Airman Certification Standards

ACS PH.VIII.F

Low Rotor Revolutions Per Minute (RPM) Recognition and Recovery

This reproduces published FAA reference text for study. It does not replace the current official FAA publication or regulation.

Knowledge

Elements related to low rotor rpm recovery energy management, including the combination of conditions that may lead to this situation.

Effects of wind, weight, temperature, and density altitude.

Aerodynamics that affect low rotor rpm conditions.

Powerplant performance.

Main rotor (Nr) limitations. 45

Difference between low rotor rpm and blade stall.

Risk Management

Powerplant limitations.

Powerplant governor operation.

Collision hazards.

Distractions, task prioritization, loss of situational awareness, or disorientation.

Low inertia rotor systems.

Skill

Complete the appropriate checklist(s).

Clear the area.

Detect the development of low rotor rpm and initiate prompt corrective action.

Execute the recovery procedure to return rotor rpm to normal limits.

Retrieved from ecfr.gov on July 17, 2026.