The aircraft is capable of rotation along the three axes namely; Pitch ,Roll and Yaw, in addition to a linear motion along the specific air route when in- flight. For any type of movement shown by the aircraft ,the weight of the aircraft must be balanced out to maintain the position of the center of gravity for stability.
An air craft can have Lateral center of gravity, Longitudinal center of gravity and even Vertical center of gravity. The most important if these being the Lateral cg, which has a critical role in stabilizing the pitch of the aircraft. Lateral cg is further partitioned into Forward and Aft cg. There are limits to the Fore and Aft cg positioning. If the Fore and Aft cg is out of range the aircraft may pitch uncontrollably up or down during take-off ,flight or landing. For example if the cg is too far forward , the plane is likely to tilt forward or crash
The Lateral cg position is to be maintained in order to control and stabilize any unwanted roll movement during any stage of flight. The position of Lateral cg can shift if there is an uneven distribution of fuel in the tanks,or in case of an uneven seating arrangement of passengers in a small aircraft.
The Vertical cg position is associated with the stability of the flight along the yaw axis. A shift in the vertical cg can result in yawing motion if not compensated for by the pilot during take-off, flight and landing.
The center of gravity is a major factor in the stability of an aircraft in all the phases of flight ; take-off ,cruise / flight and landing. A disturbance in the longitudinal, lateral or vertical cg can upset the movement of the aircraft along either of the three axes ;pitch , roll or