Which statement about static stability vs dynamic stability in pitch is correct?

• A. Static stability is the initial tendency to return to trim after a disturbance; dynamic stability describes how the motion decays over time.
• B. Static stability describes how motion decays over time; dynamic stability is the initial response.
• C. Static stability refers to yaw behavior; dynamic stability refers to roll behavior.
• D. Static stability is a function of altitude; dynamic stability is a function of airspeed.

Answer: (A)

In pitch, static stability is about the immediate tendency of the aircraft after a disturbance. If you nudge the nose up or down from the trimmed attitude, a statically stable airplane has a restoring moment that acts right away to push the nose back toward trim. Dynamic stability deals with what happens after that initial response: how the pitch motion evolves over time. It describes whether the oscillations die out (are damped), persist, or grow.

So the correct idea is that static stability concerns the initial tendency to return to trim, while dynamic stability concerns the subsequent motion and how it decays or evolves with time. The other notions mix up these concepts or misplace them on different axes or flight parameters (such as yaw/roll or altitude/airspeed), which isn’t what defines static versus dynamic stability in pitch.