CDC 2AX5X Volume 3

The question asks about the size of specks or granules of sediment in fuel that can be seen with the naked eye. The correct answer is 40 microns because it states that the sediment particles are approximately this size or larger. This means that any specks or granules of sediment in fuel that are visible to the naked eye would be at least 40 microns in size.

Inertia is the correct answer because it refers to the resistance of an object to change its motion. It is a property of matter that causes an object to resist any change in its state of motion, whether it is at rest or in motion. Inertia is related to an object's mass, where objects with more mass have greater inertia. This property is fundamental to Newton's first law of motion, also known as the law of inertia.

The two types of jet engine compressors are centrifugal and axial-flow. Centrifugal compressors use centrifugal force to compress the air, while axial-flow compressors use a series of rotating and stationary blades to compress the air in a linear direction. These two types of compressors are commonly used in jet engines to increase the pressure and density of the incoming air before it enters the combustion chamber.

Directing air around the plug electrode helps prevent igniter plug fouling by ensuring that the electrode remains clean and free from deposits. When air is directed around the electrode, it helps to cool it down and prevent the build-up of carbon and other contaminants that can interfere with the spark and cause fouling. This design feature allows for efficient combustion and reliable ignition in the engine.

Lock strips are used to secure the turbine bucket in place on some jet engines. They provide a strong and reliable method of holding the turbine bucket securely, ensuring that it does not move or become dislodged during operation. This is crucial for the safe and efficient functioning of the engine. Screws, cables, and lockwire are not typically used for this purpose.

Jet engine tachometer gauges are calibrated in percent of maximum RPM because this measurement is crucial for monitoring the engine's performance and ensuring it operates within safe limits. The tachometer provides real-time information about the rotational speed of the engine's shaft, allowing pilots and engineers to assess its health and make necessary adjustments. By calibrating the gauge in percent of maximum RPM, it becomes easier to interpret the readings and identify any deviations from the optimal operating range. This helps in preventing engine damage and maintaining efficient and safe aircraft operations.

The ducting for high-pressure/high-temperature air-conditioning is usually made of stainless steel because it is a strong and durable material that can withstand the high pressures and temperatures involved. Stainless steel is also resistant to corrosion, which is important in air-conditioning systems where moisture and condensation can occur. Additionally, stainless steel has good thermal conductivity, allowing for efficient transfer of heat or cold air.

The correct answer is without draining the fuel lines or tanks. This means that the rotary plug valve can be removed and replaced without the need to empty the fuel lines or tanks beforehand. This is a convenient feature as it saves time and effort in maintenance or repair tasks involving the valve.

A compensator is a type of capacitance-type, fuel-indicating system component that allows for changes in fuel density. It is designed to adjust the capacitance value based on the density of the fuel, which helps to accurately measure the fuel level. This allows for more precise fuel indication even when the density of the fuel changes, ensuring accurate readings regardless of variations in fuel density.

An increase in silicon indicates lubricant system contamination by dirt and sand. Silicon is a common element found in dirt and sand, and its presence in the lubricant system suggests that these contaminants have entered the system.

The crush-type gasket used in aircraft ducting is made of a soft aluminum, or fiber and metal mesh. This type of gasket is designed to provide a seal in areas where there is a need for compression and flexibility. The soft aluminum provides a pliable surface that can conform to irregularities in the ducting, while the fiber and metal mesh provide strength and durability. This combination of materials allows the gasket to effectively seal the ducting and prevent leaks.

Movable inlet and exit doors control the flow of ram air through the primary heat exchangers in an aircraft air conditioning system. These doors can be adjusted to regulate the amount of air entering and exiting the system, thereby controlling the temperature and pressure of the air flowing through the heat exchangers. By adjusting the position of these doors, the aircraft can maintain the desired temperature in the cabin and ensure efficient cooling of the air.

The correct answer is "The movement of a float in the tanks." In a direct current (DC), 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 float rises or falls with the level of the fuel, it adjusts the position of the wiper contact, which in turn changes the resistance and provides an indication of the fuel level.

The air-refueling (A/R) 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 the movement and operation of the receptacle.

When the turbine wheel absorbs the fuel energy, a portion of it, specifically 50 percent, is used for accessories. However, the remaining energy is not wasted but rather returns to the compressor. This allows for a more efficient use of the energy and helps in maintaining the overall functioning of the turbine system.

A compressible flange is a type of high-pressure/high-temperature ducting that does not require a gasket. This type of flange is designed to create a tight seal without the need for additional sealing materials like gaskets. The flange itself is made of a compressible material that can be tightened down to create a secure connection. This eliminates the need for gaskets, reducing the risk of leaks and simplifying the installation process.

The correct answer is 10 Hz because in a photoelectric circuit, the direct current (DC) voltage supplied to the lights 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 at a specific frequency allows for precise control of the lights and can be used for various applications such as dimming or flashing.

A centrifugal pump with an electrically driven, direct current (DC), series-wound motor must have a fuel- and vapor-proof housing because it is used to pump fuel. This type of pump is commonly used in automotive and industrial applications where fuel needs to be transferred. The fuel- and vapor-proof housing ensures that there is no leakage or escape of fuel or vapor, which is important for safety reasons and to prevent any damage to the pump or surrounding equipment.

A dual-impeller centrifugal pump is used when a fuel supply is required during periods of negative gravity conditions. This type of pump is designed with two impellers that rotate in opposite directions, allowing it to handle fluids in both directions of flow. This feature makes it suitable for situations where the pump needs to operate effectively in conditions where gravity is not assisting the flow of fuel.

The fuel control in a jet engine is responsible for metering the fuel for combustion. It regulates the flow of fuel into the engine based on various factors such as engine speed, temperature, and throttle position. By controlling the fuel flow, the fuel control ensures that the engine receives the right amount of fuel for efficient and safe combustion.

During the early years of jet engine design, the most basic turbine engine design used was the turbojet. Turbojets work by compressing incoming air, mixing it with fuel, and igniting the mixture to produce a high-speed exhaust jet that propels the aircraft forward. This design does not have any additional components, such as a fan or propeller, making it the most basic form of a turbine engine. Turbofan engines, on the other hand, have an additional fan that provides thrust and improves fuel efficiency, making them more advanced than turbojets.

The temperature and pressure in the aircraft engine's bleed air system are influenced by the engine throttle setting and the ambient temperature. The throttle setting determines the amount of air being taken in by the engine, which affects the temperature and pressure of the bleed air system. The ambient temperature also plays a role as it affects the temperature of the air entering the engine. Therefore, the engine throttle setting and ambient temperature are the factors that determine the temperature and pressure in the bleed air system.

The purpose of the engine bleed air (EBA) check valves is to prevent the loss of compressed bleed air. These valves ensure that the air remains contained within the system and does not escape. By preventing the loss of compressed bleed air, the EBA check valves help maintain the efficiency and functionality of the aircraft's systems that rely on this air, such as the air conditioning and pressurization systems.

Vent holes prevent fiberglass fabric ducts from swelling when the aircraft climbs to high altitudes. As the aircraft ascends, the air pressure decreases, causing a potential for the ducts to expand. However, the presence of vent holes allows the air to escape, preventing the swelling of the ducts. This ensures that the ducts maintain their shape and functionality even at high altitudes.

Float switches are most likely to control the automatic pump shutoff when all fuel is depleted from a fuel tank. Float switches are devices that consist of a buoyant float connected to an electrical switch. As the fuel level drops, the float also drops and triggers the switch to shut off the pump. This mechanism ensures that the pump does not continue to operate without fuel, preventing damage to the pump and potential safety hazards.

An aircraft taxiing at a constant speed is an example of Newton's First Law of Motion, also known as the law of inertia. This law states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and in the same direction, unless acted upon by an external force. In this case, the aircraft is in motion and continues to move at a constant speed due to the forward thrust of the engines and the absence of any opposing forces.

The third law of motion, also known as Newton's law of action and reaction, states that for every action, there is an equal and opposite reaction. In the case of an operating jet engine, the forward thrust is produced by the action of expelling high-speed gases backwards. According to Newton's third law, there is an equal and opposite reaction force that propels the jet engine and the aircraft forward. Therefore, the third law of motion is the best description for why an operating jet engine produces forward thrust.

A jet engine is named as such because it utilizes an exhaust-gas-driven turbine wheel to power its compressor. This turbine wheel is driven by the force of the exhaust gases, which in turn drives the compressor to draw in and compress air for combustion. This process allows the engine to generate the necessary power and thrust for propulsion.

The handle on a manually operated buildup and vent valve is designed to prevent the filler access door from closing in the vent position.

The frangible disc is the component of a liquid-agent fire extinguisher container that holds both the liquid agent and the nitrogen charge. A frangible disc is a thin, easily breakable disc that is designed to rupture when the pressure inside the container exceeds a certain level. This allows the liquid agent and nitrogen charge to be released, effectively extinguishing the fire. The other options, such as squib, bonnet assembly, and rubber O-ring packing, do not perform the same function as the frangible disc in holding both the liquid agent and the nitrogen charge.

A centrifugal-type aircraft fuel pump may be used for boost, transfer, or air refueling operations because it is capable of providing the necessary fuel pressure and flow rate required for these operations. This type of pump is designed to handle high volumes of fuel efficiently and is often used in situations where a pump with no moving parts is desired for reliability and durability. It is not used to scavenge remaining fuel in low areas of a fuel tank, as that is typically the function of a different type of pump. Additionally, while the output volume of the pump may vary with its speed, this is not the primary reason for its use in boost, transfer, or air refueling operations.

Bearings in an air refueling pump depend on fuel for lubrication. Bearings are mechanical components that support the rotating shafts and reduce friction between moving parts. In this case, the bearings rely on fuel to provide lubrication, ensuring smooth operation and preventing excessive wear and heat generation. Without proper lubrication, the bearings could fail, leading to pump malfunction or damage.

The isobaric section of the cabin pressure regulator consists of an aneroid, spring, and metering valve. The aneroid is a device that measures the pressure and adjusts the valve accordingly. The spring provides the necessary force to maintain the desired pressure level. The metering valve controls the flow of air to maintain a constant pressure inside the cabin. Together, these three components work together to regulate the cabin pressure and ensure a comfortable and safe environment for the passengers.

The purpose of the pneumatic relay in a cabin pressurization system is to ensure that both outflow valves operate at the same time. This is important for maintaining the desired cabin pressure and preventing any imbalances between the two valves. The pneumatic relay helps to synchronize the operation of the valves, ensuring that they open and close simultaneously to regulate the flow of air in and out of the cabin. This helps to maintain a stable and controlled pressurized environment inside the cabin for the comfort and safety of the occupants.

In a fire warning system, the normal connection for thermal switches is in parallel with each other and with the warning light. This means that all the thermal switches are connected together in a parallel circuit, and this entire parallel circuit is connected in parallel with the warning light. When any of the thermal switches detect a rise in temperature, it will close its circuit and activate the warning light. This configuration ensures that even if one of the thermal switches fails or is triggered, the warning light will still be activated.

In a dual-impeller fuel pump, an inlet screen prevents foreign objects from holding the bypass valve open. The inlet screen acts as a filter, preventing any debris or foreign objects from entering the pump and potentially interfering with the bypass valve. By blocking these objects, the inlet screen ensures that the bypass valve can function properly and prevents any unwanted interference or obstruction.

The N2 compressor rotations per minute (RPM) of a dual-spool jet engine compressor is determined by the fuel control. The fuel control regulates the amount of fuel being supplied to the engine, which in turn affects the speed of the compressor. By adjusting the fuel flow, the fuel control can increase or decrease the RPM of the N2 compressor, allowing for optimal engine performance.

The primary function of a hydromechanical fuel control on a jet engine is to meter the fuel, making certain that the engine gets the correct quantity for combustion at all times. This means that the fuel control system regulates the flow of fuel to ensure that the engine receives the appropriate amount of fuel for efficient and safe combustion. This is important in order to maintain optimal engine performance, prevent fuel-related issues such as hot starts, overtemperatures, engine overspeeding, and flameouts, and ensure that the engine operates within its designed parameters.

A gerotor is a type of positive displacement pump that consists of a gear and rotor within a housing. This design allows for efficient and reliable pumping of jet engine oil. The gear and rotor work together to create a seal and generate pressure, ensuring the proper flow of oil throughout the engine. Therefore, the correct answer is Gerotor.

The torque supplied by the jet fuel starter (JFS) is transmitted to the engine gearbox through the power takeoff (PTO) shaft. The PTO shaft serves as a mechanical link between the JFS and the engine gearbox, allowing the torque to be transferred efficiently. This shaft is specifically designed to handle the high torque generated by the JFS and ensure smooth power transmission to the engine gearbox.

The molecular sieve oxygen generating system (MSOGS) concentrator supplies the OXYGEN regulator control panel with 93 percent oxygen-enriched gas. This means that the gas produced by the MSOGS concentrator is 93 percent oxygen, making it suitable for use in medical and aviation applications where a higher concentration of oxygen is required.

Interlocking stainless steel bands form the inner and outer surfaces of an annular-type combustion chamber. These bands are designed to fit together tightly, creating a secure and durable structure for the combustion chamber. The use of stainless steel ensures that the chamber is able to withstand high temperatures and pressures without warping or deforming. This design allows for efficient and effective combustion within the chamber, making it an ideal choice for many combustion systems.

A turbofan engine with a bypass ratio of 3:1 is classified as a medium bypass engine. The bypass ratio refers to the amount of air that bypasses the engine core compared to the amount of air that goes through the core. In this case, for every 3 units of air that bypasses the core, 1 unit goes through the core. This indicates that a significant portion of the air is bypassing the core, but not to the extent of being classified as low or high bypass. Therefore, the engine falls into the medium bypass category.

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The shutoff valve is the engine bleed air (EBA) component that prevents the loss of air through the engine when it is shutdown. This valve is designed to close off the flow of air, preventing any leakage or loss of pressure. By shutting off the valve, the bleed air system is effectively sealed, ensuring that no air escapes from the engine. This is important for maintaining system efficiency and preventing any potential damage or loss of functionality.

The secondary heat exchanger removes most of the increased temperature. As the bleed air enters the compressor of the air cycle machine, its pressure is increased, which also leads to an increase in temperature. The primary heat exchanger may remove some heat, but it is the secondary heat exchanger that is primarily responsible for removing most of the increased temperature. It is designed to transfer heat from the bleed air to the outside air, cooling it down before it goes back into the system.

A flameholder is an augmenter component that creates local turbulence and reduces gas velocity. It is designed to stabilize the flame in a combustion system by promoting efficient mixing of fuel and air. The turbulence created by the flameholder helps to enhance combustion by increasing the contact between the fuel and air, resulting in better fuel-air mixing and a more stable flame. This reduces the gas velocity and prevents flame blowout, making the flameholder an effective component in combustion systems.

The purpose of a front-mounted fan in an axial-flow jet engine compressor is to increase thrust and send air through the compressor core rotor. The fan blades accelerate the incoming air, increasing the overall thrust of the engine. Additionally, the fan helps to direct the airflow towards the compressor core rotor, which is responsible for compressing the air before it enters the combustion chamber. This ensures efficient combustion and overall engine performance.

The correct answer is impulse, reaction, and reaction-impulse. Jet engines use three different turbine designs: impulse, reaction, and reaction-impulse. The impulse turbine uses the force of high-velocity gas to rotate the turbine blades. The reaction turbine uses the force of gas expanding and changing direction to rotate the blades. The reaction-impulse turbine combines both the impulse and reaction principles to generate rotational motion. These three designs are commonly used in jet engines to efficiently convert the energy of the exhaust gases into mechanical power.

The correct answer is air pressure and pump. This means that the two methods of transferring fuel are using air pressure and using a pump. Air pressure can be used to push the fuel through a system, while a pump can be used to create pressure and move the fuel. These two methods are commonly used in fuel transfer systems to ensure efficient and controlled fuel flow.

The divergent design of a jet engine diffuser increases pressure. This is because the divergent shape of the diffuser allows the airflow to expand, which in turn slows down the air velocity. As the air slows down, its kinetic energy is converted into pressure energy, resulting in an increase in pressure.

A transformer is a device that can increase or decrease the voltage of an electrical current. In this case, the jet engine AC ignition system unit requires a voltage of 20,000 volts to be delivered to the igniter plugs. A transformer is capable of stepping up the voltage from a lower value to the required 20,000 volts, making it the correct answer. An inverter, capacitor, and generator are not specifically designed for voltage transformation, so they are not suitable for developing the required voltage for the igniter plugs.

The jet engine pressure ratio (EPR) indicating system is designed to provide a reference for the engine's available thrust output. This means that it helps pilots and engineers determine the amount of thrust the engine is capable of producing at any given time. By monitoring the EPR, they can make adjustments to optimize the engine's performance and ensure that it is operating within safe and efficient parameters. Therefore, the purpose of the EPR indicating system is to provide information about the engine's available thrust output.

A check valve is a type of valve that allows the flow of fluid in only one direction. In the case of a gaseous oxygen (GOX) system, a check valve prevents a complete loss of oxygen by ensuring that the flow of oxygen can only go in one direction and cannot flow back. This is important to maintain the integrity and safety of the system, as it prevents oxygen from escaping or leaking out completely.

The air turbine (impingement) starter used on jet engines has the advantages of less weight and fewer moving parts than other starters. This means that it is more efficient and easier to maintain compared to other types of starters. The reduced weight also helps in improving the overall performance of the jet engine. Additionally, having fewer moving parts reduces the risk of mechanical failures and increases the reliability of the starter.

The spring aids piston closure and prevents fuel from entering the tank in a piston-type, fuel level control valve. It provides the necessary force to keep the piston closed and ensure that fuel does not flow back into the tank. The spring acts as a mechanical barrier, exerting pressure on the piston to maintain a tight seal and prevent any fuel leakage.

A segmented flap is a common type of variable-area orifice used on augmenters. This type of flap is divided into segments, allowing for greater control and adjustment of the flow area. By adjusting the position of the segments, the area of the orifice can be varied, which in turn affects the flow rate of the fluid passing through it. This type of design is often used in augmenters to optimize performance and achieve desired flow characteristics.

In the isobaric pressurization system, the cabin pressure controller is responsible for maintaining the desired cabin pressure. If the cabin pressure controller fails, it means that it is unable to regulate the cabin pressure effectively. In such a situation, the manual control valve is used as an alternate to manually control the cabin pressure. This allows the crew to maintain a safe and comfortable cabin environment in case of a failure in the cabin pressure controller.

A simple direct current (DC) ignition system consists of a vibrator, which is responsible for interrupting the current flow and creating the necessary high voltage pulses. The igniter plugs are essential for creating the spark that ignites the fuel-air mixture in the engine. Finally, the transformer is needed to step up the voltage from the battery to a level that can create the spark. Therefore, the correct answer is vibrator, igniter plugs, and transformer.

The components of the differential section of the cabin pressure regulator are a diaphragm, spring, and metering valve. These components work together to regulate the cabin pressure. The diaphragm responds to changes in pressure, the spring provides the necessary force for the diaphragm to function, and the metering valve controls the flow of air to maintain the desired pressure in the cabin.

The secondary seal sleeve is the part of the rotary plug valve that rotates and seals off the passage of fuel during plug valve removal. It is responsible for preventing any fuel from leaking out when the valve is being removed.

The question asks for the type of oil pump that is not classified according to structure. The options provided are gear, gerotor, rotogear, and sliding vane. Gear pumps and sliding vane pumps are both types of oil pumps classified according to structure. Gerotor pumps are also a type of oil pump, consisting of an inner rotor and an outer rotor. However, "rotogear" is not a recognized term or type of oil pump, making it the correct answer as it does not fit the classification mentioned in the question.

The compressor must be rotated to a predetermined speed in order for a jet engine starter to be considered effective. The compressor plays a crucial role in the jet engine as it compresses incoming air before it enters the combustion chamber. By rotating the compressor to a specific speed, it ensures that there is sufficient air compression and flow, allowing for proper combustion and engine startup. Without an effective compressor rotation, the jet engine may not function optimally or may not start at all.

A pressure-loaded fuel system check valve is used when gravity flow through the valve is undesirable. This means that the valve is designed to prevent fuel from flowing back due to gravity, which can cause issues such as fuel leakage or improper fuel distribution. By using a pressure-loaded check valve, the flow of fuel can be controlled and regulated in a way that ensures proper functioning of the fuel system.

If the dual-differential cabin pressure regulator fails during flight, the outflow valves will maintain the pressure. The outflow valves are responsible for controlling the flow of air out of the cabin, and they can be manually adjusted to maintain the desired cabin pressure. Therefore, even if the pressure regulator fails, the outflow valves can still be used to regulate the cabin pressure and ensure the safety and comfort of the passengers and crew.

A check valve is designed to allow fluid to flow in only one direction, preventing reverse flow. It uses a mechanical mechanism, such as a ball or a disc, to block the flow when it tries to reverse. In this case, the low-level shutoff valve is specifically designed to prevent the reverse flow of fuel, and a check valve is the most suitable type of valve for this purpose.

The cartridge-pneumatic starter is a gas-driven turbine wheel that needs to be coupled to the engine through a reduction gear system and a power takeoff (PTO) shaft. An overrunning clutch is a mechanism that allows the starter to disengage from the engine once it reaches a certain speed, preventing damage to the starter and the engine. This allows the engine to continue running independently while the starter is disengaged. Therefore, an overrunning clutch is necessary in this system to ensure the safe and efficient operation of the cartridge-pneumatic starter.

The correct answer is "leak category and fuel type." This means that the limits for leaks are determined by both the category of the leak (such as gas, oil, or water) and the type of fuel being leaked (such as gasoline, diesel, or natural gas). Different types of leaks and fuels may have different limits based on their potential hazards and environmental impact.

When automatic data systems are not available, AFTO Form 427 must be used to document fuel leaks. This form is specifically designed for recording fuel system discrepancies and is used in conjunction with the Air Force Technical Order (AFTO) Form 781A or AFTO Form 781K. It provides a standardized format for documenting and tracking fuel leaks, ensuring that accurate and consistent records are maintained for maintenance and safety purposes.

The exhaust duct connects the turbine outlet and the jet nozzle. The turbine outlet is where the exhaust gases from the turbine are expelled, and the jet nozzle is responsible for accelerating these gases to create thrust. Therefore, the exhaust duct acts as a pathway for the gases to flow from the turbine to the jet nozzle, allowing for the generation of thrust in a jet engine.

Spring-loaded relief valves are fuel system components that prevent excessive pressure from building up in trapped lines or within the valve body. These valves are designed with a spring mechanism that allows them to open and release pressure when it reaches a certain threshold. This helps to protect the fuel system from damage caused by excessive pressure, ensuring safe and efficient operation.

The rotor is the air refueling pump component that removes fuel vapors caused by the centrifugal force of the impellers. The impellers generate centrifugal force, which creates fuel vapors. The rotor is responsible for removing these vapors from the pump, ensuring the smooth operation of the refueling process. The stator, accumulator, and vapor relief valve do not have this specific function.

The nozzle diaphragm is placed directly in front of each turbine wheel in a jet engine that uses two or more turbine wheels. The nozzle diaphragm helps to direct and control the flow of exhaust gases from the combustion chamber towards the turbine blades, ensuring efficient energy transfer and propulsion.

The correct answer is sliding gate, rotary plug, and disc. These are the three types of shutoff valves used in the crossfeed fuel system. The sliding gate valve is a type of valve that uses a gate mechanism to control the flow of fuel. The rotary plug valve is a type of valve that uses a rotating plug to control the flow of fuel. The disc valve is a type of valve that uses a disc mechanism to control the flow of fuel. These three types of valves are commonly used in crossfeed fuel systems to regulate and control the flow of fuel between different fuel tanks.