What is the primary characteristic of ground effect during takeoff or landing?

The primary characteristic of ground effect during takeoff or landing is that it enhances the lift generated by the wings. Ground effect occurs when an aircraft is flying close to the ground, typically within a wingspan's length. In this proximity, the airflow over the wings is affected by the presence of the ground, leading to an increase in lift.

This is primarily due to the reduction of the induced drag that occurs when flying in ground effect. As the wings generate lift, the added proximity to the ground helps to alter the airflow patterns and increases the pressure difference above and below the wings, thereby augmenting lift without requiring a significant increase in speed.

This phenomenon is important for pilots to understand, as it affects how an aircraft performs during the critical phases of takeoff and landing, allowing for a smoother and potentially shorter takeoff roll and landing distance.