HI.XII.A.R12

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…

• 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 ... name a few. The vortex characteristics of any aircraft will be changed with the extension of flaps or other wing configuration devices, as well as changing speed. However, as the basic factors are weight and speed, the vortex strength increases…

• 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…

• Pilot's Handbook of Aeronautical Knowledgep. 14-28
  Chapter 14: Airport Operations › En Route › Vortex Avoidance Procedures

  Vortex Avoidance Procedures The following procedures are in place to assist pilots in vortex avoidance in the given scenario. • Landing behind a larger aircraft on the same runway— stay at or above the larger aircraft’s approach flight path…

• Helicopter Flying Handbookp. 11-19
  Chapter 11: Helicopter Emergencies and Hazards › System Malfunctions › Loss of Tail Rotor Effectiveness (LTE)

  Figure 11-9. Main rotor disk vortex interference. 5. A slow forward airspeed, typically at speeds where translational lift and translational thrust are in the process of change and airflow around the tail rotor will vary in direction and speed ... tailwinds from 120° to 240° [Figure 11-10], such as left crosswinds, causing high pilot workload. c. Tail rotor vortex ring state (210° to 330°). [Figure 11-11] Winds within this region will result in the development of the vortex…

• 14 CFR Part 121 — Operating Requirements: Domestic, Flag, and Supplemental OperationsOpen
  14 CFR § 121.590 Use of certificated land airports in the United States.

  certificated land airports in the United States. Domestic type operation means any domestic operation conducted with— (1) An airplane designed for at least 31 passenger seats (as determined by the aircraft type certificate issued by a competent civil aviation authority ... land airport in any State of the United States, the District of Columbia, or any territory or possession of the United States; or (2) An airplane designed for more than 9 passenger seats but less than 31 passenger seats…