What is the effect of ground effect on an aircraft's required thrust?

Ground effect significantly influences an aircraft's aerodynamic performance, particularly during takeoff and landing phases. When an aircraft flies close to the ground, typically within one wingspan distance, the air pressure between the wings and the ground leads to a reduction in induced drag, which is the drag associated with the generation of lift.

As the aircraft enters ground effect, the increased air pressure beneath the wings creates a cushion that enhances lift without requiring a proportional increase in thrust. This means that the aircraft can achieve the same lift with reduced power, as the effective lift-to-drag ratio improves. Consequently, the pilot finds that less thrust is required to maintain flight at lower altitudes.

This phenomenon is especially critical during the final stages of landing or the initial phases of takeoff, where efficient propulsion can lead to smoother transitions and improved fuel efficiency. Therefore, the correct understanding of ground effect is that it decreases the required thrust necessary for maintaining flight close to the surface.