What is the definition of "ground effect"?

The definition of "ground effect" refers to the phenomenon where an aircraft experiences increased lift and decreased drag when it is flying close to the ground, typically within a wingspan's distance above the surface. This effect is a result of the interaction between the wings and the ground, which compresses the air underneath the wings. As a result, the aircraft can achieve a higher lift-to-drag ratio, making takeoffs and landings more efficient.

When an aircraft is within this ground effect zone, it requires less power to maintain flight, allowing it to stay airborne more easily. This is particularly noticeable during the landing phase when pilots often cut power as they enter ground effect just before touchdown. This knowledge is essential for pilots to understand how to manage the aircraft's performance in relation to its proximity to the ground, especially when executing takeoffs and landings.

Options referring to high altitudes, increased drag at low altitudes, or decreased lift during takeoff do not accurately describe the ground effect, as they fail to focus on the context of flying close to the ground where the phenomenon occurs.