Cabin Atmosphere Control Systems Flashcards
How does a continuous-flow oxygen system operate?
Oxygen flows from a charged cylinder through a high-pressure line to a reducing valve and to mask outlets.
How does a basic pressure-demand oxygen system operate?
Oxygen flows from a charged cylinder to a pressure-demand regulator, adjustable by each crewmember.
What type of oxygen must be used in aircraft?
Aviator’s Breathing Oxygen.
What must be accomplished if an oxygen system has been open to atmosphere for 2 hours or more?
It must be purged to remove the moisture.
What is used to purge oxygen lines of moisture?
Dry air, Dry nitrogen or oxygen.
What safety precautions should be observed when servicing oxygen systems?
Clean, grease free tools, clothing, hands, no smoking or open flames withing 50 feet, do not use adhesive tape of any kind.
What are the two groups of independent cabin compressors?
Positive-displacement and Centrifugal.
What is a Roots Blower?
An engine-driven compressor. (USED IN OLD RECIPROCATING ENGINES FOR CABIN PRESSURIZATION)
What method is used by some turbine-powered aircraft for pressurization?
Engine Bleed Air.
What pressurization control unit will regulates the position of an outflow valve?
The cabin pressure controller.
What is the principal control of a pressurization system?
An outflow valve.
What components are used in an air-cycle cooling system?
An expansion turbine, heat exchanger and various valves.
Describe the basic operating principles that allow an air-cycle system to produce cool air.
(1) Engine air bleed is cooled in the primary heat exchanger.
(2)compressed cooled again in the second heat exchange.
(3)then goes to a turbine that extracts the energy and pressure of the air droping the air temperature.
What causes a temperature drop in an Air-cycle cooling system?
The compressed air performs the work of turning a turbine, and it undergoes a pressure and temperature drop.
How does a water separator remove moisture from the air?
The moist air passes through vanes that swril the air and the droplets are collected and drained.
What is a vapor-cycle cooling?
A closed system in which a refrigerant freon is circulated through tubing and variety of componentes to remove heat from the aircraft.
In what significant way is a vapor-cycle cooling system different from an air-cycle system?
Vapor-Cycle uses Freon.
What components are in a vapor-cycle cooling?
A Receiver Dryer, Evaporator, Compressor, Condenser and Expansion Valve.
Why is oil added to a vapor-cycle freon system?
To seal and lubricate the compressor.
What is the function of ventilating air in a combustion heater?
It transports the heat from the heater into the cabin AND prevents combustion gases from entering the cabin if the combustion chamber develops a CRACK.
Name several methods used on reciprocating engine aircraft for providing heated cabin air:
Exhaust shround heat exchangers, combustion heaters and electric heaters.
What are sources of ventilating air in a combustion heater?
A blower/fan or ram air or possibily a compressor if the airplane is pressurized.
