What Does the Rudder Do on a Plane? How It Works, and Why It Doesn’t Turn the Airplane

The rudder is the hinged panel on the back edge of an airplane’s vertical tail. It controls yaw, the left and right swing of the nose: push the left rudder pedal and the rudder swings left, the tail is pushed right, and the nose yaws left.

What surprises most people is that the rudder is not what turns the airplane. Banking the wings does that. The rudder’s real job is keeping the nose lined up with the direction of flight, and it matters most when something is trying to push the nose sideways.

That happens in every turn, on every takeoff in a propeller airplane, in every crosswind landing, and whenever an engine quits on a twin. It is also the main control for recovering from a spin, and on the ground the same pedals steer the airplane.

When Pilots Use the Rudder

Situation	What pushes the nose sideways	What the pilot does with the rudder
Rolling into or out of a turn	Adverse yaw from aileron drag	Rudder in the direction of the roll, then neutral once the bank is set
Takeoff and climb (single propeller)	Torque, slipstream and P-factor pull the nose left	Right rudder, on the usual clockwise-turning US engine
Crosswind takeoff or landing	Wind pushes the airplane sideways and the tail weathervanes	Rudder keeps the fuselage lined up with the runway
Forward slip	None, the slip is deliberate	Rudder opposite the lowered wing to lose height without gaining speed
Engine failure on a twin	Thrust from one side yaws the nose toward the dead engine	Rudder toward the working engine
Spin recovery	The airplane is stalled and rotating	Brisk, full rudder opposite the rotation
Taxiing	Nothing, the pilot wants to turn	Pedals steer the nosewheel or tailwheel, helped by the brakes

How the Rudder Works

The rudder is hinged to a fixed surface, the vertical stabilizer or fin. Together they form a small wing turned on its side, and like any wing they make lift. On the tail that lift points sideways.

When the rudder swings into the airflow, it changes the shape of that sideways wing and creates a force in the opposite direction. The FAA describes it plainly: pushing the left pedal moves the rudder left, which “moves the tail to the right and yaws the nose of the airplane to the left.”

The rudder sits at the very back for leverage. NASA’s Glenn Research Center explains that the side force acts at a distance from the center of gravity, and the turning effect is that force multiplied by the distance. A long tail arm lets a modest surface swing a large airplane.

How much a given deflection does depends on speed. Slow flight needs big rudder movements and fast flight needs small ones, and on a propeller airplane the slipstream blowing over the tail makes the rudder more effective at low speed.

Rudder pedals: which way do they go?

Push the left pedal and the nose goes left. Push the right pedal and it goes right. The two pedals are linked and move in opposite directions, so pressing one lets the other come back toward you.

The FAA teaches pilots to rest their heels on the floor and press with the ball of the foot, so small changes in pressure can be felt. In most light airplanes the brakes sit on top of the same pedals, and the pilot slides the toes up to use them.

In most aircraft the pedals are linked mechanically to the rudder. In large or high-speed aircraft, SKYbrary notes, hydraulic actuators are often added to help overcome the mechanical and aerodynamic loads on the surface.

The Rudder and the Three Axes of Flight

An airplane rotates around three axes, and each has its own primary control. The rudder is one of the three primary flight controls the FAA says are required to control an aircraft safely.

• Roll around the longitudinal axis, nose to tail: controlled by the ailerons.
• Pitch around the lateral axis, wingtip to wingtip: controlled by the elevator.
• Yaw around the vertical axis, top to bottom: controlled by the rudder.

Everything else is a secondary control. Flaps, leading-edge devices, spoilers and trim improve performance or relieve the pilot of heavy control forces, but they are not what the FAA counts as the controls needed to fly safely.

Why the Rudder Doesn’t Turn the Airplane

A boat turns with its rudder. An airplane does not, and this is one of the most common misunderstandings about flying.

To turn, an airplane needs a sideways force, and it gets one by banking. Tilt the wings and part of their lift now points toward the inside of the turn. The FAA calls this the horizontal component of lift, and it is what pulls the airplane around.

So why have a rudder at all? Because the moment you start a turn, the airplane tries to point its nose the wrong way.

Adverse Yaw: The Rudder’s Most Important Job

To roll left, the left aileron goes up and the right aileron goes down. The lowered aileron makes the right wing produce more lift, and more lift always brings more induced drag.

That extra drag slows the rising right wing slightly and yaws the nose to the right, away from the turn. This is adverse yaw. The FAA says it is worst at low airspeed, at high angles of attack, with large aileron deflections, and on airplanes with long wingspans.

The fix is rudder in the same direction as the roll. Aileron and rudder go in together, the nose tracks smoothly into the turn, and once the bank is established both are relaxed. Pilots call this a coordinated turn.

The cockpit keeps score with a small ball in a curved glass tube, the inclinometer on the turn coordinator. In coordinated flight the ball stays centered. Too little rudder and the airplane slips, too much and it skids.

Designers have spent a century trying to shrink the problem. The FAA lists four fixes: differential ailerons, Frise-type ailerons, flaperons, and coupled controls where springs move the rudder automatically with the ailerons. The two aileron designs reduce adverse yaw without eliminating it, so pilots still need the rudder.

The Ercoupe: The Airplane With No Rudder Pedals

One designer went further. Fred Weick’s ERCO Ercoupe, first flown in 1937, had no rudder pedals at all. A two-control system tied the rudders and ailerons together and linked them to a steerable nosewheel, so the pilot flew and taxied with the control wheel alone.

It worked well enough that US regulators created a new category of pilot license for Ercoupe pilots who had never used a rudder pedal. The Ercoupe was also the first aircraft the Civil Aeronautics Administration certified as “characteristically incapable of spinning.”

The idea did not take over. Later Alon Aircoupe models added limited-movement rudder pedals, partly to make them better trainers and partly to handle the extra P-factor yaw from a more powerful engine in the climb.

Other Jobs the Rudder Does

Takeoff and climb: the need for right rudder

Yes, pilots use the rudder on every takeoff. In a single-engine propeller airplane, the FAA counts four left-turning tendencies: torque reaction, the corkscrewing slipstream striking the tail, gyroscopic action of the propeller, and asymmetric blade loading, better known as P-factor.

On the usual US engine, which turns the propeller clockwise as seen from the pilot’s seat, all four pull the nose left at high power and low speed. The pilot holds right rudder down the runway and through the climb to keep the airplane straight.

As speed builds, the rudder gets more effective and the pilot needs less of it. The FAA describes the point where the airplane “is being flown more than it is being taxied,” and from there progressively smaller rudder deflections keep it straight.

Crosswind landings

A crosswind pushes the airplane sideways, and touching down while drifting sideways loads the landing gear in a direction it was not built for. In the wing-low method, the pilot lowers the upwind wing to stop the drift and holds opposite rudder to keep the fuselage lined up with the runway.

The rudder sets the limit. If the wind needs so much bank that full opposite rudder can no longer stop the airplane turning, the FAA says the crosswind is too strong to land safely on that runway in that airplane.

Slips: losing height without gaining speed

Pilots also cross the controls on purpose. In a forward slip, one wing goes down with aileron while opposite rudder yaws the nose the other way, so the fuselage meets the air at an angle and creates a lot of drag.

That lets an airplane that is too high on approach steepen its descent without picking up speed. In most light airplanes, the FAA notes, the steepness of the slip is limited by how much rudder travel is available.

Engine failure on a twin

When one engine of a twin fails, the other one keeps pushing from one side, and the airplane yaws hard toward the dead engine. Rudder toward the working engine is what holds it straight.

Multi-engine pilots use the memory aid “dead foot, dead engine.” The foot doing the work is on the side of the good engine, so the idle foot points to the one that quit.

Rudder authority fades as the airplane slows, and below a certain speed even full rudder, with a small bank toward the good engine, can no longer hold the airplane straight. That speed is VMC, the minimum control speed with the critical engine inoperative, marked by a red line on most twin airspeed indicators.

Spin recovery

In a spin, the wings are stalled and the airplane is rotating as it falls. The ailerons can make things worse, so the FAA recovery procedure has the pilot neutralize them and apply full rudder against the rotation.

The handbook is blunt about it: rudder “tends to be the most important control for recovery in typical single-engine airplanes,” and it should go in briskly, because slow and cautious rudder “can allow the airplane to spin indefinitely.” Our guide to the flat spin covers the most dangerous version.

Rudder Trim

Holding rudder pressure for a long time is tiring, so most airplanes have some way to trim it out. Many small airplanes use a ground-adjustable tab, a small fixed metal tab on the rudder that is bent on the ground, by trial and error, until the airplane stops flying slightly crooked.

As airplanes get more powerful, heavier and more complex, the FAA notes, they gain rudder trim the pilot can adjust in flight. Where all three trim axes exist, the handbook says to trim the rudder first, then the elevator, then the ailerons.

Rudder trim earns its keep after an engine failure on a twin, where the pilot can trim out the constant pedal force needed to hold the airplane straight. The FAA warns pilots to expect a rudder trim change as the good engine is throttled back just before touchdown.

Steering on the Ground

The rudder only works with air flowing over it, so at taxi speed it does very little. The pedals still steer, though.

On most light airplanes they are linked to the nosewheel, and the FAA says to start turns with pedal steering and add brake only to tighten a turn once the pedal is at full deflection.

The brakes double as a steering aid when the pilot needs more than the rudder and nosewheel can give. Pressing one toe brake harder than the other, called differential braking, pulls the airplane toward that side.

Large airplanes usually add a tiller. SKYbrary describes it as a small steering wheel, most often on the captain’s side console, used for maneuvering on the ground. On newer designs the rudder pedals also steer the nosewheel, with reduced authority, so the pilot flying can keep straight on the takeoff and landing roll.

Rudders on Airliners and Jets

A jet’s rudder does the same job as a light airplane’s, with more help. Hydraulic servos move it, and SKYbrary notes that on many sophisticated aircraft its travel is limited automatically above maneuvering speed, because a full deflection at high speed could overstress the tail.

Some large airplanes split the rudder into sections. The FAA’s diagram of the Boeing 727 shows separate upper and lower rudders on the same fin.

Swept-wing jets also tend toward Dutch roll, a rolling and yawing wobble in which the nose traces a figure eight on the horizon. The FAA notes that aircraft with continuing Dutch roll tendencies are usually fitted with a yaw damper.

As the NTSB puts it, the yaw damper “can move the rudder without a pilot or autopilot input,” making small corrections to damp the wobble.

Why Pilots Are Taught Not to Stomp on the Rudder

On November 12, 2001, American Airlines Flight 587, an Airbus A300-600, crashed into Belle Harbor, New York, shortly after takeoff from JFK. The vertical stabilizer and rudder came off in flight. All 260 people aboard and five people on the ground were killed.

The NTSB found the probable cause was the separation of the fin “as a result of the loads beyond ultimate design that were created by the first officer’s unnecessary and excessive rudder pedal inputs.”

The airplane had hit wake turbulence from a Japan Air Lines Boeing 747-400 that departed ahead of it, and the NTSB found the first officer responded with five cyclic rudder pedal inputs, swinging the rudder one way and then the other.

The Board also named contributing factors: the design of the A300-600’s rudder system and elements of American’s advanced aircraft maneuvering training.

The rule applies to new type certificates, not to airplanes already flying. The FAA noted it had been asking for this on new designs since Flight 587, and that fly-by-wire manufacturers had met it through software control laws that add no weight.

Can a Plane Fly Without a Rudder?

Yes, by design and occasionally by accident. Some airplanes are built without a conventional rudder. On a V-tail such as the Beechcraft Bonanza V35, two slanted surfaces called ruddervators do the work of both the elevator and the rudder.

The B-2 Spirit has no vertical tail at all. Northrop wanted directional control that would raise its radar profile as little as possible, and settled on a combination of split brake-rudders and differential engine thrust.

Losing a rudder in flight is a different matter, but it is not always fatal. In March 2005, Air Transat Flight 961, an Airbus A310 with 271 people aboard, was cruising at 35,000 feet about 90 nautical miles south of Miami when the crew heard a loud bang and the airplane entered a Dutch roll.

The crew flew back to Varadero, Cuba, and landed normally, steering with the nosewheel on the runway. Only after shutdown did they discover that most of the rudder was gone. Canada’s Transportation Safety Board recorded one minor injury, to a flight attendant.

Those are the exceptions. For nearly every airplane flying today, the rudder is a small, quiet control that does nothing dramatic and gets used on every single flight.

FAQ

What is the rudder on an airplane?

The rudder is the movable panel hinged to the back of the vertical stabilizer, the fin on an airplane’s tail. It is one of the three primary flight controls, alongside the ailerons and the elevator, and the pilot moves it with two foot pedals.

What does a rudder do on a plane?

The rudder controls yaw, the left and right movement of the nose. Pilots use it to counter adverse yaw when rolling into turns, to offset propeller effects on takeoff, to line up with the runway in a crosswind, to hold a twin straight after an engine failure, to recover from spins, and to steer on the ground.

Does the rudder turn the airplane?

No. An airplane turns by banking, which tilts part of the wing’s lift toward the inside of the turn. The rudder keeps the nose aligned with the direction of flight during the turn. Rudder alone will eventually turn an airplane, but slowly and in an uncoordinated skid.

What axis does the rudder control?

The rudder controls rotation around the vertical axis, the line running from the top of the airplane to the bottom. That rotation is called yaw. The ailerons control roll around the longitudinal axis and the elevator controls pitch around the lateral axis.

Which way do rudder pedals move the plane?

Pushing the left pedal swings the rudder left and yaws the nose to the left. Pushing the right pedal yaws the nose to the right. The two pedals are linked and move in opposite directions.

Do pilots use rudder during takeoff?

Yes. The pedals steer the nosewheel at the start of the takeoff roll, and the rudder takes over as speed builds. In a single-engine propeller airplane the pilot holds right rudder to counter the left-turning tendencies of the engine and propeller, and in a crosswind the rudder keeps the airplane tracking straight down the runway.

Can a plane fly without a rudder?

Yes. V-tail airplanes use ruddervators that combine the elevator and rudder, and the B-2 Spirit uses split brake-rudders and differential thrust instead of a vertical tail. An airplane can also survive losing its rudder in flight, as Air Transat Flight 961 did in 2005.

What happens if a plane loses its rudder?

It depends on how much is lost. When Air Transat Flight 961 lost most of its rudder at 35,000 feet in 2005, the Airbus A310 went into a Dutch roll that died away as the crew descended, and they landed normally back in Cuba. When American Airlines Flight 587 lost its entire vertical stabilizer and rudder in 2001, the airplane crashed.

What is rudder trim?

Rudder trim holds the rudder at a set position so the pilot does not have to keep pressing a pedal. Many small airplanes have a fixed metal tab that is bent on the ground, while larger and more powerful airplanes have trim the pilot can adjust in flight, which is especially useful after an engine failure on a twin.