2A551 Practice Test Volume 3 Test 2
Questions and Answers
- 1.
A well designed aircraft fuel system will ensure
- A.
Positive and negative flow
- B.
Negative fuel flow under all conditions
- C.
Positive fuel flow under positive conditions
- D.
Positive and reliable fuel flow under all conditions
Correct Answer
D. Positive and reliable fuel flow under all conditionsExplanation
A well-designed aircraft fuel system is crucial for ensuring the safe and efficient operation of the aircraft. It should provide a positive and reliable fuel flow under all conditions. This means that the fuel system should consistently deliver fuel to the engines, regardless of factors such as altitude, temperature, or aircraft maneuvers. A positive and reliable fuel flow ensures that the engines receive an adequate and consistent fuel supply, allowing them to function properly and maintain the desired level of performance throughout the flight.Rate this question:
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- 2.
The three types of shut off valves used in the crossfeed fuel system are the
- A.
Rotary plug, disc and check
- B.
Disc, check and sliding gate
- C.
Sliding gate, rotary plug and disc
- D.
Check, sliding gate, and rotary plug
Correct Answer
C. Sliding gate, rotary plug and discExplanation
The correct answer is sliding gate, rotary plug, and disc. These three types of shut off valves are commonly used in the crossfeed fuel system. The sliding gate valve is used to control the flow of fuel, while the rotary plug valve is used to regulate the fuel pressure. The disc valve, on the other hand, is used as a check valve to prevent backflow of fuel. Together, these three types of valves ensure the proper functioning and control of the fuel system.Rate this question:
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- 3.
The basic purpose of the fuel vent system is to
- A.
Move fuel from tank to tank
- B.
Pressurize the fuel from transfer
- C.
Remove residual fuel from manifolds
- D.
Prevent the rupture or collapse of the fuel tanks
Correct Answer
D. Prevent the rupture or collapse of the fuel tanksExplanation
The fuel vent system is designed to prevent the rupture or collapse of the fuel tanks. This is important because fuel tanks can experience changes in pressure due to factors such as temperature fluctuations or fuel consumption. If the pressure inside the tank becomes too high, it can lead to tank rupture, potentially causing fuel leakage or even an explosion. On the other hand, if the pressure inside the tank becomes too low, it can cause the tank to collapse, leading to fuel starvation and engine failure. Therefore, the fuel vent system is essential in maintaining a safe and stable pressure within the fuel tanks.Rate this question:
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- 4.
The fuel subsystem designed to minimize fuel boiling is
- A.
Vent
- B.
Scavenge
- C.
Crossfeed
- D.
Pressurization
Correct Answer
D. PressurizationExplanation
Pressurization is the correct answer because maintaining a pressurized fuel system helps to prevent fuel boiling. When fuel boils, it can form vapor bubbles that can disrupt the fuel flow and cause engine performance issues. Pressurization helps to increase the boiling point of the fuel, ensuring that it remains in a liquid state and flows smoothly through the system. This is especially important at high altitudes where the lower atmospheric pressure can cause fuel to boil more easily. By pressurizing the fuel subsystem, the risk of fuel boiling is minimized, ensuring proper fuel flow and engine operation.Rate this question:
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- 5.
The minimum distance and aircraft should be parked from the hangar prior to defueling is
- A.
50 ft
- B.
75 ft
- C.
100 ft
- D.
150 ft
Correct Answer
A. 50 ftExplanation
The minimum distance an aircraft should be parked from the hangar prior to defueling is 50 ft. This distance is necessary to ensure safety during the defueling process. Parking the aircraft at least 50 ft away from the hangar helps to prevent any potential accidents or fires that could occur during the defueling operation. It allows for a safe distance between the fuel source and the hangar, reducing the risk of any ignition or explosion.Rate this question:
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- 6.
The air-refueling (A/R) receptacle is operated
- A.
Hydraulically, but controlled electrically
- B.
Electrically, but controlled hydraulically
- C.
Electrically, but controlled pneumatically
- D.
Hydraulically but controlled pneumatically
Correct Answer
A. Hydraulically, but controlled electricallyExplanation
The air-refueling receptacle is operated hydraulically, meaning that hydraulic power is used to physically move and operate the receptacle. However, the control of the receptacle is done electrically, meaning that electrical signals are used to control and manipulate the hydraulic system.Rate this question:
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- 7.
The output pressure and the flow ratings of a centrifugal type fuel pump are greater than the system needs in order to
- A.
Prevent fuel boiling and evaporation at high altitudes
- B.
Provide an ample supply of fuel in case of a single pump failure
- C.
Provide fuel to the engines during negative g's or inverted flight conditions
- D.
Prevent the reverse flow of fuel from a pump with a greater pressure output
Correct Answer
B. Provide an ample supply of fuel in case of a single pump failureExplanation
The output pressure and flow ratings of a centrifugal type fuel pump are designed to be greater than the system needs in order to provide an ample supply of fuel in case of a single pump failure. This is done to ensure that even if one pump fails, there is still enough pressure and flow to keep the engines running and prevent any disruption in fuel supply. By having a higher capacity than necessary, the pump can compensate for the loss of one pump and maintain uninterrupted fuel delivery to the engines.Rate this question:
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- 8.
The kind of centrifugal pump is used when a fuel supply is required during periods of negative gravity conditions is
- A.
A rotary-vane
- B.
A top-mounted
- C.
A dual-impeller
- D.
An in-line ejector
Correct Answer
C. A dual-impellerExplanation
A dual-impeller centrifugal pump is used when a fuel supply is required during periods of negative gravity conditions. This type of pump has two impellers that work in tandem to create a constant flow of fuel, even when gravity is working against it. The dual-impeller design allows for efficient pumping in both positive and negative gravity conditions, making it suitable for applications where fuel needs to be supplied in such conditions.Rate this question:
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- 9.
What characteristics distinguishes the ejector-type fuel pump from other types of fuel pumps?
- A.
Is hydraulically driven.
- B.
Will operate without fuel.
- C.
Contains no moving parts.
- D.
Is activated by an electric motor.
Correct Answer
C. Contains no moving parts.Explanation
The characteristic that distinguishes the ejector-type fuel pump from other types of fuel pumps is that it contains no moving parts. Unlike other fuel pumps that rely on mechanical components to pump fuel, the ejector-type fuel pump uses a venturi effect to create a pressure difference that draws fuel into the pump and pushes it towards the engine. This design eliminates the need for any moving parts, making the ejector-type fuel pump more reliable and less prone to mechanical failures.Rate this question:
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- 10.
The arrow stamped on the body of a fuel system check valve indicates
- A.
Direction of free flow
- B.
Direction of restricted flow
- C.
Location of the drilled hole in the valve
- D.
Location of the manufacture's data block
Correct Answer
A. Direction of free flowExplanation
The arrow stamped on the body of a fuel system check valve indicates the direction of free flow. This means that the arrow shows the direction in which fuel can flow freely through the valve without any restrictions.Rate this question:
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- 11.
One disadvantage of a sliding gate fuel system is that it
- A.
Is large and heavy
- B.
Cannot control a large flow of fuel
- C.
Cannot withstand extreme pressures.
- D.
Tends to restrict fuel flow when open
Correct Answer
C. Cannot withstand extreme pressures.Explanation
A sliding gate fuel system cannot withstand extreme pressures. This means that when the pressure of the fuel becomes too high, the sliding gate may not be able to handle it, leading to potential damage or malfunction of the system. This can be a significant disadvantage as it limits the system's ability to handle high-pressure situations, which may be required in certain applications or emergencies.Rate this question:
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- 12.
The fuel system component used to prevent excessive pressure from building up in trapped lines is the
- A.
Thermal relief valve
- B.
Pressure relief valve
- C.
One way check valve
- D.
Spring loaded relief
Correct Answer
D. Spring loaded reliefExplanation
A spring loaded relief valve is a fuel system component that is designed to prevent excessive pressure from building up in trapped lines. It works by using a spring to control the pressure inside the system. When the pressure reaches a certain level, the spring is compressed and the valve opens, allowing the excess pressure to be released. This helps to protect the fuel system from damage and ensures that the pressure remains within safe limits.Rate this question:
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- 13.
Another name for the disc type valve in a fuel system is
- A.
Butterfly
- B.
Swivel vane
- C.
Sliding gate
- D.
Swinging disc
Correct Answer
A. ButterflyExplanation
The correct answer is "butterfly" because a disc type valve in a fuel system is commonly referred to as a butterfly valve. This type of valve is named after its shape, which resembles the wings of a butterfly. It is used to regulate or control the flow of fuel in the system by rotating the disc inside the valve.Rate this question:
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- 14.
A primary function of the low lever shut off valve is to control the flow of fuel
- A.
At altitudes below 10,000 ft
- B.
While taxiing on the flight line
- C.
Being added to an unpressurized tank
- D.
Being transferred out of a pressurized tank
Correct Answer
D. Being transferred out of a pressurized tankExplanation
The low-level shut-off valve is primarily used to control the flow of fuel when it is being transferred out of a pressurized tank. This valve helps to regulate the amount of fuel being transferred and ensures that it is done safely and efficiently. It is not used for controlling fuel flow at altitudes below 10,000 ft, while taxiing on the flight line, or when fuel is being added to an unpressurized tank.Rate this question:
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- 15.
The action used by the low lever shut off valve to prevent the reverse flow of fuel through the valve is
- A.
Spring
- B.
Venturi
- C.
Check valve
- D.
Hydromechanical
Correct Answer
C. Check valveExplanation
A check valve is a type of valve that allows fluid to flow in only one direction, preventing reverse flow. It uses a mechanism, such as a ball or a disc, to block the flow when it is going in the wrong direction. In the context of the given question, a check valve would be used in the low-level shut off valve to prevent the reverse flow of fuel. This ensures that the fuel only flows in the desired direction, providing safety and efficiency in the fuel system.Rate this question:
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- 16.
Malfunctions of a fuel system vent float valve can be caused by
- A.
Over filling the fuel tank
- B.
Operating the valve in a "dry" tank
- C.
Loose electrical connections on the valve
- D.
Rough handling of the valve during installation
Correct Answer
D. Rough handling of the valve during installationExplanation
Rough handling of the valve during installation can cause malfunctions of a fuel system vent float valve. This may include mishandling, dropping, or improperly installing the valve, which can lead to damage or misalignment. Such rough handling can disrupt the proper functioning of the valve, affecting its ability to regulate the flow of fuel and maintain the appropriate pressure in the fuel system.Rate this question:
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- 17.
In a direct current, liquid level fuel indicating system, the wiper contact is positioned on the resistance strip by
- A.
Signals in the amplifier
- B.
The movement of a float in the tanks
- C.
Voltage changes in the indicator circuit
- D.
The amount of bleed air pressure entering the fuel tank
Correct Answer
B. The movement of a float in the tanksExplanation
The correct answer is "the movement of a float in the tanks." In a direct current, liquid level fuel indicating system, the position of the wiper contact on the resistance strip is determined by the movement of a float in the tanks. As the fuel level changes, the float moves up or down, causing the wiper contact to make contact with different sections of the resistance strip. This change in contact position allows for the measurement and indication of the fuel level in the tank.Rate this question:
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- 18.
The primary purpose of the air pressure regulator in a fuel system is to
- A.
Indicate manifold pressure
- B.
Open the vent valves during a climb or dive
- C.
Actuate a micro switch and turn the air flow light on
- D.
Control the amount of pressure entering the fuel tank
Correct Answer
B. Open the vent valves during a climb or diveExplanation
The primary purpose of the air pressure regulator in a fuel system is to open the vent valves during a climb or dive. This is important because as an aircraft climbs or dives, the air pressure surrounding the fuel tank changes. If the vent valves are not opened, the pressure inside the fuel tank could become too high or too low, which can disrupt the flow of fuel and potentially cause engine problems. By opening the vent valves, the air pressure regulator ensures that the pressure inside the fuel tank remains balanced with the surrounding air pressure, allowing for proper fuel flow and engine operation.Rate this question:
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- 19.
Fuel system disconnect couplings are used
- A.
Only in one way systems
- B.
Only in low pressure systems
- C.
To interrrupt the flow of fuel or air and prevent the loss of fluid
- D.
To promote free flow of fuel or air and prevent loss of fluid
Correct Answer
C. To interrrupt the flow of fuel or air and prevent the loss of fluidExplanation
Fuel system disconnect couplings are used to interrupt the flow of fuel or air and prevent the loss of fluid. These couplings are designed to provide a quick and easy way to disconnect fuel lines or air lines without causing any leakage or spillage. By disconnecting the couplings, the flow of fuel or air can be stopped, ensuring that there is no loss of fluid. This feature is particularly important in situations where it is necessary to perform maintenance or repairs on the fuel system without causing any fuel or air leakage.Rate this question:
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- 20.
All of the following aircraft systems use engine bleed air (EBA) except
- A.
Anti-icing
- B.
Rain removal
- C.
Air-conditioning
- D.
Fire extinguishing
Correct Answer
D. Fire extinguishingExplanation
Engine bleed air (EBA) is used in various aircraft systems for different purposes. Anti-icing systems use EBA to prevent ice formation on critical surfaces of the aircraft, ensuring safe operation. Rain removal systems also utilize EBA to remove rainwater from the windshield, enhancing visibility for the pilots. Air-conditioning systems use EBA to regulate the temperature and humidity inside the aircraft cabin, providing a comfortable environment for passengers. However, fire extinguishing systems do not rely on EBA as they use other mechanisms, such as fire extinguisher agents or suppressants, to extinguish fires onboard the aircraft.Rate this question:
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- 21.
Aircraft engine temperature and pressure as it applies to the bleed air system is determined by the
- A.
Ambient pressure and ambient temperature
- B.
Engine throttle setting and ambient altitude
- C.
Ambient pressure and engine throttle setting
- D.
Engine throttle setting and ambient temperature
Correct Answer
C. Ambient pressure and engine throttle settingExplanation
The temperature and pressure of the aircraft engine in relation to the bleed air system are influenced by the ambient pressure and the engine throttle setting. The ambient pressure refers to the atmospheric pressure surrounding the aircraft, which affects the overall pressure within the engine. The engine throttle setting determines the amount of fuel and air mixture being supplied to the engine, which in turn affects the temperature. Therefore, both the ambient pressure and engine throttle setting play a significant role in determining the temperature and pressure of the aircraft engine in the bleed air system.Rate this question:
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- 22.
Engine bleed air (EBA) check valves are installed to
- A.
Prevent loss of compressed bleed air
- B.
Maintain a balance airflow from each engine
- C.
Provide a primary source for compressed bleed air
- D.
Reduce bleed air pressure when the pressure is too high
Correct Answer
A. Prevent loss of compressed bleed airExplanation
Engine bleed air (EBA) check valves are installed to prevent loss of compressed bleed air. These valves are designed to ensure that the high-pressure air being bled from the engine is not lost during the process. By preventing the loss of compressed bleed air, the check valves help maintain the necessary airflow and pressure in the aircraft's systems that rely on this air, such as the air conditioning and pressurization systems. This ensures the proper functioning of these systems and avoids any potential disruptions or failures that could occur due to a loss of compressed bleed air.Rate this question:
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- 23.
When installing air-conditioning ducting, the tool used to ensure alignment and sealing is the
- A.
Screwdriver
- B.
Center punch
- C.
Rawhide mallet
- D.
Ball peen hammer
Correct Answer
C. Rawhide malletExplanation
A rawhide mallet is used in the installation of air-conditioning ducting to ensure alignment and sealing. Unlike a screwdriver, center punch, or ball peen hammer, a rawhide mallet is made of soft material, usually rawhide or rubber, which prevents damage to the ducting while providing enough force to align and seal the components together. The soft material absorbs the impact, reducing the risk of denting or puncturing the ducting, and helps in achieving a secure and airtight connection.Rate this question:
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- 24.
When a compressable flange duct end becomes distorted, the corrective action that should be taken is to
- A.
Replace the duct flange
- B.
Use a gasket with the duct ends
- C.
Reposition the duct for a better seal
- D.
Reshape the duct flange end to its original shape
Correct Answer
D. Reshape the duct flange end to its original shapeExplanation
When a compressible flange duct end becomes distorted, the corrective action that should be taken is to reshape the duct flange end to its original shape. This means that the distorted flange should be carefully manipulated and adjusted to return it to its original form. This corrective action is necessary to ensure a proper seal and prevent any leaks or inefficiencies in the duct system.Rate this question:
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- 25.
Fiberglass fabric duct installations are prevented from swelling when the aircraft climbs ot high altitudes by
- A.
Thermal compensators
- B.
Expansion bellows
- C.
Puckered flaps
- D.
Vent holes
Correct Answer
D. Vent holesExplanation
Vent holes are used in fiberglass fabric duct installations to prevent swelling when the aircraft climbs to high altitudes. As the aircraft ascends, the air pressure decreases, which can cause the ducts to expand. Vent holes allow the air to escape, relieving the pressure and preventing the ducts from swelling. This ensures that the ducts maintain their shape and functionality during high altitude flights.Rate this question:
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- 26.
A depression in the duct wall, wherein the surface of the material isnt cut or removed but the depression has caused sharp bends or creases in the material, is the defination of a
- A.
Thermal compensators
- B.
Expansion bellows
- C.
Puckered flaps
- D.
Vent holes
Correct Answer
C. Puckered flapsExplanation
A depression in the duct wall that causes sharp bends or creases in the material is referred to as puckered flaps. This means that the material is not cut or removed, but it forms irregular folds or wrinkles. The term "thermal compensators" refers to devices used to compensate for thermal expansion, while "expansion bellows" are flexible components used to absorb movement caused by thermal expansion. "Vent holes" are openings in a structure or container to allow air or gas to escape.Rate this question:
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- 27.
The air-conditioning in a cargo aircraft uses a diverter valve to divert air to
- A.
The cooling turbine
- B.
The water separator
- C.
The flight station gaspers
- D.
Flight station and cargo compartments
Correct Answer
D. Flight station and cargo compartmentsExplanation
The air-conditioning in a cargo aircraft uses a diverter valve to divert air to the flight station and cargo compartments. This is necessary to ensure that both areas are properly cooled and maintained at a comfortable temperature during the flight. The flight station needs to be cooled to provide a comfortable working environment for the crew, while the cargo compartments need to be cooled to prevent any damage or spoilage to the cargo being transported. Therefore, the diverter valve plays a crucial role in directing the air to the necessary areas for efficient air-conditioning in the aircraft.Rate this question:
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- 28.
If the temperature of the bleed air from a cargo-type air conditioning system's primary heat exchanger exceeds 540 degrees F, the high limit section of the temperature anticipator will
- A.
Open the ram air valve
- B.
Turn on a warming light
- C.
Close the primary heat exchanger ejector valve
- D.
Close the bleed air regulating and shut off valve
Correct Answer
D. Close the bleed air regulating and shut off valveExplanation
When the temperature of the bleed air from a cargo-type air conditioning system's primary heat exchanger exceeds 540 degrees F, the high limit section of the temperature anticipator will close the bleed air regulating and shut off valve. This is done to prevent the temperature from rising further and causing damage to the system. By closing the valve, the flow of bleed air is stopped, reducing the temperature and preventing any potential hazards.Rate this question:
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- 29.
Bleed air systems water separators remove 70 to 85 percent of the moisture that accumulates in the conditioned air. This is a result of
- A.
Rapid expansion
- B.
Regulated airflow
- C.
Internal compression
- D.
Regulated air pressure
Correct Answer
A. Rapid expansionExplanation
The correct answer is rapid expansion. When air is rapidly expanded, its temperature drops, causing the moisture in the air to condense and separate from the conditioned air. This process allows the water separators in bleed air systems to remove a significant amount of the accumulated moisture, typically ranging from 70 to 85 percent.Rate this question:
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- 30.
The action of the outflow valve in a fixed-isobaric, single differential pressurization system is controlled by
- A.
A jet pump
- B.
Filtering cabin air
- C.
The unpressurized range
- D.
Regulating control chamber pressure
Correct Answer
D. Regulating control chamber pressureExplanation
In a fixed-isobaric, single differential pressurization system, the action of the outflow valve is controlled by regulating control chamber pressure. This means that the pressure in the control chamber is adjusted to determine the position of the outflow valve. By regulating the control chamber pressure, the system can maintain a constant pressure inside the cabin, ensuring the comfort and safety of the occupants. The other options, such as a jet pump or filtering cabin air, are not directly responsible for controlling the outflow valve in this type of pressurization system.Rate this question:
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- 31.
The purpose of the pneumatic relay in a cabin pressurization system is to
- A.
Control the venting of cabin pressure
- B.
Control the reference chamber pressure
- C.
Ensure both outflow valves operate at the same time
- D.
Ensure the aneroid and diaphragm inlet ports remain open
Correct Answer
C. Ensure both outflow valves operate at the same timeExplanation
The purpose of the pneumatic relay in a cabin pressurization system is to ensure both outflow valves operate at the same time. This means that the relay ensures that both valves open and close simultaneously, maintaining proper control over the cabin pressure. By synchronizing the operation of the outflow valves, the pneumatic relay helps to maintain a stable and controlled pressurized environment inside the cabin.Rate this question:
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- 32.
The manual control valve in the variable isobaric pressureization system is used as an alternate when the
- A.
Safety valve fails
- B.
Outflow valve fails
- C.
Pneumatic relay fails
- D.
Cabin pressure controller fails
Correct Answer
D. Cabin pressure controller failsExplanation
In a variable isobaric pressureization system, the manual control valve serves as a backup or alternate option when the cabin pressure controller fails. The cabin pressure controller is responsible for regulating and maintaining the desired pressure inside the cabin. If it malfunctions or fails, the manual control valve can be manually adjusted to control the cabin pressure and ensure the safety and comfort of the occupants.Rate this question:
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- 33.
Frequently used in fire warning systems, the fire detector that has a high nickel steel rod located along the centerline of a stainless steel tube assembly is called
- A.
An Iron Fireman switch
- B.
A photoconductive cell
- C.
A FENWAL switch
- D.
A continuous cable
Correct Answer
A. An Iron Fireman switchExplanation
The correct answer is an Iron Fireman switch. This type of fire detector is commonly used in fire warning systems. It consists of a high nickel steel rod that is positioned along the centerline of a stainless steel tube assembly. This configuration allows the switch to detect the presence of fire or heat and trigger appropriate actions to mitigate the risk. The use of high nickel steel and stainless steel materials ensures durability and resistance to heat, making it suitable for fire detection applications.Rate this question:
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- 34.
The maximum circuit resistance within a thermocouple circuit is
- A.
5 ohms
- B.
50 ohms
- C.
500 ohms
- D.
Infinity
Correct Answer
A. 5 ohmsExplanation
The maximum circuit resistance within a thermocouple circuit is 5 ohms because any resistance higher than this value can cause errors in the measurement of temperature. A higher resistance can introduce additional voltage drops in the circuit, affecting the accuracy of the temperature reading. Therefore, it is important to keep the circuit resistance below 5 ohms to ensure reliable and accurate temperature measurements.Rate this question:
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- 35.
The DC voltage supplied to the lights in a photoelectric circuit is pulsed at a rate of
- A.
10 hz
- B.
100 hz
- C.
200 hz
- D.
400 hz
Correct Answer
A. 10 hzExplanation
The DC voltage supplied to the lights in a photoelectric circuit is pulsed at a rate of 10 Hz. This means that the voltage is being turned on and off 10 times per second. Pulsing the voltage allows for control over the amount of light emitted by the lights. By pulsing the voltage at a specific frequency, the lights can be made to emit a steady and controlled amount of light. A lower frequency, such as 10 Hz, means that the lights are being turned on and off at a slower rate, resulting in a slower and more gradual change in the emitted light.Rate this question:
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- 36.
A liquid fire extinguishing agent douses a fire by
- A.
Releasing a fine mist vapor
- B.
Releasing nitrogen in the area
- C.
Removing oxygen from the area
- D.
Dispersing a heavy concentration of liquid
Correct Answer
C. Removing oxygen from the areaExplanation
A liquid fire extinguishing agent douses a fire by removing oxygen from the area. Oxygen is necessary for combustion to occur, so by removing it, the fire is deprived of the element it needs to sustain itself. This effectively extinguishes the fire and prevents it from spreading further.Rate this question:
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- 37.
A principle disadvantage of liquid fire extinguishing agents is they
- A.
Are extremely cold
- B.
Do not support combustion
- C.
Are poisonous or highly toxic
- D.
Require extremely heavy storage containers
Correct Answer
C. Are poisonous or highly toxicExplanation
Liquid fire extinguishing agents have a significant drawback in that they are poisonous or highly toxic. This means that their use can pose a risk to human health and safety, especially if there is exposure to these agents. While they may effectively extinguish fires, their toxicity can cause harm to individuals who come into contact with them, making them potentially dangerous to handle or be exposed to. Therefore, this disadvantage highlights the potential hazards associated with the use of liquid fire extinguishing agents.Rate this question:
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- 38.
A steady red light on the fire emergency control handle in a liquid fire extinguishing system indicates
- A.
An open fuel valve
- B.
Close air valves
- C.
An over heat
- D.
A fire
Correct Answer
D. A fireExplanation
A steady red light on the fire emergency control handle in a liquid fire extinguishing system indicates a fire. This is because a red light is commonly used as a universal symbol for danger or emergency situations. In the context of a fire extinguishing system, the red light serves as a clear indication that there is a fire present and immediate action needs to be taken to control or extinguish it.Rate this question:
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- 39.
When the pressure in a T-handle liquid fire extinguisher container becomes too low
- A.
The check valve will open
- B.
The check valve will close
- C.
The pressure switch will open
- D.
A light on the cockpit panel will glow
Correct Answer
D. A light on the cockpit panel will glowExplanation
When the pressure in a T-handle liquid fire extinguisher container becomes too low, a light on the cockpit panel will glow. This indicates that the pressure in the container is insufficient and needs to be refilled or replaced. The light serves as a visual alert for the pilot or crew to take necessary action to ensure the fire extinguisher is in proper working condition.Rate this question:
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- 40.
At no time shall fire extinguishing residue , such as that resulting from the use of CB type or foam type fire extinguishing materials, be allowed to remain on the equipment for a period exceeding
- A.
2 hours
- B.
4 hours
- C.
6 hours
- D.
8 hours
Correct Answer
B. 4 hoursExplanation
Fire extinguishing residue, such as that from CB type or foam type fire extinguishing materials, should not be left on the equipment for more than 4 hours. This is important because if the residue is not cleaned promptly, it can cause damage to the equipment or impair its functionality. Additionally, leaving the residue for an extended period may also pose safety risks. Therefore, it is necessary to remove the residue within 4 hours to ensure the equipment remains in good working condition and to maintain a safe environment.Rate this question:
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- 41.
Oxygen is described as being
- A.
Tasteless, colorless, odorless
- B.
Tasteless, volumless, and odorless
- C.
Tasteless, colorless, weightless
- D.
Volumless, weightless, colorless
Correct Answer
A. Tasteless, colorless, odorlessExplanation
Oxygen is described as tasteless because it does not have a distinct flavor. It is also described as colorless because it does not have any color. Additionally, it is described as odorless because it does not have a noticeable smell.Rate this question:
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- 42.
At altitudes between 10,000 and 15,000 feet, the greatest danger from hypoxia is
- A.
A headache
- B.
A convulsion
- C.
Excessive fatique
- D.
An error in judgement
Correct Answer
D. An error in judgementExplanation
At altitudes between 10,000 and 15,000 feet, the greatest danger from hypoxia is an error in judgment. Hypoxia is a condition caused by insufficient oxygen supply to the body, which can impair cognitive function and decision-making abilities. At higher altitudes, the brain may not receive enough oxygen, leading to impaired judgment and decision-making skills. This can be particularly dangerous in activities such as flying or mountaineering, where making the wrong decision can have severe consequences. Therefore, an error in judgment is the greatest danger in this situation.Rate this question:
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- 43.
The disadvantage of a continuous-flow oxygen regulator is it
- A.
Waste oxygen
- B.
Is unusable below 10,000 ft
- C.
Is usable only above 20,000 ft
- D.
Delivers oxygen at varying pressure
Correct Answer
A. Waste oxygenExplanation
A continuous-flow oxygen regulator is disadvantageous because it wastes oxygen.Rate this question:
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- 44.
You are operationally checking a pressure-demand oxygen regulator. When you blow into the mask with the diluter toggle set at 100% OXYGEN, you should get
- A.
No resistance
- B.
Continuous flow
- C.
Oxygen pressure
- D.
Positive resistance
Correct Answer
D. Positive resistanceExplanation
When you blow into the mask with the diluter toggle set at 100% OXYGEN, you should get positive resistance. This means that there should be some level of resistance when you blow into the mask, indicating that the pressure-demand oxygen regulator is functioning properly. If there was no resistance, it would suggest a malfunction in the regulator. Continuous flow and oxygen pressure are not expected when blowing into the mask, so they are not the correct answers.Rate this question:
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- 45.
An H-2 emergency assembly (bailout bottle) supplies oxygen to the user for a maximum of about
- A.
5 min
- B.
10 min
- C.
15 min
- D.
20 min
Correct Answer
B. 10 minExplanation
The H-2 emergency assembly, also known as a bailout bottle, is designed to provide oxygen to the user in emergency situations. The correct answer of 10 minutes indicates that the bailout bottle can supply oxygen for a maximum duration of 10 minutes. This time frame is crucial in allowing the user to safely evacuate or complete necessary tasks before seeking additional oxygen or assistance.Rate this question:
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- 46.
In a molecular sieve oxygen generating system (MSOGS), water droplets from the air are removed by a(n)
- A.
Water seperator
- B.
Molecular sieve bed
- C.
MSOGS shutoff valve
- D.
MSOGS concentrator inlet filter
Correct Answer
D. MSOGS concentrator inlet filterExplanation
The MSOGS concentrator inlet filter is the correct answer because it is responsible for removing water droplets from the air in a molecular sieve oxygen generating system. This filter ensures that the air entering the system is free from water, which could potentially affect the performance and efficiency of the system. By removing water droplets, the filter helps to maintain the integrity and functionality of the MSOGS, allowing it to effectively generate oxygen.Rate this question:
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- 47.
What does the molecular sieve oxygen generating system (MSOGS) concentrator supply to the OXYGEN regulator control panel?
- A.
Nitrogen
- B.
16 man-minutes of oxygen
- C.
93 percent oxygen-enriched gas
- D.
100 percent oxygen enriched gas
Correct Answer
C. 93 percent oxygen-enriched gasExplanation
The molecular sieve oxygen generating system (MSOGS) concentrator supplies 93 percent oxygen-enriched gas to the oxygen regulator control panel. This means that the gas being supplied has a higher concentration of oxygen compared to regular atmospheric air, which typically contains around 21 percent oxygen. The MSOGS concentrator uses a molecular sieve to selectively remove nitrogen and other gases from the air, leaving behind a higher concentration of oxygen. This oxygen-enriched gas is then supplied to the regulator control panel for further distribution and use.Rate this question:
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- 48.
LOX converts to gaseous oxygen (GOX) at the expansion ratio of
- A.
600 to 1
- B.
680 to 1
- C.
800 to 1
- D.
860 to 1
Correct Answer
D. 860 to 1Explanation
LOX (Liquid Oxygen) converts to gaseous oxygen (GOX) at an expansion ratio of 860 to 1. This means that for every unit of liquid oxygen, it expands to 860 times its original volume when it becomes gaseous. This expansion ratio is important to consider in various applications such as rocket propulsion systems, where the conversion of liquid oxygen to gaseous form is necessary for combustion to occur efficiently.Rate this question:
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- 49.
The safety feature that protects liquid oxygen (LOX) containers from excessive pressure caused by leaks in the inner container is the
- A.
Poppet valve
- B.
Blowout disc
- C.
Low-pressure relief valve
- D.
High pressure relief valve
Correct Answer
B. Blowout discExplanation
A blowout disc is a safety feature that protects liquid oxygen (LOX) containers from excessive pressure caused by leaks in the inner container. It is designed to rupture and release pressure when the pressure inside the container exceeds a safe level. This helps prevent the container from exploding or causing any other hazardous situations. The blowout disc acts as a last line of defense to ensure the safety of the container and its surroundings.Rate this question:
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- 50.
A liquid cooling system (LCS) keeps electronic components cool by
- A.
Cycling coolant through the electronic component
- B.
Directing coolant across the electronic component
- C.
Cycling conditioned air through the electric component
- D.
Directing conditioned air across the electric component
Correct Answer
A. Cycling coolant through the electronic componentExplanation
The correct answer is cycling coolant through the electronic component. A liquid cooling system works by circulating a coolant, typically water or a mixture of water and antifreeze, through the electronic component. This coolant absorbs heat from the electronic component and carries it away, keeping the component cool. This method is more efficient than air cooling as liquids have higher heat capacity and can transfer heat more effectively. By continuously cycling the coolant, the liquid cooling system ensures that the electronic component remains at an optimal temperature, preventing overheating and potential damage.Rate this question:
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