CH.IX.A.R2c

From the FAA library

• Pilot's Handbook of Aeronautical Knowledgep. 14-27
  Chapter 14: Airport Operations › Wake Turbulence › Terminal Area

  Vortex Strength Terminal Area Wake turbulence has historically been thought of as only a function of aircraft weight, but recent research considers additional parameters, such as speed, aspects of the wing, wake decay rates, and aircraft resistance to wake, just ... aircraft speed. The greatest vortex strength occurs when the generating aircraft is heavy, slow, and clean, since the turbulence from a “dirty” aircraft configuration hastens wake decay. En Route En route wake turbulence events have been influenced by changes…

• Pilot's Handbook of Aeronautical Knowledgep. 13-16
  Chapter 13: Aviation Weather Services › ATC Radar Weather Displays

  Since the intensity level is not available, the controller states “INTENSITY UNKNOWN.” ATC radar is not able to detect turbulence. Generally, turbulence can be expected to occur as the rate of rainfall or intensity of precipitation increases. Turbulence associated with ... greater rates of precipitation is normally more severe than any associated with lesser rates of precipitation. Turbulence should be expected to occur near convective activity, even in clear air. Thunderstorms are a form of convective activity that imply severe…

• Pilot's Handbook of Aeronautical Knowledgep. 12-24
  Chapter 12: Weather Theory › Air Masses › Turbulence

  Turbulence Potentially hazardous turbulence is present in all thunderstorms, and a severe thunderstorm can destroy an aircraft. Strongest turbulence within the cloud occurs with shear between updrafts and downdrafts. Outside the cloud, shear turbulence has been encountered several thousand feet ... above and 20 miles laterally from a severe storm. A low-level turbulent area is the shear zone associated with the gust front. Often, a “roll cloud” on the leading edge of a storm marks the top of the eddies…

• Pilot's Handbook of Aeronautical Knowledgep. 5-9
  Chapter 5: Aerodynamics of Flight › Wingtip Vortices › Avoiding Wake Turbulence

  vortices should be avoided because helicopter forward flight airspeeds are often very slow and can generate exceptionally strong wake turbulence. Wind is an important factor in avoiding wake turbulence because wingtip vortices drift with the wind at the speed ... Figure 5-13. Avoid following another aircraft at an altitude within 1,000 feet. Figure 5-14. Avoid turbulence from another aircraft. Figure 5-15. When the vortices of larger aircraft sink close to the ground (within…

• Pilot's Handbook of Aeronautical Knowledgep. 14-26
  Chapter 14: Airport Operations › Wake Turbulence

  Wake Turbulence All aircraft generate wake turbulence during flight. This disturbance is caused by a pair of counter-rotating vortices trailing from the wingtips. The vortices from larger aircraft pose problems to encountering aircraft. The wake of these aircraft ... impose rolling moments exceeding the rollcontrol authority of the encountering aircraft. Also, the turbulence generated within the vortices can damage aircraft components and equipment if encountered at close range. For this reason, a pilot must envision the location…

• Helicopter Flying Handbookp. 11-15
  Chapter 11: Helicopter Emergencies and Hazards › Low-G Conditions and Mast Bumping

  other portions of the helicopter. Figure 11-8. Result of improper corrective action in a low-G condition. Turbulence, especially severe downdrafts, can also cause a low-G condition and, when combined with high airspeed, may lead to mast bumping ... Typically, helicopters handle turbulence better than a light airplane due to smaller surface area of the rotor blades. During flight in turbulence, momentary excursions in airspeed, altitude, and attitude are to be expected. Pilots should respond with smooth, gentle control…