Adverse yaw is the airplane’s tendency to yaw away from the direction you are rolling when you use the ailerons. The aileron that goes down raises its wing by adding lift, and that extra lift brings extra induced drag, so the rising wing is held back and the nose swings toward it, opposite the turn. You cancel it with rudder in the direction of the turn, applied together with the aileron, and you need the most rudder at low airspeed, high angle of attack and large aileron deflections, which is why adverse yaw matters most in slow flight and near a stall.
Part of our How Airplanes Work guide. Its companion pages are left-turning tendencies, the other yaw you correct with your feet, and ground effect, another induced drag story.
What causes adverse yaw
Turn the control wheel to the right and, as the FAA’s Pilot’s Handbook of Aeronautical Knowledge (PHAK) describes it, the right aileron deflects up and the left aileron deflects down. The down aileron increases the left wing’s camber and lift; the up aileron decreases the right wing’s. The airplane rolls right. But the left wing’s extra lift comes with extra induced drag, the drag that is a by-product of lift, while the right wing’s drag goes down. The PHAK says that added drag slows the rising wing slightly, so the airplane yaws toward it. From the pilot’s seat, the nose swings left while the airplane banks right.
The FAA glossary puts it in one line: the nose tends to yaw toward the outside of the turn because of the higher induced drag on the outside wing, which is also producing more lift. The same thing happens when you roll out. The down aileron is then on the low wing, so the nose tries to keep yawing into the old turn.
When adverse yaw is strongest
The PHAK says the amount of rudder needed is greatest at low airspeeds, high angles of attack and large aileron deflections, and those conditions travel together. At low airspeed the controls are less effective, so you need bigger aileron inputs for the same roll, and bigger inputs make more adverse yaw. The rudder loses effectiveness at low speed too, which magnifies the problem. The PHAK adds that the yaw is especially evident in airplanes with long wingspans. At cruise speed the same small input makes much less yaw, so lazy feet can go unnoticed until you are slow, in the traffic pattern or in slow flight.
How to fly it: coordinated rudder
The rudder does not turn the airplane; the horizontal component of lift does. The Airplane Flying Handbook (AFH) says the rudder’s job in a turn is to counteract adverse yaw so the turn is coordinated. In practice:
- Roll in with aileron and rudder together, in the same direction. The AFH’s cues: if the nose starts to move before the bank starts, the rudder came too soon; if the bank starts before the nose starts turning, or the nose moves the opposite way, the rudder came too late.
- Relax once the bank is set. In a medium bank, about 20 to 45 degrees, the AFH says to neutralize the ailerons and rudder. A shallow bank needs a little aileron and rudder held into the turn; a steep bank needs opposite aileron and rudder to keep it from steepening, as you will feel in steep turns.
- Roll out the same way in reverse, with aileron and rudder toward the high wing.
- Check the ball. The PHAK’s rule for the inclinometer is “step on the ball”: press the rudder on the side the ball has moved to. Its example: too little right rudder in a right turn produces a slip, and the ball moves to the inside of the turn.
More is not better. The AFH’s cross-control stall warning describes the opposite mistake: excess rudder in the direction of the turn in a poorly planned base-to-final turn, which creates a skid and can turn a stall into a spin. The goal is just enough rudder to keep the ball centered.
Rest your heels on the floor with the balls of your feet on the rudder pedals. The AFH recommends exactly that so you can feel slight changes in rudder pressure, and rudder applied with the aileron, not after it, is what keeps adverse yaw in check.
Why it matters in slow flight and near the stall
Slow flight puts you in adverse yaw’s worst corner: low airspeed, high angle of attack and big control inputs. The private pilot ACS slow flight task lists yaw effects as a knowledge element (PA.VII.A.K1), uncoordinated flight as a risk element (PA.VII.A.R3), and requires coordinated straight-and-level flight, turns, climbs and descents (PA.VII.A.S4). Our slow flight guide walks through the task.
Near the stall, aileron use itself can bite. The AFH gives the example of an airplane that rolls left at the stall: if you apply right aileron to pick up the left wing, the down aileron raises that wing’s angle of attack and induced drag and can deepen the stall at the tip, rolling you further left. Add yaw to a stall and you have the ingredients of a spin, and the AFH names adverse yaw from aileron deflection as one source of that yaw. That is why its stall recovery reduces angle of attack first, then rolls the wings level while the rudder cancels any yaw. Practice it in power-on and power-off stalls, and see our stalls guide for the aerodynamics.
How designers reduce adverse yaw
The PHAK describes four systems manufacturers use to reduce adverse yaw. None eliminates it, so you still need your feet.
- Differential ailerons: the up aileron travels farther than the down aileron. The extra parasite drag from the up aileron, on the descending wing, helps balance the induced drag of the down aileron.
- Frise-type ailerons: the aileron pivots on an offset hinge, so when it goes up its leading edge projects below the wing and adds drag on the descending wing. The design also forms a slot that keeps air flowing smoothly over the lowered aileron at high angles of attack, and Frise ailerons can be rigged to work differentially too.
- Coupled ailerons and rudder: interconnect springs deflect the rudder automatically with the ailerons. You can override the springs when you need to slip.
- Flaperons: one set of surfaces works as both ailerons and flaps through a mixer; many designs mount them away from the wing for undisturbed airflow at high angles of attack.
Adverse yaw on the checkride
Expect your examiner to probe coordination in steep turns (the ACS lists maintaining coordinated flight under PA.V.A.K2a), slow flight and stalls, and to ask on the oral exam what adverse yaw is, what causes it, how you correct it and why it is worse at slow speed. A strong answer names the down aileron, the induced drag that comes with its extra lift, the yaw toward the rising wing, and coordinated rudder as the fix.
What you'll need
The FAA handbooks that explain adverse yaw and coordinated flight, plus an oral exam guide to practice your answers, from PilotMall.com.
Frequently asked questions
What is adverse yaw in simple terms?
It is the nose swinging the opposite way from your turn when you use the ailerons. The down aileron on the rising wing adds lift and induced drag, so that wing is held back and the nose yaws toward it, away from the turn.
How do you correct adverse yaw?
Apply rudder in the direction of the turn at the same time as the aileron, then relax both once the bank is set. Keep the ball centered: step on the ball. Roll out the same way, with aileron and rudder toward the high wing.
Why is adverse yaw worse at slow speed?
At low airspeed the controls are less effective, so you need larger aileron deflections to roll, and larger deflections make more adverse yaw. The rudder is less effective too. The PHAK says the most rudder is needed at low airspeed, high angle of attack and large aileron deflection.
Which wing causes adverse yaw?
The rising wing, the one with the down aileron. It is producing more lift and therefore more induced drag, so the nose yaws toward it. In a right roll that is the left wing, and the nose yaws left.
Do differential or Frise ailerons eliminate adverse yaw?
No. The PHAK says both reduce adverse yaw but do not eliminate it, so coordinated rudder is still needed whenever you use the ailerons. Coupled ailerons and rudder and flaperons are the other two design approaches it describes.