Which switch controls the flow of fresh air to the cockpit during ground operations and unpressurized flight?

The switch that controls the flow of fresh air to the cockpit during ground operations and unpressurized flight is the RAM AIR switch. This switch is specifically designed to allow ambient air to flow into the cockpit, increasing ventilation when the aircraft is not pressurized and ensuring a comfortable environment for the pilots.

During ground operations, this system helps prevent overheating and ensures that the cockpit remains tolerable, especially during warm weather when the aircraft is stationary. In unpressurized flight, it allows for fresh air to circulate, which is important for both comfort and safety, maintaining a breathable atmosphere inside the aircraft.

The other options relate to different functions: some may manage cockpit temperatures or airflow under other specific conditions, but the RAM AIR switch is uniquely responsible for introducing outside air into the cockpit during the stated situations.