To learn to recognize and recover from low rotor RPM.
- Discuss indications of a low rotor RPM condition.
- Demonstrate the change in noise and vibration that indicates a change in rotor RPMs.
- Practice rotor RPM recovery during cruising flight.
- Practice rotor RPM recovery during hover/hover taxi.
Instructional aids and pre-requisites
- Lessons BM-1 through BM-8 are pre-requisites
- Ground Lesson pre-requisite: Emergency Procedures, Robinson R22 Safety Notices, Aerodynamics
- This lesson can be combined with Lesson PS-2 (Governor-off Procedures)
- Discuss the signs of low rotor RPM (increase in vibration, decrease in engine noise, cyclic shake, and activation of the low rotor RPM system) and the proper recovery (lower collective, increase throttle, and add aft cyclic in forward flight)
- Prior to take-off and with collective full-down, have the student close his eyes while the instructor increases and decreases throttle until the student perceives a change in noise
- Allow the governor to restore RPMs to the normal range and conduct a normal take-off
- During cruise flight, the instructor will repeat the demonstration so the student can focus on the signs of the low rotor RPM condition
- Once the student can recognize a loss of RPMs, the instructor will demonstrate the recovery
- Simultaneously and smoothly lower the collective and add throttle to restore RPMs to 104%
- Aft cyclic in forward flight can be used to assist with the recovery, but the collective and throttle inputs should be the primary means for recovering RPMs
- Forward cyclic will cause a further decay in rotor RPMs
- Collective can be increased once RPMs have been recovered
- Allow student to practice recognition and recovery while the instructor initiates the maneuver by reducing throttle
- In a hover or while hover taxiing, perform the same demonstration for the recognition and recovery
- As the throttle is reduced, allow the student to raise the collective in an attempt to maintain hover altitude
- Initiate the recovery by adding throttle and momentarily reducing the collective
- If ground contact cannot be avoided, ensure that the aircraft touches down in a level attitude
- Allow the student to practice recognition and recovery while the instructor initiates the manuever by reducing throttle
- Conduct demonstrations in a controlled and secure way to reduce student anxiety
- Emphasize that the recovery can be accomplished with smooth and deliberate inputs
- Guard against overspeeds from an abrupt decrease in collective, excessive aft cyclic, or aggressive throttle inputs
- The student should be able to recognize increases and decreases in engine/rotor RPM
- In cruise flight, the student should be able to initiate the recovery before rotor RPM reaches 90% or the instructor’s predetermined minimum
- In a hover or hover taxi, the student should be able to initiate the recovery without making ground contact
- Be a model for how your student should react: smooth and deliberate
- Consider teaching before autorotations
- Demonstrate low rotor RPM recovery during a normal take-off (may be conducted during a later lesson or during commercial training)
- Demonstrate low rotor RPM recovery during a maximum performance take-off after completion of Lesson PM-1 (Maximum Performance Take-off)
- None specified