Negative dynamic stability results in what kind of response?

• A. Damped
• B. Neutral
• C. Divergent
• D. Oscillates with constant amplitude

Answer: (C)

Dynamic stability describes how the aircraft’s motion after a disturbance behaves over time. If the motion dies away, the system is stable; if it stays with a constant size oscillation, that’s neutral stability; if the disturbance grows, the response is divergent and the aircraft becomes uncontrollable. Negative dynamic stability means the forces that would normally damp or restore the motion actually amplify the disturbance, causing the oscillations or motions to increase in amplitude with time. That growth without bound is what makes the response divergent. In contrast, damped motion fades away, neutral stability keeps a constant amplitude, and oscillating with a constant amplitude is a neutral case, not an unstable one.