Final answer:
Placing the engine start switch to 'stop' in flight for engine #1 or #4 will cause the propellers to either stop rotating or feather, depending on the type of engine.
Step-by-step explanation:
Placing the engine start switch to 'stop' in flight for engine #1 or #4 will cause the propellers to stop rotating or feather, depending on the type of engine.
For engines that use liquid fuel/oxidant mixture, the propellers will stop rotating. This is because stopping the engine will cut off the fuel supply and stop the combustion process, resulting in the propellers coming to a halt.
For engines that use a solid mixture, the propellers will feather. Feathering means that the blades of the propellers are aligned along the direction of the airflow, reducing drag and allowing the aircraft to continue flying with reduced power on the remaining engines.