What are the main reasons to exercise a propeller from fine to coarse pitch after warm-up?

Exercising a propeller from fine to coarse pitch after warm-up is primarily aimed at ensuring the proper functioning of the pitch change mechanism and optimizing performance. As the oil in the pitch change mechanism warms up, it becomes less viscous, allowing for more effective operation. By exercising the propeller, the pilot ensures that the system can smoothly transition through its entire range from fine to coarse pitch, which is crucial for performance during different phases of flight.

Additionally, this procedure helps ascertain that the full range of control is available at take-off boost, which is vital for engine response and safety. Checking the RPM control during this process allows the pilot to confirm that the propeller can respond correctly to adjustments, ensuring reliable operation once airborne.

The other options, while related to propeller operation, do not emphasize the critical importance of verifying that the pitch change mechanism is functioning correctly with the warmed medium, thereby reinforcing the significance of this procedure before take-off.