What is the purpose of the stabilator?

• A. Provides Lateral Stability
• B. Improves Hover Stability
• C. Provides Longitudinal Stability
• D. Controls Rotor RPM

Answer: (C)

The stabilator’s purpose is to provide longitudinal stability. It’s an all-moving horizontal tail surface that changes its angle of attack to produce a pitching moment, helping the helicopter maintain and trim its nose-up or nose-down attitude. With pilot inputs and gusts during hover and forward flight, the stabilator moves to oppose unwanted pitch changes, keeping the aircraft stable along the longitudinal axis. It acts like an elevator for pitch control, but its primary role is stability rather than changing rotor speed. Since lateral stability and rotor RPM control come from other surfaces and systems, the stabilator’s main job is longitudinal stability.