves.

Now, to be fair, there is merit to this Noble Lie. It does work, when understood correctly, and when someone is flying well, this is pretty much what you'd see them do. The way I've carefully stated it here is the way it's been passed down from generation to generation, like folklore.  Most CFIs will still parrot it out just the way they learned it, and they'll tell you you're wrong if you disagree.  It has legitimate origins in a superceded FAA manual called the Flight Training Handbook. Interestingly, it's still mentioned in the current edition of the Airplane Flying Handbook as somethng to avoid (p. 8-19), but it's no longer given as the proper technique for "Slow Flight." Instead, they warn you about the same effect, but they call it "speed instability" and tell you how to get out of it (p. 4-2).

That's a good thing.  As a student, this confused the crap out of me. Jerry, my regular CFI, spat the Noble Lie out at me chapter-and-verse, and stood by it. I tried to nail him down to a specific speed at which “reverse command” takes effect, and, after some reflection, he said “best glide speed.” Since that was within three or four knots of my final approach speed, it looked to me like we’d be in-and-out of it as my speed wobbled around on final the way it usually did.  As a result, I was perpetually torn between trying to micro-manage airspeed with pitch, and trying to hold the aiming point steady in the windscreen.


I finally asked Jeff, the chief pilot, and he just sighed and lowered his head. Now I know why. That was his big "Oh, Dear." He told me not to worry about reverse command until I was deeply into the flair. That worked! It worked even better because I still wasn't worried about it deeply into the flair, since I was completely distracted by the process of landing. So, I ended up ignoring it completely. Wise man, that Jeff.

But, back to my student, Chris. He’d learned this stuff from somewhere, attempted to transition between "normal" and "reversed" commands, and got lost trying to connect the dots. His problem wasn’t just that he was too fast for it. He was flying perfectly well, then he started thinking about this, and got disoriented about what to do. Here’s how his gears were grinding-

• I need to both descend and slow down. According to this “reverse command” thing, I don’t see how I can do both at the same time. Which should I do first?
• I’m about to maneuver to land. Am I in ‘the region of reverse command’ or not?

• If not, I need to push forward on the stick to descend, but if so, I need to pull back on the throttle to descend instead, and,
• If not, I need to pull back on the throttle to slow down, but if so, I need to pull back on the stick to slow down instead…

• …and that’s if I’m getting it right. Do I have it right?

It’s fairly easy to bemoan someone’s lack of basic flying skills, or complain that people aren’t teaching the “four fundamentals,” or that the guy wasn’t using trim properly. But that's not the problem. Chris’s “four fundamentals” were solid, because his flying was okay both (a) before this confusion occurred to him, and (b) after I’d told him to ignore this concern. The problem was that thinking about the Noble Lie of “reverse command” derailed his essentially solid flying skills by making him believe that he’d have to start doing everything "backwards."

So, after the touch-and-go, I took the controls on the downwind departure, and showed him this (which also works at 100 knots, and 80, and 60, and any speed at which the stall horn isn't screaming bloody murder into both of your ears): 

• Trimmed out at 90 knots, level, I push the throttle forward, with no change to elevator pressure. What happens? We gain RPM and speed up. What else happens? The extra speed makes us pitch up and climb. Then what? The nose going up makes us lose RPM and slow down. The overall effect? Adding power creates a dynamically stable oscillation into a climb, close to our trimmed-out airspeed.

• Again, trimmed out at 90 knots, I pull the throttle back, with no change to elevator pressure. What happens? We lose RPM and slow down. What else happens? Our nose drops and we descend. Then what? The nose dropping builds RPM and speeds us up. The overall effect? Decreasing power creates a dynamically stable oscillation into a descent, close to our trimmed-out airspeed.

•  Again, trimmed out at 90 knots, I pull back on the stick, with no change in throttle setting. What happens? The nose goes up. What else happens? We slow down and lose RPM. Then what? Slowing down drops our nose a bit. The overall effect? Pulling back on the stick creates a dynamically stable oscillation into a climb, below our trimmed-out airspeed.

• Again, trimmed out at 90 knots, I push forward on the stick, with no change in throttle setting. What happens? The nose drops. What else happens? We speed up and gain RPM. Then what? The gain in speed and RPM pitches our nose back up. The overall effect? Pushing forward on the stick creates a dynamically stable oscillation into a descent, above our trimmed-out airspeed.

The moral of the story: Any change you make in the throttle shows up in RPM, speed, and pitch attitude. Any change you make in elevator pressure also shows up in pitch attitude, speed, and RPM. Those two controls are tied together through the performance and stability of the airplane.  Therefore, if you want to climb, descend, speed up, or slow down, you have to work both controls together. It doesn’t make sense to try to isolate their functions while learning to do this.

Putting it all together-

• Climb = add power and pull up the nose.
• Descend = reduce power and let the nose down.
• Speed up = add power and hold the nose down.
• Slow down = reduce power and hold the nose up

"Reverse command” doesn’t change that when you're at or below best glide speed, or on an approach. Flying the plane is always about finding the balance of attitude and power which produces the behavior you want, and trimming away control pressure when stabilized.

Put more simply- Just Fly It.  Screw the Noble Lie.

That was Chris’s “Aha!” moment. “Oh,” he said on his next approach, “I can just fly it.” And that time, he did a nice job.