SYSEMS FINAL

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

Pressure test with water.

Oxygen systems in unpressurized aircraft are generally of the

continuous-flow and pressure-demand types

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

regulate airflow in relation to cabin altitude when in diluter demand position.

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

Department of Transportation

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

hydrostatically tested within the proper time interval.

A contaminated oxygen system is normally purged with

oxygen

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

Read the pressure gauge mounted on the cylinder.

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

Teflon tape

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

The green thermal expansion disk missing.

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.

2 & 3

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

Chemical oxygen generator systems

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

Every 5 years.

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

24 years or 4,380 filling cycles

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

Continuous flow.

The main cause of contamination in gaseous oxygen systems is

moisture

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

15 years or 10,000 filling cycles whichever occurs first

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

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

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

moisture to collect in the bottle

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

Calibrated orifice.

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

When the user breathes

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

aviation breathing oxygen has had all the water vapor removed

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

Pressure reducer valve

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

Pressure relief valve.

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

green color and the words 'AVIATOR'S BREATHING OXYGEN' stenciled in 1-inch white letters

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

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

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

Pressure relief valves

(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,

only No. 1 is true.

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

Expansion turbine

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

Ambient air.

What is ventilating air used for on a combustion heater?

Carries heat to the places where needed.

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

Either a combustion air relief valve or a differential pressure regulator

The basic air-cycle cooling system consists of

a source of compressed air, heat exchangers, and a turbine.

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?

Compressor

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

Air bubbles in the sight glass disappear

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

Blockage in the system

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

Expansion valve.

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

inadequate airflow through the evaporator.

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

ram air cycle cooling unit

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

Expansion turbine

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

condenser

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

evaporator

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?

Supplement physical inspections with periodic operational carbon monoxide detection tests.

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

lower the temperature of the cabin air.

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

Control the supply of hot, cool, and cold air.

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

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

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

freon in the outlet of the evaporator

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

transfer heat from the freon gas to ambient air.

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

reduce the pressure of the liquid freon.

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

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

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

all connections checked for leaks

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

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

The air-cycle cooling system produces cold air by

extracting heat energy across an expansion turbine

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

low

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

Receiver-dryer.

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

High-pressure vapor.

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

Low-pressure liquid

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

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

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

Low-pressure vapor.

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

High-pressure liquid

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

Vertical with the outlet at the bottom

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?

Prevent excessive loss of refrigerant oil.

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

Oil seepage

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?

The expansion valve is not metering freon properly

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

cool the freon to prevent premature vaporization.

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

changes to phosgene gas

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

Special high grade refrigeration oil

Which of the following is the most abundant gas in Earth's atmosphere?

Nitrogen

Oxygen makes up ______ percentage of the Earth's atmosphere.

20.9

As altitude increases, the total quantity of all of the gases in the atmosphere reduces, however the relative proportions remain the same up to an altitude of 50 miles

true

Hypoxia is the result of too high of a concentration of oxygen

false

In which of the following does the exchange of oxygen and carbon dioxide occur

Alveoli

What is atmospheric pressure at sea level

760 mm/Hg

At what altitude does severe hypoxia occur?

22,000 ft

The body uses your oxygen level to trigger your body to breath

False

Hyperventilation can cause hypoxia-like symptoms to occur

True

Carbon monoxide poisoning is not a concern for aircraft pilots

False

Aircraft utilizing exhaust shroud-type heating systems or combustion heaters are least likely to have carbon monoxide introduced into the cabin

False

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

Low or high pressure compressor.

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

bleed air.

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

controlling the rate at which air leaves the cabin.

What controls the operation of the cabin pressure regulator?

Cabin altitude.

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

all positive pressure from the cabin.

The altitude controller maintains cabin altitude by modulation of the

outflow valve.

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

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

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

main landing gear operated switch.

The cabin pressure control setting has a direct influence upon the

outflow valve opening.

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

Negative pressure relief valve.

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

outflow valve to close faster.

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

Delivery air duct check valve.

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

maintain the desired cabin pressure.

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

provide for augmentation of airflow in some areas of the aircraft.

An aircraft pressurization cycle is normally considered to be

one complete series of events or operations that recur regularly.

Which best describes cabin differential pressure?

Difference between the ambient and internal air pressure.

The cabin pressurization modes of operation are

differential, unpressurized, and isobaric.

A pressurization controller uses

barometric pressure, cabin altitude, and cabin rate of change.

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,

both No. 1 and No. 2 are true.

Prior to installation of a pneumatic surface-bonded type deicer boots, on the leading edge of the wing, you should

remove all paint from the area to be covered by the deicer boot.

What is one check for proper operation of a pitot/static tube heater after replacement?

Ammeter reading.

What controls the inflation sequence in a pneumatic deicer boot system?

Distributor valve.

What is the source of pressure for inflating deicer boots on reciprocating engine aircraft?

Vane-type pump