Turns

Here are four black-and-white, factual statements to chew on:

• The turn is the most common maneuver in aviation.

• The turn is the most commonly misunderstood maneuver in aviation.

• The turn is the most poorly done maneuver in aviation.

• The turn is the most underrated maneuver in aviation.

Now, let’s talk about turns. A sizeable portion of readers are wrinkling up their noses and saying, “Turns? How can we possibly have a long-winded conversation about such a simple maneuver that is so easily accomplished? How complicated can it be?” The answer is that a turn is far more complicated than it appears and is often done poorly.

Adverse yaw. Before we can get into the mechanics of making a turn, we need to review adverse yaw.

As the name implies, adverse yaw is yaw (a flat, horizontal motion of the nose) that is going against something. It is adverse. In this case it is working opposite, or against, the turn. Adverse yaw is created when the ailerons are deflected. The down aileron increases the airfoil camber, thereby increasing lift. Increased lift is always accompanied by increased drag; that’s just the way the vectors work. Because the ailerons are down on only one wing (outboard), that wing has more lift, so it moves vertically up, rolling the airplane into a bank, which in turn increases drag. The inboard aileron is up, so that wing has less lift and less drag. The increased drag holds the outside wing back, causing the airplane to yaw to the outside of a turn while banking. Think of it in terms of bank left, yaw right, or vice versa. Knowing this, it makes thus makes sense that the drag on the two wings is imbalanced only while the ailerons are deflected and disappears when the bank is stabilized. At that point, all forces are balanced and aileron and rudder do not need to be deflected.

Adverse yaw is cancelled out by creating positive yaw via rudder in the direction of the turn. Left turn, left rudder, and so on

Define a good turn. A good place to start defining “good turn” would be to simply say, “Throughout the entire turn, roll-in to roll-out, the ball stays in the middle.” That’s a pretty basic statement. So, why aren’t all turns done that way?

Modern aircraft have been carefully designed to minimize some of the effects we’ve been discussing. The adverse yaw is there, but it is so small that it’s easy to overlook. More damaging, it’s easy to just ignore the rudder altogether when making normal turns that require minor aileron displacements.

A logical question would be, “Is the ball moving when these feet-on-the-floor turns are being made?” Yes, it is. It’s impossible for it not to move to one degree or another, depending on the airplane. Such nuances are easily ignored, but nuances are what spell the difference between doing it right and doing it more or less right.

Ignoring the rudder during turns leads to a general complacency in which aileron movements and rudder movements aren’t terminally linked together in the pilot’s brain. So, when extreme situations happen, such as battling really nasty turbulence/wind conditions on short final where the trusty old Cessna 172 requires all the aileron it has in both directions, the feet aren’t subconsciously part of the equation. It’s in this kind of situation in any airplane—making rapid, big aileron deflections—that even the most modern aircraft with state-of-the-art aileron design will be sliding the ball back and forth. The result will be that the nose will also be yawing right and left at a time when we’d really like to have it straight in front of us for a decent touchdown.

Common mistakes. There are a number of common turn mistakes.

The roll-in is anticipated with aileron: The pilot starts the aileron in a little early, which induces a slight yaw opposite to the direction of the turn. Ball is to the inside.

The rudder (assuming there is any) comes in late.

Just as the bank angle is stabilized, the ailerons often cross the neutral position slightly, deflecting the inboard aileron down, when it’s not needed in a normal bank turn. Since the ailerons are in a slightly out-of-turn position, the rudder is pressured in the direction of the turn to keep the turn going, so the ball is out of center opposite to the direction of the turn: The airplane is slightly cross-controlled (sometimes more than slightly).

The rollout is anticipated with the ailerons being deflected to begin leveling the wings long before the nose has completed the turn. If the rudder is used, it usually comes in late.

You should be consciously watching yourself make turns and see how many items on the list are living in your cockpit.

Pay special attention while approaching for a landing because, as speed goes down and angle of attack goes up, adverse yaw also goes up—so all of the foregoing effects become more noticeable.

Compartmentalizing turns helps. The easiest way to clean up our turns is to view them in a compartmentalized fashion, where the turn is broken into three parts, with the borders between being very distinct.

As would be expected, the three parts are the roll-in; the turn itself; and the rollout. The important aspect of these compartments is that the borders of each are not to be violated.

For instance, as the roll-in happens, rudder and aileron go in together in a clean fashion. Where the roll-in becomes the stabilized turn, the controls come out together. The same thing applies to the rollout: The pilot stays in a stabilized, controls-centered bank until the aircraft is almost exactly where it should be, then the controls come out.

The problem is timing. Many pilots have a difficult time realizing that they aren’t very precise. Anticipating the roll-in and roll-out with the ailerons is where the timing most often is wrong. The timing should be such that an aileron is never out into the wind (except when slipping) without a corresponding amount of rudder applied to compensate for the adverse yaw. Hands and feet should be permanently and unconsciously linked together.

Every airplane has a distinct mix in terms of how much rudder is needed for a given amount of aileron and how quickly the rudder goes in compared to the aileron. This isn’t a big factor in modern aircraft, but that’s why every time you get into a new airplane type, you should do some of the so-called “Dutch roll” coordination exercises to determine the airplane’s coordination personality.

Climbing and gliding turns. Everything that has been discussed becomes slightly altered when making climbing or gliding turns. When at full power or power-off, the effects of P-factor skew the neutral position of the rudder inputs, requiring a different mindset. This is where many of the difficulties above become most obvious.

In a full-power climb, the P-factor does its best to slide the ball—however minimally—off to the right, so a little right rudder is needed to keep it in the middle to maximize performance. So, the “zero rudder” position is shifted to the right because of the anti-P-factor rudder that’s always there. For that reason, when rolling into a full-power, climbing left turn, left rudder usually isn’t needed. Just reduce the amount of right rudder being held while rolling in. Then reestablish the rudder when the bank is stabilized.

Power-off gliding sees the ball sliding the other way, to the left, so left rudder is needed all the time. This skews the neutral position the other way.

Incidentally, the most common situation in which a pilot is cross-controlled, with rudder into the turn and aileron out of it, will be on approach to landing.

A lot of pilots make perfect turns every time. Others don’t. The way for you to know where you fit in the coordination spectrum is to monitor the ball while in the act of rolling into a turn, while in the turn, and while rolling out. The airplane will tell you how you’re doing. Then, it’s up to you to decide whether good enough actually is good enough, or whether you want to improve by paying a little more attention to what you thought was a simple maneuver but isn’t. The turn tells the truth every time.