Control Surfaces Explained (Ailerons, Rudder, Elevator)

An airplane does not steer through the sky the way a car steers along a road.

When a pilot moves the yoke, stick, or rudder pedals, those controls change the aerodynamic forces acting on the aircraft. Those forces create turning effects called moments, and the airplane begins rotating around one or more of its axes.

On a conventional airplane, three primary flight controls provide the basic model:

• Ailerons create roll.
• The elevator creates pitch.
• The rudder creates yaw.

That mapping is important—but incomplete.

Ailerons can also create unwanted yaw. Rudder can produce secondary roll. Elevator input can change angle of attack, airspeed, flight path, and load factor depending on the situation.

And on a modern fly-by-wire airliner, the pilot may not even command a particular surface position directly. A flight-control computer may interpret the pilot's input and decide how several surfaces should move together.

The useful way to understand aircraft controls is therefore not:

"This control makes the airplane go this direction."

It is:

control input → aerodynamic force → moment → aircraft response → flight-path change

What Is a Control Surface?#

Control surfaces are movable aerodynamic surfaces used to change the forces and moments acting on an aircraft.

When a surface deflects, it changes the pressure distribution and airflow around the wing, tail, or other structure to which it is attached.

That produces a change in aerodynamic force.

Because the force usually acts some distance from the aircraft's center of gravity, it creates a rotational effect.

A simplified sequence looks like this:

1. The pilot or flight-control system commands an input.
2. One or more control surfaces move.
3. Local airflow and pressure change.
4. Aerodynamic forces change.
5. A rolling, pitching, or yawing moment develops.
6. The airplane begins rotating.
7. The changed attitude alters the aircraft's aerodynamic state and possibly its flight path.

The airplane therefore does not respond instantaneously as though its controls were steering wheels connected directly to the sky.

It responds because the controls change aerodynamics.

The Three Axes of an Airplane#

A fixed-wing aircraft can rotate around three body axes that normally intersect near its center of gravity.

Longitudinal Axis: Roll#

The longitudinal axis runs roughly from the nose through the fuselage toward the tail.

Rotation around this axis is called roll.

When an aircraft rolls:

• One wing moves upward.
• The other moves downward.
• The aircraft's bank angle changes.

Ailerons are the conventional primary roll controls.

Lateral Axis: Pitch#

The lateral axis runs roughly from wingtip to wingtip.

Rotation around this axis is called pitch.

Pitch changes the aircraft's nose attitude relative to the horizon.

A conventional elevator or an all-moving horizontal tail normally provides primary pitch control.

Vertical Axis: Yaw#

The vertical axis passes through the aircraft from top to bottom.

Rotation around it is called yaw.

Yaw moves the nose left or right relative to the aircraft's body axes.

The rudder is the conventional primary yaw control.

The Axes Move With the Aircraft#

The three axes are attached to the airplane.

If the aircraft rolls 45 degrees, its lateral and vertical axes roll with it.

This matters because aircraft motion is not always well described by saying "up," "down," "left," or "right" relative to the ground.

An airplane can also point in one direction while moving through the air in another.

That distinction becomes especially important in:

• Slips
• Skids
• Crosswinds
• Turns
• Angle-of-attack discussions

Attitude Is Not the Same as Flight Path#

This is one of the most important distinctions in the entire subject.

Attitude describes how the airplane is oriented.

Flight path describes where the airplane is actually moving.

The two are related, but they are not the same.

For example:

• An airplane can point slightly upward while descending.
• It can point downward while temporarily climbing.
• It can point into a crosswind while traveling along a runway centerline.
• It can yaw without immediately following the direction its nose points.
• It can change pitch without immediately changing altitude.

The primary controls initially change the aircraft's attitude and aerodynamic forces.

The resulting forces then change the flight path.

Ailerons: How an Airplane Rolls#

Ailerons are normally mounted near the outer trailing edges of the wings.

They generally move in opposite directions.

If the pilot commands a right roll:

• The right aileron normally moves upward.
• The left aileron normally moves downward.
• Aerodynamic force decreases on part of the right wing.
• Aerodynamic force increases on part of the left wing.
• A rolling moment develops toward the right.

The aircraft then begins to roll.

The exact force changes are more complicated than simply saying one wing "gets lift" and the other "loses lift," but that model is useful for understanding the basic mechanism.

Ailerons Do Not Directly Command a Turn#

This distinction is easy to miss.

Moving the ailerons primarily creates a rolling moment.

That changes the bank angle.

The banked airplane can then turn because the direction of its overall aerodynamic force changes.

So the chain is closer to:

aileron input → roll → bank → tilted lift vector → curved flight path

rather than:

aileron input → airplane turns

This is why understanding roll and understanding a turn are not exactly the same thing.

Ailerons Do Not Simply "Set" Bank Angle#

When the pilot holds lateral control input, the ailerons continue producing a rolling tendency.

As the aircraft approaches the desired bank angle, the pilot normally reduces that input to stop the roll.

The ailerons may then return close to neutral.

That does not mean every airplane will perfectly remain at that bank angle forever.

Depending on aircraft design and flight condition, the airplane may:

• Tend toward wings level
• Remain near the selected bank
• Gradually increase bank
• Require repeated small corrections
• Be disturbed by turbulence

The stability characteristics of the aircraft determine what happens after the initial roll input is removed.

Adverse Yaw#

Ailerons can create a second effect in addition to roll.

It is called adverse yaw.

Suppose the pilot commands a right roll.

The left aileron moves downward and the left wing's aerodynamic loading increases.

That can also increase drag on the left side.

The additional drag tends to pull the left wing backward.

The airplane may therefore initially yaw left while rolling right.

The nose moves opposite the direction of the intended bank.

That is adverse yaw.

The exact amount depends on:

• Aircraft design
• Aileron geometry
• Airspeed
• Wing geometry
• Lift distribution
• Aileron deflection
• Roll rate

It is often more noticeable at lower airspeed, when larger control deflections may be required.

How Designers Reduce Adverse Yaw#

Aircraft designers use several techniques to reduce adverse yaw.

Differential ailerons#

A differential aileron system typically allows the upward-moving aileron to deflect farther than the downward-moving one.

Reducing the downward aileron's deflection can reduce the extra drag produced on the rising wing.

At the same time, the larger upward deflection on the opposite wing may contribute useful drag.

The result is less adverse yaw.

Frise ailerons#

A Frise-type aileron is shaped so that when it moves upward, part of its leading edge projects below the lower wing surface.

That projection can create additional drag on the wing that is moving downward.

This helps counter the yaw caused by the opposite aileron.

Frise geometry can also affect control forces and airflow around the aileron.

Aileron-rudder interconnection#

Some aircraft mechanically or electronically coordinate rudder movement with roll input.

This can automatically compensate for some adverse yaw.

Spoiler-assisted roll#

Some aircraft supplement ailerons with spoilers.

A spoiler raised on one wing reduces lift and increases drag on that side.

That assists the aircraft in rolling toward the spoiler-equipped side.

Large transport aircraft may combine multiple ailerons and spoiler panels to produce roll control across different parts of the flight envelope.

How an Airplane Actually Turns#

A conventional airplane primarily turns by banking.

Imagine the aircraft flying straight and level.

Its aerodynamic lift acts mostly upward relative to the flight path.

When the airplane banks, the overall lift vector tilts with it.

That force can now be considered as having two components:

• A vertical component
• A horizontal component

The horizontal component accelerates the airplane toward the center of the turn.

The flight path curves.

So the airplane does not turn simply because its nose points left or right.

It turns because a force acts inward.

Bank Angle and Turn Rate Are Not the Same Thing#

Bank angle influences turn performance, but bank angle by itself does not define one fixed turn rate.

Turn rate also depends on airspeed.

At the same bank angle:

• A slower airplane generally completes a tighter, faster-rate turn.
• A faster airplane generally follows a larger-radius turn with a slower angular rate.

This is why bank angle, turn rate, and turn radius should not be treated as interchangeable concepts.

Why a Level Turn Requires More Lift#

When the lift vector tilts during a bank, less of the total aerodynamic force points vertically.

If the pilot wants to maintain altitude, the airplane must produce more total lift so that the vertical component remains sufficient to support the aircraft's weight.

The pilot generally accomplishes this by increasing angle of attack, usually through elevator input.

As the bank becomes steeper:

• Required total lift increases.
• Load factor increases.
• Required angle of attack increases.
• Induced drag increases.
• Additional power may be required.
• Stall speed rises if altitude is maintained.

This is why steep turns require more than simply moving the ailerons farther.

The entire aerodynamic balance changes.

Rudder: Controlling Yaw#

The rudder is normally attached to the vertical stabilizer.

Pressing the left rudder pedal usually moves the rudder so that the aerodynamic side force on the tail yaws the nose left.

Pressing the right pedal produces the opposite effect.

But saying "the rudder turns the airplane left or right" is misleading.

The rudder's primary aerodynamic function is to control yaw.

It is used for tasks such as:

• Counteracting adverse yaw
• Maintaining coordinated flight
• Managing crosswinds
• Countering asymmetric engine thrust
• Managing propeller-induced yaw
• Establishing deliberate slips
• Certain stall or spin recovery actions when specified by the aircraft procedure

Rudder Is Not a Steering Wheel#

Suppose a pilot presses left rudder while keeping the wings level.

The aircraft yaws left.

But simply pointing the nose left does not create the efficient inward force required for a normal airplane turn.

The airplane may begin to sideslip.

Aerodynamic coupling can then create secondary roll and eventually alter the flight path.

So rudder can influence the turn.

But a conventional, coordinated airplane does not normally turn by being "steered" with the rudder.

It turns primarily because the aircraft is banked and the lift vector is tilted.

The better rule is:

Ailerons establish the bank. Rudder manages yaw and coordination.

Coordinated Flight#

A coordinated flight condition is one in which the aircraft's lateral acceleration and yaw/bank relationship are appropriately balanced for the maneuver.

In a coordinated turn, occupants generally feel the apparent load mainly through the seat rather than being pushed strongly sideways.

A turn can be uncoordinated in two broad ways:

• Slip
• Skid

What Is a Slip?#

An aerodynamic slip occurs when the relationship between bank and yaw produces a lateral airflow across the aircraft.

In a turn, this can be thought of as having too much bank for the existing rate of turn, or insufficient yaw toward the turn.

The airplane's longitudinal axis is not aligned with its actual flight path.

A slip is not automatically a mistake.

Pilots deliberately use slips for purposes such as:

• Increasing descent rate
• Losing altitude without excessive airspeed
• Correcting crosswind drift
• Aligning the airplane with a runway

What Is a Skid?#

A skid occurs when the airplane has too much yaw toward the inside of the turn relative to its bank.

One common cause is excessive rudder in the direction of the turn.

The airplane is effectively being forced around the corner faster than its bank angle supports.

Skids are particularly important near a stall.

High angle of attack combined with yaw can cause one wing to stall more deeply than the other and can lead to a spin.

The Base-to-Final Skid#

One classic training scenario demonstrates why rudder is not a substitute for bank.

Imagine an airplane turning from base to final.

The pilot realizes the airplane will overshoot the runway centerline.

Instead of going around, the pilot presses additional inside rudder to force the nose toward the runway while applying opposite aileron to keep the bank from becoming too steep.

This creates a cross-control condition and a skid.

If angle of attack then reaches the critical value, the asymmetric stalled condition can develop rapidly into a spin.

At traffic-pattern altitude, there may be insufficient height for recovery.

The appropriate response to a badly overshot turn is normally to abandon the approach and go around.

What Is a Stall? explains the aerodynamic connection among angle of attack, yaw, stall, and spin in greater detail.

The Slip-Skid Indicator#

Many airplanes use an inclinometer—a ball in a curved tube—as part of a turn coordinator or related instrument.

In ordinary maneuvering:

• A centered ball indicates coordinated flight.
• A ball displaced toward the inside of a turn indicates a slip.
• A ball displaced toward the outside indicates a skid.

The traditional mnemonic is:

Step on the ball.

That means applying rudder pressure toward the side where the ball is displaced.

But coordination may also require adjusting bank.

The instrument is showing the result of the airplane's lateral acceleration, not prescribing one control input in isolation.

Elevator: Controlling Pitch#

The elevator is normally mounted on the trailing edge of a conventional horizontal stabilizer.

Its purpose is to change the pitching moment acting on the airplane.

In many conventional airplanes, the tail produces a downward aerodynamic force during normal flight.

When the pilot pulls back:

• The elevator normally moves upward.
• Tail force changes.
• A pitching moment develops.
• The nose rotates upward.

Pushing forward produces the opposite pitching tendency.

The exact aerodynamics depend on the aircraft's tail design and flight condition.

Elevator Does Not Directly "Control Altitude"#

This is another common oversimplification.

The elevator controls pitching moment.

The resulting pitch change alters the airplane's angle of attack, attitude, energy state, and eventually its flight path.

What happens next depends on many factors.

Pulling back might:

• Begin a climb
• Reduce airspeed
• Increase load factor
• Tighten a turn
• Reduce a descent rate
• Cause a stall
• Increase structural loading

Pushing forward might:

• Begin a descent
• Increase airspeed
• Reduce angle of attack
• Recover from a stall
• Reduce load factor

So statements such as:

"Elevator controls altitude."

or:

"Elevator controls airspeed."

are too rigid to describe real flight.

Pitch, power, configuration, and energy work together.

Pitch Attitude Is Not Angle of Attack#

The airplane's pitch attitude is measured relative to the horizon.

Angle of attack is measured relative to the relative wind.

Those references are different.

An airplane can therefore:

• Have a nose-high pitch attitude and modest angle of attack
• Have a level pitch attitude and high angle of attack
• Have the nose below the horizon while still operating at a high angle of attack

This distinction is fundamental to understanding stalls.

A wing stalls when it exceeds its critical angle of attack, not when the nose reaches one particular attitude.

Elevator, Horizontal Stabilizer, and Tail Force#

The horizontal tail is located some distance from the aircraft's center of gravity.

That distance gives the tail substantial leverage.

Changing the aerodynamic force at the tail therefore produces a pitching moment around the center of gravity.

This is why a relatively small tail surface can exert powerful control over the aircraft's pitch.

The exact force direction depends on aircraft design and flight condition.

Many conventional airplanes operate with a downward tail force during much of normal flight, but that should not be treated as a universal requirement for every aircraft or every condition.

Stabilators#

Not every airplane uses a fixed horizontal stabilizer with a separate hinged elevator.

A stabilator is an all-moving horizontal tail.

The entire surface pivots to control pitch.

Because an all-moving surface can be powerful, some stabilator systems use an anti-servo tab to increase control forces and provide more suitable control feel.

The basic purpose remains the same:

create the pitching moment required to control the aircraft.

Trimmable Horizontal Stabilizers#

Many transport aircraft use conventional elevators together with a movable horizontal stabilizer.

The elevator handles relatively short-term maneuvering inputs.

The stabilizer can be adjusted to change the aircraft's trimmed pitching balance.

This allows the aircraft to accommodate changes in:

• Speed
• Configuration
• Weight
• Center of gravity
• Power
• Flight condition

The exact relationship among elevator, stabilizer, autopilot, trim system, and flight-control computers varies by aircraft.

Canards#

Some aircraft use a horizontal surface ahead of the main wing.

This is called a canard.

Depending on the design, the canard may contribute to:

• Pitch control
• Stability
• Lift
• Trim

This demonstrates why the phrase "the elevator is on the tail" describes a common configuration—not a universal law of aircraft design.

Center of Gravity Changes Pitch Control#

The center of gravity determines where the aircraft's weight effectively acts and strongly influences pitch stability and control authority.

Aircraft must remain within the approved CG envelope.

A forward CG generally tends to:

• Increase longitudinal stability
• Increase the balancing force required from the tail
• Increase required pitch-control forces
• Reduce some available nose-up control margin

An excessively forward CG can make rotation or landing flare difficult or impossible within the approved control range.

An aft CG generally tends to:

• Reduce longitudinal stability
• Make pitch response more sensitive
• Reduce some control forces
• Make stall or spin recovery more difficult

An excessively aft CG can leave inadequate recovery authority.

This is why an airplane can be below its maximum permitted weight and still be unsafe because that weight is distributed incorrectly.

See Weight & Balance Explained for the complete relationship.

What Is Trim?#

Trim reduces the continuous control force required to maintain a flight condition.

Suppose a pilot establishes cruise flight but must continuously hold backward pressure.

Rather than holding that force for an hour, the pilot adjusts pitch trim.

The trim system changes the aerodynamic or mechanical balance so that the pilot can relax most of that sustained pressure.

The primary controls still control the airplane.

Trim simply reduces the force required to hold the desired condition.

How Trim Is Provided#

Depending on aircraft design, trim systems can include:

• Trim tabs
• Servo tabs
• Anti-servo tabs
• Spring systems
• Adjustable stabilizers
• Mechanically repositioned control surfaces
• Hydraulic or electronic commands

Aircraft may provide trim in pitch, roll, and yaw.

Pitch trim is particularly important because changes in speed, power, configuration, loading, and center of gravity can all change the airplane's pitching balance.

The Correct Way to Think About Trim#

A useful technique is:

1. Use the primary controls to establish the desired attitude and flight condition.
2. Hold the control pressure required to maintain it.
3. Adjust trim until most of that sustained pressure disappears.
4. Confirm the aircraft remains in the desired condition.

The pilot should not normally use trim as though it were the primary elevator control.

Trim is primarily a control-force management system.

Propeller and Engine Effects on Rudder#

Single-engine propeller aircraft often require rudder input during high-power, low-speed conditions.

Several effects can contribute to yaw, including:

• Propeller torque
• Asymmetric propeller loading
• Spiraling slipstream
• Gyroscopic effects

The relative importance of each depends on aircraft design and operating condition.

During takeoff and climb, the combined yawing tendency can require significant rudder input.

On multiengine airplanes, the rudder becomes even more important after an engine failure.

If one engine loses thrust, the remaining engine or engines can create a large asymmetric thrust moment.

The rudder helps oppose that yaw.

The amount of available rudder authority depends strongly on airspeed, configuration, power, loading, and aircraft design.

Crosswind Control#

A crosswind provides a clear example of why roll and yaw controls perform different jobs.

During a sideslip crosswind landing:

• Aileron is applied into the wind to control bank and lateral drift.
• Opposite rudder is used to keep the airplane aligned with the runway.

The controls are intentionally cross-controlled.

That is not automatically dangerous.

Cross-control becomes dangerous when it creates the wrong aerodynamic condition—particularly a skid near the stall.

In a properly managed crosswind sideslip, the aircraft is intentionally using a combination of bank and yaw to control both flight path and alignment.

See Crosswind Explained for the complete landing techniques.

Crab Versus Sideslip#

Another crosswind technique is the crab.

In a crab:

• The airplane points partly into the wind.
• Its ground track remains aligned with the runway.

Before or during touchdown, depending on aircraft and approved technique, the crab may be removed so that the airplane is appropriately aligned with the runway.

The important distinction is:

• Aileron primarily manages bank and lateral drift.
• Rudder primarily manages yaw and longitudinal alignment.

They often have to be blended together.

Primary and Secondary Flight Controls#

The traditional primary flight controls are:

• Ailerons
• Elevator or equivalent pitch control
• Rudder

But aircraft have many other movable aerodynamic devices.

These are often described as secondary flight controls.

Flaps#

Flaps alter wing geometry.

Depending on the flap type and setting, extending them can:

• Increase camber
• Increase maximum lift coefficient
• Increase drag
• Reduce stall speed
• Change pitching moment
• Change trim
• Change airflow around the aircraft

Flaps allow the airplane to produce the required lift at lower airspeeds during phases such as takeoff and landing.

They are not normally used as the pilot's primary pitch or roll controls, although some aircraft combine flap and aileron functions.

Leading-Edge Devices#

Slats and leading-edge flaps alter airflow near the wing's leading edge.

They can help the wing remain effective at higher lift coefficients by delaying large-scale airflow separation.

These systems are particularly useful during low-speed, high-lift operation.

Depending on aircraft design, they may operate:

• Manually
• Automatically
• According to flap selection
• Under computer control

Spoilers#

Spoilers are panels that rise from the upper wing surface.

They deliberately disturb airflow.

This causes:

• Reduced lift
• Increased drag

Aircraft use spoilers for several different purposes.

They may act as:

• In-flight speed brakes
• Descent devices
• Roll-control supplements
• Ground lift dumpers after landing

When deployed asymmetrically, spoilers can help produce roll.

When deployed symmetrically, they can increase drag and reduce lift without requiring a large pitch change.

After touchdown, ground spoilers help transfer aircraft weight onto the wheels, improving braking effectiveness.

Speed Brakes#

A speed brake is primarily intended to increase drag.

On some airplanes, the same surfaces serve as both spoilers and speed brakes.

Other aircraft have dedicated speed-brake surfaces.

The terminology and exact functions are aircraft-specific.

Flaperons and Elevons#

Some aircraft combine control functions.

A flaperon performs both flap and aileron functions.

An elevon combines elevator and aileron functions, commonly on tailless or delta-wing aircraft.

A mechanical mixer or flight-control computer combines pilot commands so that the same surface can produce different movements for pitch and roll.

This is another reason the simple aileron/elevator/rudder model should be viewed as a foundation rather than a complete catalog of aircraft control systems.

Mechanical Flight Controls#

Many light airplanes use direct mechanical control systems.

These can include:

• Cables
• Pulleys
• Push-pull rods
• Bellcranks
• Torque tubes
• Chains

Pilot force is mechanically transmitted to the control surface.

One advantage is that the pilot can often feel aerodynamic loading directly through the controls.

As airspeed increases, control forces may become heavier.

At low airspeed, the controls may feel softer and less authoritative.

Hydraulic Flight Controls#

On larger or faster aircraft, aerodynamic loads may become too large for practical direct manual control.

Hydraulic actuators provide the force required to move the surfaces.

Pilot inputs may control:

• Hydraulic valves
• Servo systems
• Flight-control computers

rather than physically moving the aerodynamic surface through direct cable tension.

Aircraft can use multiple independent hydraulic systems to provide redundancy.

Some designs retain limited mechanical or manual-reversion capabilities.

Others depend almost entirely on powered control.

Fly-by-Wire#

In a fly-by-wire aircraft, pilot inputs are converted into electrical signals.

Flight-control computers then decide how the aircraft's actuators should move the available control surfaces.

This creates an important conceptual shift.

The pilot may not be commanding:

"Move the elevator five degrees upward."

Instead, the pilot may effectively be commanding something such as:

• A pitch response
• A roll rate
• A load factor
• A flight-path response

The flight-control system then determines which surfaces and deflections are required.

Exactly what the pilot commands depends on the aircraft and its current control law.

Fly-by-Wire Does Not Change the Aerodynamics#

A computer does not make lift, drag, or moments disappear.

The aircraft still has to move aerodynamic surfaces.

Those surfaces still change airflow.

The resulting forces still determine how the aircraft moves.

Fly-by-wire changes the relationship between pilot input and surface movement.

It can also allow designers to:

• Coordinate multiple surfaces automatically
• Provide artificial stability
• Limit certain commands
• Reduce pilot workload
• Optimize control response across the flight envelope
• Integrate autopilot and envelope-protection functions

But the physical aircraft remains governed by the same aerodynamic principles.

Yaw Dampers and Automatic Coordination#

Large or swept-wing aircraft can experience oscillatory yaw-and-roll motion commonly associated with lateral-directional dynamics.

Automatic systems such as yaw dampers can command rudder inputs to reduce unwanted oscillation.

A modern airplane may therefore be moving its rudder even when the pilot is not touching the pedals.

That does not mean the rudder has changed purpose.

The system is automatically using yaw control to improve the aircraft's response.

Automatic coordination may also blend aileron, rudder, spoilers, or other effectors.

What Determines Control Effectiveness?#

A control surface does not produce the same effect under every condition.

Its authority depends on the airflow and aircraft state.

Airspeed#

Aerodynamic force depends strongly on airflow speed.

At higher airspeed, a given control-surface deflection generally produces more aerodynamic force.

At low speed:

• Controls may feel less effective.
• Larger surface deflections may be needed.
• Control response may develop more slowly.

At high speed:

• Small movements can create large aerodynamic forces.
• Structural loads can increase rapidly.
• Direct mechanical controls may feel much heavier.

Powered controls and fly-by-wire systems can change what the pilot physically feels, but they do not remove the underlying aerodynamic loading.

Angle of Attack#

At high angle of attack, airflow reaching a control surface may change considerably.

Near an aerodynamic stall, separated airflow over the wing can reduce or alter roll-control effectiveness.

This is one reason aggressive aileron use can be undesirable in some stalled conditions.

Stall recovery begins with reducing angle of attack according to the aircraft-specific procedure.

See What Is a Stall? for the full explanation.

Propeller Slipstream#

On many propeller aircraft, accelerated airflow from the propeller passes over portions of the tail.

That can make the elevator or rudder respond strongly even when the airplane's forward airspeed is relatively low.

A power change can therefore change both:

• Propulsive force
• Control effectiveness

This is particularly noticeable during high-power, low-speed flight.

Configuration#

Changing flaps, spoilers, landing gear, or other devices can alter:

• Lift
• Drag
• Pitching moment
• Stability
• Tail airflow
• Required trim

A configuration change can therefore require immediate control input followed by retrimming.

Center of Gravity#

The center of gravity changes:

• Moment arms
• Stability
• Required tail force
• Available pitch-control margin
• Recovery characteristics

This is why control authority and pitch stability cannot be considered separately from weight and balance.

Icing and Contamination#

Icing can affect control surfaces as well as the wing.

Ice can:

• Change surface shape
• Disturb airflow
• Increase hinge forces
• Restrict movement
• Change control effectiveness

Under some conditions, icing can also create serious aerodynamic problems involving the tailplane.

The exact symptoms and recovery procedure can differ from an ordinary wing stall, so aircraft-specific icing procedures matter.

See Aircraft Icing Explained for the broader hazard.

Control Surfaces During Takeoff#

During the takeoff roll:

• Rudder maintains directional control and counters yawing tendencies.
• Aileron may be used to manage crosswind effects.
• Elevator or equivalent pitch control initiates rotation at the appropriate speed.
• Trim reduces required control force.

As the airplane accelerates, control effectiveness increases.

Excessive pitch input during rotation can:

• Increase drag
• Reduce acceleration
• Increase angle of attack excessively
• Cause a tail strike on susceptible aircraft

The correct technique is aircraft-specific.

During Climb#

During a climb:

• Elevator controls pitching moment and angle of attack.
• Thrust supplies energy.
• Rudder manages yaw and coordination.
• Ailerons manage roll and bank.
• Trim reduces sustained control force.

Simply pitching the nose higher does not guarantee a better climb.

If angle of attack becomes excessive, airspeed can fall and induced drag can rise.

Eventually the wing can reach its critical angle of attack and stall.

During Cruise#

In cruise, the main control surfaces may remain close to streamlined positions, but they are rarely guaranteed to be perfectly neutral.

Small deflections can remain because of:

• Trim
• Center-of-gravity position
• Fuel imbalance
• Engine thrust
• Structural rigging
• Turbulence
• Autopilot commands

The absence of visible control movement does not mean the airplane is aerodynamically "doing nothing."

During a Turn#

A coordinated level turn requires the controls to work together.

The pilot:

• Establishes roll with aileron.
• Coordinates yaw with rudder as required.
• Uses elevator to produce the lift and load factor needed for the desired flight path.
• Adjusts power as required to manage energy.

These inputs are blended.

There is no universal recipe such as:

"aileron left, rudder left, pull back exactly this much."

The required amount changes continuously with:

• Airspeed
• Bank angle
• Aircraft design
• Power
• Loading
• Turbulence

During Approach and Landing#

On approach:

• Elevator and power work together to manage speed and flight path.
• Flaps change lift and drag.
• Ailerons control roll and lateral drift.
• Rudder controls yaw and alignment.
• Trim reduces sustained force.

During the flare, elevator input changes pitch and angle of attack to reduce the descent rate and establish the landing attitude.

Excessive control input cannot create unlimited lift.

Too much can produce:

• Ballooning
• Excessive angle of attack
• Stall
• Tail strike

depending on the aircraft and conditions.

During Stall Recovery#

A stall is fundamentally an excessive-angle-of-attack condition.

The first aerodynamic requirement is therefore to reduce angle of attack below the critical value.

After that, aileron, rudder, power, and configuration are used according to the aircraft's approved recovery procedure.

There is no universal control recipe suitable for every airplane.

Common Myths About Aircraft Controls#

Myth: Ailerons turn the airplane#

Ailerons primarily create roll.

Banking then tilts the lift vector, producing the horizontal aerodynamic force that curves the flight path.

Myth: The elevator makes the airplane climb#

The elevator produces a pitching moment.

Whether the aircraft climbs, descends, speeds up, slows down, or increases load factor depends on the existing energy state, power, configuration, and resulting flight path.

Myth: Pulling back always makes the airplane go up#

Pulling back generally increases pitch and often angle of attack.

Depending on the situation, that can:

• Start a climb
• Reduce a descent
• Slow the airplane
• Tighten a turn
• Increase G
• Cause a stall
• Overstress the structure

Myth: Rudder steers the airplane#

Rudder controls yaw.

A normal airplane turn is primarily created by banking the lift vector.

Rudder helps coordinate that process and manages other yawing forces.

Myth: Rudder has nothing to do with a turn#

That is also wrong.

Yaw and roll are aerodynamically coupled.

Rudder influences the airplane's orientation and can create secondary roll and flight-path changes.

It is simply not a conventional airplane's primary steering control in a normal banked turn.

Myth: A centered ball means the wings are level#

The ball indicates coordination.

An aircraft can be in a steep coordinated turn with the ball centered.

Myth: Feeling pushed outward is normal in a coordinated turn#

In a steady coordinated turn, the apparent load is directed mainly into the seat.

A strong sideways sensation indicates an uncoordinated condition or transient maneuver.

Myth: Trim flies the airplane#

Trim reduces sustained control pressure.

The primary flight-control system still controls the aircraft.

Myth: Fly-by-wire means there are no control surfaces#

Fly-by-wire changes how commands reach the surfaces.

The airplane still uses aerodynamic forces produced by movable surfaces.

Myth: Every airplane has one aileron, one elevator, and one rudder system that works the same way#

Many aircraft use:

• Multiple ailerons
• Spoilers
• Stabilators
• Flaperons
• Elevons
• Canards
• Split rudders
• Adjustable stabilizers
• Computer-controlled combinations

The three-axis model describes the physics, not every mechanical implementation.

Frequently Asked Questions#

Key Takeaways#

• Aircraft rotate around three body axes: longitudinal, lateral, and vertical.
• Roll occurs around the longitudinal axis, pitch around the lateral axis, and yaw around the vertical axis.
• Control surfaces change aerodynamic forces and moments; they do not directly steer an airplane through space.
• Ailerons primarily create roll, not the turn itself.
• A banked airplane turns because the lift vector tilts and gains a horizontal component.
• Turn rate depends on both bank angle and airspeed.
• Maintaining altitude in a bank requires increased total lift, which increases load factor.
• Ailerons can create adverse yaw, which rudder and aircraft-design features help manage.
• Elevator creates pitching moment; it does not independently determine altitude or airspeed.
• Pitch attitude and angle of attack are different quantities.
• Rudder primarily controls yaw and coordinates flight rather than functioning as a steering wheel.
• Slips and skids are different forms of uncoordinated flight; a skid near a stall can contribute to spin entry.
• Trim relieves sustained control force but does not replace the primary controls.
• Flaps, leading-edge devices, spoilers, speed brakes, flaperons, and elevons expand the aircraft's control and aerodynamic capabilities.
• Mechanical, hydraulic, and fly-by-wire systems are different ways of translating pilot intent into aerodynamic surface movement.
• Fly-by-wire changes the command chain, not the underlying aerodynamics.
• Control effectiveness changes with airspeed, angle of attack, configuration, center of gravity, power, and contamination.
• Aircraft-specific AFM, POH, checklist, and manufacturer guidance take precedence during abnormal control situations.

Sources & References#

• FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 6: Flight Controls. Primary and secondary flight controls, adverse yaw, differential and Frise ailerons, trim systems, stabilators, spoilers, and flight-control-system architecture.
• FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 5: Aerodynamics of Flight. Aircraft axes, stability, turns, load factor, angle of attack, stalls, and aerodynamic coupling.
• FAA Airplane Flying Handbook (FAA-H-8083-3C), Chapter 3: Basic Flight Maneuvers. Coordinated use of controls, straight-and-level flight, turns, climbs, descents, slips, and skids.
• FAA Airplane Flying Handbook (FAA-H-8083-3C). Current FAA operational flying handbook.
• NASA: Principles of Flight — Axes and Control Surfaces. Illustrated introduction to roll, pitch, yaw, ailerons, elevator, and rudder.
• NASA Glenn Research Center: Rotation — Control Axes. Overview of aircraft rotation and conventional control surfaces.