What type of stability evaluates aircraft behavior over time?

Dynamic stability refers to how an aircraft responds over time after being disturbed from its equilibrium position. It is not only about the immediate response to a disturbance but also involves the behavior of the aircraft as it continues to move after the initial response. This means observing whether oscillations diminish, remain constant, or increase as time progresses.

For instance, if an aircraft is disturbed by a gust of wind, dynamic stability looks at how the aircraft settles back into its original flight path. A dynamically stable aircraft will eventually return to its original state, while a dynamically unstable one may continue to oscillate or diverge away from that path.

Static stability, conversely, focuses solely on the initial response to a disturbance without considering what happens after that. It tells us whether the aircraft tends to return to its original position but does not provide information about how it behaves in the longer term. Other types like positional stability and directional stability are specific aspects of stability and control, but they do not directly address the temporal evaluation of stability, which is the essence of dynamic stability.