Longitudinal stability is primarily controlled by which control surface?

Longitudinal stability is primarily controlled by which control surface?

• A. Elevator
• B. Rudder
• C. Ailerons
• D. Flaps

Answer: (D)

Longitudinal stability is about the aircraft’s pitch attitude and how it resists nose-up or nose-down disturbances. The main lever for that is the elevator on the horizontal stabilizer. By changing the tail’s lift, the elevator creates a pitching moment about the center of gravity, providing a restoring force when the airplane nose tends to rise or fall. In other words, the elevator directly controls pitch and sets the aircraft’s tendency to return to level flight. Rudder handles yaw, and the ailerons control roll, so they don’t govern nose-up/down stability. Flaps do affect lift and can change the airplane’s trim moment, especially during takeoff and landing, but they are not the primary surface that provides longitudinal stability.

Longitudinal stability is about the aircraft’s pitch attitude and how it resists nose-up or nose-down disturbances. The main lever for that is the elevator on the horizontal stabilizer. By changing the tail’s lift, the elevator creates a pitching moment about the center of gravity, providing a restoring force when the airplane nose tends to rise or fall. In other words, the elevator directly controls pitch and sets the aircraft’s tendency to return to level flight.

Rudder handles yaw, and the ailerons control roll, so they don’t govern nose-up/down stability. Flaps do affect lift and can change the airplane’s trim moment, especially during takeoff and landing, but they are not the primary surface that provides longitudinal stability.