Which statement best describes static stability?

• A. The initial tendency an aircraft displays when disturbed from a state of equilibrium.
• B. The aerodynamic pitching moments required to return to the equilibrium angle of attack.
• C. The static pressure of the air.
• D. The rate of turn during a standard rate turn.

Answer: (A)

Static stability is about the airplane’s initial reaction when it’s nudged away from its trimmed attitude. If you give it a small disturbance in pitch, a statically stable aircraft tends to produce forces/moments that push it back toward that original attitude. If it tends to continue the disturbance, it would be unstable; if it stays where it ends up, it’s neutrally stable. The statement described matches this immediate, initial tendency to return to equilibrium.

The other ideas don’t define static stability. The amount of pitching moment needed to return to equilibrium relates to the restoring forces, but static stability is about the initial tendency itself, not the required moment. Static pressure is unrelated to stability, and the rate of turn describes turning behavior, not stability.