What mechanism does the overspeed governor use to keep the propeller at 1802 RPM?

The overspeed governor is designed to maintain the propeller speed within safe operational limits, specifically at 1802 RPM in this scenario. It operates by using a specific mechanism that relies on the characteristics of oil. As the propeller speed increases, centrifugal force causes a governor weight to move outward. When the propeller exceeds the set RPM, the governor reduces the fuel flow to the engine, which in turn decreases power and allows the propeller to slow down back to its desired RPM.

In this context, the correct answer highlights the role of oil, which is utilized within the governor's hydraulic system to actuate adjustments that control propeller speed. This mechanism is critical in ensuring the propeller does not reach an unsafe RPM, where excessive speeds could lead to potential mechanical failure or safety hazards. The oil also serves to transmit the forces generated by the governor's response to propeller speed changes, allowing for precise control over the engine's output and therefore the propeller's RPM.

Understanding the use of oil in this system is vital for maintaining safe and efficient aircraft operations under Part 135 regulations.