Describe the function of the governor in a constant-speed propeller system.

In a constant-speed propeller system, the governor plays a crucial role in managing the propeller's performance by adjusting the blade pitch to maintain the desired revolutions per minute (RPM). The primary function of the governor is to sense the current RPM of the engine and propeller and make adjustments to the pitch of the propeller blades accordingly.

When the engine RPM decreases due to increased load or power demands, the governor will automatically increase the blade pitch to reduce the angle of attack, allowing the propeller to maintain a constant speed despite the change in load. Conversely, if the RPM increases, the governor will decrease the blade pitch to allow for greater engine output and maintain the RPM at the desired level. This automatic adjustment ensures optimal performance and efficiency of the aircraft's propulsion system under varying flight conditions.

The other options refer to functions that are not related to the specific operation of a constant-speed propeller. For instance, controlling the fuel injection rate is essential for the engine's performance but does not pertain to the propeller's RPM management, while regulating engine temperature and measuring atmospheric pressure are separate systems critical for overall engine operation but are not functions of the governor in a constant-speed propeller system.