During in-flight constant-speed operation, which range governs the propeller behavior?

• A. Gamma Range
• B. Alpha Range
• C. Delta Range
• D. Zeta Range

Answer: (B)

A constant-speed propeller works by using a governor to adjust blade angle so engine RPM stays at the set value. In flight, the part of operation where this pitch adjustment actively controls speed is the Alpha Range. When the load on the propeller changes—due to airspeed, power setting, or altitude—the governor responds by increasing blade pitch to slow the RPM or decreasing blade pitch to let the RPM rise. This feedback loop keeps the propeller running at the commanded speed despite varying aerodynamic load.

Other ranges aren’t the governing regime for maintaining constant speed in flight; they refer to different operating modes or conditions outside the normal constant-speed pitch control. So, the behavior that directly ensures a stable RPM in flight is driven by the Alpha Range.