Aircraft Environmental Control Systems

The external environment at 41000 ft (12500 m), a typical cruise altitude for modern civil aircraft, is hostile to human life. Aircraft environmental control systems are designed to ensure the survival of the aircraft occupants as well as providing them with a comfortable atmosphere. Major design drivers for the environmental control system are thermal comfort, pressurisation and cabin air quality. However, these parameters cannot be considered independently. They interact between themselves and with other parameters, which may or may not be controllable by the system designer. These interactions occur in a highly complex manner. Research has led to a good understanding of the basic functions to allow safe and comfortable aircraft environmental conditions. Future research efforts will be increasingly focussed on identifying and elaborating the interdependency of factors in order to further enhance the aircraft cabin environment.