If an aircraft has negative dynamic and positive static stability, what will this result in?

When an aircraft exhibits negative dynamic stability and positive static stability, it leads to a scenario where any displacement from the equilibrium position will initially cause the aircraft to return towards that equilibrium due to the positive static stability. However, once it begins to move back toward equilibrium, the system lacks the necessary dynamic stability to dampen the oscillations. This manifests as oscillations that increase in amplitude over time, resulting in divergent oscillations.

In essence, the positive static stability provides a restoring force when the aircraft is displaced from its neutral position, while the lack of dynamic stability means that the oscillations created by this displacement are not dampened. Instead, these oscillations will amplify, reflecting the concept of divergence in motion. This phenomenon indicates that while the aircraft may start to correct itself, it will ultimately spiral out of control due to the inability to stabilize the oscillations properly. As a result, the aircraft can become increasingly unstable over time, leading to potential loss of control.