What is the primary concern if the center of gravity is outside the prescribed limits?

When the center of gravity is outside the prescribed limits, the primary concern is that the aircraft might become unstable and difficult to control. The center of gravity plays a crucial role in determining the stability and handling characteristics of an aircraft. If the center of gravity is too far forward or too far aft, it can significantly affect the aircraft's pitch behavior, making it harder to control during flight.

An aircraft with a forward center of gravity tends to require more control stick input to change pitch and may have a tendency to dive, while an aircraft with an aft center of gravity could be more prone to pitch oscillations or even stall behavior. These changes in handling can make the aircraft challenging to control, especially during critical phases of flight such as takeoff and landing.

As such, maintaining the center of gravity within specified limits is essential for safe and effective aircraft operation, as it directly impacts stability and controllability.