What is the primary purpose of an aircraft's fuel jettison system?

The primary purpose of an aircraft's fuel jettison system is to quickly achieve a lower landing weight. During certain flight situations, such as being above the maximum landing weight due to fuel load or in the event of an emergency, it is crucial for the aircraft to reduce its weight before landing. This is important because exceeding the maximum landing weight can affect the structural integrity of the aircraft and complicate landing dynamics, potentially leading to a dangerous situation. The fuel jettison system allows pilots to safely and efficiently dispose of excess fuel, ensuring the aircraft is within safe operational limits for landing.

Managing fuel contamination or enhancing engine performance are secondary considerations in the overall fuel system design but do not directly relate to the purpose of the jettison system. Similarly, maintaining fuel temperature can be important for fuel system operation, yet it does not align with the primary function of quickly reducing land weight in critical situations.