What will happen if an unbalanced fuel load exists in flight?

When an unbalanced fuel load exists in flight, the aircraft's flight management system (FMS) or fuel system typically allows for fuel to be used from the "heavy" wing to maintain balance. This process is part of the wing-leveling capabilities built into modern aircraft design, aimed at ensuring stability and control during flight.

Maintaining a balanced fuel load is essential because it contributes to the aircraft's overall aerodynamic efficiency and handling qualities. When one wing has more fuel than the other, it can lead to a roll tendency, making the aircraft harder to control. Using fuel from the heavier wing helps correct this imbalance, allowing for smoother flight operations and aiding in maintaining proper flight attitude.

In contrast, some other options are not standard practices. Automatic jettisoning of fuel is typically used during specific emergency scenarios, not merely due to imbalance. The idea that fuel would only be redistributed to the center tank is inaccurate, as fuel management systems are designed to address wing loads directly. An automatic descent as a response to an unbalanced load does not occur as it isn’t a direct safety feature related to balance; instead, pilots can manage the imbalance while in flight.