Which static stability describes the initial tendency to return to the original equilibrium after disturbance?

Which static stability describes the initial tendency to return to the original equilibrium after disturbance?

• A. Neutral static stability
• B. Positive static stability
• C. Negative static stability
• D. Dynamic stability

Answer: (B)

Static stability is about how an aircraft initially responds to a small disturbance from its trimmed state. If, after a slight push, the aerodynamic and gravitational forces create a restoring moment that tends to bring the aircraft back to its original attitude, that is positive static stability. In other words, the initial deflection is opposed by a restoring force, so the system wants to return to equilibrium (think of a marble in a bowl). If the disturbance would cause a moment that pushes the aircraft farther from equilibrium, that would be negative static stability, while no restoring or overturning tendency would be neutral static stability. The question is asking about this initial tendency to return, which is described by positive static stability.

Static stability is about how an aircraft initially responds to a small disturbance from its trimmed state. If, after a slight push, the aerodynamic and gravitational forces create a restoring moment that tends to bring the aircraft back to its original attitude, that is positive static stability. In other words, the initial deflection is opposed by a restoring force, so the system wants to return to equilibrium (think of a marble in a bowl). If the disturbance would cause a moment that pushes the aircraft farther from equilibrium, that would be negative static stability, while no restoring or overturning tendency would be neutral static stability. The question is asking about this initial tendency to return, which is described by positive static stability.