SH.V.B.R2e

From the FAA library

• Helicopter Flying Handbookp. 11-9
  Chapter 11: Helicopter Emergencies and Hazards › Vortex Ring State

  helicopter begins to descend vertically, it settles into its own downwash, which greatly enlarges the tip vortices. In this vortex ring state, most of the power developed by the engine is wasted in circulating the air in a doughnut pattern ... result, the airflow of the inner blade sections is upward relative to the disk. This produces a secondary vortex ring in addition to the normal tip vortices. The secondary vortex ring is generated about the point on the blade where…

• Aeronautical Information Manualp. 7-4-4
  Chapter 7. Safety of Flight › Section 4. Wake Turbulence › 7-4-4. Vortex Behavior

  Vortex Movement Near Ground - with Cross Winds 5. Pilots should be alert at all times for possible wake vortex encounters when conducting approach and landing operations. The pilot is ultimately responsible for maintaining an appropriate interval, and should consider ... vortices can rise with the air mass in which they are embedded. The effects of wind shear can cause vortex flow field “tilting.” In addition, ambient thermal lifting and orographic effects (rising terrain or tree lines) can cause a vortex…

• Helicopter Flying Handbookp. 10-5
  Chapter 10: Advanced Flight Maneuvers › Steep Approach

  considered a steep approach. [Figure 10-4] Caution must be exercised to avoid the parameters for vortex ring state (20–100 percent of available power applied, airspeed of less than 10 knots, and a rate of descent greater than ... feet per minute (fpm)). For additional information on vortex ring state (formerly referenced as settling-with-power), refer to Chapter 11, Helicopter Emergencies and Hazards. Figure 10-4. Steep approach to a hover…

• Helicopter Flying Handbookp. 11-20
  Chapter 11: Helicopter Emergencies and Hazards › System Malfunctions › Tail Rotor Vortex Ring State (210–330°)

  imperative to maintain positive control of the yaw rate and devote full attention to flying the helicopter. Tail Rotor Vortex Ring State (210–330°) Winds within this region cause a tail rotor vortex ring state to develop. [Figure ... result is a nonuniform, unsteady flow into the tail rotor. The vortex ring state causes tail rotor thrust variations, which result in yaw deviations. The net effect of the unsteady flow is an oscillation of tail rotor thrust. Rapid…