FH.XI.I.R2

From the FAA library

• Pilot's Handbook of Aeronautical Knowledgep. 12-10
  Chapter 12: Weather Theory › Wind and Currents › Low-Level Wind Shear

  flows down the leeward side of the mountain, the air follows the contour of the terrain and is increasingly turbulent. This tends to push an aircraft into the side of a mountain. The stronger the wind, the greater the downward ... pressure and turbulence become. Figure 12-16. Turbulence in mountainous regions. Due to the effect terrain has on the wind in valleys or canyons, downdrafts can be severe. Before conducting a flight in or near mountainous terrain, it is helpful…

• Helicopter Flying Handbookp. 2-10
  Chapter 2: Aerodynamics of Flight › Airflow and Reactions in the Rotor Disk › Resultant Relative Wind

  blade speed decreases nearer the center of the disk, downward velocity is less. Figure 2-19. Rotational relative wind. Resultant Relative Wind The resultant relative wind at a hover is rotational relative wind modified by induced flow. This is inclined ... downward at some angle and opposite the effective flightpath of the airfoil, rather than the physical flightpath (rotational relative wind). The resultant relative wind also serves as the reference plane for development of lift, drag, and total aerodynamic force…

• Pilot's Handbook of Aeronautical Knowledgep. 12-7
  Chapter 12: Weather Theory › Wind and Currents › Wind Patterns

  Wind Patterns In the Northern Hemisphere, the flow of air from areas of high to low pressure is deflected to the right and produces a clockwise circulation around an area of high pressure. This is known as anticyclonic circulation ... Thus, bad weather is commonly associated with areas of low pressure. A good understanding of high- and low-pressure wind patterns can be of great help when planning a flight because a pilot can take advantage of beneficial tailwinds. [Figure…

• Helicopter Flying Handbookp. 2-9
  Chapter 2: Aerodynamics of Flight › Airflow and Reactions in the Rotor Disk › Rotational Relative Wind (Tip-Path Plane)

  Airflow and Reactions in the Rotor Disk Relative Wind Knowledge of relative wind is essential for an understanding of aerodynamics and its practical flight application for the pilot. Relative wind is airflow relative to an airfoil. Movement of an airfoil ... through the air creates relative wind. Relative wind moves in a direction parallel to but opposite of the movement of the airfoil. [Figure 2-15] There are two parts to wind passing a rotor blade: • Horizontal part—caused…

• 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 ... wind. For example, a wind speed of 10 knots causes the vortices to drift at about 1,000 feet in a minute in the wind direction. When following another aircraft, a pilot should consider wind speed and direction when selecting…

• Pilot's Handbook of Aeronautical Knowledgep. 16-13
  Chapter 16: Navigation › Dead Reckoning › Wind Triangle or Vector Analysis

  means of computations based on time, airspeed, distance, and direction. The products derived from these variables, when adjusted by wind speed and velocity, are heading and GS. The predicted heading takes the aircraft along the intended path ... country flying. The heading and GS, as calculated, is constantly monitored and corrected by pilotage as observed from checkpoints. Wind Triangle or Vector Analysis If there is no wind, the aircraft’s ground track is the same as the heading…