Air units have this built into the cart?

• A. APU
• B. Turbine
• C. Battery
• D. Compressor

Answer: (A)

Air units on the ramp are designed to operate independently, supplying both power and, when needed, pneumatic air to the system. An Auxiliary Power Unit is exactly that kind of self-contained power source—compact, integrated into the mobile equipment, and able to run the air unit without relying on the aircraft’s engines or external power supply. This lets the cooling unit operate while the aircraft is parked or not connected to ground power.

Why this made sense: the APU provides the necessary electrical power and often the bleed/pneumatic air the air unit needs to function, keeping the cart and its cooling capability self-sufficient. A turbine would imply a larger engine not typically used purely for a cart-based air unit. A battery alone generally cannot sustain the required cooling load for the needed duration. A compressor is a component inside the air conditioning cycle, not the defining power source of the cart itself.