What does ground effect refer to?

Ground effect refers to the phenomenon where the proximity of an aircraft or rotorcraft to the ground influences its airflow and lift characteristics. When an aircraft is close to the ground, the airflow around the wings is modified due to the surface beneath creating a cushion of high-pressure air. This can reduce the intensity of induced drag and enhance lift, leading to improved lift performance at lower altitudes.

This altered airflow allows for more efficient flight characteristics as the aircraft or rotorcraft operates in this zone, resulting in benefits such as enhanced stability and improved lift while descending or hovering near the ground. Understanding ground effect is crucial for pilots as it can impact landing and takeoff performance, especially in various aircraft configurations and during different flight phases.