What is "ground effect"?

Ground effect refers to the phenomenon experienced when an aircraft is flying close to the ground, typically within one wingspan's distance. In this scenario, the airflow around the aircraft is altered due to the proximity of the ground, leading to an increase in lift while simultaneously decreasing drag. This effect is particularly noticeable during the landing and takeoff phases.

As the aircraft approaches the ground, the high-pressure air beneath the wings gets compressed, which enhances lift. Meanwhile, the interference of the ground reduces the amount of induced drag, allowing the aircraft to maintain a higher lift-to-drag ratio than it would at greater altitudes. Pilots need to be aware of this effect, as it can influence the aircraft's behavior during approach and landing, as well as during takeoff when transitioning from ground effect to free flight. Understanding ground effect helps pilots manage their aircraft's performance effectively as they approach or depart from landing surfaces.