Is the air conditioning system functional when the engine is off?

The air conditioning system in the T-6B aircraft is not functional when the engine is off. This is because the air conditioning system relies on the airflow generated by the engine's operation to function effectively. The engine powers the environmental control system, which includes the air conditioning unit, and without the engine running, there is no power or airflow to circulate cool air throughout the cabin.

Additionally, the air conditioning system is designed to operate within specific parameters that are only met when the engine is generating the necessary electrical power and airflow. Therefore, without engine power, the system cannot perform its cooling functions, making it inoperative in that scenario.