CABIN ATMOSPHERE CONTROL SYSTEM

Question 1

Which section of a turbine engine provides high pressure bleed air to an air cycle machine for pressurization and air-conditioning?

Answer 1

low or high pressure compressor

Question 2

At which component in an air-cycle cooling system does air undergo a pressure and temperature drop?

Answer 2

expansion turbine

Question 3

In a freon vapor-cycle cooling system, where is cooling air obtained for the condenser?

Answer 3

ambient air

Question 4

What is ventilating air used for on a combustion heater?

Answer 4

carries heat to the places where needed

Question 5

Turbine engine air used for air-conditioning and pressurization is generally called

Answer 5

bleed air

Question 6

In the combustion heater, combustion air system, what prevents too much air from entering the heaters as air pressure increases?

Answer 6

either a combustion air relief valve or a differential pressure regulator

Question 7

The cabin pressure of an aircraft in flight is maintained at the selected altitude by

Answer 7

controlling the rate at which air leaves the cabin

Question 8

What controls the operation of the cabin pressure regulator?

Answer 8

cabin altitude

Question 9

The basic air-cycle cooling system consists of

Answer 9

a source of compressed air, heat exchangers and a turbine

Question 10

The purpose of the dump valve in a pressurized aircraft is to relieve

Answer 10

all positive pressure from the cabin

Question 11

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?

Answer 11

compressor

Question 12

How can it be determined that a vapor-cycle cooling system is charged with the proper amount of freon?

Answer 12

air bubbles in the sight glass disappear

Question 13

When charging a vapor-cycle cooling system after evacuation, the low-pressure gauge fails to come out of a vacuum. What is indicated?

Answer 13

blockage in the system

Question 14

What component in a vapor-cycle cooling system would most likely be at fault if a system would not take a freon charge?

Answer 14

expansion valve

Question 15

Frost or ice buildup on a vapor-cycle cooling system evaporator would most likely be caused by

Answer 15

inadequate airflow through the evaporator

Question 16

What test is used to determine the serviceability of an oxygen cylinder?

Answer 16

pressure test with water

Question 17

How often should standard weight high-pressure oxygen cylinders be hydrostatically tested?

Answer 17

every 5 years

Question 18

To be eligible for recharging, a DOT 3HT oxygen cylinder must have been hydrostatically tested every three years and be retired from service after

Answer 18

24 years or 4,380 filling cycles

Question 19

What type of oxygen system uses the rebreather bag-type mask?

Answer 19

continuous flow

Question 20

The altitude controller maintains cabin altitude by modulation of the

Answer 20

outflow valve

Question 21

Hot compressor bleed air operates the conditioned air system on some turbine aircraft, cold air supplied by the

Answer 21

ram air cycle cooling unit

Question 22

For use in pressurized aircraft, which is generally the least complicated and requires the least maintenance?

Answer 22

chemical oxygen generator systems

Question 23

The main cause of contamination in gaseous oxygen systems is

Answer 23

moisture

Question 24

Where does the last stage of cooling in an air-cycle air-conditioning system occur?

Answer 24

expansion turbine

Question 25

The point at which freon flowing through a vapor-cycle cooling system gives up heat and changes from a gas to a liquid is the

Answer 25

condenser

Question 26

The point at which freon flowing through a vapor-cycle cooling system absorbs heat and changes from a liquid to a gas is the

Answer 26

evaporator

Question 27

How is the cabin pressure of a pressurized aircraft usually controlled?

Answer 27

by an automatic outflow valve that dumps all the pressure in excess of the amount for which it is set

Question 28

Which is considered a good practice concerning the inspection of heating and exhaust systems of aircraft utilizing a jacket around the engine exhaust as a heat source?

Answer 28

supplemental physical inspections with periodic operational carbon monoxide detection tests

Question 29

On some cabin pressurization systems, pressurization on the ground is restricted by the

Answer 29

main landing gear operated switch

Question 30

The cabin pressure control setting has a direct influence upon the

Answer 30

outflow valve opening

Question 31

The function of the evaporator in a freon cooling system is to

Answer 31

lower the temperature of the cabin air

Question 32

What is the purpose of a mixing valve in a compressor bleed air air-conditioning system?

Answer 32

control the supply of hot, cool, and cold air

Question 33

What component of a pressurization system prevents the cabin altitude from becoming higher than airplane altitude?

Answer 33

negative pressure relief valve

Question 34

If the liquid level gauge in a vapor-cycle cooling system indicates a low freon charge, the system should

Answer 34

be operated for a period of time to reach a stable condition and then the Freon level rechecked

Question 35

If the cabin rate of climb is too great, the control should be adjusted to cause the

Answer 35

outflow valve to close faster

Question 36

The position of the thermostatic expansion valve in a vapor-cycle cooling system is determined by temperature and pressure of the

Answer 36

Freon in the outlet of the evaporator

Question 37

The function of the condenser in a freon cooling system is to

Answer 37

transfer heat from the Freon gas to ambient air

Question 38

The function of an expansion valve in a freon cooling system is to act as a metering device and to

Answer 38

reduce the pressure of the liquid Freon

Question 39

Which prevents a sudden loss of pressurization in the event that there is a loss of the pressurization source?

Answer 39

delivery air duct check valve

Question 40

When servicing an air-conditioning system that has lost all of its freon, it is necessary to

Answer 40

check oil and add as necessary, evacuate the system , and add Freon

Question 41

The primary function of the cabin pressurization system outflow valve is to

Answer 41

maintain the desired cabin pressure

Question 42

One purpose of a jet pump in a pressurization and air-conditioning system is to

Answer 42

provide for augmentation of airflow in some areas of the aircraft

Question 43

After cleaning or replacing the filtering element in a combustion heater fuel system, the system should be pressurized and

Answer 43

all connection checked for leaks

Question 44

The operation of an aircraft combustion heater is usually controlled by a thermostat circuit which

Answer 44

alternately turns the fuel on and off, a process known as cycling

Question 45

The air-cycle cooling system produces cold air by

Answer 45

extracting heat energy across an expansion turbine

Question 46

When checking a freon system, a steady stream of bubbles in the sight gauge indicates the charge is

Answer 46

low

Question 47

An aircraft pressurization cycle is normally considered to be

Answer 47

one complete series of events or operations that recur regularly

Question 48

Which best describes cabin differential pressure?

Answer 48

difference between the ambient and internal air pressure

Question 49

Composite oxygen bottles that conform to DOT-E-8162 have a service life of

Answer 49

15 years or 10,000 filling cycles whichever occurs first

Question 50

The cabin pressurization modes of operation are

Answer 50

differential, unpressurized and isobaric

Question 51

(1) Usually bleed air from a gas-turbine engine compressor can be safely used for cabin pressurization. (2) Independent cabin condition air machines (air cycle machine) can be powered by bleed air from an aircraft turbine engine compressor. Regarding the above statements,

Answer 51

both no. 1 and no. 2 are true

Question 52

A pressurization controller uses

Answer 52

barometric pressure, cabin altitude and cabin rate of change

Question 53

What unit in a vapor-cycle cooling system serves as a reservoir for the refrigerant?

Answer 53

receiver-dyer

Question 54

What is the condition of the refrigerant as it enters the condenser of a vapor-cycle cooling system?

Answer 54

high pressure vapor

Question 55

What is the condition of the refrigerant as it enters the evaporator of a vapor-cycle cooling system?

Answer 55

low pressure liquid

Question 56

The evacuation of a vapor-cycle cooling system removes any water that may be present by

Answer 56

lowering the boiling point of the water and drawing out the vapor

Question 57

What is the condition of the refrigerant as it leaves the evaporator of a vapor-cycle cooling system?

Answer 57

low pressure vapor

Question 58

What is the condition of the refrigerant as it leaves the condenser of a vapor-cycle cooling system?

Answer 58

high pressure liquid

Question 59

In what position should the bottle be placed when adding liquid freon to a vapor-cycle cooling system?

Answer 59

vertical with the outlet at the bottom

Question 60

When purging a freon air-conditioning system, it is important to release the charge at a slow rate. What is the reason for the slow-rate discharge?

Answer 60

prevent excessive loss of refrigerant oil

Question 61

When a vapor-cycle cooling system is not in operation, what is an indication that the system is leaking freon?

Answer 61

oil seepage

Question 62

In an operating vapor-cycle cooling system, if the two lines connected to the expansion valve are essentially the same temperature, what does this indicate?

Answer 62

the expansion valve is not metering Freon properly

Question 63

The purpose of a subcooler in a vapor-cycle cooling system is to

Answer 63

cool the Freon to prevent premature vaporization

Question 64

(1) A small amount of water in a vapor-cycle cooling system can freeze in the receiver-dryer and stop the entire system operation. (2) Water in a vapor-cycle cooling system will react with refrigerant to form hydrochloric acid which is highly corrosive to the metal in the system. Regarding the above statements,

Answer 64

only no. 2 is true

Question 65

When Refrigerant-12 is passed over an open flame, it

Answer 65

changes to phosgene gas

Question 66

What type of oil is suitable for use in vapor-cycle cooling system?

Answer 66

special high grade refrigeration oil

Question 67

When an aircraft's oxygen system has developed a leak, the lines and fittings should be

Answer 67

bubble tested with a special soap solution manufactured specifically for this purpose

Question 68

If oxygen bottle pressure is allowed to drop below a specified minimum, it may cause

Answer 68

moisture to collect in the bottle

Question 69

What controls the amount of oxygen delivered to a mask in a continuous-flow oxygen system?

Answer 69

calibrated orifice

Question 70

In the diluter demand oxygen regulator, when does the demand valve operate?

Answer 70

when the user breathes

Question 71

The primary difference between aviation breathing oxygen and other types of commercially available compressed oxygen is that

Answer 71

aviation breathing oxygen has had all water vapor removed

Question 72

What is used in some oxygen systems to change high cylinder pressure to low system pressure?

Answer 72

pressure reducer valve

Question 73

In a high-pressure oxygen system, if the pressure reducer fails, what prevents high-pressure oxygen from entering the system downstream?

Answer 73

pressure relief valve

Question 74

High-pressure cylinders containing oxygen for aviation use can be identified by their

Answer 74

green color and the words ‘AVIATOR’S BREATHING OXYGEN’ stenciled in 1 – inch white letters

Question 75

An aircraft oxygen bottle may be considered airworthy if it has been hydrostatically tested and identified

Answer 75

with the test date, DOT number and serial number stamped on the cylinder near the neck

Question 76

In a gaseous oxygen system, which of the following are vented to blow out plugs in the fuselage skin?

Answer 76

pressure relief valves

Question 77

The purpose of pressurizing aircraft cabins is to (1) create the proper environment for prevention of hypoxia. (2) permit operation at high altitudes. Regarding the above statements,

Answer 77

both no. 1 and no. 2 are true

Question 78

(1) Oxygen used in aircraft systems is at least 99.5 percent pure and is practically water free. (2) Oxygen used in aircraft systems is 99.5 percent pure and is hospital quality. Regarding the above statements,

Answer 78

only no. 1 is true

Question 79

Oxygen systems in unpressurized aircraft are generally of the

Answer 79

continuous flow and pressure demand types

Question 80

The purpose of the airflow metering aneroid assembly found in oxygen diluter demand regulators is to

Answer 80

regulate airflow in relation to oxygen flow when operating in emergency or diluter demean position

Question 81

If a high-pressure oxygen cylinder is to be installed in an airplane, it must meet the specifications of the

Answer 81

department of transportation

Question 82

Before a high-pressure oxygen cylinder is serviced, it must be the correct type and have been

Answer 82

hydrostatically tested within the proper time interval

Question 83

A contaminated oxygen system is normally purged with

Answer 83

oxygen

Question 84

How should you determine the amount of oxygen in a portable, high-pressure cylinder?

Answer 84

read the pressure gauge mounted on the cylinder

Question 85

What may be used as a lubricant on oxygen system tapered pipe thread connections?

Answer 85

Teflon tape

Question 86

On transport category aircraft what might be an indication of an over pressure event of the aircraft oxygen system?

Answer 86

the green thermal expansion disk missing

Question 87

Which of the following are characteristic of a chemical or solid state oxygen system? 1. An adjustable oxygen release rate. 2. A volume storage capacity about three times that of compressed oxygen. 3. The system generators are inert below 400°F even under severe impact. 4. A distribution and regulating system similar to gaseous oxygen systems.

Answer 87

2, 3