Chapter 14 - Cabin Atmosphere Control System - Oral Questions Flashcards Preview

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Flashcards in Chapter 14 - Cabin Atmosphere Control System - Oral Questions Deck (20):

Is there any special requirement as to the type of oxygen used in an aircraft system, and if so, what is it?

Only aviators breathing oxygen should be used


Describe the operating principle of a continuous-flow oxygen system

High-pressure Oxygen flows from the storage cylinder to a pressure regulator where its pressure is reduced and then to the mask outlets when the system is turned on


Describe the operating principle of a pressure-demand oxygen system

Demand systems allow oxygen to flow from the cylinder to the regulator and then to the mask only when the user inhales. Pressure-demand systems provide O2 to the user at higher than atmospheric pressure when used at extremely high altitudes, forcing oxygen into users lungs


What should be used to purge an oxygen system of moisture?

Oxygen, dry air, or nitrogen


What action must be taken when an oxygen system has been open to the atmosphere?

The system must be purged of any moisture


Describe the safety precautions that should be observed when servicing oxygen systems

Avoid all contact with petroleum-based oil or grease,

don't smoke,

keep everything very clean,

service systems outdoors if possible,

keep caps on bottles to protect valves


What is a Roots blower?

A type of engine driven compressor


Name two different types of independent cabin air compressors

Positive displacement and centrifugal


What is the source of pressurization air in most jet aircraft?

Engine bleed air


What device provides the principle means of controlling cabin pressure?

The outflow valve


What unit regulates the position of an outflow valve

The cabin pressure controller


Name several methods used on reciprocating-engine aircraft for providing heated cabin air

Exhaust shroud heat exchangers,

combustion heaters,

electric heaters


What is the function of the ventilating air in a combustion heater?

Ventilating air transports the heat from the heater into the cabin and prevents combustion gases from entering the cabin if the combustion chamber develops a crack


What are the sources of ventilating air in a combustion heater?

Ram air in flight,

a blower on the ground, or

possibly a compressor if the airplane is pressurized


Name the basic components of an air cycle cooling system


heat exchangers,

expansion turbine,



Describe the basic operation of an air-cycle system

Hot engine bleed air is cooled in the primary heat exchanger, compressed, then cooled again in the secondary heat exchanger. This air is expanded across the expansion turbine, where energy is extracted and pressure reduced- this creates a drop in temperature.


Describe the basic operating principles of a water separator

Cool, moist air is swirled so that water droplets are separated by centrifugal force, captured by a sock, and drained


Name the principle components of a vapor cycle system

A compressor, condenser, expansion valve, and an evaporator


In what significant way is a vapor cycle cooling system different from air cycle?

Vapor cycle uses a refrigerant liquid, usually Freon


Why is oil added to the refrigerant in a vapor cycle system?

To lubricate the compressor