1.
(601) The heater control unit (HCU) on the New Generation Heater (NGH) starts the main air fan for output air when
Correct Answer
D. The inside temperature reaches 140 degrees Fahrenheit (°F).
Explanation
The correct answer is "the inside temperature reaches 140 degrees Fahrenheit (°F)." This means that the main air fan for output air will start when the inside temperature of the heater reaches 140 degrees Fahrenheit. This temperature threshold triggers the HCU to activate the fan and circulate the heated air. The other options, such as selecting a heat setting or establishing a constant flame, are not mentioned as conditions for starting the main air fan.
2.
(602) When should starting aids be used to start the New Generation Heater (NGH)?
Correct Answer
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 means that using starting aids such as jump-starting or using additional equipment to start the NGH can cause harm to the engine. It is important to avoid using starting aids to prevent any potential damage to the engine.
3.
(602) When operating the New Generation Heater (NGH), turn the heat control switch to the desired position after
Correct Answer
C. System voltage indicates 120 volts alternating current (VAC).
Explanation
The correct answer is "system voltage indicates 120 volts alternating current (VAC)". This is the correct answer because it is the only option that is directly related to the operation of the New Generation Heater (NGH). The other options mention warm-up time, a minimum of 45 seconds, and the inside chamber temperature reaching 140 degrees Fahrenheit, but these factors are not mentioned in relation to operating the NGH. Therefore, the correct answer is the option that specifically refers to the system voltage indicating 120 volts alternating current.
4.
(603) Repair of ground heater equipment should never be attempted
Correct Answer
C. Unless accurate technical data is available.
Explanation
Repairing ground heater equipment can be a complex task that requires accurate technical data. Without this data, attempting to repair the equipment can lead to further damage or even injury. Therefore, it is important to have access to accurate technical data before attempting any repairs on ground heater equipment.
5.
(604) Heat that can be felt and added or subtracted to a substance without changing its state is called
Correct Answer
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. This means that the temperature of the substance can be directly measured and sensed. Superheat refers to the heat added to a substance above its boiling point, latent heat refers to the heat absorbed or released during a phase change, and specific heat refers to the amount of heat required to raise the temperature of a substance by a certain amount. Therefore, the correct answer is sensible heat.
6.
(604) Heat added to a gas is
Correct Answer
C. Super heat.
7.
(605) A good refrigerant will
Correct Answer
B. Operate in low to moderate pressure.
Explanation
A good refrigerant needs to operate in low to moderate pressure in order to efficiently transfer heat and cool the surrounding area. Operating in high pressure can lead to safety concerns and potential damage to the refrigeration system. Additionally, operating in low to moderate pressure allows for better control of the refrigerant flow and ensures optimal performance of the refrigeration system.
8.
(606) Which MA–3D air conditioner control switch allows the operator to control the overall volume of air leaving the unit?
Correct Answer
B. Airflow.
Explanation
The MA-3D air conditioner control switch that allows the operator to control the overall volume of air leaving the unit is the "Airflow" switch. This switch allows the user to adjust the speed and intensity of the air being blown out by the air conditioner, giving them control over the airflow in the room. The blower switch controls the fan speed, the evaporator switch controls the cooling process, and the temperature switch controls the desired temperature. However, none of these switches specifically control the overall volume of air leaving the unit like the airflow switch does.
9.
(606) Refrigerant leaving the evaporator coil, in the MA–3D air conditioner, is a
Correct Answer
A. Low-pressure gas.
Explanation
The refrigerant leaving the evaporator coil in the MA-3D air conditioner is in a low-pressure gas state. This is because the evaporator coil is responsible for absorbing heat from the surroundings, causing the refrigerant to evaporate and turn into 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.
10.
(606) When starting the MA–3D air conditioner, hold the safety override switch until
Correct Answer
A. 30 pounds of oil pressure is reached on the engine oil pressure gauge.
Explanation
When starting the MA-3D air conditioner, it is necessary to hold the safety override switch until 30 pounds of oil pressure is reached on the engine oil pressure gauge. This indicates that the engine has sufficient oil pressure to operate effectively. Once this pressure is reached, it is safe to release the start switch and proceed with starting the engine.
11.
(606) On the MA–3D air conditioner, which component shuts off the compressor when suction pressure drops below 5 pounds of pressure?
Correct Answer
B. Temperature controller.
Explanation
The temperature controller is the component on the MA-3D air conditioner that shuts off the compressor when the suction pressure drops below 5 pounds of pressure. It is responsible for monitoring the temperature and pressure levels in the system and initiating the necessary actions to maintain optimal operation. When the suction pressure falls below the specified threshold, the temperature controller detects this and signals the compressor to shut off, preventing any potential damage or malfunction.
12.
(607) Which type of refrigeration system leak occurs when the pressure within the system is less than atmospheric pressure?
Correct Answer
A. Inward.
Explanation
When the pressure within a refrigeration system is less than atmospheric pressure, it creates a vacuum. In this scenario, the leak occurs inward, meaning that air or other substances from the surroundings are pulled into the system due to the pressure difference. This is why the correct answer is "Inward."
13.
(607) A refrigerant reclaimer is used to
Correct Answer
D. Remove and store refrigerant and separate oil and acids from the refrigerant.
Explanation
A refrigerant reclaimer is a device used to safely remove refrigerant from a system and store it for future use. Additionally, it is designed to separate oil and acids from the refrigerant to ensure its purity and prevent any damage to the system. This helps in maintaining the efficiency and performance of the refrigeration system.
14.
(607) Refrigerant is always removed through the
Correct Answer
C. Receiver outlet valve.
Explanation
The correct answer is receiver outlet valve. Refrigerant is removed from the receiver through the outlet valve. The receiver is a storage tank for the refrigerant in a refrigeration system, and the outlet valve allows the refrigerant to flow out of the receiver and continue through the system. The purge valve is used to remove air or non-condensable gases from the system, while the receiver inlet valve controls the flow of refrigerant into the receiver. The discharge service valve is used to control the flow of refrigerant from the compressor to the condenser.
15.
(608) An A/M32C–10D air conditioner air cycle machine consists of
Correct Answer
D. An expansion turbine and a compressor fan.
Explanation
The correct answer is "an expansion turbine and a compressor fan." This means that the A/M32C-10D air conditioner air cycle machine consists of both an expansion turbine and a compressor fan. The expansion turbine is responsible for expanding the compressed air, while the compressor fan is used to circulate the air throughout the system.
16.
(608) Which A/M32C–10D air conditioner component extracts energy from bleed air on the air cycle machine?
Correct Answer
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. The expansion turbine is responsible for converting the high-pressure, high-temperature bleed air into low-pressure, low-temperature air, which is then used to cool the aircraft cabin. This process allows for the efficient extraction and utilization of energy from the bleed air, making the expansion turbine the correct answer.
17.
(609) The ACE 802S air conditioner compressor switch must be held in the HOLD position when engaging the compressor in order to
Correct Answer
B. Allow compressor oil and discharge pressures to stabilize.
Explanation
When engaging the compressor in an ACE 802S air conditioner, it is important to hold the compressor switch in the HOLD position. This is done to allow the compressor oil and discharge pressures to stabilize. By holding the switch in the HOLD position, it ensures that the oil and pressure within the compressor have reached a stable state before engaging the compressor fully. This helps to prevent any sudden surges or fluctuations in the oil and pressure levels, which could potentially damage the compressor or affect its performance.
18.
(609) Which is the compressor displacement when the ACE 802S air conditioner compressor is in the HOLD position?
Correct Answer
C. Constant.
Explanation
The compressor displacement refers to the volume of air that the compressor can move in a given time. When the ACE 802S air conditioner compressor is in the HOLD position, it means that the compressor is not actively compressing or moving air. Therefore, the compressor displacement remains constant, as there is no change in the volume of air being moved.
19.
(609) Which medium does the ACE 802S air conditioner heat boost system use to trim output air temperature?
Correct Answer
D. Engine coolant.
Explanation
The ACE 802S air conditioner heat boost system uses engine coolant to trim the output air temperature. Engine coolant is a liquid that circulates through the engine and absorbs heat, which can then be used to regulate the temperature of the air being released by the air conditioner. This allows for precise control and adjustment of the output air temperature.
20.
(609) Which action occurs in the ACE 802S air conditioner evaporator?
Correct Answer
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 is in a low-pressure state and is boiling. As the warm air from the room passes over the evaporator coils, the boiling refrigerant absorbs heat from the air stream, cooling the air in the process. This cooled air is then circulated back into the room, while the heated refrigerant flows to the condenser to release the absorbed heat.
21.
(610) Which valve must be opened prior to starting the ACE 802S air conditioner engine?
Correct Answer
A. Air shutoff.
Explanation
Prior to starting the ACE 802S air conditioner engine, the air shutoff valve must be opened. This is because the air shutoff 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 efficiently.
22.
(610) Which must be accomplished to avoid damage prior to operating the ACE 802S air conditioner in the HEATING mode after COOLING mode operation?
Correct Answer
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 when switching from COOLING to HEATING mode, there may be a pressure difference in the refrigerant system. Allowing the pressure to equalize ensures that there is no excessive pressure buildup or sudden changes in the system, which could potentially lead to damage.
23.
(611) In troubleshooting, which is the first step that must be completed when a unit comes in with a write-up?
Correct Answer
D. Recognize the write-up as a malfunction.
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 malfunction. This means acknowledging that there is an issue or problem reported by the customer or operator. By recognizing the write-up as a malfunction, the technician can then proceed to investigate and troubleshoot the specific problem in order to find a solution.
24.
(611) How can a restriction in a refrigerant system be identified?
Correct Answer
B. Frosting at the outlet of a component.
Explanation
Frosting at the outlet of a component can be an indication of a restriction in a refrigerant system. When there is a restriction, the flow of refrigerant is impeded, causing a drop in pressure and temperature. This drop in temperature can cause moisture in the air to freeze and form frost on the outlet of the component. Therefore, the presence of frosting can help identify a restriction in the system.
25.
(612) On a basic rotary compressor, which prevents air from leaving the discharge port while the intake port is taking air in?
Correct Answer
A. Sliding barrier.
Explanation
A basic rotary compressor has a sliding barrier that prevents air from leaving the discharge port while the intake port is taking air in. The sliding barrier acts as a seal, ensuring that the compressed air flows in the desired direction and does not escape through the discharge port when the intake port is active. This mechanism allows for efficient compression and prevents any loss of compressed air during the compression process.
26.
(612) Oil in a rotary vane compressor
Correct Answer
C. Forms a seal between the vanes and the stator.
Explanation
Oil in a rotary vane compressor forms a seal between the vanes and the stator. This is important because it prevents leakage of compressed gases and ensures efficient compression. The oil fills the small gaps between the vanes and the stator, creating a tight seal that allows the compressor to build up pressure effectively. Without this seal, there would be significant loss of compressed gases, leading to reduced performance and efficiency of the compressor.
27.
(612) Which provides pressurized oil to the rotor blades of the MC–2A rotary sliding vane compressor?
Correct Answer
C. Hollow rotor shaft.
Explanation
The correct answer is hollow rotor shaft. In a MC-2A rotary sliding vane compressor, the rotor blades require pressurized oil to function properly. This pressurized oil is provided through a hollow rotor shaft, which allows the oil to flow into the blades and lubricate them. The hollow rotor shaft acts as a conduit for the oil, ensuring that it reaches the blades and keeps them lubricated during operation.
28.
(612) On the MC–2A rotary sliding vane compressor, the minimum pressure valve does all of the following except
Correct Answer
B. Ensure minimum pressure to the condensate drain.
Explanation
The MC-2A rotary sliding vane compressor has a minimum pressure valve that serves multiple functions. It ensures minimum pressure within the oil chamber, prevents receiver air from flowing back to the compressor by working as a check valve, and increases 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.
29.
(613) The MC–20 air compressor provides which kind of air for pneumatic tools and tire inflation?
Correct Answer
B. Low pressure.
Explanation
The MC-20 air compressor provides low pressure air for pneumatic tools and tire inflation. This means that it delivers air at a lower pressure, which is suitable for tasks that require less force or power. Low pressure air is commonly used for tasks such as inflating tires, operating pneumatic tools like nail guns or paint sprayers, and other applications where high pressure is not necessary.
30.
(613) Every how many years is the hydrostatic test due on the receiver tank on a MC–20 air compressor?
Correct Answer
C. 5.
Explanation
The hydrostatic test is due on the receiver tank of a MC-20 air compressor every 5 years. This means that after every 5 years, the tank needs to undergo a hydrostatic test to check for any leaks or weaknesses. This is important to ensure the safety and efficiency of the air compressor.
31.
(613) Which is the proper compressor oil level when checking the sight glass on a MC–20 air compressor?
Correct Answer
C. Any oil level present in the sight glass.
Explanation
The proper compressor oil level when checking the sight glass on a MC-20 air compressor 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 level is considered proper. It does not matter if the oil level is at the bottom, halfway up, or at the top of the sight glass, as long as there is oil present.
32.
(614) Which position should the vent valve be in when liquid oxygen (LOX) carts are being transported?
Correct Answer
B. Closed.
Explanation
When liquid oxygen (LOX) carts are being transported, the vent valve should be in the closed position. This is important to prevent any leaks or spills of the highly volatile and potentially dangerous liquid oxygen. Closing the vent valve ensures that the cart is properly sealed and secure during transportation, minimizing the risk of accidents or incidents.
33.
(615) How is the air compressor in the self generating nitrogen servicing cart (SGNSC) categorized?
Correct Answer
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 store nitrogen at high pressures. This is necessary for servicing aircraft systems that require nitrogen at high pressures, such as hydraulic systems and landing gear. The high-pressure air compressor ensures that an adequate supply of nitrogen is available at the required pressure levels for efficient and safe aircraft maintenance.
34.
(616) To start the self generating nitrogen servicing cart (SGNSC), the operator places the ignition switch in the start position for no more than how many seconds?
Correct Answer
B. 10.
Explanation
To start the self-generating nitrogen servicing cart (SGNSC), the operator must place the ignition switch in the start position for no more than 10 seconds. This time limit ensures that the engine is given enough time to start without causing any damage or unnecessary strain. Going beyond this time limit may result in potential issues or malfunctions with the cart's engine.
35.
(616) At which storage cylinder pressure, in pounds per square inch gauge (psig), should the self generating nitrogen servicing cart (SGNSC) nitrogen booster compressor stop?
Correct Answer
C. 4,400.
Explanation
The self generating nitrogen servicing cart (SGNSC) nitrogen booster compressor should stop at a storage cylinder pressure of 4,400 pounds per square inch gauge (psig).
36.
(617) Which is the proper level in the self generating nitrogen servicing cart (SGNSC) hydraulic reservoir?
Correct Answer
D. 1/2 inch below the top of the glass.
Explanation
The proper level in the self-generating nitrogen servicing cart (SGNSC) hydraulic reservoir is 1/2 inch below the top of the glass. This ensures that there is enough hydraulic fluid in the reservoir to properly operate the equipment without overflowing. Keeping the level below the top also allows for any expansion of the fluid due to temperature changes.
37.
(618) During an operational check of a self-generating nitrogen servicing cart (SGNSC) the engine is running at 3,000 revolutions per minute (rpm), but the nitrogen purity does not reach 95.5 percent within 30 minutes. Which is a probable cause of this malfunction?
Correct Answer
A. Warming door is not lowered for cold weather operating conditions.
Explanation
The probable cause of the malfunction is that the warming door is not lowered for cold weather operating conditions. This is because the question states that the nitrogen purity does not reach 95.5 percent within 30 minutes while the engine is running at 3,000 rpm. The warming door is responsible for maintaining the appropriate temperature inside the self-generating nitrogen servicing cart (SGNSC), and if it is not lowered during cold weather, it can lead to a decrease in nitrogen purity.
38.
(618) Which is important to keep in mind when performing maintenance on the self generating nitrogen servicing cart (SGNSC)?
Correct Answer
D. Safety.
Explanation
When performing maintenance on the self-generating nitrogen servicing cart (SGNSC), it is important to keep safety in mind. This means following all necessary safety protocols and precautions to ensure the well-being of the maintenance personnel and the equipment being worked on. Safety measures may include wearing appropriate personal protective equipment (PPE), using lockout/tagout procedures, and being aware of potential hazards in the work area. Weather conditions, wind direction, and ventilation may also be important factors to consider, but safety should always be the top priority.
39.
(619) The purpose of the MJ–2A–1 hydraulic test stand fill-and-bleed system is to fill the hydraulic system with fluid and
Correct Answer
B. Purge entrapped air before operation.
Explanation
The purpose of the MJ-2A-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 bubbles can cause issues with the performance and operation of the hydraulic system, so it is necessary to remove them before use.
40.
(619) Which position must the reservoir selector valve be in when filling and bleeding the MJ–2A–1 hydraulic test stand hydraulic system?
Correct Answer
C. AIRCRAFT.
Explanation
The reservoir selector valve must be in the AIRCRAFT position when filling and bleeding the hydraulic system of the MJ-2A-1 hydraulic test stand. This position allows the system to be connected to the aircraft's hydraulic system, enabling the transfer of fluid between the two systems. It ensures that the correct fluid is being used and that any air trapped in the system can be properly bled out.
41.
(619) Which valve protects the MJ–2A–1 hydraulic test stand from over pressurization when the unit is not operating?
Correct Answer
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 when the temperature of the hydraulic fluid rises above a certain threshold, preventing damage to the system. Unlike the other options, the thermal relief valve specifically addresses the issue of over pressurization due to temperature changes, making it the correct answer in this context.
42.
(619) The purpose of the low pressure pump on the MJ–2A–1 is to ensure a constant flow of fluid to the
Correct Answer
D. High pressure pump.
Explanation
The purpose of the low pressure pump on the MJ-2A-1 is not to ensure a constant flow of fluid to the relief valves, aircraft pumps, or low pressure filters. Instead, the low pressure pump is responsible for supplying fluid to the high pressure pump.
43.
(619) The output volume (gallons per minute) of the MJ–2A–1 hydraulic test stand high pressure pump is controlled by the
Correct Answer
A. Volume control.
Explanation
The correct answer is volume control. The output volume of the hydraulic test stand high pressure pump is controlled by the volume control. This means that the pump's output can be adjusted by manipulating the volume control, allowing for precise control over the amount of fluid being pumped per minute. The other options, flow control valve, compensator control, and flowmeter assembly, may play a role in the overall hydraulic system but they do not directly control the output volume of the pump.
44.
(620) Which MJ–2A–1 hydraulic test stand engine system safety device sounds the warning horn in the event of an engine system malfunction?
Correct Answer
B. Oil pressure switch.
Explanation
The oil pressure switch is the correct answer because it is a safety device in the MJ-2A-1 hydraulic test stand engine system that sounds the warning horn in the event of an engine system malfunction. When the oil pressure drops below a certain level, the switch activates the horn to alert the operator of the issue. This is important for ensuring the safe operation of the test stand and preventing any potential damage or accidents that may occur due to engine system malfunctions.
45.
(620) 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?
Correct Answer
A. Fill switch, LS4.
Explanation
The Fill switch, LS4, 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 fail, the Fill switch can still be used to activate the fill pump.
46.
(621) Which valve must be opened when setting up the MJ–2A–1 hydraulic test stand controls for operation?
Correct Answer
A. Return system bypass.
Explanation
When setting up the MJ-2A-1 hydraulic test stand controls for operation, the valve that needs to be opened is the return system bypass. This valve allows the hydraulic fluid to bypass the system and return directly to the reservoir, preventing any pressure build-up and ensuring smooth operation of the test stand. By opening the return system bypass valve, the hydraulic system can be properly calibrated and controlled during operation.
47.
(621) Which is the setting of the MJ–2A–1 hydraulic test stand system relief valve?
Correct Answer
B. 300 psi above required test pressure.
Explanation
The setting of the MJ-2A-1 hydraulic test stand system relief valve is 300 psi above the required test pressure. This means that the relief valve will open and release pressure when the pressure in the system exceeds the required test pressure by 300 psi.
48.
(622) Which type of wrench should be used on brass or aluminum fittings?
Correct Answer
C. Tubing.
Explanation
The correct answer is "Tubing." This type of wrench should be used on brass or aluminum fittings because it is specifically designed for working with tubing. Using a tubing wrench ensures a secure grip on the fittings without causing any damage, as it has a rounded jaw that can easily fit around the cylindrical shape of the tubing. This prevents any potential stripping or distortion of the fittings, which could occur if using other types of wrenches such as open end wrench or brass wrench.
49.
(622) The hydraulic test stand high pressure pump is difficult to repair because of its
Correct Answer
A. Precision tolerances.
Explanation
The correct answer is precision tolerances. The hydraulic test stand high pressure pump is difficult to repair because it requires precise measurements and alignments. Any slight deviation from the specified tolerances can result in malfunctioning or failure of the pump. Therefore, repairing it requires a high level of expertise and precision to ensure that all parts are properly calibrated and aligned.
50.
(623) Which type of pump is used on the MJ–1B bomblift truck hydrostatic system?
Correct Answer
A. Variable displacement.
Explanation
The correct answer is variable displacement. A variable displacement pump is used on the MJ-1B bomblift truck hydrostatic system. This type of pump allows for the adjustment of the pump's displacement, which in turn allows for the control of fluid flow and pressure. This flexibility is important in a system like the bomblift truck, where precise control is needed to safely and efficiently lift and transport heavy loads.