Which procedure should be followed if the flaps stick during a preflight check?

When flaps stick during a preflight check, the appropriate procedure is to set the flap handle to 25° and lift lightly on the flap. This action allows the pilot to address the issue while still on the ground, making it a practical way to potentially rectify the problem without delaying flight operations unnecessarily. By applying light pressure on the flap, the pilot may be able to free it if it is just a minor mechanical obstruction or a problem with the flap linkage.

This approach is proactive and helps ensure that the flaps are functioning correctly before takeoff, which is crucial for aircraft performance and safety during flight. Proper functioning of flaps is vital for takeoff and landing phases, where they significantly contribute to the aircraft's lift capabilities and landing characteristics. The method demonstrates a hands-on approach to resolving a mechanical issue that could affect flight safety, ensuring the aircraft is fully operational before departing.