2A656 Aircraft Electrical and Environmental Systems Journeyman Volume 3

The correct answer is 8,000 rpm. The constant speed drive (CSD) is used to drive a 60/80 kVA generator, which indicates the power output of the generator. Since the CSD is a constant speed drive, it means that it maintains a consistent speed regardless of the load. Therefore, the output of the CSD is approximately 8,000 revolutions per minute (rpm), ensuring a stable power supply from the generator.

Remote terminals in the data bus are designed to transfer data between the aircraft system and the data bus controller (DBC). The data bus is a communication network that allows different systems within the aircraft to exchange information. Remote terminals act as intermediaries between the individual systems and the data bus controller, facilitating the transfer of data. This enables efficient communication and coordination between various aircraft systems, ensuring smooth operation and functionality.

After releasing the stick grip trim selector switch, the trim indicator light extinguishes. This indicates that the trim adjustment has been completed and the aircraft's control surfaces are now properly trimmed.

After replacing a bad indicator in the landing gear system, the final step is to perform an operational check of the system. This is necessary to ensure that the replacement was successful and that the landing gear system is functioning properly. It allows for any potential malfunctions or discrepancies to be identified and addressed before the aircraft is put back into operation. Taking meter readings, limiting the malfunction, and defining the discrepancy may be steps that are taken earlier in the troubleshooting process, but the operational check is the final step to verify the system's functionality.

Placing the landing gear control handle in the up position provides 28 VDC from the essential DC bus. This means that when the landing gear control handle is raised, the essential DC bus supplies the necessary power to operate the landing gear system. The essential DC bus is a critical power source in the aircraft, providing power to essential systems even in emergency situations. Therefore, when the landing gear handle is in the up position, the essential DC bus is the correct power source for the landing gear system.

INCONEL is the correct answer because it is a high-performance alloy that is commonly used in fire detector systems. It has excellent resistance to high temperatures, corrosion, and oxidation, making it suitable for withstanding the harsh conditions in a continuous loop fire detector system. Soft iron, aluminum, and malleable tin do not possess the same level of durability and resistance, making them less suitable for constructing the shield of the continuous loop.

The data bus controller is the component that manages the flow of information on the data bus. It controls the timing and synchronization of data transfers between different devices connected to the bus. It ensures that data is transferred accurately and efficiently, coordinating the communication between the sender and receiver devices. The data bus controller plays a crucial role in maintaining the integrity and reliability of data transmission on the data bus.

After replacing the 43 degree position switch on the speedbrake system, the next and final step is to perform an operational check. This is necessary to ensure that the newly replaced switch is functioning correctly and is properly integrated into the speedbrake system. By performing an operational check, any potential issues or malfunctions can be identified and addressed before the system is put back into regular use. This step is crucial in maintaining the safety and efficiency of the speedbrake system.

The correct answer is open, hold, and retract. The speedbrake switch has three positions that control the movement of the speedbrake. When the switch is in the open position, the speedbrake is fully extended. In the hold position, the speedbrake remains in its current position. And in the retract position, the speedbrake returns to its stowed position. These three positions allow the pilot to control the deployment and retraction of the speedbrake during different phases of flight.

The Air Force Technical Order (AFTO) form 781A is reviewed during the troubleshooting step of defining the discrepancy. This form provides detailed information about the specific problem or issue that needs to be addressed. By reviewing the AFTO form 781A, technicians can gain a better understanding of the discrepancy and gather necessary information to effectively troubleshoot and resolve the issue.

The generator control unit in an AC power supply system maintains the generator output at a voltage range of 115 VAC with a tolerance of +/- 2 VAC. This means that the generator control unit ensures that the generator output remains within the range of 113 VAC to 117 VAC. This specific voltage range is important for the proper functioning of the AC power supply system and to ensure that the electrical devices connected to it receive the appropriate voltage for their operation.

The correct answer is "on the ground with weight on the wheels." This is because the NLG weight on wheels relay C is responsible for detecting if the aircraft is on the ground with weight on its wheels. When this condition is met, the relay is energized, indicating that the NLG is in contact with the ground. This information is crucial for various aircraft systems, such as anti-skid braking and landing gear indication.

The transformer rectifier units in a VDC power system convert three-phase 115 VAC into 26 to 31 VDC.

The correct answer is 115 VAC, 400 hertz. This means that the AC ignition system requires an input voltage of 115 volts and a frequency of 400 hertz in order to operate properly. The voltage and frequency specifications are important for ensuring the system functions correctly and efficiently.

Before the anti-collision light can come on, both the anti-collision relay and the flasher relay must be energized. The anti-collision relay controls the power supply to the anti-collision light, while the flasher relay controls the flashing function of the light. Therefore, both relays need to be activated in order for the anti-collision light to operate correctly.

Before operating the aileron trim system, you must supply power to both the electrical and hydraulic systems. This is because the aileron trim system requires electrical power to operate the controls and hydraulic power to move the ailerons. Without power in both systems, the aileron trim system will not function properly.

The scissors assembly in the nose wheel steering system provides a quick disconnect capability for turning the nose wheel beyond the steerable range. This component allows for easy disengagement and re-engagement of the steering system, enabling the nose wheel to be turned further when necessary.

Before removing any connector plugs in the nose wheel steering system, it is necessary to disconnect the power. This is important to ensure safety and prevent any electrical hazards. Disconnecting the power will eliminate the risk of accidental activation of the system while working on it, reducing the chances of injury or damage. It also allows for a controlled environment to analyze any malfunctions or check for continuity in the system. Therefore, disconnecting the power is a crucial step in the process.

If the pilot uses the ramp and cargo door switch while the aircraft is in flight, the ramp and door will open at the same time. This means that both the ramp and the cargo door will open simultaneously, allowing for the loading or unloading of cargo while the aircraft is still in the air.

Flood lights help to reduce the blinding effect of lighting flashes in aircraft interiors. Flood lights are designed to provide a wide and even distribution of light, which helps to minimize the contrast between the bright flashes of lightning and the surrounding cabin environment. This reduces the discomfort and potential temporary blindness that passengers and crew may experience during a lightning strike. Flood lights also ensure that the cabin remains adequately illuminated during the duration of the lightning event, allowing occupants to move around safely.

The auxiliary fuel tank indicating system gives a no-flow indication through a flashing amber light. This indicates that there is a problem with the flow of fuel in the auxiliary tank. The flashing light is used to draw attention and signal an issue that needs to be addressed. It serves as a warning to the pilot or operator that there may be a blockage or malfunction in the fuel system, and further investigation or action is required to resolve the issue.

The slotted wing flaps are used on heavy aircraft to increase the chamber or curvature of the wing. By extending forward and downward, they form a slot between the flap of the wing. This slot helps to improve the lift characteristics of the wing by allowing air to flow smoothly over the top surface of the wing, reducing turbulence and increasing lift. The slot also lowers the trailing edge of the wing to about 40 degrees below its retracted (UP) position, further enhancing the lift generation capability of the wing.

The load controller is the component that controls load division during parallel generator operation in an AC power supply system. It ensures that the load is evenly distributed among the generators to prevent overloading or underloading. By monitoring the load demand and adjusting the output of each generator, the load controller helps maintain a balanced and stable power supply.

The correct answer is "locked wheel circuit". When a wheel stops rotating, it indicates that the wheel is locked. In such a situation, the locked wheel circuit supplies a DC voltage to the Mark II antiskid system valve driver. This voltage is used to control the valve and release the brake pressure on the locked wheel, preventing skidding and improving vehicle control.

If the normal battery will not charge but the standby battery is OK, the problem is likely with the normal battery relay. The normal battery relay is responsible for controlling the charging of the normal battery. If it is faulty or not functioning properly, it would prevent the normal battery from charging even if the standby battery is working fine. Therefore, taking meter readings at the normal battery relay would help identify any issues with it and potentially resolve the charging problem.

The centrifugal switch is responsible for opening the ground circuit to the starter relay when a pneumatic starter reaches maximum speed. This switch is designed to activate at a specific rotational speed, allowing it to disconnect the starter relay and prevent further power supply to the starter. This mechanism ensures that the starter does not continue running at high speeds, which could lead to damage or malfunction.

The position switch is designed to activate the locked solenoid of the ramp up-lock control valve only when the ramp is in the fully up position. This means that when the ramp reaches its maximum raised position, the position switch will send a voltage signal to the locked solenoid, allowing it to lock the ramp in place. This ensures that the ramp remains securely in the fully up position during operation.

The strobe light power supply provides a trigger voltage to the strobe anti-collision light at a rate of 50 to 60 pulses per minute.

The auxiliary trim switch is used as an emergency means of controlling the aileron trim control circuit. This switch is typically located in a convenient location for the pilot to quickly access and operate in case of an emergency or failure of the primary trim control switches. It allows the pilot to manually adjust the aileron trim to maintain proper control and balance of the aircraft.

The APU/external power disconnect contactor (AEDC) is the external power system component that disconnects external power from the aircraft.

When the horn silence switch for the landing gear warning circuit is momentarily depressed, it provides a ground for the horn silence relay. This means that it completes the electrical circuit and allows current to flow through the relay, activating it. The ground connection is necessary for the relay to function properly and silence the horn.

An iron fireman switch is frequently used in fire warning systems. It consists of a high-nickel steel rod located along the center line of a stainless steel tube assembly. This switch is designed to detect fire and trigger the necessary actions to control it. It is a reliable and effective component in fire detection systems.

The output of gallons per min (GPM) of the scavenge pumps is approximately 2 gpm. This means that the scavenge pumps are capable of pumping out approximately 2 gallons of fluid per minute.

Before completing a troubleshooting cycle, it is essential to perform an operational check. This step ensures that the repaired or replaced item is functioning correctly and meets the required specifications. By conducting an operational check, any potential issues or malfunctions can be identified and resolved before considering the troubleshooting process complete. This final step helps to validate the effectiveness of the troubleshooting efforts and ensures that the problem has been successfully resolved.

The correct answer is interconnect. Interconnect valves are fuel system valves that link the left wing and aft body tanks to the right wing, mid body, and forward body tanks. These valves allow fuel to flow between the different tanks, ensuring a balanced distribution of fuel throughout the aircraft. This is important for maintaining stability and performance during flight.

Limit switches are components in the landing gear system that initiate a signal to identify the position of the landing gear at any given time. These switches are designed to detect the physical movement or position of a mechanism and provide feedback to the system. In the case of the landing gear, limit switches are used to determine whether the gear is in the up or down position. When the landing gear reaches its limit, the switch is activated, sending a signal to indicate the gear's position.

There are four boost pumps in main fuel tank number 1.

The correct answer is to check for 28 VDC at pin F of the actuator connector plug with either of the horizontal stabilizer trim control switches actuated. This is the best place to start taking meter readings because it directly tests the voltage at the actuator connector plug, which is where the issue with the stabilizer not moving down is likely to be. The other options either test for voltage at different pins or at the up-limit switch, which may not provide accurate information about the problem at hand.

When the stick grip trim selector switch is moved to the left, it adjusts the trim of the aircraft's ailerons. Ailerons are control surfaces on the wings that help in rolling the aircraft. Moving the switch to the left indicates a desire to trim the left aileron. In order to trim the left aileron, it needs to be moved in the opposite direction, which means the left wing should be moved down. Therefore, the correct answer is "up (left wing down)."

The amplifiers used in the photoelectric fire detector system are sensitive only to signals with a frequency between 7 and 60 Hz. This means that they can detect and amplify signals within this frequency range, while being less sensitive or unresponsive to signals outside of this range. This frequency range is likely chosen because it corresponds to the typical frequency range of fire-related phenomena, such as flickering flames or smoldering fires. By focusing on this specific frequency range, the amplifiers can effectively detect and amplify the signals associated with fire, increasing the sensitivity and accuracy of the fire detection system.

Knowing the system operation is the first step in troubleshooting when the normal battery is supplying DC to the battery bus and emergency DC bus. Understanding how the system is supposed to work will help identify any deviations or abnormalities that may be causing the issue. By having a clear understanding of the system operation, it becomes easier to pinpoint the problem and determine the appropriate course of action to resolve it.

The minimum VAC requirement to energize the emergency power disconnect relay (EPDR) is 93 VAC from the C phase. This means that in order for the EPDR to be activated, a voltage of at least 93 VAC needs to be present in the C phase.

Performing an operational check is the first step in troubleshooting a fuel pump inoperative writeup. This involves testing the fuel pump to see if it is functioning properly. By performing this check, you can determine if the fuel pump is the cause of the issue or if there is another problem within the system. Once the operational check is completed, further steps can be taken to limit the malfunction or replace the fuel pump if necessary.

The reverse current relays (RCR) in the DC power supply system deenergize when the potential at the GEN terminal is less than the battery terminal. This means that the voltage at the GEN terminal is lower than the voltage at the battery terminal, indicating a reverse current flow. When this occurs, the RCRs are designed to deenergize in order to protect the system from any potential damage or malfunction caused by the reverse current.

Thermal switches in a fire warning system are connected in parallel with each other to ensure that if one switch is triggered, it does not affect the operation of the others. However, they are also connected in series with the warning light to ensure that if any of the switches are triggered, the warning light will be activated. This configuration allows for redundancy in the system and ensures that a fire can be detected and indicated even if one or more switches fail to activate.

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If the nosewheel steering (NWS) fail light illuminates, the first place to take ohmmeter readings should be at the command and feedback potentiometer. This is because the potentiometer is responsible for providing the input and feedback signals for the nosewheel steering system. By measuring the resistance using an ohmmeter, any discrepancies or faults in the potentiometer can be identified, which could be causing the NWS fail light to illuminate.

When the cargo and personnel doors close and lock, the open relay will de-energize. This means that power supply to the open relay will be cut off, causing it to deactivate.

The correct answer is APU/external power contactor (AEPC). The AEPC is responsible for selecting the auxiliary power unit (APU) or external power as the source to power the tie bus. The tie bus is a common electrical bus that connects different power sources and distributes power to various systems in an aircraft. The AEPC ensures that the appropriate power source is selected based on the operational requirements and availability of the APU and external power.

The maximum circuit resistance within a thermocouple circuit is 5 ohms. This is because a thermocouple generates a voltage based on the temperature difference between its two junctions. To accurately measure this voltage, the circuit resistance should be as low as possible to minimize any voltage drops across the circuit. A higher circuit resistance would result in a larger voltage drop, leading to inaccurate temperature measurements. Therefore, a maximum circuit resistance of 5 ohms is recommended for thermocouple circuits.