Stabilized ground operation of the propeller is prohibited in which RPM range?

• A. 0-300 RPM
• B. 300-900 RPM
• C. 900-1200 RPM
• D. 1200-1500 RPM

Answer: (B)

Stabilized ground operation uses the propeller governor to hold engine RPM steady while the aircraft is on the ground. This relies on enough aerodynamic loading on the propeller to damp RPM fluctuations. In the mid-range around 300 to 900 RPM, there isn’t sufficient ground-load dampening, so small throttle changes or gusts can cause the RPM to wander more than is safe. That’s why using stabilized ground operation in this RPM window is prohibited. In very low RPM (near idle) and higher RPM beyond this range, the system isn’t as prone to those fluctuations on the ground, making stabilized operation acceptable in those conditions. The practical takeaway is to avoid enabling stabilized ground operation when the propeller is in the 300–900 RPM range.