Sport Flight Instructor Helicopter - Simplified Flight Controls › XII. Special Operations › Task B. Pinnacle Operations

FH.XII.B.R9

Risk management

Low rotor rpm.

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. 11-16
Chapter 11: Helicopter Emergencies and Hazards › Low Rotor RPM and Rotor Stall
Other causes of a power-on low rotor rpm condition include the pilot rolling the throttle the wrong way in helicopters not equipped with a governor or a governor failure in helicopters so equipped. As the rpm decreases, the amount ... upon itself rapidly leading to rotor stall. There are a number of ways the pilot can recognize the low rotor rpm situation. Visually, the pilot can not only see the rotor rpm indicator decrease but also the change in torque…
Helicopter Flying Handbook p. 11-15
Chapter 11: Helicopter Emergencies and Hazards › Low-G Conditions and Mast Bumping
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 as airplanes will ... pilot allows the rotor rpm to fall below the safe operating range, the helicopter is in a low rpm situation. If the rotor rpm continues to fall, the rotor will eventually stall…
Helicopter Flying Handbook p. 10-11
Chapter 10: Advanced Flight Maneuvers › Pinnacle and Ridgeline Operations › Approach and Landing
If downdrafts are encountered, it may become necessary to make an immediate…
Helicopter Flying Handbook p. 10-10
Chapter 10: Advanced Flight Maneuvers › Confined Area Operations › Approach
confined area operations, with the exception of a pinnacle operation (see next section, Takeoff), the angle of descent should be no steeper than necessary to clear any barrier with the tail rotor in the approach path and still land ... barrier by a few feet and maintaining normal operating rpm, with perhaps a reserve of power, is better than clearing a barrier by a wide margin but with a dangerously low rpm and no power reserve…
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 ... including cruise airspeeds, is critical for all operations during the entry of an autorotation. The applicable Rotorcraft Flight Manual (RFM) should be consulted to determine the appropriate procedure(s) for safely entering an autorotation. This is vitally important since…
Helicopter Flying Handbook p. 11-2
Chapter 11: Helicopter Emergencies and Hazards › Autorotation
Following this general procedure of fitting airspeed and rotor rpm to existing conditions, a pilot can achieve approximately the same glide angle in any set of circumstances, and thereby estimate the touchdown point accurately. Figure 11-1. During an autorotation ... upward flow of relative wind permits the main rotor blades to rotate at their normal speed. In effect, the blades are “gliding” in their rotational plane. It is important that pilots experience autorotations from various airspeeds. This provides better understanding…