What is meant by "ground effect" in aviation?

"Ground effect" in aviation refers to a phenomenon that occurs when an aircraft is flying very close to the ground, typically within one wingspan distance from the surface. In this situation, the airflow patterns around the wings change due to the proximity of the ground, resulting in an increase in lift. This occurs because the ground interferes with the wingtip vortices that normally create drag and reduce lift. As a result, pilots often notice that their aircraft requires a longer distance to decelerate and land when operating at very low altitudes, as the increase in lift can lead to a floating sensation during the landing phase.

Understanding ground effect is crucial for pilots, especially during takeoff and landing, as it influences the aircraft's performance and handling characteristics in this critical phase of flight. While the other options touch upon various aspects of aviation, they do not accurately capture the specific aerodynamic principles associated with ground effect.