⟩ What criteria need to be followed for an aircraft to be longitudinal statically stable?
★ To have a nose-down pitching disturbance that is used to produce the aerodynamics forces to give a nose-up restoring moment.
★ This restoring moment that is produced should be large enough to return the aircraft to its original position after the disturbance.
★ The requirements are met by using the tail-plain that is horizontal stabilizer used to provide the stability to the aircraft.