Regardless of the stage of flight - aircraft accommodation on the ground or the flight in the air - air crew and passengers must be in appropriate for the life and comfortable environment.Onboard of aircraft should be maintained normal temperature, suitable for inhalation of air, comfortable environment with appropriate humidity and air pressure.
Control systems of environments for human activity must ensure operation in a wide temperature range and create conditions of optimum humidity and ensure the availability of adequate quantity oxygen for a comfortable feel. These systems include: air conditioning system, system of creation of proper pressure, oxygen equipment and automatic environment control systems.
Air conditioning inside the aircraft is designed for heating (or cooling) of aircraft, cockpit ventilation and maintenance passenger cabin's comfortable structure of the air. In addition, aircraft conditioning system provides all users with air. Air is supplied to the system of engines' compressors, emergency generator or special air intake openings on the surface of aircraft.
The air-conditioning systems consist of: air preparation, automatic temperature control, distribution and circulation.
The system of air preparation has two channels, each of them contains equipment for adjusting of air flow rate, air filters and air cooling equipment (Fig. 191). Air gets into air preparation system from special holes on the surface of the aircraft and from turbine of engine. After cooling and filtering air from two preparation subsystems is mixed and fed into the distribution system.
Each channel of air preparation system is controlled by its own control equipment that monitors air quality at every stage of processing and control of operation regimes of equipment
In case of emergency is provided in system a direct air intake and feeding of it into the cabin.
Fig. 191 . The system of air preparation
The distribution system ensures air supply in the cockpit and passenger cabin and luggage space. Typically, internal aircraft space is divided into several distinct areas, air quality in each of them is controlled separately (Fig.192).
Fig. 192 . The distribution of air inside the aircrat
Control of preparation systems and air quality in different areas of your aircraft by using ECAM (Fig. 193 and 194).
Fig. 193 . The information display system of air preparation A-320
Fig. 194. Information display of air conditioning A320
Air preparation and air distribution systems provide a continuous supply of air to the different zones of aircraft, thus creating pressure.
The required value of air pressure is controlled by pressure control equipment in the cabin (Cabin Pressure Controllers - CPC). CPC equipment adjusts air pressure in the aircraft with the help of ventilation equipment providing releasing of air outside (Fig.195).
Comfortable conditions are determined not only by necessary pressure value, but also by the speed of its change. Usually, till the height of 2400 m, pressure inside the aircraft is the same as the outside pressure. If this limit is exceeded a certain value of absolute pressure is maintained (Fig.196) .
Fig. 195 . Pressure Control System
Fig. 196 . Changing of air pressure during flight
Example of information about the state of operation of CPC, displayed on the ECAM display, is shown on Fig. 197.
Fig. 197 . Display of parameters related to pressure on ECAM display
To ensure proper temperature provision, control operation of avionics equipment and its cooling system is used local ventilation. Generally, ventilation system consists of holes of intake and release of air, ventilation equipment and control units (Fig.198).
Fig. 198 . Avionics ventilation equipment
Oxygen in the air plays very important role. Change in percentage composition of the air, especially of oxygen, can lead to undesirable consequences. In the case of cockpit or passenger compartment depressurization oxygen supply system is automatically triggered. It consists of masks and chemical oxygen generators. The presence of oxygen equipment on board is a required for flight conduction .