PL.IV.A.R4

From the FAA library

• Pilot's Handbook of Aeronautical Knowledgep. 5-7
  Chapter 5: Aerodynamics of Flight › Induced Drag

  vortices) roll off the back of your wing, they angle down, which is known as downwash. Figure 5-10 shows the difference in downwash at altitude versus near the ground. Bearing in mind the direction of rotation of these vortices ... seen that they induce an upward flow of air beyond the tip and a downwash flow behind the wing’s trailing edge. This induced downwash has nothing in common with the downwash that is necessary to produce lift…

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

  vertical component of the airflow around the wing is restricted by the surface. This alters the wing’s upwash, downwash, and wingtip vortices. [Figure 5-16] Ground effect, then, is due to the interference of the ground (or water) surface ... wing encounters ground effect and is maintained at a constant AOA, there is consequent reduction in the upwash, downwash, and wingtip vortices…

• Pilot's Handbook of Aeronautical Knowledgep. 6-6
  Chapter 6: Flight Controls › Flight Control Systems › T-Tail

  This is because the conventional-tail aircraft has the downwash from the propeller pushing down on the tail to assist in raising the nose. Aircraft controls are rigged so that an increase in control force is required to increase control…

• Pilot's Handbook of Aeronautical Knowledgep. G-13
  Glossary › Domestic Reduced Vertical Separation Minimum

  within approximately one wing span or one rotor diameter from the ground. It results from a reduction in upwash, downwash, and wingtip vortices, and provides a corresponding decrease in induced drag. Ground proximity warning system (GPWS). A system designed…

• Aeronautical Information Manualp. 4-3-23
  Chapter 4. Air Traffic Control › Section 3. Airport Operations › 4-3-17. VFR Helicopter Operations at Controlled Airports

  Pilots should avoid this procedure if rotor downwash is likely to cause damage to parked aircraft or if blowing dust/snow could obscure visibility. If it is necessary to operate above 25 feet AGL when hover taxiing, the pilot should initiate ... altitude/operation being conducted. Use of air taxi enables the pilot to proceed at an optimum airspeed/altitude, minimize downwash effect, conserve fuel, and expedite movement from one point to another. Helicopters should avoid overflight of other aircraft, vehicles, and personnel during…