What is negative static stability?

• A. The initial tendency to continue away from the original equilibrium after disturbance
• B. The tendency to return to the original equilibrium after disturbance
• C. The tendency to remain in a new equilibrium after disturbance
• D. The ability to recover from a stall

Answer: (A)

Negative static stability means that after the aircraft is disturbed from its steady flight condition, the initial response is to move further away from that original condition rather than toward it. In practical terms, a disturbance causes aerodynamic forces that produce a moment in the same direction as the disturbance, amplifying the deviation at the start. That’s why the aircraft is considered unstable in a static sense—the restoring effect is absent.

By contrast, positive static stability would produce a restoring moment that tends to bring the airplane back to its original attitude, while neutral static stability would leave the airplane at a new attitude after the disturbance. The ability to recover from a stall relates to post-stall behavior and controllability, not static stability.