FAA Ground School Practice Test

When is floating caused by ground effect most realized during an approach to land?

1. When above the maximum landing weight

2. When less than the length of the wingspan above the surface

3. When flying at the same altitude as the runway

4. When using full flaps during landing

The correct answer is: When less than the length of the wingspan above the surface

Floating caused by ground effect is most pronounced when an aircraft is less than a wingspan's length above the surface. Ground effect occurs as an aircraft approaches the ground, where the air pressure between the wings and the surface meets, effectively increasing lift and reducing drag. This phenomenon generally begins to take effect approximately one wingspan above the ground, which can lead to floating during the landing if the pilot is not prepared for the sudden change in lift that occurs when the aircraft descends into this region. In practical terms, if an aircraft is at this altitude, pilots may feel as though they are being lifted slightly higher than expected, causing them to float past the intended landing point if they do not adjust their descent rate appropriately. The other choices do not accurately relate to the point at which ground effect is most realized. Factors like weight or flap setting can influence the landing dynamics, but the specific height relative to the surface is what directly pertains to ground effect and its impact on floating during an approach.