Refer to figure.
The longitudinal, lateral and directional stability of a airplane is dependent on Centre of Gravity (CG) position and the distance of the horizontal and vertical stabilizer from the CG. The CG position also affects the flight characteristics of pitching, rolling and yawning about the longitudinal, lateral and vertical axis. If the CG is aft, the shorter distance between the CG and tail rotor decreases the effectiveness of yaw input.

The airplane axes are the following:

• The fore/aft axis is called the Longitudinal axis. Stability about this axis is called Lateral Stability. Movement around the longitudinal axis is called rolling.
• The side-to-side axis is called Lateral axis. Stability about this axis is called Longitudinal Stability. Movement around the lateral axis is called pitching.
• The axis which runs vertically through the airplane is called Vertical or Normal axis. Stability about this axis is called Directional Stability. Movement around the normal axis is called yawing.