Private Pilot License (PPL) Aerodynamics Practice Exam

How does the height above the surface when landing affect ground effect?

1. Higher altitude leads to less ground effect

2. Lower altitude increases lift outside of ground effect

3. Height has no impact on ground effect

4. Ground effect is more pronounced at lower altitudes

The correct answer is: Ground effect is more pronounced at lower altitudes

Ground effect refers to the increased lift and decreased drag that an aircraft experiences when it is flying close to the surface. This phenomenon is particularly important during the final stages of landing and takeoff. When an aircraft is at a lower altitude, especially within a few wingspans of the ground, the airflow under the wings is compressed. This compression increases the air pressure directly beneath the wings, enhancing lift. Consequently, the aircraft experiences a reduction in induced drag, allowing it to become more buoyant. Therefore, ground effect is more pronounced at lower altitudes, which explains why this is the correct answer. As the aircraft ascends higher above the surface, the influence of ground effect diminishes. At higher altitudes, the wings do not benefit as much from the altered airflow patterns that occur close to the ground. Understanding ground effect is crucial for pilots to manage their aircraft during landing and takeoff, as well as to ensure safe and efficient performance during these critical phases of flight.