What is a downside to having a center of gravity too far aft during flight?

Having a center of gravity that is too far aft during flight can indeed lead to a higher likelihood of spin conditions. When the center of gravity is positioned too far back, it alters the aircraft's stability and control characteristics. In particular, an aft CG can reduce the effectiveness of the elevator, making it more difficult to maintain a nose-up attitude or recover from a stall.

As the aircraft approaches a stall, the increased nose-up attitude combined with reduced elevator authority can lead to a loss of control and a propensity for the aircraft to enter a spin more easily. In a spin, the aircraft descends rapidly in a downward spiral, which can be challenging to recover from, especially in aircraft that are not designed with spins in mind.

In contrast, having the center of gravity within the appropriate range enhances stability and control, making it easier to manage the aircraft safely, especially during critical phases of flight such as takeoff, approach, and landing.