The air conditioner compressor will be inoperative when which of the following is the primary power source?

• A. Primary generator
• B. Auxiliary generator
• C. Battery
• D. GPU

Answer: (B)

The correct answer is that the air conditioner compressor will be inoperative when the auxiliary generator is the primary power source. In aviation systems, particularly in helicopters like the TH-73A, the air conditioning compressor is typically designed to function optimally with a steady and reliable power supply.

When the auxiliary generator is the primary power source, it may not produce sufficient output to support high-demand systems like the air conditioning unit. Auxiliary generators often have limitations in power output compared to the primary generators, which are designed to handle the principal operational loads of the aircraft. Consequently, if the system is unable to draw enough power from the auxiliary generator, the air conditioning compressor will be inoperative.

Other options have different implications. The primary generator usually provides adequate power for all systems, including the air conditioning compressor. The battery can also supply power, particularly for startup functions and emergency operations, ensuring that systems like air conditioning can initially operate if needed. A ground power unit (GPU) is typically used to power the aircraft while on the ground and can provide sufficient power for all systems, including the air conditioning compressor.