FAA Powerplant Written Practice Test

What is the function of the prop governor cockpit control?

1. To increase engine RPM.

2. To adjust tension on the speeder spring.

3. To manually increase blade pitch.

4. To regulate fuel flow to the engine.

The correct answer is: To adjust tension on the speeder spring.

The function of the prop governor cockpit control is to adjust tension on the speeder spring. In a constant-speed propeller system, the prop governor controls the propeller's blade pitch and, consequently, its speed. The speeder spring's tension plays a crucial role in this regulation process. When the cockpit control is adjusted, it alters the tension of the speeder spring, which affects the RPM setting that the governor tries to maintain. By increasing this tension, the governor will attempt to maintain a higher RPM by increasing the propeller blade pitch, allowing the propeller to effectively adjust against changes in engine power or load during flight. This operation is vital for optimizing performance and ensuring proper engine operation in different flight conditions. In contrast, other options do not accurately describe the primary function of the prop governor cockpit control. The control is not directly responsible for increasing engine RPM, manually changing blade pitch directly (this is more automated within the governor mechanism itself), or regulating fuel flow to the engine, as these functions are managed through different systems.