The Static Margin is a measure of the longitudinal stability of an aircraft. It represents the distance between the center of gravity  and the aerodynamic center  normalized by the mean aerodynamic chord
- is the static margin,
- is the location of the aircraft’s center of gravity,
- is the location of the aerodynamic center,
- is the mean aerodynamic chord
A positive static margin () typically indicates a stable configuration, where the center of gravity is ahead of the aerodynamic center. A negative static margin () may indicate an unstable configuration.