What is the green operating range for APU RPM?

The green operating range for APU RPM is indeed from 0% to 106%. This range indicates the RPM levels at which the Auxiliary Power Unit (APU) is considered to be operating normally and efficiently. When the APU RPM is within this range, it ensures that the unit can supply the necessary electrical power and bleed air for engine starting and other ground operations without risk of damage or operational issues.

Operating outside of this green range can lead to stress on the APU, potential failure, or even safety hazards. Having a maximum of 106% for the APU RPM is crucial because exceeding this value can indicate that the unit is not functioning within its designed parameters. This understanding helps pilots and operators monitor system performance effectively to ensure safe and reliable operation during pre-flight checks and ground operations.

Therefore, recognizing that the green operating range defines the normal operational limits allows the flight crew to maintain awareness and ensure the APU remains within safe parameters for optimal functioning.