Electrical And Environmental 2A656 Volume 4

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  • 1/74 Questions

    (604) Leaks can best be detected during an operational check of the bleed air distribution system by

    • Listening and feeling.
    • Using an ultrasonic leak detector only.
    • Feeling only because leaking air may be hot.
    • Listening only because leaking air may be at high pressure.
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About This Quiz

This quiz assesses knowledge on aircraft systems, focusing on the use of engine bleed air in various components. It covers topics like system components, operational settings, and safety mechanisms, crucial for professionals in aerospace and mechanical engineering.

Electrical And Environmental 2A656 Volume 4 - Quiz

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  • 2. 

    (606) An aircraft’s bleed air cooling air system pre-cooler is also known as the

    • Air cycle machine.

    • Contained air cooler.

    • Primary heat exchanger.

    • Regenerative temperature changer.

    Correct Answer
    A. Primary heat exchanger.
    Explanation
    The correct answer is "primary heat exchanger." The pre-cooler in an aircraft's bleed air cooling air system is responsible for cooling the high-pressure air from the engine before it enters the air cycle machine. The primary heat exchanger is designed to efficiently transfer heat from the hot bleed air to the cooler ambient air, ensuring that the air entering the air cycle machine is at the correct temperature for cooling the aircraft's systems.

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  • 3. 

    (603) When installing air-conditioning ducting, what tool is used to ensure alignment and sealing?

    • Screwdriver.

    • Center punch.

    • Rawhide mallet.

    • Ball peen hammer.

    Correct Answer
    A. Rawhide mallet.
    Explanation
    A rawhide mallet is used when installing air-conditioning ducting to ensure alignment and sealing. This type of mallet is made from rawhide material, which is soft and non-damaging to the ducting. It allows for precise adjustments and helps to create a tight seal between the ducting components. A screwdriver, center punch, and ball peen hammer are not suitable for this task as they can cause damage to the ducting or result in misalignment.

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  • 4. 

    (603) Which lubricant can be used on a beaded channel clamp sleeve to ease installation?

    • Soap

    • Water

    • Grease

    • Silicone

    Correct Answer
    A. Water
    Explanation
    Water can be used as a lubricant on a beaded channel clamp sleeve to ease installation. Water reduces friction between the sleeve and the surface, making it easier to slide the sleeve into place. It acts as a temporary lubricant that allows for smooth and effortless installation.

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  • 5. 

    (606) Some cooling turbines have a pair of unused wires that are cut-off close to the turbine housing. What level of maintenance uses these wires?

    • Depot.

    • Squadron.

    • Intermediate.

    • Organizational.

    Correct Answer
    A. Depot.
    Explanation
    The pair of unused wires that are cut-off close to the turbine housing are typically used for diagnostic purposes during maintenance. This level of maintenance, known as depot maintenance, involves more extensive repairs and overhauls that are performed at a centralized facility. Therefore, the correct answer is depot.

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  • 6. 

    (608) What air-conditioning component prevents excessive moisture from reaching the cockpit of a fighter aircraft?

    • Defog valve.

    • Anti-ice valve.

    • Water separator.

    • Cabin dual-temperature mixing valve.

    Correct Answer
    A. Water separator.
    Explanation
    The correct answer is water separator. In a fighter aircraft, the water separator is an air-conditioning component that prevents excessive moisture from reaching the cockpit. It separates the water vapor from the air, ensuring that only dry air enters the cockpit. This is important as excessive moisture can lead to fogging and reduce visibility in the cockpit, which can be dangerous during flight operations. Therefore, the water separator plays a crucial role in maintaining a clear and safe cockpit environment.

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  • 7. 

    (601) Each of these examples of aircraft systems use engine bleed air except

    • anti-G.

    • anti-icing.

    • Rain removal.

    • Fire extinguishing.

    Correct Answer
    A. Fire extinguishing.
    Explanation
    Engine bleed air is used in aircraft systems for various purposes, such as providing air for anti-icing, rain removal, and anti-G systems. However, it is not used for fire extinguishing. Fire extinguishing systems in aircraft typically rely on other methods, such as fire suppression agents or halon gas, rather than engine bleed air. Therefore, the correct answer is fire extinguishing.

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  • 8. 

    (603) What important fact must you remember when replacing gaskets used in aircraft ducting?

    • Only replace gaskets if they are distorted.

    • Always replace a gasket each time it is removed.

    • Only replace gaskets in high-pressure/high-temperature ducting.

    • Always reuse a gasket because it is already shaped to fit the ducts.

    Correct Answer
    A. Always replace a gasket each time it is removed.
    Explanation
    When replacing gaskets used in aircraft ducting, it is important to remember to always replace the gasket each time it is removed. This is because gaskets can become worn or damaged over time, and reusing them may result in leaks or other issues. Therefore, it is necessary to install a new gasket to ensure proper sealing and prevent any potential problems in the ducting system.

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  • 9. 

    (606) One purpose of the fan in the bleed air system cooling turbine and fan assembly is to prevent

    • Excessive air flow.

    • Low system pressure.

    • Turbine over speeding.

    • Moisture in the cold air.

    Correct Answer
    A. Turbine over speeding.
    Explanation
    The fan in the bleed air system cooling turbine and fan assembly prevents turbine over speeding. This is because the fan helps regulate the flow of air, ensuring that it does not exceed the safe operating speed of the turbine. By controlling the air flow, the fan prevents the turbine from spinning too fast and potentially causing damage or malfunctions.

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  • 10. 

    (607) What air source ventilates the cockpit when smoke or fumes are discharged from the air-conditioning system?

    • Liquid air.

    • Compressed air.

    • Conditioned air.

    • Atmospheric air.

    Correct Answer
    A. Atmospheric air.
    Explanation
    When smoke or fumes are discharged from the air-conditioning system, the cockpit is ventilated with atmospheric air. This means that the air from outside the aircraft is used to remove the smoke or fumes from the cockpit, ensuring the safety and well-being of the crew and passengers. The other options, such as liquid air, compressed air, and conditioned air, are not suitable for ventilating the cockpit in such situations.

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  • 11. 

    (601) Engine bleed air check valves are installed to

    • Prevent the loss of bleed air.

    • Provide a primary source for bleed air.

    • Maintain a balance airflow from each engine.

    • Reduce bleed air pressure when the pressure is to high.

    Correct Answer
    A. Prevent the loss of bleed air.
    Explanation
    Engine bleed air check valves are installed to prevent the loss of bleed air. These valves are designed to ensure that the high-pressure bleed air from the engine does not escape unintentionally. By preventing the loss of bleed air, these check valves help maintain the proper functioning of various aircraft systems that rely on bleed air, such as air conditioning, pressurization, and anti-ice systems.

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  • 12. 

    (611) The anti-G suit prevents

    • Blood from rushing to the brain.

    • A restricted flow of blood to the heart.

    • Blood from pooling in the lower portions of the body.

    • Overexertion of the heart when G-forces are encountered.

    Correct Answer
    A. Blood from pooling in the lower portions of the body.
    Explanation
    The anti-G suit is designed to prevent blood from pooling in the lower portions of the body. This pooling of blood can occur when a person is subjected to high G-forces, such as during rapid acceleration or maneuvers in an aircraft. The suit applies pressure to the lower body, helping to push blood back up towards the heart and prevent it from collecting in the legs and feet. By preventing blood pooling, the suit helps to maintain proper blood circulation and prevent symptoms like dizziness, loss of vision, or even loss of consciousness that can occur when blood flow to the brain is compromised.

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  • 13. 

    (601) The engine section from which bleed air is usually taken is the  

    • Intake.

    • Turbine.

    • Exhaust.

    • Compressor.

    Correct Answer
    A. Compressor.
    Explanation
    Bleed air is usually taken from the compressor section of the engine. The compressor is responsible for compressing the incoming air before it enters the combustion chamber. This compressed air is then used for various purposes, such as aircraft pressurization, air conditioning, and anti-icing. Taking bleed air from the compressor section ensures that it is at a high enough pressure and temperature to be used effectively for these purposes.

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  • 14. 

    (603) What corrective action should be taken when a compressible flange duct end becomes distorted?

    • Replace the duct flange ends.

    • Use a gasket with the duct ends.

    • Reposition the duct for better sealing.

    • Reshape the duct flange ends to its original shape.

    Correct Answer
    A. Reshape the duct flange ends to its original shape.
    Explanation
    When a compressible flange duct end becomes distorted, the correct corrective action is to reshape the duct flange ends to its original shape. This means that the distorted flange ends should be carefully manipulated and reshaped back to their original form. This is important for ensuring a proper seal and preventing any leaks or inefficiencies in the duct system.

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  • 15. 

    (611) The purpose of the anti-G suit system is to supply air pressure to

    • Inflate the pilot’s anti-G suit.

    • Exert pressure on the pilots lungs.

    • Offset the effects of negative G-forces.

    • Prevent blood from rushing to the pilot’s brain.

    Correct Answer
    A. Inflate the pilot’s anti-G suit.
    Explanation
    The purpose of the anti-G suit system is to inflate the pilot's anti-G suit. This is important because during high G-force maneuvers, such as rapid acceleration or tight turns, blood tends to pool in the lower extremities and away from the brain. By inflating the anti-G suit, it applies pressure to the pilot's legs and abdomen, helping to prevent blood from pooling and thus reducing the risk of the pilot experiencing G-induced loss of consciousness.

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  • 16. 

    (616) Which pressurization range maintains a constant cabin pressure?

    • Isobaric.

    • Differential.

    • Unpressurized.

    • Dual differential.

    Correct Answer
    A. Isobaric.
    Explanation
    Isobaric pressurization maintains a constant cabin pressure throughout the flight. This means that the pressure inside the cabin remains the same as the pressure at sea level, regardless of changes in altitude. This type of pressurization helps to ensure the comfort and safety of passengers by preventing rapid changes in pressure that can cause discomfort or health issues.

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  • 17. 

    (606) To create a greater cooling effect, atomized water is sprayed across the inlet of the bleed air system secondary heat exchanger by the

    • Jet pump.

    • Jet sprayer.

    • Water aspirator.

    • Water separator.

    Correct Answer
    A. Water aspirator.
    Explanation
    A water aspirator is used to create a greater cooling effect by spraying atomized water across the inlet of the bleed air system secondary heat exchanger. This device uses the Venturi effect to create a vacuum, which draws in and mixes the water with the air. As the water and air mix, the water evaporates and absorbs heat from the air, resulting in a cooling effect. This helps to efficiently cool the bleed air system secondary heat exchanger.

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  • 18. 

    (608) The temperature of conditioned air going to the crew compartment depends on the position of the

    • Cabin air inlet valve.

    • Ground cooling ejector valve.

    • Water separator bypass valve.

    • Cabin dual-temperature mixing valve.

    Correct Answer
    A. Cabin dual-temperature mixing valve.
    Explanation
    The temperature of conditioned air going to the crew compartment depends on the position of the cabin dual-temperature mixing valve. This valve controls the mixture of hot and cold air to achieve the desired temperature. By adjusting the position of the valve, the temperature of the conditioned air can be regulated accordingly.

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  • 19. 

    (614) In the bleed air anti-icing system, the engine bleed air supply duct has a distribution duct (piccolo tube) that may be attached to the leading edge section. If it is, then what must happen to replace the tube?

    • Can only be replaced at depot level.

    • Remove tube through the wing butt access panel.

    • Remove tube through the trailing edge access panels.

    • Leading edge section must be removed to replace the tube.

    Correct Answer
    A. Leading edge section must be removed to replace the tube.
    Explanation
    The correct answer is that the leading edge section must be removed to replace the tube. This suggests that the attachment of the distribution duct (piccolo tube) to the leading edge section is such that it cannot be easily accessed or replaced without removing the leading edge section.

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  • 20. 

    (602) What is the pressure and flow control device that restricts airflow and protects aircraft engines against air starvation?

    • Orifice.

    • Air regulator.

    • Pressure limiter.

    • Pressure regulator.

    Correct Answer
    A. Orifice.
    Explanation
    An orifice is a pressure and flow control device that restricts airflow. It is used to protect aircraft engines against air starvation by regulating the amount of air that enters the engine. By restricting the airflow, the orifice ensures that the engine receives a consistent and controlled supply of air, preventing any damage or issues that could arise from air starvation.

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  • 21. 

    (603) While installing a bleed air system bolted flanged face duct end, you use a new crush-type gasket, align the flange, and insert the bottom bolts first to form a cradle. Then, you install the remaining bolts and tighten all the nuts. After the installation is complete you perform an operational check that reveals a leak. From the above information what important procedure did you overlook?

    • A sealing compound was not used with the gaskets.

    • Flange bolts were not torqued in the proper sequence.

    • The flange was not tapped with a rawhide mallet while torquing.

    • Gasket should have been installed before cradle bolts were installed.

    Correct Answer
    A. Flange bolts were not torqued in the proper sequence.
    Explanation
    The important procedure that was overlooked is that the flange bolts were not torqued in the proper sequence. Torquing the bolts in the correct sequence is crucial to ensure even pressure and proper sealing of the flange. This could have resulted in a leak during the operational check.

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  • 22. 

    (603) What type of high-pressure/high-temperature ducting does not require a gasket?

    • Clamp flange.

    • Bolted flange.

    • Beaded flange.

    • Compressible flange.

    Correct Answer
    A. Compressible flange.
    Explanation
    A compressible flange is a type of high-pressure/high-temperature ducting that does not require a gasket. This type of flange is designed with a compressible material, such as rubber, that creates a tight seal when the flange is bolted together. The compressible material allows for flexibility and compensates for any irregularities or misalignments in the flange connection, eliminating the need for a separate gasket. This makes the compressible flange a convenient and cost-effective option for high-pressure/high-temperature applications.

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  • 23. 

    (607) The bleed air system water separator anti-icing system prevents the condenser bag from icing by keeping the turbine

    • Inlet temperature above 32°.

    • Inlet temperature below 32°.

    • Outlet temperature above 32°.

    • Outlet temperature below 32°.

    Correct Answer
    A. Outlet temperature above 32°.
    Explanation
    The correct answer is "outlet temperature above 32°." The bleed air system water separator anti-icing system prevents the condenser bag from icing by maintaining the outlet temperature above 32°. This ensures that any moisture or water in the system does not freeze and cause blockages or damage.

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  • 24. 

    (610) Pressure to the floor heat ejector on a cargo aircraft floor heat system is regulated by the

    • Floor heat shutoff valve.

    • Pneumatic control thermostat.

    • Pneumatic temperature anticipator.

    • Floor heat modulating and shutoff valve.

    Correct Answer
    A. Floor heat modulating and shutoff valve.
    Explanation
    The pressure to the floor heat ejector on a cargo aircraft floor heat system is regulated by the floor heat modulating and shutoff valve. This valve controls the flow of air to the ejector, which in turn controls the amount of heat being supplied to the cargo floor. By adjusting the position of the valve, the pressure to the ejector can be increased or decreased, allowing for precise regulation of the floor heat system. The other options, such as the floor heat shutoff valve, pneumatic control thermostat, and pneumatic temperature anticipator, do not have direct control over the pressure to the ejector and therefore are not correct answers.

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  • 25. 

    (618) Components that are susceptible to separating from an aircraft during a ground pressure test

    • Double locked.

    • Anchored with a chain.

    • Tied with a net or strap.

    • Removed before testing.

    Correct Answer
    A. Tied with a net or strap.
    Explanation
    During a ground pressure test, there is a risk that components may separate from the aircraft. To prevent this, the components need to be securely fastened. Tying them with a net or strap is the most effective way to ensure that they remain in place during the test. Double locking, anchoring with a chain, or removing the components before testing may not provide sufficient security and could lead to separation. Therefore, tying with a net or strap is the correct answer.

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  • 26. 

    (604) You perform a bleed air system leakage check using the pressure decay method with an aircraft engine; the time for the pressure to drop 30 pounds per square inch (psi) took 11 seconds.This indicates that the system leakage test

    • Needs to be repeated.

    • Results are dangerously excessive.

    • Results are below allowable limits.

    • Results are within allowable limits.

    Correct Answer
    A. Results are within allowable limits.
    Explanation
    The correct answer is "results are within allowable limits." The pressure decay method is used to check for leakage in the bleed air system of an aircraft engine. In this case, the pressure dropped 30 psi in 11 seconds, which indicates that the leakage is within the allowable limits. If the leakage was dangerously excessive or if the test needed to be repeated, the pressure would have dropped at a faster rate.

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  • 27. 

    (602) To remedy the limitations of a flow control valve, which bleed air system component is usually installed upstream of the flow control valve?

    • Metering valve.

    • Pressure limiter.

    • System shutoff valve.

    • Pressure regulator and shutoff valve.

    Correct Answer
    A. Pressure regulator and shutoff valve.
    Explanation
    A pressure regulator and shutoff valve is usually installed upstream of the flow control valve to remedy its limitations. This component helps regulate and control the pressure of the air flow, ensuring that it is at the desired level before entering the flow control valve. Additionally, the shutoff valve allows for complete shut off of the air flow when needed.

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  • 28. 

    (606) A pre-cooler assembly is usually a self-contained cooling package with its own

    • Flow control system.

    • Safety control system.

    • Pressure control system.

    • Temperature control system.

    Correct Answer
    A. Temperature control system.
    Explanation
    A pre-cooler assembly is a cooling package that is designed to lower the temperature of a fluid or gas. It is typically equipped with its own temperature control system to regulate and maintain the desired temperature. This system ensures that the fluid or gas being cooled is kept at the appropriate temperature for optimal performance and efficiency.

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  • 29. 

    (611) What is the maximum G force that the average pilot can withstand when wearing an anti-G suit?

    • 4–5 Gs.

    • 6–7 Gs.

    • 8–9 Gs.

    • 10–11 Gs.

    Correct Answer
    A. 6–7 Gs.
    Explanation
    The average pilot can withstand a maximum of 6-7 Gs when wearing an anti-G suit. G-force is a measurement of the force of gravity on a body and can be experienced during high-speed maneuvers or acceleration. An anti-G suit is designed to counteract the effects of G-forces by applying pressure to the lower body, preventing blood from pooling in the lower extremities and helping to maintain blood flow to the brain. This allows the pilot to tolerate higher G-forces without losing consciousness or experiencing negative physiological effects.

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  • 30. 

    (601) Aircraft engine temperature and pressure as it applies to the bleed air system is determined by the

    • Ambient pressure and ambient temperature.

    • Ambient pressure and engine throttle setting.

    • Engine throttle setting and ambient altitude.

    • Engine throttle setting and ambient temperature

    Correct Answer
    A. Engine throttle setting and ambient temperature
    Explanation
    The temperature and pressure of the aircraft engine in relation to the bleed air system are influenced by the engine throttle setting and the ambient temperature. The engine throttle setting determines the amount of air being drawn into the engine, which affects the temperature and pressure. The ambient temperature also plays a role in determining the temperature and pressure of the air entering the engine.

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  • 31. 

    24. (604) Bleed air leaks are permissible

    • Around valve shafts.

    • At low-pressure connections.

    • Before the bleed air engine tapoff.

    • On the bleed air ducting center wing section.

    Correct Answer
    A. Around valve shafts.
    Explanation
    Bleed air leaks are permissible around valve shafts.

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  • 32. 

    (605) The small drill hole in the outlet of some engine bleed air shutoff valves serves to

    • Check the valve position.

    • Connect a pressure gage.

    • Relieve excess pressure.

    • Secure valve insulation.

    Correct Answer
    A. Check the valve position.
    Explanation
    The small drill hole in the outlet of some engine bleed air shutoff valves serves to check the valve position. This hole allows the operator to visually inspect whether the valve is open or closed by observing the flow of air through the hole. It provides a simple and effective way to verify the position of the valve without the need for additional equipment or tools.

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  • 33. 

    (601) Which component determines the amount of bleed air bled from a gas turbine compressor (GTC)?

    • Themocouple.

    • Fuel control valve.

    • Load control valve.

    • Bleed air control governor.

    Correct Answer
    A. Load control valve.
    Explanation
    The load control valve is the component that determines the amount of bleed air bled from a gas turbine compressor (GTC). It regulates the flow of bleed air based on the load requirements of the system. The thermocouple measures temperature, the fuel control valve regulates fuel flow, and the bleed air control governor maintains constant pressure in the bleed air system. Therefore, the load control valve is the correct answer as it specifically controls the amount of bleed air.

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  • 34. 

    (602) What happens if electrical power is interrupted to the solenoid of an electrically-controlled,pneumatically-operated air-conditioning system shutoff valve that has a fail-safe feature?  

    • The valve opens.

    • The valve closes.

    • If closed, the valve opens; if open, the valve closes.

    • The valve opens or closes depending on system design requirements.

    Correct Answer
    A. The valve opens or closes depending on system design requirements.
    Explanation
    If electrical power is interrupted to the solenoid of an electrically-controlled, pneumatically-operated air-conditioning system shutoff valve that has a fail-safe feature, the valve will either open or close depending on the design requirements of the system. The fail-safe feature ensures that the valve will move to a specific position in the event of a power failure, which could be either open or closed depending on the desired safety mechanism of the system.

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  • 35. 

    (602) Due to a loss of energy, the outlet air pressure of an orifice is

    • Lower than the inlet.

    • Higher than the inlet.

    • Lower than the throat.

    • The same as the throat.

    Correct Answer
    A. Lower than the inlet.
    Explanation
    When fluid flows through an orifice, there is a loss of energy due to factors such as friction and turbulence. This loss of energy causes a decrease in pressure. Therefore, the outlet air pressure of an orifice is lower than the inlet pressure.

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  • 36. 

    (602) The lockout butterfly of the airflow regulator has an offset center of rotation. This design gives the butterfly a pressure that is unbalanced towards which position?

    • Open.

    • Closed.

    • Locked.

    • Unlocked.

    Correct Answer
    A. Closed.
    Explanation
    The lockout butterfly of the airflow regulator has an offset center of rotation, which means that the butterfly is not evenly balanced. When the butterfly is in the closed position, the offset center of rotation creates an unbalanced pressure that helps to keep the butterfly securely closed. Therefore, the correct answer is closed.

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  • 37. 

    (610) On a cargo type aircraft, the function of the floor heat system pneumatic anticipator is to

    • Control the floor heat shutoff valve.

    • Respond to rapid temperature changes.

    • Respond to gradual temperature changes.

    • Send a signal to the control box amplifier section.

    Correct Answer
    A. Respond to rapid temperature changes.
    Explanation
    The function of the floor heat system pneumatic anticipator on a cargo type aircraft is to respond to rapid temperature changes. This means that the system is designed to detect sudden increases or decreases in temperature and adjust the floor heat accordingly. This is important in order to maintain a comfortable and safe temperature in the cargo area of the aircraft. The anticipator helps to prevent extreme temperature fluctuations and ensures that the floor heat system is responsive to changes in temperature.

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  • 38. 

    (614) A portion of the bleed air used for wing anti-icing is dumped overboard, the remaining air

    • Controls the modulating valve.

    • Returns to the jet pump as recirculating air.

    • Becomes a reference temperature for the thermostat.

    • Assists the ejector nozzles in drawing air across the heat exchanger.

    Correct Answer
    A. Returns to the jet pump as recirculating air.
    Explanation
    The correct answer is "returns to the jet pump as recirculating air." When the bleed air is used for wing anti-icing, a portion of it is released overboard, while the remaining air is recirculated back to the jet pump. This recirculating air helps maintain the flow and pressure needed for the system to function properly.

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  • 39. 

    (603) Expansion joints in bleed air systems are best used on

    • Ram air ducting.

    • Long runs of ducting.

    • Low-pressure ducting.

    • Short runs of ducting.

    Correct Answer
    A. Short runs of ducting.
    Explanation
    Expansion joints in bleed air systems are best used on short runs of ducting. This is because expansion joints are designed to absorb the thermal expansion and contraction of the ducting caused by the high temperatures of the bleed air. Short runs of ducting experience less thermal expansion and contraction compared to long runs, making them more suitable for the use of expansion joints. Additionally, expansion joints are typically used in low-pressure ducting systems, as the high pressures in the system can cause the joints to fail. Therefore, short runs of low-pressure ducting are the ideal application for expansion joints in bleed air systems.

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  • 40. 

    (605) Low engine pressure ratio (EPR) could be caused by a bleed air system that has

    • An orifice that is defective.

    • A clamp that has been improperly installed.

    • A precooler air ejector valve that is defective.

    • A pressure regulator that is installed backwards.

    Correct Answer
    A. A clamp that has been improperly installed.
    Explanation
    Low engine pressure ratio (EPR) refers to a lower than normal ratio between the pressure at the engine inlet and the pressure at the engine exhaust. In this case, the correct answer suggests that a clamp that has been improperly installed could be the cause of the low EPR. Improper installation of the clamp may result in a leak in the bleed air system, causing a decrease in pressure and subsequently leading to a low EPR.

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  • 41. 

    (605) An excessive pressure in the bleed air system can cause an unusually high cockpit temperature due to

    • A bleed air leak.

    • An over-speeding turbine.

    • High exhaust gas temperature.

    • A stuck open pressure relief valve.

    Correct Answer
    A. An over-speeding turbine.
    Explanation
    An excessive pressure in the bleed air system can cause an unusually high cockpit temperature due to an over-speeding turbine. When the turbine spins too fast, it generates more heat, which can lead to higher temperatures in the cockpit. This can be caused by a malfunction or failure in the turbine's control system, resulting in an increase in pressure and speed.

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  • 42. 

    (606) The bleed air pre-cooler assembly maintains a constant outlet temperature with the aid of a

    • Sensor, modulating valve, and jet pump. sensor, temperature control circuit, and jet pump.

    • Sensor, temperature control circuit, and jet pump.

    • Modulating valve, sensor, and temperature control circuit.

    • Modulating valve, temperature control circuit, and jet pump.

    Correct Answer
    A. Modulating valve, sensor, and temperature control circuit.
    Explanation
    The correct answer is "modulating valve, sensor, and temperature control circuit." The modulating valve helps regulate the flow of bleed air, while the sensor measures the outlet temperature. The temperature control circuit then adjusts the modulating valve based on the sensor readings to maintain a constant outlet temperature.

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  • 43. 

    (602) What component stops the flow of air to the air-conditioning system?

    • Pressure limiter.

    • Flow control valve.

    • Air regulator valve.

    • System shutoff valve.

    Correct Answer
    A. System shutoff valve.
    Explanation
    The system shutoff valve is the component that stops the flow of air to the air-conditioning system. It is responsible for controlling the flow of refrigerant and preventing it from entering the system when necessary, such as during maintenance or repairs. This valve is typically located near the compressor or in the high-pressure line, and it can be manually operated or controlled by the air-conditioning system itself. Its main function is to ensure the safety and efficiency of the air-conditioning system by allowing for proper maintenance and preventing damage to the system.

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  • 44. 

    (602) The downstream air temperature of the bleed air air-conditioning system has exceeded the predetermined temperature. This has caused the butterfly to close. What flow control and shutoff valve component will now open?

    • Thermal switch.

    • Fusible switch.

    • Breakaway switch.

    • Pneumatic switch.

    Correct Answer
    A. Thermal switch.
    Explanation
    When the downstream air temperature of the bleed air air-conditioning system exceeds the predetermined temperature, the butterfly valve closes. In order to prevent any damage or overheating, a thermal switch is activated. This thermal switch will then open the flow control and shutoff valve component to allow for proper cooling and regulation of the air temperature.

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  • 45. 

     (618) What is the maximum allowable temperature of the air provided to the aircraft during a cabin leakage test?

    • 100 °F.

    • 110°F.

    • 120°F.

    • 130°F.

    Correct Answer
    A. 120°F.
    Explanation
    During a cabin leakage test, the maximum allowable temperature of the air provided to the aircraft is 120°F. This temperature limit ensures that the test is conducted under realistic conditions and simulates the potential temperature variations that the aircraft may experience during normal operations. It helps to evaluate the performance of the cabin pressure control system and identify any potential leaks or issues that may affect the safety and comfort of the passengers and crew.

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  • 46. 

    (608) When a fighter aircraft air-conditioning system (ACS) is being operated on the ground, the ram air necessary to cool the bleed air flowing through the heat exchangers is provided by the

    • Airflow valve.

    • Ejector valve.

    • Ram air nozzle.

    • Air-to-air valve.

    Correct Answer
    A. Ejector valve.
  • 47. 

    (609) The water separator over temperature switch actuates at

    • 175 ± 20 (°F).

    • 175 ± 10°F.

    • 155 ± 20°F.

    • 155 ± 10°F.

    Correct Answer
    A. 175 ± 10°F.
    Explanation
    The correct answer is 175 ± 10°F. This means that the water separator over temperature switch will actuate when the temperature reaches 175°F, with a tolerance of plus or minus 10 degrees. This allows for a range of temperatures between 165°F and 185°F for the switch to activate.

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  • 48. 

    The cargo aircraft temperature control component that produces an electrical signal that causes the temperature control valve to increase or decrease compartment temperature as required to correct an unbalanced bridge condition is the temperature control

    • Box.

    • Sensor.

    • Limiter.

    • Rheostat.

    Correct Answer
    A. Box.
    Explanation
    The cargo aircraft temperature control component that produces an electrical signal that causes the temperature control valve to increase or decrease compartment temperature as required to correct an unbalanced bridge condition is the temperature control box.

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  • 49. 

    (618) The timed pressure drop method determines cabin pressure leakage by measuring

    • The pressure decrease.

    • Pressure in pounds per minute.

    • Pressure in cubic feet per minute

    • How long pressure stabilization takes.

    Correct Answer
    A. The pressure decrease.
    Explanation
    The timed pressure drop method determines cabin pressure leakage by measuring the pressure decrease. This means that the method calculates the difference in pressure before and after a certain period of time to determine the amount of leakage. By measuring the pressure decrease, it gives an accurate indication of the leakage rate in the cabin.

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Quiz Review Timeline (Updated): Mar 18, 2023 +

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

  • Current Version
  • Mar 18, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Jul 09, 2011
    Quiz Created by
    Gdobby
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