2A656 Aircraft Electrical And Environmental Systems Journeyman Volume 3

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Quizzes Created: 2 | Total Attempts: 259

Questions: 72 | Attempts: 138 | Updated: Mar 20, 2023

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2A656 Aircraft Electrical And Environmental Systems Journeyman Volume 3 - Quiz

Questions and Answers

1.

The constant speed drive (CSD) that is used to drive a 60/80 kilovolts amperes (kVA) generator has an output of approximately
- A.
  
  4,000 revolutions per minute
- B.
  
  6,000 rpm
- C.
  
  8,000 rpm
- D.
  
  10,000 rpm
Correct Answer
C. 8,000 rpm

Explanation
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.

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2.

In an AC power supply system, which component controls load division during parallel generator operation?
- A.
  
  Load controller
- B.
  
  Underspeed switch
- C.
  
  Constant speed drive
- D.
  
  Generator control unit
Correct Answer
A. Load controller

Explanation
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.

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3.

The under voltage activation point for the main generator in a volts alternating current (VAC) power supply system is
- A.
  
  93 [+/-3] VAC
- B.
  
  103 [+/-3] VAC
- C.
  
  115 [+/-2] VAC
- D.
  
  125 [+/-2] VAC
Correct Answer
B. 103 [+/-3] VAC

Explanation
The under voltage activation point for the main generator in a VAC power supply system is 103 [+/-3] VAC. This means that when the voltage drops below 103 VAC, the main generator will be activated to provide power. The +/-3 indicates a tolerance range, so the activation point can be anywhere between 100 VAC and 106 VAC. This ensures that the generator is not activated unnecessarily due to minor voltage fluctuations, but is triggered when there is a significant drop in voltage.

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4.

At what volts alternating current (VAC) range does the generator control unit in an AC power supply system maintain generator output?
- A.
  
  135 [+/-3] VAC
- B.
  
  125 [+/-3] VAC
- C.
  
  115 [+/-2] VAC
- D.
  
  105 [+/-2] VAC
Correct Answer
C. 115 [+/-2] VAC

Explanation
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.

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5.

In an AC power supply system, what component connects the 115/200 VAC main generator output to the main power buses?
- A.
  
  Bus tie lockout (BTL)
- B.
  
  Bus tie contactor (BTC)
- C.
  
  Generator Control Unit (GCU)
- D.
  
  Generator line contactor (GLC)
Correct Answer
D. Generator line contactor (GLC)

Explanation
The generator line contactor (GLC) is the component that connects the 115/200 VAC main generator output to the main power buses in an AC power supply system. This contactor is responsible for controlling the flow of electrical power from the generator to the buses, allowing the generated power to be distributed and utilized throughout the system.

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6.

Which emergency AC power system component connects the output of the emergency generator to the essential bus?
- A.
  
  Emergency power disconnect relay (EPDR)
- B.
  
  Emergency power interlock relay (EPIR)
- C.
  
  Emergency generator test switch (EGTS)
- D.
  
  Power fail relay (PFR)
Correct Answer
A. Emergency power disconnect relay (EPDR)

Explanation
The emergency power disconnect relay (EPDR) is the component that connects the output of the emergency generator to the essential bus. This relay is responsible for ensuring a seamless transfer of power from the generator to the essential bus in case of a power failure. It acts as a switch that disconnects the normal power source and connects the emergency generator to the essential bus, providing uninterrupted power supply during emergencies.

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7.

Which emergency AC power system component prevents the emergency generator from dropping off-line when the aircraft lands?
- A.
  
  Emergency power disconnect relay (EPDR)
- B.
  
  Emergency power interlock relay (EPIR)
- C.
  
  Emergency generator test switch (EGTS)
- D.
  
  Power fail relay (PFR)
Correct Answer
B. Emergency power interlock relay (EPIR)

Explanation
The emergency power interlock relay (EPIR) is the component that prevents the emergency generator from dropping off-line when the aircraft lands. This relay ensures that the emergency power supply remains connected and operational even during landing, providing continuous power in case of any power failures or emergencies. It acts as a safety measure to ensure that the emergency power system remains active and reliable during critical phases of flight, such as landing.

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8.

What is the minimum VAC requirement to energize the emergency power disconnect relay (EPDR)?
- A.
  
  90 VAC from A phase
- B.
  
  90 VAC from C phase
- C.
  
  93 VAC from A phase
- D.
  
  93 VAC from C phase
Correct Answer
D. 93 VAC from C pHase

Explanation
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.

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9.

What external power system component disconnects external power from the aircraft?
- A.
  
  Bus protection panel (BPP)
- B.
  
  Auxiliary power unit (APU)
- C.
  
  APU/External power contactor (AEPC)
- D.
  
  APU/external power disconnect contactor (AEDC)
Correct Answer
D. APU/external power disconnect contactor (AEDC)

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

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10.

The auxiliary source selected to power the tie bus in the APU is determined by the
- A.
  
  Lockout relay (LOR)
- B.
  
  Bus protection panel (BPP)
- C.
  
  APU/external power contactor (AEPC)
- D.
  
  APU/exernal power disconnect contactor (AEDC)
Correct Answer
C. APU/external power contactor (AEPC)

Explanation
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.

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11.

What relays connect the auxiliary power source to the aircraft buses?
- A.
  
  Bus tie connector (BTC)
- B.
  
  Bus protection panel (BPP)
- C.
  
  APU/external power contactor (AEPC)
- D.
  
  APU/extrernal power disconnect contactor (AEDC)
Correct Answer
A. Bus tie connector (BTC)

Explanation
The bus tie connector (BTC) is responsible for connecting the auxiliary power source to the aircraft buses. It serves as a relay that allows power to flow between different electrical buses in the aircraft. By connecting the auxiliary power source to the buses, the BTC ensures that power is distributed properly throughout the aircraft's electrical system.

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12.

During which troubleshooting step do you review the Air Force Technical Order (AFTO) form 781A?
- A.
  
  Learn normal system operation
- B.
  
  Define the descrepancy
- C.
  
  Limit the malfunction
- D.
  
  Take meter readings
Correct Answer
B. Define the descrepancy

Explanation
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.

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13.

The transformer rectifier units in a volts direct current (VDC) power system convert thee-phase 115 volts alternating current (VAC) into
- A.
  
  10 to 12 VDC
- B.
  
  26 to 31 VDC
- C.
  
  32 to 36 VDC
- D.
  
  52 to 56 VDC
Correct Answer
B. 26 to 31 VDC

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

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14.

In the direct current (DC) power supply system, the delta-wound secondaries of the internal transformer in the transformer rectifier (TR) unit are used to provide a more stable
- A.
  
  Current input
- B.
  
  Voltage input
- C.
  
  Current output
- D.
  
  Voltage output
Correct Answer
C. Current output

Explanation
The delta-wound secondaries of the internal transformer in the transformer rectifier (TR) unit are used to provide a more stable current output. This is because the delta configuration allows for better current regulation and reduces the effects of load fluctuations. By having a stable current output, the DC power supply system can ensure consistent and reliable power to the connected devices or equipment.

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15.

In the DC power supply system, the reverse current relays (RCR) deenergize when the potential at the
- A.
  
  GEN terminal is greater than the indicator terminal
- B.
  
  GEN terminal is less than the battery terminal
- C.
  
  GEN terminal is greater than the SW terminal
- D.
  
  BAT terminal is less than the SW terminal
Correct Answer
B. GEN terminal is less than the battery terminal

Explanation
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.

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16.

If the normal battery is supplying DC to the battery bus and emergency DC bus, your first step in troubleshooting is to
- A.
  
  Define the problem
- B.
  
  Take meter readings
- C.
  
  Know system operation
- D.
  
  Perform an operational check
Correct Answer
C. Know system operation

Explanation
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.

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17.

If the normal battery will not charge but the standby battery is OK, then you start taking meter readings at the
- A.
  
  No. 1 transformer rectifier (TR)
- B.
  
  No. 2 TR
- C.
  
  Standby battery relay
- D.
  
  Normal battery relay
Correct Answer
D. Normal battery relay

Explanation
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.

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18.

Which flight control system operates the disconnect clutch in the stabilized trim actuator assembly?
- A.
  
  Manual system
- B.
  
  Autopilot system
- C.
  
  Hydraulic system
- D.
  
  Electric power system
Correct Answer
A. Manual system

Explanation
The manual system operates the disconnect clutch in the stabilized trim actuator assembly. This means that the pilot can manually disconnect the clutch to override the system and make adjustments to the trim. The manual system provides a backup option in case the other systems fail or need to be overridden for any reason.

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19.

The aircraft write up states that the leading edge of the stabilizer does not move down when either horizontal stabilizer trim control switch is put to the NOSE UP position. Where is the best place to start taking meter readings?
- A.
  
  Check for 28 VDC between pins A and H, B and H, and G and H of the actuator connector plug.
- B.
  
  Check for 115 VAC between pins A and H, B and H, and G and H of the actuator connector plug.
- C.
  
  Check for 28 VDC at the up-limit switch with either of the horizontal stabilizer trim control switches actuated
- D.
  
  Check for 28 VDC at pin F of the actuator connector plug with either of the horizontal stabilizer trim control switches actuated.
Correct Answer
D. Check for 28 VDC at pin F of the actuator connector plug with either of the horizontal stabilizer trim control switches actuated.

Explanation
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.

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20.

Which component is used as an emergency means of controlling the aileron trim control circuit?
- A.
  
  Control stick grip trim switch
- B.
  
  Aileron trim control switch
- C.
  
  Trim selector switch
- D.
  
  Auxiliary trim switch
Correct Answer
D. Auxiliary trim switch

Explanation
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.

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21.

When the stick grip trim selector switch is moved to the left, the position of the aircraft left aileron is
- A.
  
  Up (left wing up)
- B.
  
  Up (left wing down)
- C.
  
  Down (right wing up)
- D.
  
  Down (right wing down)
Correct Answer
B. Up (left wing down)

Explanation
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)."

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22.

After you release the stick grip trim selector switch, the trim indicator light
- A.
  
  Extinguishes
- B.
  
  Remains illuminated
- C.
  
  Flashes on and off briefly
- D.
  
  Remains on throughout the full cycle of the ailerons
Correct Answer
A. Extinguishes

Explanation
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.

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23.

Before operating the aileron trim system, you must supply power to
- A.
  
  Both the electrical and hydraulic systems
- B.
  
  The electrical system
- C.
  
  The hydraulic system
- D.
  
  The bleed air system
Correct Answer
A. Both the electrical and hydraulic systems

Explanation
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.

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24.

When you achieve maximum aileron travel, you should see the aileron takeoff trim indicator lights
- A.
  
  Change from red to green
- B.
  
  Turn on
- C.
  
  Go out
- D.
  
  Flash
Correct Answer
D. Flash

Explanation
When you achieve maximum aileron travel, the aileron takeoff trim indicator lights should flash. This indicates that the ailerons have reached their maximum deflection and are functioning properly. The flashing of the lights is a visual indication for the pilot that the ailerons are in the correct position for takeoff.

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25.

The slotted wing flaps are used on heavy aircraft and
- A.
  
  Extended forward and downward
- B.
  
  Form a slot between the flap of the wing
- C.
  
  Increase the chamber or curvature of the wing
- D.
  
  Lowers the trailing edge to about 40 degrees below its retracted (UP) position
Correct Answer
B. Form a slot between the flap of the wing

Explanation
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.

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26.

The three positions for the speedbrake switch are
- A.
  
  Open, hold, and land
- B.
  
  Open, hold, and retract
- C.
  
  Open, release, and retract
- D.
  
  Actuate, hold, and retract
Correct Answer
B. Open, hold, and retract

Explanation
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.

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27.

After replacing the 43 degree position switch on the spreedbrake system, your next and final step is to
- A.
  
  Ohms check the switch
- B.
  
  Voltage check the switch
- C.
  
  Perform an operational check
- D.
  
  Turn in all tools and test equipment
Correct Answer
C. Perform an operational check

Explanation
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.

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28.

The operation of the air compressor in an engine fuel-air starter system is controlled by
- A.
  
  The ground crew
- B.
  
  A pressure switch
- C.
  
  A centrifugal switch
- D.
  
  The pilot using an on-off switch
Correct Answer
B. A pressure switch

Explanation
The operation of the air compressor in an engine fuel-air starter system is controlled by a pressure switch. This switch is responsible for monitoring the pressure levels in the system and activating the air compressor when the pressure falls below a certain threshold. Once the pressure reaches the desired level, the pressure switch will deactivate the compressor. This ensures that the engine fuel-air mixture is properly pressurized for efficient starting. The pressure switch eliminates the need for manual control by the ground crew or the pilot, making the system more automated and reliable.

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29.

When a pneumatic starter reaches maximum speed, the ground circuit to the starter relay is opened by
- A.
  
  The pilot valve
- B.
  
  A pressure switch
- C.
  
  Centrifugal switch
- D.
  
  The on-off switch in the cock-pit
Correct Answer
C. Centrifugal switch

Explanation
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.

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30.

The VAC power requirement for operation of an AC ignition system is
- A.
  
  115 VAC, 60 hertz
- B.
  
  208 VAC, 60 hertz
- C.
  
  115 VAC, 400 hertz
- D.
  
  208 VAC, 400 hertz
Correct Answer
C. 115 VAC, 400 hertz

Explanation
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.

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31.

Once the voltage goes through the transformer in the direct current ignition system, it is then applied to the
- A.
  
  Igniter plug
- B.
  
  Vibrator unit
- C.
  
  Small generator
- D.
  
  Step up transformer
Correct Answer
A. Igniter plug

Explanation
In a direct current ignition system, the voltage is first passed through the transformer. After going through the transformer, the voltage is then applied to the igniter plug. The igniter plug is responsible for creating a spark that ignites the fuel-air mixture in the combustion chamber of an engine. Therefore, it makes sense that the correct answer is the igniter plug.

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32.

The engine ignition circuit for the B model of C-135 aircraft does not contain
- A.
  
  A throttle switch
- B.
  
  Two ignition units
- C.
  
  Two spark igniters
- D.
  
  An ignition control-and-start switch
Correct Answer
A. A throttle switch

Explanation
The engine ignition circuit for the B model of C-135 aircraft does not contain a throttle switch. The throttle switch is responsible for controlling the flow of fuel and air mixture to the engine, but in this particular model, it is not included in the ignition circuit. The ignition circuit consists of two ignition units, two spark igniters, and an ignition control-and-start switch, which are all essential components for starting and operating the engine.

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33.

The gas turbine compressor (GTC) is stopped manually by turning the control switch to OFF or by puling the GTC fire emergency handle and causing the
- A.
  
  Fuel control relay to deengergize
- B.
  
  Fuel control relay to energize
- C.
  
  GTC fuel relay to de-energize
- D.
  
  GTC fuel relay to energize
Correct Answer
A. Fuel control relay to deengergize

Explanation
The correct answer is "fuel control relay to deengergize". When the gas turbine compressor (GTC) is manually stopped, the fuel control relay is deenergized. This means that the power supply to the fuel control relay is cut off, causing it to stop functioning. As a result, the flow of fuel to the GTC is interrupted, leading to the shutdown of the GTC.

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34.

What is the last thing you must do before completing a troubleshooting cycle?
- A.
  
  Repair the defective item
- B.
  
  Bench check any new parts
- C.
  
  Perform an operational check
- D.
  
  Replace any malfunction part
Correct Answer
C. Perform an operational check

Explanation
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.

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35.

What type of fuel system valves link to the left wing and aft body tanks to the right wing, mid body, and forward body tanks?
- A.
  
  Crossfeed
- B.
  
  Fire shutoff
- C.
  
  Interconnect
- D.
  
  Fuel-level control
Correct Answer
C. Interconnect

Explanation
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.

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36.

How does the auxiliary fuel tank indicating system give a no-flow indication?
- A.
  
  Steady red light
- B.
  
  Flashing red light
- C.
  
  Stead amber light
- D.
  
  Flashing amber light
Correct Answer
D. Flashing amber light

Explanation
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.

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37.

How many boost pumps are there in main fuel tank number 1?
- A.
  
  Two
- B.
  
  Three
- C.
  
  Four
- D.
  
  Five
Correct Answer
C. Four

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

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38.

The output of gallons per min (GPM) of the scavenge pumps is approximately
- A.
  
  1/2 gpm
- B.
  
  1 gpm
- C.
  
  2 gpm
- D.
  
  3 gpm
Correct Answer
C. 2 gpm

Explanation
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.

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39.

To begin troubleshooting a fuel pump inoperative writeup; you would know the system, and then
- A.
  
  Perform an operational check
- B.
  
  Limit the malfunction
- C.
  
  Take meter readings
- D.
  
  Replace a bad pump
Correct Answer
A. Perform an operational check

Explanation
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.

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40.

Thermal switches in a fire warning system are normally connected in
- A.
  
  Series with each other
- B.
  
  Series with the power source and with the warning light
- C.
  
  Parallel with the power source and in serious with each other
- D.
  
  Parallel with the each other and in series with the warning light
Correct Answer
D. Parallel with the each other and in series with the warning light

Explanation
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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41.

Frequently used in fire warning systems, the fire detector that has a high-nickel steel rod located along the center line of a stainless steel tube assembly is called
- A.
  
  A photoconductive cell
- B.
  
  An iron fireman switch
- C.
  
  A FENWAL switch
- D.
  
  A continuous cable
Correct Answer
B. An iron fireman switch

Explanation
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.

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42.

The maximum circuit resistance within a thermocouple circuit is
- A.
  
  Infinity
- B.
  
  5 ohms
- C.
  
  50 ohms
- D.
  
  500 ohms
Correct Answer
B. 5 ohms

Explanation
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.

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43.

Amplifiers used in the photoelectric fire detector system are sensitive only to
- A.
  
  Sunlight
- B.
  
  Light emitted from flash lights
- C.
  
  Signals with a frequency between 7 and 60 hz
- D.
  
  Signals with a frequency between 60 and 160 hz
Correct Answer
C. Signals with a frequency between 7 and 60 hz

Explanation
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.

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44.

The direct currect (DC) voltage that is supplied to the lights in a photoelectric circuit is pulsed at a rate of
- A.
  
  10 hz
- B.
  
  100 hz
- C.
  
  200 hz
- D.
  
  400 hz
Correct Answer
A. 10 hz

Explanation
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. This pulsing of the voltage allows for precise control over the lights and can be used for various applications such as dimming or flashing effects.

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45.

In a continuous loop fire detector system, the shield of the continuous loop is constructed of
- A.
  
  Soft iron
- B.
  
  Aluminum
- C.
  
  Malleable tin
- D.
  
  INCONEL
Correct Answer
D. INCONEL

Explanation
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.

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46.

For the master caution lamp in the master caution system to illuminate,
- A.
  
  Transistor Q1 must remain at the CUTOFF position
- B.
  
  Transistor Q2 must remain at the CUTOFF position
- C.
  
  Controller rectifier SCR2 must forward bias transistor Q2
- D.
  
  Controller rectifier SCR2 conducts current to forward bias transistor Q2
Correct Answer
D. Controller rectifier SCR2 conducts current to forward bias transistor Q2
47.

When a fault occurs, the individual caution lamps n the master caution system remains on until
- A.
  
  The shutter closes
- B.
  
  The fault is corrected
- C.
  
  The reset circuit is energized
- D.
  
  Another system fault is detected
Correct Answer
C. The reset circuit is energized

Explanation
The individual caution lamps in the master caution system remain on until the reset circuit is energized. This means that once a fault occurs, the caution lamps will continue to stay on until the reset circuit is activated. This allows for the fault to be acknowledged and cleared before the caution lamps can be reset and turned off.

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48.

When the cargo and personnel doors close and lock, the door-
- A.
  
  Open relay will energize
- B.
  
  Open relay will de-energize
- C.
  
  Position relay will energize
- D.
  
  Position relay will de-energize
Correct Answer
B. Open relay will de-energize

Explanation
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.

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49.

When all systems are configured for flight, the pilot or copilot must press the
- A.
  
  Aileron roll trim lever
- B.
  
  Autopilot engage lever
- C.
  
  Hydraulic pitch trim levers
- D.
  
  Thrust reverser locked lever
Correct Answer
C. Hydraulic pitch trim levers

Explanation
The hydraulic pitch trim levers are the correct answer because when all systems are configured for flight, the pilot or copilot must press these levers to adjust the pitch trim of the aircraft. This helps in maintaining the desired pitch attitude and stability during flight. The aileron roll trim lever is used to adjust the roll trim, the autopilot engage lever is used to engage the autopilot system, and the thrust reverser locked lever is used to lock the thrust reverser during landing. However, in this scenario, it is specifically mentioned that the correct action to be taken is related to the hydraulic pitch trim levers.

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50.

You determine the bulbs are good and the circuit breakers are working for a typical take-off warning system problem:you then check for 28 volts direct current (VDC) at the sockets of the take-off lights and you do not find voltage. Where is the next place you should check?
- A.
  
  Spoiler controls take-off warning relay contacts
- B.
  
  Hydraulic system No. 3 relay contacts
- C.
  
  Stabilizer trim relay contacts
- D.
  
  Touch down relay contacts
Correct Answer
A. Spoiler controls take-off warning relay contacts

Explanation
The next place to check would be the spoiler controls take-off warning relay contacts. If there is no voltage at the sockets of the take-off lights, it suggests that there may be an issue with the relay contacts that control the take-off warning system. By checking the spoiler controls take-off warning relay contacts, you can determine if there is a problem with the relay that is preventing the voltage from reaching the sockets.

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Quiz Review Timeline +

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Current Version
Mar 20, 2023

Quiz Edited by
ProProfs Editorial Team
May 27, 2015

Quiz Created by
Mirand Rudd

2A656 Aircraft Electrical And Environmental Systems Journeyman Volume 3

The constant speed drive (CSD) that is used to drive a 60/80 kilovolts amperes (kVA) generator has an output of approximately

In an AC power supply system, which component controls load division during parallel generator operation?

The under voltage activation point for the main generator in a volts alternating current (VAC) power supply system is

At what volts alternating current (VAC) range does the generator control unit in an AC power supply system maintain generator output?

In an AC power supply system, what component connects the 115/200 VAC main generator output to the main power buses?

Which emergency AC power system component connects the output of the emergency generator to the essential bus?

Which emergency AC power system component prevents the emergency generator from dropping off-line when the aircraft lands?

What is the minimum VAC requirement to energize the emergency power disconnect relay (EPDR)?

What external power system component disconnects external power from the aircraft?

The auxiliary source selected to power the tie bus in the APU is determined by the

What relays connect the auxiliary power source to the aircraft buses?

During which troubleshooting step do you review the Air Force Technical Order (AFTO) form 781A?

The transformer rectifier units in a volts direct current (VDC) power system convert thee-phase 115 volts alternating current (VAC) into

In the direct current (DC) power supply system, the delta-wound secondaries of the internal transformer in the transformer rectifier (TR) unit are used to provide a more stable

In the DC power supply system, the reverse current relays (RCR) deenergize when the potential at the

If the normal battery is supplying DC to the battery bus and emergency DC bus, your first step in troubleshooting is to

If the normal battery will not charge but the standby battery is OK, then you start taking meter readings at the

Which flight control system operates the disconnect clutch in the stabilized trim actuator assembly?

The aircraft write up states that the leading edge of the stabilizer does not move down when either horizontal stabilizer trim control switch is put to the NOSE UP position. Where is the best place to start taking meter readings?

Which component is used as an emergency means of controlling the aileron trim control circuit?

When the stick grip trim selector switch is moved to the left, the position of the aircraft left aileron is

After you release the stick grip trim selector switch, the trim indicator light

Before operating the aileron trim system, you must supply power to

When you achieve maximum aileron travel, you should see the aileron takeoff trim indicator lights

The slotted wing flaps are used on heavy aircraft and

The three positions for the speedbrake switch are

After replacing the 43 degree position switch on the spreedbrake system, your next and final step is to

The operation of the air compressor in an engine fuel-air starter system is controlled by

When a pneumatic starter reaches maximum speed, the ground circuit to the starter relay is opened by

The VAC power requirement for operation of an AC ignition system is

Once the voltage goes through the transformer in the direct current ignition system, it is then applied to the

The engine ignition circuit for the B model of C-135 aircraft does not contain

The gas turbine compressor (GTC) is stopped manually by turning the control switch to OFF or by puling the GTC fire emergency handle and causing the

What is the last thing you must do before completing a troubleshooting cycle?

What type of fuel system valves link to the left wing and aft body tanks to the right wing, mid body, and forward body tanks?

How does the auxiliary fuel tank indicating system give a no-flow indication?

How many boost pumps are there in main fuel tank number 1?

The output of gallons per min (GPM) of the scavenge pumps is approximately

To begin troubleshooting a fuel pump inoperative writeup; you would know the system, and then

Thermal switches in a fire warning system are normally connected in

Frequently used in fire warning systems, the fire detector that has a high-nickel steel rod located along the center line of a stainless steel tube assembly is called

The maximum circuit resistance within a thermocouple circuit is

Amplifiers used in the photoelectric fire detector system are sensitive only to

The direct currect (DC) voltage that is supplied to the lights in a photoelectric circuit is pulsed at a rate of

In a continuous loop fire detector system, the shield of the continuous loop is constructed of

For the master caution lamp in the master caution system to illuminate,

When a fault occurs, the individual caution lamps n the master caution system remains on until

When the cargo and personnel doors close and lock, the door-

When all systems are configured for flight, the pilot or copilot must press the

You determine the bulbs are good and the circuit breakers are working for a typical take-off warning system problem:you then check for 28 volts direct current (VDC) at the sockets of the take-off lights and you do not find voltage. Where is the next place you should check?