Cabin atmosphere control systems Flashcards
What is the principal control element in a cabin pressurization system
The cabin out flow valve
What is the purpose of the negative pressure relief valve in a pressurization system
Prevent accidentally obtaining a cabin altitude which is higher than the altitude of the aircraft
What control changes the position of the outflow valve
The pressurization controller
Located in the cockpit is used to set the cabin air pressure to a desired altitude, normally between six and 8000 feet
What are two groups of independent cabin Compressors
Positive displacement and centrifugal compressors
What method is used by turban powered aircraft for pressurization
Bleed air from the engine compressor is used for pressurization
What limits the degree of Cabin pressurization
The structural design feature of a fuselage, and by capacity of the supperchargers to maintain a constant volume of air flow to the fuselage
Where does the warm air for cabin heating come from in most small reciprocating engines
The shroud around the engine muffler
What are three methods of supplying heat to the conditioned air when the heat of the compressor 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
Ventilation airs to be used to carry heat to the place 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 the combustion heater
The thermostat
What are the sources for ventilation air
For air circulation and heater operation on the ground a blower is used. In-flight, ram air inlet, or cabin compressors on pressurized Aircraft
What are the components of an air cycle cooling system
And expansion turbine, and air to air heat exchanger, and various valves which control airflow through the system
What causes a temperature drop in an air cycled cooling system
As a 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 cooling system
The compressor, condenser, receiver dryer, expansion valve, and evaporator
How do you determine the liquid level in a vapor Cycle cooling system
Operates a system for about five minutes to reach a stabilized condition, then observes the flow of Freon through the site glass. A steady flow indicates significant charge. If the Freon is low, bubbles will appear in sight glass
How is the vapor cycle cooling system compressor lubricated
Specialized refrigerant oil
What are the components of a continuous flow oxygen system
Oxygen will flow continuously from the high-pressure cylinder, through the high pressure Line to the pressure regulator reducing valve. The oxygen will then flow through a calibrated office in the outlet, controlling the amount of oxygen delivered to the breathing mask
What must be done if an oxygen system has been depleted and not recharge within two hours
It must be purged with dry nitrogen or dry air and oxygen
What safety considerations must be observed when filling oxygen cylinders
Oxygen cylinders should be filled in an oil free environment. The mechanic who fills the cylinder should not have any petroleum products on their clothes, Hans, or in their hair
What is the main chemical agent inside and oxygen generator
Sodium chlorate Is used In the main chemical agent use an aviation oxygen generators
The chemical is ignited by a spark admitting cap, and when it burns, O2 is generated. These systems are lighter and less complex than oxygen storage-based systems. The main drawback of the oxygen generators is that once the burning of the sodium chloride begins, it cannot be stopped into the chemical is Consumed
How are high and low pressure oxygen cylinders identified
High pressure oxygen cylinders are green in color and have the words aviators breathing oxygen stenciled lengthwise and white 1 inch letters. Low pressure cylinders are painted light yellow
What are the three ways supplemental oxygen can be carried into the aircraft
As liquid oxygen, a high-pressure gas, or a chemical candle
What is the acceptable lubricant for installing oxygen system fittings
Teflon, or water-based lubricant
