2A656 Vol 4 Ure (2013)

The moisture in the conditioned air is removed by the aircraft bleed air system water separators through rapid expansion. When the air expands rapidly, its temperature drops, causing the moisture to condense and separate from the air. This process allows the system to remove 70 to 85 percent of the accumulated moisture and provide dry air for the aircraft's systems.

Engine bleed air is used in aircraft systems for various purposes such as anti-gravity (anti-G), rain removal, and anti-icing. It is used to pressurize and de-ice the aircraft, as well as to power various systems. However, engine bleed air is not used for fire extinguishing. Fire extinguishing systems in aircraft typically use specialized agents such as foam or halon to suppress and extinguish fires.

Engine bleed air check valves are installed to prevent the loss of compressed bleed air. These valves ensure that the high-pressure bleed air does not escape from the system when it is not needed. By preventing the loss of compressed bleed air, the valves help maintain the efficiency and effectiveness of the aircraft's bleed air system. This is important because bleed air is used for various purposes such as cabin pressurization, air conditioning, and anti-icing.

When replacing gaskets used in aircraft ducting, it is important to remember to always install a new gasket each time a joint is reconnected. This is because gaskets can become worn or damaged over time, and reusing them may result in leaks or other issues. Installing a new gasket ensures a proper seal and helps maintain the integrity of the aircraft ducting system.

Isobaric pressurization range maintains a constant cabin pressure. This means that the pressure inside the aircraft cabin remains the same regardless of the altitude. This is achieved by continuously adjusting the air pressure inside the cabin to match the outside atmospheric pressure. Isobaric pressurization ensures a comfortable and safe environment for passengers and crew by preventing rapid changes in pressure that could cause discomfort or health issues.

Cooling turbines in a depot level of maintenance often have a pair of unused wires that are cut-off close to the turbine housing. This indicates that the depot level of maintenance uses these wires.

The correct answer is "primary heat exchanger." The pre-cooler in an aircraft's bleed air cooling system is responsible for cooling the hot bleed air before it enters the air cycle machine. This is achieved by transferring heat from the hot air to a cooler medium, which is typically ambient air or engine coolant. The pre-cooler acts as the primary heat exchanger in this process, as it is the first component that cools the air.

The leak in the aircraft's bleed air system could have been caused by an improperly installed clamp. This means that the clamp was not secured properly or was not tightened enough, leading to a gap or space where air can escape.

Water is the correct answer because it is the only lubricant that can be used on a medium-pressure/medium-temperature beaded channel clamp sleeve to ease installation. Soap, grease, and silicone are not suitable lubricants for this specific application.

The purpose of the fan in the aircraft bleed air system cooling turbine and fan assembly is to prevent turbine over speeding. The fan helps regulate the airflow and prevents the turbine from spinning too fast, which could lead to damage or malfunction. By controlling the speed of the turbine, the fan ensures the safe and efficient operation of the aircraft's bleed air system.

If a bleed air system leak is found in a high pressure/high temperature area, the next logical step would be to inspect for heat damage. This is because the high pressure and temperature can cause damage to the surrounding components, such as blistered paint, insulation peeling back, or deterioration. Therefore, inspecting for heat damage would help identify any potential issues and ensure the safety and functionality of the system.

The correct answer is to listen and feel for leaks. When performing a leakage test on an entire bleed air distribution system, you can listen for the sound of leaking high-pressure air and also feel for any air escaping through leaks. This method allows you to detect any potential leaks in the system by using your senses of hearing and touch. Using an ultrasonic leak detector is not mentioned as a method for this specific test, and feeling for hot leaking air is not specified as a step in the process.

A rawhide mallet is the correct tool to use when installing a high-pressure/high-temperature V-band clamp to ensure it is aligned and sealed properly. Rawhide mallets are made of rawhide material, which is soft and non-damaging to the clamp or other surfaces. It provides a controlled and gentle force to align and seal the clamp without causing any damage. Using a screwdriver, center punch, or ball peen hammer could potentially damage the clamp or create an improper seal, making the rawhide mallet the best tool for the job.

Bleed air is usually taken from the compressor section of an aircraft engine. The compressor is responsible for compressing the incoming air to increase its pressure and deliver it to the combustion chamber. During this process, a small amount of compressed air is bled off for various purposes such as cabin pressurization, anti-icing, and pneumatic systems. Therefore, the correct answer is the compressor.

An orifice is a pressure and flow control device that restricts airflow. It is commonly used to protect aircraft engines against air starvation by maintaining a consistent and controlled flow of air. By limiting the amount of air that can pass through, the orifice ensures that the engine receives enough air for proper combustion while also preventing excessive airflow that could cause damage or inefficiency. Therefore, the orifice is the correct answer as it effectively restricts airflow and protects aircraft engines from air starvation.

When air 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.

When smoke or fumes are discharged from the aircraft's air-conditioning system, the cockpit is ventilated by the atmospheric air source. This means that the air in the cockpit is refreshed and replaced with outside air from the atmosphere. This is important to ensure the safety and well-being of the crew members in the cockpit, as it helps to remove any potential harmful substances or odors caused by the smoke or fumes.

The correct answer is soft aluminum or fiber and metal mesh. This type of crush-type gasket is commonly used in bolted flange aircraft-ducting ends. It is made of a combination of soft aluminum and either fiber or metal mesh. The soft aluminum provides a flexible and malleable component, while the fiber or metal mesh adds strength and durability to the gasket. This combination allows the gasket to effectively seal the flange and prevent leaks in the aircraft ducting system.

When a high-pressure/high-temperature compressible flange duct end becomes distorted, the correct corrective action to take is to reshape the duct flange ends to its original shape. This means that instead of replacing the entire duct flange ends or using a gasket, the distorted ends should be carefully reshaped to restore their original form. This is the most efficient and cost-effective solution to ensure proper sealing and functionality of the duct.

A water aspirator is used to create a greater cooling effect by spraying atomized water across the inlet of the aircraft bleed air system's secondary heat exchanger. The water aspirator is designed to draw in air and mix it with water, creating a fine mist or spray that can effectively cool the incoming air. This process helps to enhance the cooling capabilities of the system and maintain optimal operating temperatures.

The correct answer is to check the small drill hole for escaping air. This is because a small drill hole is intentionally made in the outlet side of the engine bleed air (EBA) shutoff valve. If there is escaping air from this hole, it indicates that the valve is working properly. This method helps in leak checking the aircraft bleed air system and ensuring the functionality of the EBA shutoff valve.

The load control valve is the component that determines the amount of bleed air bled from a gas turbine compressor (GTC). This valve regulates the flow of bleed air based on the load requirements of the turbine. By adjusting the position of the load control valve, the amount of bleed air can be controlled, ensuring that the turbine operates efficiently and effectively. The other options, such as the thermocouple, fuel control valve, and bleed air control governor, do not have a direct role in determining the amount of bleed air bled from the compressor.

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. By ensuring that both valves open and close simultaneously, the pneumatic relay helps to regulate the flow of air in and out of the cabin, thus maintaining a stable and comfortable pressurized environment for passengers and crew.

The correct answer suggests that the first step to determine if the non-electrostatic application (NESA) autotransformer is operating properly is to disconnect either the X1 or X2 lead and check for voltage. By disconnecting one of the leads and checking for voltage, it can be determined if there is a proper voltage supply to the autotransformer. This step helps in identifying any issues with the power supply or connections before proceeding to other troubleshooting steps.

The aircraft pilot's anti-gravity (G) suit prevents blood from pooling in portions of the body below the heart. When an aircraft experiences high G-forces, blood tends to be pulled downward due to gravity, causing a decrease in blood flow to the upper body. The G-suit applies pressure to the lower body, particularly the legs, to help prevent this pooling of blood and maintain adequate blood flow to the brain and upper body. This helps the pilot avoid the negative effects of G-forces, such as loss of consciousness or impaired vision.

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 ensures that they are tightened evenly and prevents leaks in the system. Failing to follow the proper torquing sequence can result in uneven pressure distribution and cause a leak to occur during the operational check.

Aircraft high-pressure/high-temperature air-conditioning ducting is usually made of stainless steel because it is a strong and corrosion-resistant material that can withstand the high pressures and temperatures involved in aircraft operations. Titanium is also a strong material, but it is more commonly used in applications where weight reduction is a priority. Aluminum is lightweight but not as strong as stainless steel, making it less suitable for high-pressure/high-temperature environments. Aluminum/nickel alloy is not commonly used for air-conditioning ducting in aircraft.

The correct answer is "opens or closes depending on system design requirements." This is because the valve has a fail-safe feature, which means that in the event of an interruption in electrical power to the solenoid, the valve will either open or close based on the specific design of the system. The system may be designed to open the valve to allow for the flow of air or close the valve to stop the flow, depending on the requirements of the system.

Close-assault attack aircraft often fly at slower speeds, which results in lower amounts of ram air entering the air conditioning system (ACS). Ram air is the air that is forced into the system by the aircraft's forward motion. At slower speeds, there is less air entering the ACS, leading to insufficient cooling. This is the most likely explanation for the development of insufficient cooling in the ACS of close-assault attack aircraft.

Expansion joints in aircraft bleed air systems are best used on short runs of ducting. This is because short runs of ducting are more prone to thermal expansion and contraction, which can cause stress and damage to the ducting if not properly accommodated. Expansion joints are designed to allow for this movement, absorbing the expansion and contraction without causing harm to the ducting. In contrast, long runs of ducting are less susceptible to these thermal effects and may not require expansion joints. Therefore, short runs of ducting are the most appropriate application for expansion joints in aircraft bleed air systems.

The correct answer is 175 ± 10°F. This means that the water separator over temperature switch in the bomber aircraft's air-conditioning system actuates at a temperature range of 165°F to 185°F. This range allows for a tolerance of ±10°F, ensuring that the switch will activate within the specified temperature range.

The aircraft bleed air system water separator anti-icing system prevents the condenser bag from icing by keeping the outlet temperature above 32°. This means that the system is designed to ensure that the temperature of the air leaving the system is above freezing point, which prevents the formation of ice on the condenser bag.

The correct answer is Cabin dual-temperature mixing. The position of this valve depends on the temperature of conditioned air going to the crew compartment. This suggests that the valve is responsible for mixing air of different temperatures to achieve the desired temperature in the cabin. The other options, such as cabin air inlet, ground cooling ejector, and water separator bypass, do not directly relate to the temperature control in the crew compartment.

During ground pressurized testing, there is a risk that certain components may separate from the aircraft. To prevent this from happening, it is necessary to secure the components in place. Tying them with a net or strap would be the most appropriate solution in this case, as it would provide a secure attachment and prevent the components from becoming detached during the test.

The engine bleed air is tapped from the engine compression section at an approximate pressure of 200 pounds per square inch (psi) and a maximum temperature of 900 degrees Fahrenheit (°F).

The components that aid the aircraft's bleed air pre-cooler assembly in maintaining a constant outlet temperature are a sensor, a temperature control circuit, and a modulating valve. The sensor measures the outlet temperature, which is then fed into the temperature control circuit. The temperature control circuit processes this information and sends signals to the modulating valve, which adjusts the flow of bleed air to maintain a constant outlet temperature.

The purpose of the aircraft pilot's anti-gravity (G) suit system is to inflate the pilot's anti-G suit. The anti-G suit is designed to apply pressure to the pilot's lower body, particularly the legs, to prevent blood from pooling in the lower extremities and maintain blood flow to the brain during high G-forces. By inflating the suit, it helps to counteract the effects of negative G-forces and maintain the pilot's consciousness and ability to control the aircraft.

The hand survey air-leakage test method is performed on the aircraft bleed air distribution system after replacing any couplings or valves. This is because replacing couplings or valves can potentially introduce air leaks into the system. The hand survey air-leakage test is conducted to ensure that there are no leaks in the system that could affect its performance and safety. By performing the test after replacing couplings or valves, any potential leaks can be identified and addressed before the system is put back into operation.

The function of the floor heat system's pneumatic anticipator on a cargo aircraft is to respond to rapid temperature changes. This means that when there is a sudden increase or decrease in temperature, the pneumatic anticipator will adjust the floor heat system accordingly. It ensures that the floor heat shutoff valve is controlled effectively in response to these rapid temperature changes, maintaining the desired temperature inside the aircraft.

When the aircraft pressurizes, the outflow safety valve opens to release excess pressure. At the same time, the pneumatic relay opens, allowing the pressurized air to flow into the cabin. This ensures that the pressurization system operates properly by maintaining the desired cabin pressure. The rate control system closing or the cabin pressure controller closing are not related to the opening of the outflow safety valve and the functioning of the pressurization system.

The amount of airflow through a pressure limiter is affected by the inlet pressure, inlet temperature, and differential pressure. However, the outlet pressure does not have any impact on the airflow through the pressure limiter.

A compressible high-pressure/high-temperature flange ducting does not require a gasket because it is designed to create a tight seal by compressing the flange material itself. This type of ducting is able to withstand high pressures and temperatures without the need for an additional gasket, making it a more efficient and cost-effective option. The compressible nature of the flange allows it to conform to the mating surface, ensuring a secure and leak-free connection.

The correct answer is "Thermal." In this scenario, the downstream air temperature of the bleed air air-conditioning system has exceeded the predetermined temperature, causing the butterfly to close. To address this issue, a flow control and shutoff switch that is specifically designed to respond to temperature changes is needed. A thermal switch is capable of opening when the temperature reaches a certain threshold, allowing for proper flow control and shutoff in this situation.

After replacing a bleed air system air-conditioning airflow regulator fusible plug, you must also reset the pneumatic switch. This is because the fusible plug is designed to melt at a specific temperature to prevent excessive pressure build-up in the system. When the fusible plug melts, it triggers the pneumatic switch to shut off the airflow. Therefore, after replacing the fusible plug, the pneumatic switch needs to be reset to restore the airflow and ensure proper functioning of the air-conditioning system.

The flow control valve in the bleed air air-conditioning system maintains a constant differential pressure between the inlet and throat of the venturi. This means that the valve regulates the flow of air by ensuring that there is a consistent pressure difference between the two points. By doing so, it controls the flow rate and ensures that the air-conditioning system operates effectively.

The air pressure regulator and shutoff valve is installed upstream of the flow control valve to control the valve's inlet pressure. This component regulates the pressure of the bleed air before it enters the flow control valve, ensuring that the valve receives the appropriate pressure for its operation. Additionally, the shutoff valve allows for the complete closure of the bleed air system when needed.

The correct answer is the floor heat modulating and shutoff valve. This valve is responsible for regulating the pressure to the floor heat ejector on a cargo aircraft floor heat system. It controls the flow of heat and can modulate or shut off the heat as needed. The other options mentioned, such as the floor heat shutoff valve, pneumatic control thermostat, and pneumatic temperature anticipator, do not directly regulate the pressure to the floor heat ejector.

After the cooling turbine in an air-conditioning system cools the air, the air goes to the water separator. The water separator is responsible for removing any moisture or water vapor that may have condensed during the cooling process. This ensures that the air that is circulated back into the system is dry and does not cause any issues or damage to the system.

The correct answer is "returns to the jet pump as re-circulating air." In wing anti-icing systems, a portion of the bleed air is used to de-ice the wings, while the remaining air is recirculated back to the jet pump. This recirculating air helps maintain the necessary pressure and flow rate in the system. By returning the air to the jet pump, it can be used again for anti-icing purposes, making the system more efficient.

The correct answer is the leading edge section. In the bleed air anti-icing system, the engine bleed air supply duct has a distribution duct (piccolo tube) that can be attached to the leading edge section. If it is attached, the tube will need to be replaced by removing the leading edge section.