HI.VII.A.K4

From the FAA library

• Pilot's Handbook of Aeronautical Knowledgep. 5-11
  Chapter 5: Aerodynamics of Flight › Ground Effect

  Figure 5-16. Ground effect changes airflow. Ground effect also alters the thrust required versus velocity. Since induced drag predominates at low speeds, the reduction of induced drag due to ground effect will cause a significant reduction of thrust required ... downwash, and wingtip vortices, there may be a change in position (installation) error of the airspeed system associated with ground effect. In the majority of cases, ground effect causes an increase in the local pressure at the static source…

• Helicopter Flying Handbookp. 2-12
  Chapter 2: Aerodynamics of Flight › Airflow and Reactions in the Rotor Disk › Induced Flow (Downwash)

  rear of the rotor disk, the angle of attack is less and the induced flow is greater. In Ground Effect (IGE) Ground effect is the increased efficiency of the rotor disk caused by interference of the airflow when near ... ground. The air pressure or density is increased, which acts to decrease the downward velocity of air. Ground effect permits relative wind to be more horizontal, lift vector to be more vertical, and induced drag to be reduced. These conditions…

• Airplane Flying Handbookp. 6-10
  Chapter 6: Takeoffs and Departure Climbs › Ground Effect on Takeoff

  Ground Effect on Takeoff Ground effect is a condition of improved performance encountered when the airplane is operating very close to the ground. Ground effect can be detected and normally occurs up to an altitude equal to one wingspan above ... surface. [Figure 6-7] Ground effect is most significant when the airplane maintains a constant attitude at low airspeed at low altitude (for example, during takeoff when the airplane lifts off and accelerates to climb speed, and during the landing…