In what situation might a fuel jettison system be needed on a small aircraft?

A fuel jettison system may be needed on a small aircraft when the aircraft's takeoff weight exceeds its landing weight. This scenario is crucial because an aircraft must be within its maximum landing weight limits to land safely and effectively. If the aircraft takes off with a weight that exceeds the allowable landing weight, a fuel jettison system becomes necessary to reduce the weight quickly and ensure compliance with safety regulations during the landing phase. This system allows pilots to safely reduce fuel load without having to fly excessively long distances to burn off fuel, thus making it a vital tool during situations of overweight departures.

Other scenarios such as engine malfunction or inefficiency during climb may not directly lead to the need for jettisoning fuel. While flying at high altitudes can affect fuel consumption and performance, it is not usually a primary reason for needing a fuel jettison system in smaller aircraft, since weight management during takeoff and landing is more critical.