level 3

5 / 6 / 2025

Aircraft Stability: Static & Dynamic

Stability is an aircraft’s ability to return to steady flight after disturbance.

1. Static Stability

The initial tendency to return to original flight after a small disturbance.

• Positive: Moves back to original position (good).
• Neutral: Stays in new position.
• Negative: Moves further away (bad).

2. Dynamic Stability

How the aircraft behaves over time after disturbance.

• Positive: Returns smoothly or oscillates less.
• Neutral: Oscillates at constant amplitude.
• Negative: Oscillations grow or diverges (unsafe).

Aircraft Control Surfaces

Control surfaces help pilots control an aircraft’s movement around three axes: roll, pitch, and yaw.

Primary Control Surfaces

• Ailerons: Control roll by moving opposite directions on wings.
• Elevator: Controls pitch by moving the nose up or down.
• Rudder: Controls yaw by turning the nose left or right.

Secondary Control Surfaces

• Flaps: Increase lift for slow speeds during takeoff and landing.
• Slats: Prevent stall at high angles by directing airflow.
• Spoilers: Reduce lift and increase drag, aiding descent and landing.
• Trim Tabs: Adjust control surfaces for stable flight with less pilot effort.

These surfaces ensure smooth, stable, and controlled flight during different phases.

Basic Aircraft Components: Pitot Tube & Radio Altimeter

The Pitot Tube measures an aircraft's airspeed by capturing dynamic pressure as air flows into it. Located on the nose or wings, it works with a static port measuring still air pressure. The airspeed indicator calculates speed by subtracting static pressure from total pressure.

The Radio Altimeter measures the plane’s height above ground (AGL) by sending radio waves downward, timing their return, and calculating distance. Unlike barometric altimeters, it provides true terrain height, aiding safe takeoff, landing, and low-altitude flight.

Both instruments are vital for flight safety and accurate navigation.