Maximum Normal Operating RPM Law and Legal Definition

According to 14 CFR 36.1 (Title 14 - Aeronautics and Space; Chapter I - Federal Aviation Administration, Department Of Transportation; Subchapter C - Aircraft ; Part 36 - Noise Standards: Aircraft Type And Airworthiness Certification; Subpart A – General), Maximum normal operating RPM means "the highest rotor speed corresponding to the airworthiness limit imposed by the manufacturer and approved by the FAA. Where a tolerance on the highest rotor speed is specified, the maximum normal operating rotor speed is the highest rotor speed for which that tolerance is given. If the rotor speed is automatically linked with flight condition, the maximum normal operating rotor speed corresponding with that flight condition must be used during the noise certification procedure. If rotor speed can be changed by pilot action, the highest normal operating rotor speed specified in the flight manual limitation section for power-on conditions must be used during the noise certification procedure."