What is the main variable controlled by the TEMP CONTROL switch?

The TEMP CONTROL switch primarily regulates cockpit temperature. This switch is part of the environmental control system in the T-6 aircraft, which is designed to maintain a comfortable and safe environment for the pilots operating the aircraft. By adjusting this switch, pilots can manage the airflow and temperature within the cockpit, ensuring optimal operating conditions during flight.

The other options relate to factors outside the direct control of the TEMP CONTROL switch: cabin altitude is managed by pressurization systems, outside air temperature is an external variable that does not influence the switch's function, and engine coolant temperature is monitored and controlled through a different system focused on engine performance and cooling. Understanding the specific role of the TEMP CONTROL switch helps clarify its importance in maintaining cockpit comfort and the overall in-flight experience.