Cabin Atmosphere Control Systems

Question 1

How does a continuous flow oxygen system operate?

Answer 1

Oxygen flows from a charged cylinder through a high-pressure line to a reducing valve and to mask outlets

Question 2

How does a basic pressure demand oxygen system operate?

Answer 2

Oxygen flows from a charged cylinder to a pressure demand regulator, adjustable by each crewmember

Question 3

What type of oxygen must be used an aircraft?

Answer 3

Aviators breathing oxygen

Question 4

What must be accomplished if an oxygen system that has been open to the atmosphere for two hours or more?

Answer 4

It must be purged to remove the moisture

Question 5

What is used to purge oxygen lines of moisture?

Answer 5

Dry air, dry nitrogen, or oxygen

Question 6

What safety precaution should be observed when servicing oxygen systems?

Answer 6

Clean and grease free tools, clothing, hands, no smoking or open flames within 50 feet and do not use adhesive tape of any kind

Question 7

What are two groups of independent cabin compressors?

Answer 7

Positive displacement and centrifugal

Question 8

What is a roots blower?

Answer 8

An engine driven compressor, which is used in old reciprocating engines for cabin pressurization

Question 9

What method is used by some turbine powered aircraft for pressurization?

Answer 9

Engine bleed air

Question 10

What pressurization control unit will regulate the position of an outflow valve?

Answer 10

The cabin pressure controller

Question 11

What is the principal control of a pressurization system?

Answer 11

An outflow valve

Question 12

What components are used in an air cycle cooling system?

Answer 12

An expansion turbine, heat exchanger and various valves

Question 13

Describe the basic operating principles that allow an air cycle system to produce cool air

Answer 13

1. Engine bleed air is cooled in the primary heat exchanger
2. compressed air cooled again in the second heat exchanger
3. Then goes to a turbine that extracts the energy and pressure of the air and drops the air temperature

Question 14

What causes a temperature drop in an air cycle cooling system?

Answer 14

The compressed air performs the work of turning a turbine and it undergoes a drop in pressure and temperature

Question 15

How does the water separator remove moisture from the air?

Answer 15

The moist air passes through vanes that swirl the air and the droplets are collected and drained

Question 16

What is a vapor cycle cooling?

Answer 16

A closed system which a refrigerant Freon is circulated through tubing and a variety of components to remove heat from the aircraft

Question 17

What significant way is a vapor cycle cooling system different from an air cycle system?

Answer 17

Vapor cycle uses Freon

Question 18

What components are in a vapor cycle cooling system?

Answer 18

A receiver dryer, evaporator, compressor, condenser and expansion valve

Question 19

Why is oil added to a vapor cycle Freon system?

Answer 19

To seal and lubricate the compressor

Question 20

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

Answer 20

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

Question 21

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

Answer 21

Exhaust shroud heat exchangers, combustion heaters and electric heaters

Question 22

What are sources of ventilating air in a combustion heater?

Answer 22

A blower/fan or Ram Air or possibly a compressor if airplanes pressurized