Sport Flight Instructor Helicopter - Simplified Flight Controls › XI. Emergency Operations › Task H. Ground Resonance

FH.XI.H.K3

Knowledge

Corrective actions during low and normal rotor rpm speeds.

Study note

Get a short, cited explanation of this element written from the FAA handbooks: the core idea, the numbers that matter, common test traps, and a quick self-check.

From the FAA library

Helicopter Flying Handbook p. 11-15
Chapter 11: Helicopter Emergencies and Hazards › Low-G Conditions and Mast Bumping
normal cruise speed. Turbulence (where high rotor flapping angles are already present), and higher airspeeds (where the controls are more sensitive) both increase susceptibility to low-G conditions. • Use a flight simulator to learn to recognize and experience low ... flapping clearances are exceeded, but because they retain some control authority at low G, occurrences are less common than for teetering rotors. Low Rotor RPM and Rotor Stall Rotor rpm is a critically important parameter for all helicopter operations. Just…
Helicopter Flying Handbook p. 11-3
Chapter 11: Helicopter Emergencies and Hazards › Autorotation › RPM Control
RPM Control Rotor rpm in low inertia rotor systems has been studied in simulator flight evaluations which indicate that the simultaneous application of aft cyclic, down collective, and alignment with the relative wind (trim) at a wide range of airspeeds ... vary with specific makes and/or models of helicopters. A basic discussion of the aerodynamics and control inputs for single rotor systems is in order here. Helicopter pilots must understand the use of the collective for rotor rpm control during power…
Helicopter Flying Handbook p. 11-2
Chapter 11: Helicopter Emergencies and Hazards › Autorotation
Therefore, autorotative descents at very low or very high airspeeds are more critical than those performed at the minimum rate of descent airspeed. Refer to the height/velocity diagram discussion in Chapter 7, Helicopter Performance. Each type of helicopter ... specific airspeed and rotor rpm at which a power-off glide is most efficient. The specific airspeed is somewhat different for each type of helicopter, but certain factors affect all configurations in the same manner. In general, rotor rpm maintained…
Helicopter Flying Handbook p. 11-22
Chapter 11: Helicopter Emergencies and Hazards › Recovery Technique (Uncontrolled Right Yaw) › Governor or Fuel Control Failure
Governor or Fuel Control Failure Governors and fuel control units automatically adjust engine power to maintain rotor rpm when the collective pitch is changed. If the governor or fuel control unit fails, any change in collective pitch requires manual adjustment ... throttle to maintain correct rpm. In the event of a high side failure, the engine and rotor rpm tend to increase above the normal range due to the engine being commanded to put out too much power. If the rpm…
Helicopter Flying Handbook p. 2-15
Chapter 2: Aerodynamics of Flight › Hovering Flight › Translating Tendency (Drift)
Translating Tendency (Drift) During hovering flight, a single main rotor helicopter tends to move in the direction of tail rotor thrust. This lateral (or sideward) movement is called translating tendency. [Figure 2-27] To counteract this tendency, one or more ... following features may be used. All examples are for a counterclockwise rotating main rotor disk. Figure 2-27. A tail rotor is designed to produce thrust in a direction opposite torque. The thrust produced by the tail rotor is sufficient…