Chapter 14 - Cabin Atmosphere Control System - Oral Questions Flashcards
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
Compressor,
heat exchangers,
expansion turbine,
valves
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.
Name the principle components of a vapor cycle system
A compressor, condenser, expansion valve, and an evaporator
