Airframe Systems & Components: Cabin Atmosphere Control Systems 🔊 Flashcards
What is the principal control element in a cabin pressurization system?
The cabin overflow valve
What is the purpose of the negative pressure relief valve in the pressurization system?
It prevents accidentally obtaining a cabin altitude which is higher than the altitude of the aircraft
What control changes the position of the overflow valve?
The pressurization controller
What are the two groups of independent cabin compressors?
Positive displacement and centrifugal compressors
What method is used by turbine powered aircraft for pressurization?
Bleed air from the engine compressor
What limits the degree of cabin pressurization?
The structural design features of the fuselage and by the capacity of the superchargers to maintain a constant volume of airflow to the fuselage
Where does the warm air for cabin heating come from in most small reciprocating engine aircraft?
From the shroud around the engine muffler
What are three methods of supplying heat to the conditioned air when the “heat of compression” is not sufficient for this purpose?
Fuel burning combustion heaters, electric heaters, and exhaust gas air-to-air heat exchangers
What is the function of ventilating air in a combustion heater?
It is used to carry the heat to the places where it is needed
Where does the fuel used in an aircraft combustion heater come from?
The aircraft fuel tanks
What controls the temperature in an aircraft cabin that is heated with a combustion heater?
A thermostat
What are the sources for ventilation air in a combustion heater?
For air circulation and heater operation on the ground a blower is used. Inflight, ram-air inlets, or cabin compressors on pressurized aircraft.
What are the components of an air cycle cooling system?
An expansion turbine (cooling system), an air-to-air heat exchanger, and various valves which control airflow through the system
What causes a temperature drop in an air cycle cooling system?
As the compressed air passes through the expansion turbine, it performs the work of turning the turbine, and undergoes a pressure and temperature drop
What are the components in a vapor cycle (Freon) cooling system?
The compressor, condenser, receiver/dryer, expansion valve, and evaporator
