Cabin Atmosphere Control Systems Flashcards
Which section of a turbine engine provides high pressure bleed air to an air cycle machine for pressurization and air conditioning?
Low or high pressure compressor.
At which component in an air-cycle cooling system does air undergo a pressure and temperature drop?
Expansion turbine.
In a freon vapor-cycle cooling system, where is cooling air obtained for the condenser?
Ambient air.
What is ventilating air used for on a combustion heater?
Carries heat to the places where needed.
Turbine engine air used for air conditioning and pressurization is generally called…
bleed air.
In the combustion heater, combustion air system, what prevents too much air from entering the heaters as pressure increase?
Either a combustion air relief valve or a differential pressure regulator.
How is the cabin pressure of an aircraft maintained in flight?
By controlling the rate of the air flowing out of the cabin.
What controls the operation of the cabin pressure regulator?
Cabin altitude.
The basic air-cycle cooling system consists of…
a source of compressed air, heat exchangers, and a turbine.
The purpose of the dump valve in a pressurized aircraft is to relieve…
all positive pressure from the cabin.
What component might possibly be damaged if liquid refrigerant is introduced into the low side of a vapor-cycle cooling system when the pressure is too high or the outside air temperature is too low?
Compressor.
How can it be determined that a vapor-cycle cooling system is charged with the proper amount of freon?
Air bubbles in the sight glass disappear.
When charging a vapor-cycle cooling system after evacuation, the low-pressure gauge fails to come out of a vacuum. What is indicated?
Blockage in the system.
What component in a vapor-cycle cooling system would most likely be at fault if a system would not take a freon charge?
Expansion valve.
Frost or ice buildup on a vapor-cycle cooling system evaporator would most likely be caused by…
inadequate airflow through the evaporator.
What test is used to determine the serviceability of an oxygen cylinder?
Pressure test with water.
How often should standard weight high-pressure oxygen cylinders be hydrostatically tested?
Every 5 years.
To be eligible for recharging, a DOT 3HT oxygen cylinder must have been hydrostatically tested every three years and be retired from service after…
24 years or 4,380 filling cycles.
Which oxygen system employs a regulator that operates only when the user inhales?
Demand-flow system.
The component that determines the pressure level in the cabin is the cabin air pressure…
outflow valve.
Hot compressor bleed air operates the conditioned air system on some turbine aircraft, cold air supplied by the…
air cycle air conditioning.
For use in pressurized aircraft, which is generally the least complicated and requires the least maintenance?
Chemical oxygen generator systems.
What is the main cause of contamination in a gaseous oxygen system?
Moisture.
Where does the last stage of cooling in an air-cycle air conditioning system occur?
Expansion turbine.