3 Principle Airplane Axes—Pitch, Roll, & Yaw

Here’s a look at the three principal airplane axes, how the plane moves around them, and how a pilot controls everything. 

One of the unique things about learning to fly an aircraft is that it moves in three dimensions.

To understand how this works, we describe the airplane moving around three axes—an axis for each type of movement. 

The Three Axes of Flight, Flight Controls, and Pilot Inputs 

An axis of flight is an imaginary line drawn through the aircraft. All axes meet at a central point—the center of gravity, or CG.

Each axis represents a sort of pivot point. The aircraft moves around that axis thanks to a specific flight control, and each movement has its own name. 

Since the aircraft moves in three dimensions, there are three different axes controlled by three different flight controls and movements.

• The aircraft pitches around the lateral axis with the elevator.
• The aircraft rolls around the longitudinal axis with the ailerons.
• The aircraft yaws around the vertical axis with the rudder.

Lateral Axis and Pitch 

The lateral axis of the airplane runs from wingtip to wingtip.

When a plane moves around the lateral axis, it is called pitch. Pitch is controlled by the elevator.

The elevator is mounted to the horizontal stabilizer on the empennage of an airplane. It’s controlled by the pilot’s control yoke or stick.

Pushing the stick forward moves the elevator downward, which in turn pitches the nose of the plane down.

Pulling the stick back (pull up!) moves the elevator upward, which moves the nose of the plane up in relation to the horizon.

Longitudinal Axis and Roll

The airplane’s longitudinal axis runs from the tip of the nose to the tip of the tail.

An airplane rolls around its longitudinal axis. Roll is controlled with the ailerons on the wingtips.

The ailerons are also connected to the pilot’s control yoke or stick.

Moving the stick from side to side moves the ailerons on the wings. When the pilot moves the stick left, the left wing’s aileron goes up, and the right wing’s goes down. Moving the stick to the right does the opposite. 

The ailerons work by adding and subtracting the lift over the outer wings.

The upward aileron subtracts lift, and the downward one adds it.

So, when the pilot moves the stick left, the left wing makes less lift than the right wing, and the plane rolls around the longitudinal axis until the stick is centered again.

Vertical Axis and Yaw

The vertical axis of the airplane runs up and down through the CG. 

The plane yaws around the vertical axis, and the rudder controls that.

Yaw is probably the hardest motion to visualize because planes are seldom seen yawing. Yaw is combined with other forces to coordinate turns.

In other words, the pilot usually uses the rudder in combination with the ailerons.

Yaw is controlled with the rudder, which is mounted on the vertical stabilizer on the empennage. The rudder is moved by pressing the pedals on the floor.

Push the left pedal, and the rudder deflects left. That, in turn, moves the nose of the aircraft to the left. 

Putting It All Together

Of course, a pilot likely isn’t thinking about all that in flight. 

Flying a plane is like riding a bike—once you learn what the controls do and what to do with them, you just do it automatically.

But getting to that point and knowing when to do what requires studying how the plane works and the aerodynamics behind it. And that’s where the principle airplane axes come in.

Factors Affecting Stability and Control

An aircraft’s ability to maintain or return to its intended flight path depends on several key factors. Understanding these elements helps you better control your aircraft and anticipate how it will behave during different flight conditions.

Stability Principles

Stability in aircraft comes in two main forms: static stability and dynamic stability. Static stability is your aircraft’s initial tendency to return to its original position after a disturbance. Think of it like a ball in a bowl – when pushed, it wants to roll back to center.

Dynamic stability describes how your aircraft actually moves over time after being disturbed. Some planes may oscillate before settling down, while others return smoothly.

Aircraft exhibit three types of stability:

• Longitudinal stability: Stability around the lateral axis (pitch)
• Lateral stability: Stability around the longitudinal axis (roll)
• Directional stability: Stability around the vertical axis (yaw)

Good stability means your plane naturally wants to fly straight and level without constant input from you. This makes for a more comfortable, predictable flight experience.

Center of Gravity Considerations

The center of gravity (CG) position dramatically affects your aircraft’s stability. It represents the point where all the aircraft’s weight is balanced.

When your CG is too far forward:

• Your aircraft becomes too nose-heavy
• You’ll need more back pressure on controls
• Takeoffs require more runway
• Landing speeds increase

When your CG is too far aft:

• Your aircraft becomes dangerously unstable
• Control responses become overly sensitive
• Recovery from unusual attitudes becomes difficult

The ideal CG position varies by aircraft model but typically falls within a narrow range called the “CG envelope.” Always check your weight and balance calculations before flight to ensure your CG remains within limits.

Proper loading of passengers, cargo, and fuel helps maintain this critical balance point.

Aerodynamic Factors

Various aerodynamic features influence your aircraft’s stability. The horizontal stabilizer on the tail creates a downward force that balances the nose-down tendency created by the wings.

Dihedral (wings that angle upward from the fuselage) enhances lateral stability. When your plane rolls, the lower wing creates more lift, helping the aircraft self-level.

Airspeed affects stability too. At higher speeds:

• Control surfaces become more effective
• Your plane responds more quickly to inputs
• Stability generally improves

Angle of attack changes dramatically impact stability. As angle increases:

1. Lift increases (up to the critical angle)
2. Stability decreases
3. Control effectiveness changes

Aircraft designers carefully balance these factors to create planes with the right mix of stability and control response. Too stable, and your aircraft feels sluggish. Too unstable, and it becomes difficult or dangerous to fly.