What is 'ground effect' when landing an aircraft?

Ground effect refers to the aerodynamic phenomenon that occurs when an aircraft is landing close to the ground, typically within one wingspan of the surface. As an aircraft approaches the ground, it experiences an increase in lift and a decrease in drag due to the modified airflow patterns caused by the proximity of the ground.

When the aircraft is nearing the ground, the air pressure beneath the wings increases, which enhances lift. Simultaneously, the interference with the airflow around the wing reduces drag, allowing the aircraft to maintain altitude more efficiently before touching down. This effect can lead to a smoother landing, as the aircraft can experience a floating feeling just above the runway due to the increased lift.

Understanding ground effect is crucial for pilots, as it impacts their approach and landing techniques. A pilot must be aware of how to manage their descent rate and airspeed when transitioning through this phase to ensure a safe landing.