The Three Axes of an Airplane

Unlike a car or truck, an airplane can move in three dimensions. It can pitch up or down, roll from side to side, and yaw left or right. These movements happen around three imaginary lines called the airplane’s axes:

All three axes intersect at the airplane’s center of gravity. The motion you see is perpendicular to the axis around which the airplane rotates. That wording can sound confusing at first, but the table above makes it easier: pitch occurs around the lateral axis, roll occurs around the longitudinal axis, and yaw occurs around the vertical axis.

What Is the Center of Gravity?

The center of gravity, usually shortened to CG, is the point at which the airplane’s weight is considered to be concentrated. A simple way to picture it is to imagine supporting a model airplane at one point. If it balances, that support point is near its center of gravity.

Moving passengers, baggage, fuel, or cargo changes the airplane’s center of gravity. Adding weight toward the nose moves the CG forward. Adding weight toward the tail moves it aft. This matters because an airplane must be loaded within the approved CG range listed by the manufacturer.

You may also hear the term center of lift or center of pressure. That is a useful way to describe where the wing’s aerodynamic force is considered to act, but an airplane does not literally hang from that point in flight. In steady flight, lift, weight, thrust, drag, and the airplane’s pitching moments must work together in balance. Most conventional training airplanes are designed with the CG ahead of the wing’s main lifting force, while the horizontal tail helps provide stability and pitch control.

Pitch: Movement Around the Lateral Axis

Pitch is the airplane’s nose-up or nose-down movement. The airplane pitches around the lateral axis, which runs from one wingtip to the other through the center of gravity.

In a conventional airplane, pitch is controlled by the elevator on the horizontal tail. The pilot moves the elevator with the yoke or control stick:

• Pull back: The elevator moves up, the tail is forced downward, and the nose pitches up.
• Push forward: The elevator moves down, the tail rises, and the nose pitches down.

That is the basic relationship, although the exact response also depends on airspeed, power, trim, aircraft design, and the amount of control input. The controls should be moved smoothly. A good pilot does not yank the airplane around; small, measured inputs usually work best.

Roll: Movement Around the Longitudinal Axis

Roll is the movement that raises one wing while lowering the other. The airplane rolls around its longitudinal axis, which runs from the nose through the tail and passes through the center of gravity.

The ailerons control roll. They are mounted near the outer trailing edges of the wings and move in opposite directions. When the pilot turns the yoke to the left or moves the stick left:

• The left aileron moves up, reducing lift on the left wing.
• The right aileron moves down, increasing lift on the right wing.
• The airplane rolls left.

Move the controls right, and the opposite happens. The right aileron rises, the left aileron lowers, and the airplane rolls right.

Ailerons are how the pilot establishes bank. Banking tilts the airplane’s total lift, creating a horizontal component that turns the airplane. That is why a normal airplane turn is made primarily by banking—not by simply pushing a rudder pedal and trying to steer the airplane like a boat.

Yaw: Movement Around the Vertical Axis

Yaw is the airplane’s left-or-right nose movement around the vertical axis. Imagine a line running vertically through the center of gravity. The airplane’s nose twists left or right around that line.

The rudder, located on the vertical tail, controls yaw. It is operated by the rudder pedals:

• Press the right pedal and the rudder moves right, causing the nose to yaw right.
• Press the left pedal and the rudder moves left, causing the nose to yaw left.

The rudder helps the pilot maintain directional control and coordinate the airplane. It is especially important during turns, climbs, takeoffs, landings, crosswind operations, and situations involving asymmetric thrust.

The rudder is not normally used by itself to make a standard turn. Instead, it works with the ailerons so the airplane remains aligned with its flight path.

What Is Adverse Yaw?

When an aileron moves down, it generally increases both lift and drag on that wing. The extra drag can pull the airplane’s nose in the direction opposite the intended roll. This is called adverse yaw.

Suppose you begin a left turn:

1. You move the yoke or stick left.
2. The right aileron moves down and produces more lift to raise the right wing.
3. That down aileron also creates additional drag on the right wing.
4. The nose tends to yaw right while the airplane is trying to roll left.
5. A small amount of left rudder helps keep the airplane coordinated.

When rolling out of the left turn, you apply right aileron to bring the wings level and normally add the appropriate right rudder to remain coordinated. The amount of rudder needed varies with the airplane, airspeed, power setting, and rate of roll.

How Do You Know the Airplane Is Coordinated?

The inclinometer—the ball in the turn coordinator or slip-skid indicator—helps show whether the airplane is slipping or skidding. In coordinated flight, the ball stays centered.

Student pilots often hear the phrase “step on the ball.” If the ball moves to one side, apply rudder pressure on that same side to bring it back toward the center. Use smooth pressure rather than stomping on the pedal.

How the Flight Controls Work Together in a Turn

A properly coordinated turn uses all three primary flight controls:

1. Ailerons establish the bank angle.
2. Rudder counters adverse yaw and keeps the airplane coordinated.
3. Elevator helps maintain the desired pitch attitude and altitude as the lift vector tilts.

Power may also need to change. The throttle is not one of the three primary aerodynamic flight controls, but it is essential to energy management. Power changes can affect airspeed, climb, descent, pitch tendencies, and the amount of rudder needed.

Trim, flaps, and other systems are considered secondary or auxiliary controls. Trim reduces the control pressure required to hold a desired attitude. Flaps change the wing’s lift and drag characteristics. Those systems matter, but the foundation remains the same: elevator for pitch, ailerons for roll, and rudder for yaw.

Written-Exam Memory Guide

The Bottom Line

An airplane rotates around three axes that intersect at its center of gravity. The elevator controls pitch around the lateral axis, the ailerons control roll around the longitudinal axis, and the rudder controls yaw around the vertical axis.

The controls are separate, but they do not work in isolation. Good flying comes from blending them smoothly, keeping the airplane coordinated, and making small corrections before large corrections become necessary. Learn these relationships now, and you will have a much stronger foundation for every maneuver that follows.