What is the definition of ground effect in aviation?

Ground effect refers to the phenomenon where an aircraft experiences improved performance when it is close to the ground, typically within one wingspan's height. This effect occurs due to the reduction in induced drag and the increase in lift as the aircraft approaches the ground surface. When flying at low altitudes, the airflow around the wings is influenced by the ground, which alters the pressure distribution and enhances lift while minimizing drag.

Improved performance in this context means that an aircraft may require a shorter takeoff distance and can achieve a better climb rate at low altitudes. This is particularly noticeable during takeoff and landing phases, where pilots can experience a more efficient lift-to-drag ratio compared to higher altitudes. Understanding ground effect is crucial for pilots, especially during critical phases of flight, as it can affect handling, control, and overall safety when maneuvering close to the ground.