What system is essential if the maximum takeoff weight exceeds the maximum landing weight?

In aircraft design, when the maximum takeoff weight exceeds the maximum landing weight, a fuel jettison system becomes essential. This is primarily because if an aircraft takes off at its maximum weight and cannot land at that weight due to limitations, it needs a method to reduce its weight during flight.

A fuel jettison system is specifically designed to allow the aircraft to release fuel in a controlled manner while in flight. This is critical during situations like aborted takeoffs or go-arounds, where the aircraft may have to return to land shortly after takeoff while still heavily loaded. By enabling the aircraft to jettison fuel, the pilot can bring the aircraft down to a safe landing weight efficiently and safely, ensuring compliance with operational limits and performance criteria.

The other systems mentioned, while important in their capacities, do not address the direct need for weight reduction in this context. A fuel management system optimizes fuel usage but does not facilitate weight reduction. A fuel heating system is used to prevent fuel from becoming too viscous at low temperatures, and a fuel filtration system ensures clean fuel delivery. However, none of these directly address the need for reducing the fuel load to meet landing weight requirements.