# 2a6x2 CDC Vol 4

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| By D. Crook
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D. Crook
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Quizzes Created: 1 | Total Attempts: 171
Questions: 89 | Attempts: 171

Settings

• 1.

### The heater control unit (HCU) on the New Generation Heater (NGH) starts the main air fan for output air when

• A.

A heat setting is selected

• B.

A constant flame is established

• C.

The temperature guage reads COOL

• D.

The inside temperature reaches 140 degrees Fahrenheit

D. The inside temperature reaches 140 degrees Fahrenheit
Explanation
When the inside temperature reaches 140 degrees Fahrenheit, the heater control unit (HCU) on the New Generation Heater (NGH) starts the main air fan for output air.

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• 2.

### When should starting aids be used to start the New Generation Heater (NGH)?

• A.

When the temperature guage reads COOL

• B.

Never, as it will result in serious engine damage

• C.

When ambient temperature is below 32 degrees Fahrenheit

• D.

During the engine startup with the ignition switch in PREHEAT position

B. Never, as it will result in serious engine damage
Explanation
Starting aids should never be used to start the New Generation Heater (NGH) as it will result in serious engine damage. This implies that using starting aids can cause harm to the engine and is not recommended.

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• 3.

### When operating the New Generation Heater (NGH), turn the heat control switch to the desired position after

• A.

Ample warm up time

• B.

A minimum of 45 seconds

• C.

System voltage indicates 120 volts alternating current (VAC)

• D.

The inside chamber temperature reaches 140 degrees fahrenheit

C. System voltage indicates 120 volts alternating current (VAC)
Explanation
The correct answer is to turn the heat control switch to the desired position after the system voltage indicates 120 volts alternating current (VAC). This means that the NGH should only be operated when the system voltage reaches the specified level to ensure safe and proper functioning.

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• 4.

### Repair of ground heater equipment should never be attempted

• A.

Without first talking with the operator

• B.

Without first consulting your supervisor

• C.

Unless accurate technical data is available

• D.

Unless in the presence of an experienced mechanic

C. Unless accurate technical data is available
Explanation
Repairing ground heater equipment without accurate technical data can be dangerous and may lead to further damage or injury. It is important to have access to the necessary technical information and specifications before attempting any repairs to ensure that the equipment is fixed correctly and safely.

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• 5.

### Heat that can be felt and added or subtracted to a substance without changing its state is called

• A.

Super heat

• B.

Latent heat

• C.

Specific heat

• D.

Sensible heat

D. Sensible heat
Explanation
Sensible heat refers to the heat that can be felt and added or subtracted to a substance without changing its state. Unlike latent heat, which is absorbed or released during a change in state (such as melting or vaporization), sensible heat affects the temperature of a substance directly. Specific heat, on the other hand, is the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. Superheat, in the context of thermodynamics, refers to the temperature of a substance above its boiling point at a given pressure.

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• 6.

### Heat added to a gas is

• A.

Sensible heat

• B.

Specific heat

• C.

Super heat

• D.

Latent heat

C. Super heat
Explanation
When heat is added to a gas and it undergoes a phase change, such as changing from a gas to a superheated gas, it is referred to as superheat. Superheated gas is a state where the gas is heated above its boiling point without changing into a liquid. This additional heat energy is known as superheat and is used in various applications such as in power plants or industrial processes.

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• 7.

### A good refirgerant will

• A.

Operate in moderate to high pressure

• B.

Operate in low to moderate pressure

• C.

Be semi-corrosive to metals

• D.

Have a high boiling point

B. Operate in low to moderate pressure
Explanation
A good refrigerant should operate in low to moderate pressure because high-pressure refrigerants can be dangerous and increase the risk of leaks or explosions. Low to moderate pressure refrigerants are safer to handle and less likely to cause damage to the refrigeration system. Additionally, operating in low to moderate pressure allows for more efficient heat transfer and better performance of the refrigeration system.

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• 8.

### Which MA-3D air conditioner control switch allows the operator to control the overall volume of air leaving the unit?

• A.

Blower

• B.

Airflow

• C.

Evaporator

• D.

Temperature

B. Airflow
Explanation
The correct answer is "Airflow" because the airflow control switch on the MA-3D air conditioner allows the operator to control the overall volume of air leaving the unit. This switch regulates the speed at which the blower fan operates, determining the amount of air that is being circulated and ultimately controlling the airflow. By adjusting the airflow, the operator can increase or decrease the amount of air being delivered, providing control over the cooling or heating capacity of the air conditioner.

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• 9.

### Refirgerant leaving the evaporator coil, in the MA-3D air conditioner, is a

• A.

Low pressure gas

• B.

High pressure gas

• C.

Low pressure liquid

• D.

High pressure liquid

A. Low pressure gas
Explanation
The refrigerant leaving the evaporator coil in the MA-3D air conditioner is a low pressure gas. This is because the evaporator coil is where the refrigerant absorbs heat from the surrounding air and evaporates, changing from a liquid to a gas. As a result, the refrigerant exits the evaporator coil as a low pressure gas, ready to be compressed and condensed in the next stage of the cooling process.

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• 10.

### When starting the MA-3D air conditioner, hold the safety override switch until

• A.

30 pounds of oil pressure is reached on the engine oil pressure gauge.

• B.

The start switch is released

• C.

The engine warms up

• D.

The engine starts

A. 30 pounds of oil pressure is reached on the engine oil pressure gauge.
Explanation
The correct answer is to hold the safety override switch until 30 pounds of oil pressure is reached on the engine oil pressure gauge. This is because the air conditioner should not be started until there is sufficient oil pressure in the engine. The oil pressure gauge is used as a measure of this pressure, and reaching 30 pounds ensures that the engine is ready to start and operate properly.

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• 11.

### On the MA-3D air conditioner, which component shuts off the compressor when suction pressure drops below 5 pounds of pressure?

• A.

Low pressure cut out

• B.

Temperature controller

• C.

Pressure control cutout

• D.

Compressor pump down overload

B. Temperature controller
Explanation
The temperature controller is responsible for shutting off the compressor when the suction pressure drops below 5 pounds of pressure. It senses the temperature and pressure in the system and activates or deactivates the compressor accordingly. This ensures that the compressor does not operate when the pressure is too low, which could potentially damage the system.

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• 12.

### Which type of refrigeration system leak occurs when the pressure within the system is less than atmospheric pressure?

• A.

Inward

• B.

Vacuum

• C.

Pressure

• D.

Outward

A. Inward
Explanation
Inward refrigeration system leak occurs when the pressure within the system is less than atmospheric pressure. This means that air or other gases from the atmosphere are being drawn into the system, causing a leak.

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• 13.

### A refrigerant reclaimer is used to

• A.

Remove refrigerant

• B.

Remove and store refrigerant

• C.

Remove refrigerant and separate acids from the refrigerant

• D.

Remove and store refrigerant and separate oil and acids from the refrigerant

D. Remove and store refrigerant and separate oil and acids from the refrigerant
Explanation
A refrigerant reclaimer is a device that is used to remove refrigerant from a system and store it for future use. Additionally, it is also capable of separating oil and acids from the refrigerant. This is important because oil and acids can contaminate the refrigerant and affect its performance. Therefore, a refrigerant reclaimer serves the purpose of both removing and storing the refrigerant, as well as ensuring its purity by separating any impurities present in it.

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• 14.

### Refrigerant is always removed through the

• A.

Purge valve

• B.

• C.

• D.

Discharge service valve

C. Receiver outlet valve
Explanation
The receiver outlet valve is the correct answer because it is the valve through which refrigerant is removed from the receiver. The receiver is a storage tank in a refrigeration system where the refrigerant is stored after it has been condensed. When the refrigerant needs to be removed from the system, it is done so through the receiver outlet valve.

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• 15.

### An A/M32C-10D air conditioner air cycle machine consists of

• A.

An air compressor fan only

• B.

An expansion turbine only

• C.

A heat exchanger and an expansion turbine

• D.

An expansion turbine and a compressor fan

D. An expansion turbine and a compressor fan
Explanation
The A/M32C-10D air conditioner air cycle machine consists of an expansion turbine and a compressor fan. The expansion turbine is responsible for expanding the compressed air, which cools it down. The compressor fan then compresses the cooled air, increasing its pressure. This cycle of expansion and compression helps to regulate the temperature of the air and provide cooling.

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• 16.

### Which A/M32C-10D airconditioner component extracts energy from bleed air on the air cycle machine?

• A.

Compressor

• B.

Heat Exchanger

• C.

Expansion turbine

• D.

Temperatur controller

C. Expansion turbine
Explanation
The expansion turbine is the component of the A/M32C-10D air conditioner that extracts energy from bleed air on the air cycle machine. This turbine is responsible for expanding the high-pressure air, which in turn drives the compressor and provides the necessary energy for the air conditioning system to function effectively.

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• 17.

### The ACE 802S air conditioner compressor switch must be held in the HOLD position when engaging the compressor in order to

• A.

Ensure the engine is at governed speed before engaging compressor

• B.

Allow compressor oil and discharge pressures to stabilize

• C.

Defrost the evaporator

• D.

Buildup oil pressure

B. Allow compressor oil and discharge pressures to stabilize
Explanation
When engaging the compressor, holding the ACE 802S air conditioner compressor switch in the HOLD position allows the compressor oil and discharge pressures to stabilize. This is important because it ensures that the compressor operates efficiently and effectively. Stabilizing the oil and discharge pressures helps to prevent any sudden surges or fluctuations that could potentially damage the compressor or other components of the air conditioning system. By allowing these pressures to stabilize, the compressor can function properly and provide the desired cooling effect.

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• 18.

### Which is the compressor displacement when the ACE 802S air conditioner compressor is in the HOLD  position?

• A.

Maximum

• B.

Minimum

• C.

Constant

• D.

C. Constant
Explanation
The compressor displacement refers to the volume of air that the compressor is capable of moving in a given amount of time. In the HOLD position, the compressor is not actively compressing or moving any air, so the compressor displacement remains constant.

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• 19.

### Which medium does the ACE 802S airconditioner heat boost system use to trim output air temperature?

• A.

Air

• B.

Refrigerant

• C.

Electric heater

• D.

Engine Coolant

D. Engine Coolant
Explanation
The ACE 802S air conditioner heat boost system uses engine coolant to trim the output air temperature. Engine coolant is circulated through the system to absorb heat from the air and then release it outside the vehicle. This allows the air conditioner to effectively cool the interior of the vehicle by reducing the temperature of the air blown into the cabin.

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• 20.

### Which action occurs in the ACE 802A air conditioner evaporator?

• A.

Condensiong refirgerant Absorbs heat from the air stream

• B.

Boiling refrigerant absorbs heat from the air stream

• C.

Condensing refrigerant looses heat to the air stream

• D.

Boiling refrigerant looses heat to the air stream

B. Boiling refrigerant absorbs heat from the air stream
Explanation
The correct answer is "Boiling refrigerant absorbs heat from the air stream." In an air conditioner evaporator, the refrigerant undergoes a phase change from a liquid to a gas. This phase change is caused by the low pressure and temperature in the evaporator coil. As the refrigerant boils, it absorbs heat from the surrounding air stream, resulting in the cooling effect that is desired in an air conditioner.

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• 21.

### Which valve must be opened prior to starting the ACE 802S air conditioner engine?

• A.

Air shutoff

• B.

Fuel shutoff

• C.

Coolant control

• D.

Refrigerant flow

A. Air shutoff
Explanation
Prior to starting the ACE 802S air conditioner engine, the air shutoff valve must be opened. This valve controls the flow of air into the engine, allowing it to start and operate properly. Opening the air shutoff valve ensures that the engine receives the necessary air supply for combustion, which is essential for the engine to function correctly.

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• 22.

### Which must be accomplished to avoid damage prior to operating the ACE 802S air conditioner in the HEATING mode after COOLING mode operation?

• A.

Permit refrigerant pressure to equalize

• B.

Perform maximum refrigerant pump down

• C.

Place heating/cooling switch in HEATING position

• D.

Place the reversing valve lever in the HEATING position

A. Permit refrigerant pressure to equalize
Explanation
To avoid damage prior to operating the ACE 802S air conditioner in the HEATING mode after COOLING mode operation, it is necessary to permit refrigerant pressure to equalize. This is important because the refrigerant pressure needs to stabilize and equalize before switching between the two modes. If the pressure is not allowed to equalize, it can cause damage to the system and affect its performance.

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• 23.

### In troubleshooting, which is the first step that must be completed when a unit comes in with a write-up?

• A.

Isolate the problem

• B.

Perform a service inspection

• C.

Perform an operational check

• D.

Recognize the write-up as a problem

D. Recognize the write-up as a problem
Explanation
The first step that must be completed when a unit comes in with a write-up is to recognize the write-up as a problem. This means acknowledging that there is an issue or complaint that needs to be addressed. By recognizing the write-up as a problem, the technician can then proceed to investigate and diagnose the issue further. It is important to acknowledge the write-up before moving on to other troubleshooting steps to ensure that all concerns are properly addressed.

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• 24.

### How can a restriction in a refrigerant system be identified?

• A.

Sweating at the outlet of a component

• B.

Frosting at the outlet of a component

• C.

Abnormal compressor noise

• D.

Increased suction pressure

B. Frosting at the outlet of a component
Explanation
A restriction in a refrigerant system can be identified by observing frosting at the outlet of a component. When there is a restriction in the system, the flow of refrigerant is reduced, causing a decrease in pressure and temperature at the outlet of the component. This leads to the formation of frost on the component. Therefore, the presence of frosting indicates a restriction in the refrigerant system.

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• 25.

### On a basic rotary compressor, which prevents air from leaving the discharge port while the intake port is taking air in?

• A.

Sliding barrier

• B.

Rotating barrier

• C.

Discharge valve

• D.

Stationary barrier

A. Sliding barrier
Explanation
A sliding barrier is a component in a basic rotary compressor that prevents air from leaving the discharge port while the intake port is taking air in. It is designed to create a seal and ensure that the compressed air flows in the desired direction, improving the compressor's efficiency and performance.

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• 26.

### Oil in a rotary vane compressor

• A.

Lubricates the connection rods.

• B.

Has high viscosity and is very inflammable

• C.

Froms a seal between the vanes and the stator

• D.

Permits it to be classified as a high pressure unit

C. Froms a seal between the vanes and the stator
Explanation
The oil in a rotary vane compressor forms a seal between the vanes and the stator. This is important because it prevents leakage of compressed air and ensures efficient operation of the compressor. Without the oil seal, there would be loss of pressure and decreased performance. Therefore, the oil plays a crucial role in maintaining the proper functioning of the compressor by creating a tight seal between the moving parts.

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• 27.

### Which provides pressurized oil to the rotor blades of the MC-2A rotary slicing vane compressor?

• A.

Hollow-ported bolt

• B.

Hollow stator shaft

• C.

Hollow rotor shaft

• D.

Drilled passages

C. Hollow rotor shaft
Explanation
The hollow rotor shaft provides pressurized oil to the rotor blades of the MC-2A rotary slicing vane compressor. The hollow design allows oil to flow through the shaft and reach the blades, ensuring proper lubrication and cooling. This helps maintain the efficiency and performance of the compressor by reducing friction and heat buildup.

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• 28.

### On the MC-2A rotary sliding vane compressor, the minimim pressure valve does all of the following except

• A.

Ensure minimum pressure within the oil chamber

• B.

Ensure minimum pressure to condensate drain

• C.

Prevent receiver air from flowin gback to the compressor by working as a check valve

• D.

Increase the efficiency of the felt pads by ensuring they receive a constant minimum air pressure

B. Ensure minimum pressure to condensate drain
Explanation
The MC-2A rotary sliding vane compressor's minimum pressure valve is responsible for ensuring minimum pressure within the oil chamber, preventing receiver air from flowing back to the compressor by working as a check valve, and increasing the efficiency of the felt pads by ensuring they receive a constant minimum air pressure. However, it does not have a direct role in ensuring minimum pressure to the condensate drain.

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• 29.

### The MC20 air compressor provides which kind of air for pneumatic tools and tire inflation?

• A.

High pressure

• B.

Low pressure

• C.

High volume

• D.

Low volume

B. Low pressure
Explanation
The MC20 air compressor provides low pressure air for pneumatic tools and tire inflation. Low pressure air is typically used for tasks that require less force or power, such as inflating tires or operating smaller pneumatic tools. High pressure air, on the other hand, is used for tasks that require more force or power, such as operating heavy-duty pneumatic tools or machinery. Therefore, the MC20 air compressor is specifically designed to deliver low pressure air for these specific applications.

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• 30.

### Every how many years is the hydrostatic test due on the receiver tank on a MC-20 air compressor?

• A.

9

• B.

7

• C.

5

• D.

3

C. 5
Explanation
The hydrostatic test is due on the receiver tank of a MC-20 air compressor every 5 years. This test is important to ensure the tank's structural integrity and safety. By conducting the test regularly, any potential weaknesses or leaks can be identified and addressed promptly, reducing the risk of accidents or equipment failure.

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• 31.

### Which is the proper compressor oil level when checking the sight glass on the MC20 air compressor

• A.

Between the bottom and half way up on the sight glass

• B.

Between half way and the top of the sight glass

• C.

Any oil level present in the sight glass

• D.

At least one third up the sight glass

C. Any oil level present in the sight glass
Explanation
The correct answer is "Any oil level present in the sight glass." This means that as long as there is some oil visible in the sight glass, the compressor oil level is considered proper. It doesn't matter if the oil level is at the bottom, halfway up, or even close to the top of the sight glass. As long as there is oil present, it indicates that there is enough lubrication for the compressor to function properly.

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• 32.

### Which position should the vent valve be in when liquid oxygen (LOX) carts are being transported?

• A.

Tow

• B.

Closed

• C.

Opened

• D.

Transport

B. Closed
Explanation
When liquid oxygen (LOX) carts are being transported, the vent valve should be in the closed position. This is because liquid oxygen is highly reactive and can easily ignite or explode if it comes into contact with flammable materials or if the pressure inside the cart increases. By keeping the vent valve closed, it ensures that the oxygen remains contained and prevents any potential accidents or hazards during transportation.

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• 33.

### How is the air compressor in the self generating nitrogen servicing cart (SGNSC) categorized?

• A.

High Pressure

• B.

Low pressure

• C.

High volume

• D.

Low volume

A. High Pressure
Explanation
The air compressor in the self-generating nitrogen servicing cart (SGNSC) is categorized as high pressure because it is designed to generate and deliver compressed air at a high pressure level. This is necessary for tasks such as inflating aircraft tires, where a significant amount of pressure is required to properly inflate the tires and ensure safe operation.

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• 34.

### To start the SGNSC the operator places the ignition switch in the start position for no more than how many seconds?

• A.

5

• B.

10

• C.

15

• D.

20

B. 10
Explanation
The operator must place the ignition switch in the start position for no more than 10 seconds to start the SGNSC.

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• 35.

### At which storage cylinder pressure, in pounds per square inch gauge (psig), should the SGNSC nitrogen booster compressor stop?

• A.

2400

• B.

4100

• C.

4400

• D.

6400

C. 4400
Explanation
The SGNSC nitrogen booster compressor should stop at a storage cylinder pressure of 4400 pounds per square inch gauge (psig).

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• 36.

### Which is the proper level in the SGNSC hydraulic reservoir?

• A.

2/3 to 3/4 inch from the bottom of the glass

• B.

2/3 to 3/4 inch from the top of the glass

• C.

1/2 inch from the bottom of the glass

• D.

1/2 inch below the top of the glass

D. 1/2 inch below the top of the glass
Explanation
The correct answer is 1/2 inch below the top of the glass. This is the proper level in the SGNSC hydraulic reservoir because it allows for enough space for the hydraulic fluid to expand when heated without overflowing. It also ensures that there is enough fluid in the reservoir to properly lubricate and cool the hydraulic system.

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• 37.

### During an operation check of a SGNSC the engine is running at 3000 revolutions per minute (rpm), but the nitrogen purity does not reach 95.5 percent within 30 minutes. Which is the probable cause?

• A.

Warming door is not lowered for cold weather operating conditions

• B.

Low oil level in the feed air compressor lubricant separator tank

• C.

Booster compressor defective

• D.

Poor air ventilation

A. Warming door is not lowered for cold weather operating conditions
Explanation
The warming door not being lowered for cold weather operating conditions is the probable cause for the engine not reaching the required nitrogen purity within 30 minutes. This suggests that the engine is not receiving the necessary warm air for proper operation in cold weather, which is affecting the nitrogen purity.

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• 38.

### The purpose of the MJ2A-1 hydraulic test stand fill and bleed system is to fill the hydraulic system with fluid and

• A.

Bleed air from the reservoir during operation

• B.

Purge entrapped air before operation

• C.

Fill the outlet hoses to the aircraft

• D.

Remove contaminants

B. Purge entrapped air before operation
Explanation
The purpose of the MJ2A-1 hydraulic test stand fill and bleed system is to purge entrapped air before operation. This means that the system is designed to remove any air that may be trapped within the hydraulic system before it is put into operation. This is important because air can cause issues with the performance and operation of the hydraulic system, and it needs to be removed to ensure proper functioning.

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• 39.

### Which position must the reservoir selector valve be in when filling and bleeding the MJ-2A-1 hydraulic test stand hydraulic system?

• A.

OPEN

• B.

STAND

• C.

AIRCRAFT

• D.

EXTERNAL

C. AIRCRAFT
Explanation
The reservoir selector valve must be in the "AIRCRAFT" position when filling and bleeding the MJ-2A-1 hydraulic test stand hydraulic system. This position allows the hydraulic fluid to flow directly from the aircraft's hydraulic system into the test stand, ensuring that the system is properly filled and bled.

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• 40.

### Which valve protects the MJ-2A-1 hydraulic test stand from over pressurization when the unit is not operating?

• A.

High pressure relief

• B.

Thermal relief

• C.

Check relief

• D.

Fill relief

B. Thermal relief
Explanation
The thermal relief valve protects the MJ-2A-1 hydraulic test stand from over pressurization when the unit is not operating by releasing excess pressure caused by thermal expansion. This valve is designed to open at a specific temperature and relieve the pressure to prevent damage to the system.

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• 41.

### Which valve protects the MJ-2A-1 hydraulic test stand from over pressurization when the unit is not operating?

• A.

High pressure relief

• B.

Thermal relief

• C.

Check/relief

• D.

Fill relief

B. Thermal relief
Explanation
The thermal relief valve protects the MJ-2A-1 hydraulic test stand from over pressurization when the unit is not operating. This valve is designed to open and release excess pressure in the system when the temperature exceeds a certain limit, preventing damage to the equipment. It ensures the safety and longevity of the test stand by relieving pressure caused by thermal expansion.

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• 42.

### The purpose of the low pressure pump on the MJ-2A-1 is to ensure a constant flow of fluid to the

• A.

Relief valves

• B.

Aircraft pumps

• C.

Low pressure filters

• D.

High pressure pump

D. High pressure pump
Explanation
The purpose of the low pressure pump on the MJ-2A-1 is to ensure a constant flow of fluid to the high pressure pump. The high pressure pump requires a steady supply of fluid in order to function properly and generate the necessary pressure for the system. The low pressure pump helps maintain this flow by providing a consistent source of fluid, ensuring that the high pressure pump can operate efficiently and effectively.

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• 43.

### The out put volume (gallons per minute) of the MJ-2A-1 hydraulic test stand high pressure pump is controlled by the

• A.

Volume control

• B.

Flow control valve

• C.

Compensator control

• D.

Flowmeter assembly

A. Volume control
Explanation
The output volume of the MJ-2A-1 hydraulic test stand high pressure pump is controlled by the volume control. This means that the volume of hydraulic fluid being pumped per minute can be adjusted using this control. The other options listed, such as the flow control valve, compensator control, and flowmeter assembly, do not directly control the output volume of the pump.

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• 44.

### Which MJ-2A-1 hydraulic test stand engine system safety device sounds the warning horn in the event of an engine system malfunction?

• A.

Water level switch

• B.

Oil pressure switch

• C.

Fuel level indicator

• D.

Fuel pressure switch

B. Oil pressure switch
Explanation
The oil pressure switch is the correct answer because it is a safety device that monitors the oil pressure in the engine system. In the event of an engine system malfunction, such as low oil pressure, the oil pressure switch will detect this and sound the warning horn to alert the operator. This is important as low oil pressure can cause engine damage or failure, and the warning horn ensures that the operator is aware of the issue and can take appropriate action.

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• 45.

### Which MJ-2A-1 hydraulic test stand switch provides an alternate means of energizing the fill pump when either of the micro switches are defective?

• A.

Fill switch, LS4

• B.

Fill master switch

• C.

Fill micro switch, FS1

• D.

Fill to start relay switch

A. Fill switch, LS4
Explanation
The LS4 fill switch provides an alternate means of energizing the fill pump when either of the micro switches are defective. This means that if either of the micro switches that are responsible for energizing the fill pump are not working properly, the LS4 fill switch can be used as a backup to still activate the fill pump.

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• 46.

### Which valve must be opened when setting up the MJ-2A-1 hydraulic test stand controls for operation?

• A.

Return system bypass

• B.

Compensator control

• C.

Supply shut off

• D.

System selector

A. Return system bypass
Explanation
The return system bypass valve must be opened when setting up the MJ-2A-1 hydraulic test stand controls for operation. This valve allows the hydraulic fluid to bypass the return system, ensuring that the fluid flows back to the reservoir instead of going through the test stand controls. By opening this valve, the hydraulic system can operate smoothly and efficiently without any restrictions or pressure build-up.

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• 47.

### Which is the setting of the MJ02A-1 hydraulic test stand system relief valve?

• A.

300 pounds per square inch above compensator valve pressure

• B.

300 psi above required test pressure

• C.

500 psi above compensator valve pressure

• D.

500 psi above required test pressure

B. 300 psi above required test pressure
Explanation
The setting of the MJ02A-1 hydraulic test stand system relief valve is 300 psi above the required test pressure. This means that the relief valve will open when the pressure in the system exceeds the required test pressure by 300 psi.

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• 48.

### Which type of wrench should be used on brass or aluminum fittings?

• A.

Aluminum

• B.

Open end

• C.

Tubing

• D.

Brass

C. Tubing
Explanation
The correct answer is "Tubing". When working with brass or aluminum fittings, it is recommended to use a tubing wrench. This type of wrench is designed specifically for tightening or loosening fittings on tubing, providing a secure grip without damaging the fittings. Using an open-end wrench or any other type of wrench may result in damage to the fittings or improper tightening, which can lead to leaks or other issues.

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• 49.

### The hydraulic test stand high pressure pump is difficult to repair because of its

• A.

Precision tolerances

• B.

Weight an size

• C.

Intricate parts

• D.

Age

A. Precision tolerances
Explanation
The hydraulic test stand high pressure pump is difficult to repair because of its precision tolerances. This means that the pump requires very precise measurements and alignments in order to function properly. Any slight deviation or error in these tolerances can lead to malfunctioning or inefficiency of the pump. Therefore, repairing such a pump requires a high level of skill and expertise to ensure that the precision tolerances are maintained.

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• 50.

### Which type of pump is used on the MJ-1B bomblift truch hydrostatic system?

• A.

Variable displacement

• B.

Fized displacement

• C.

Rotary type

• D.

Gear type

A. Variable displacement
Explanation
The correct answer is variable displacement. Variable displacement pumps are commonly used in hydraulic systems where the flow rate needs to be adjusted based on the load requirements. In the case of the MJ-1B bomblift truck hydrostatic system, a variable displacement pump would allow for precise control of the hydraulic fluid flow, enabling efficient operation of the system. This type of pump can vary the displacement of the fluid, allowing for flexibility in adjusting the flow rate as needed.

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Quiz Review Timeline +

Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

• Current Version
• May 21, 2024
Quiz Edited by
ProProfs Editorial Team
• Mar 29, 2018
Quiz Created by
D. Crook

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