This SAE Aerospace Recommended Practice (ARP) contains guidelines and recommendations for subsonic airplane air conditioning systems an components, including requirements, design philosophy, testing and ambient conditions. The airplane air conditioning system comprises that arrangement of equipment, controls and indicators that supply and distribute air to the occupied compartments for ventilation, pressurization, and temperature and moisture control. The principal features of the system are: a. a supply of outside air with independent control valve(s); b. a means for heating; c. a means for cooling (air or vapor cycle units and heat exchangers); d. a means for removing excess moisture from the air supply; e. a ventilation subsystem; f. a temperature control subsystem; and g. a pressure control subsystem.

Other system components for treating cabin air such as filtration and humidification would be included, as are the ancillary functions of equipment cooling and cargo compartment conditioning. The interface with the major associated system, the pneumatic system, is at the inlet of the air conditioning shutoff valves. This boundary definition aligns with that in the ATA 100 Specification.