B757 Electrical

Front 1

31. What occurs if a Bus Tie switch is manually opened?
A. Only flight instrument switching will not occur
B. Flight instrument switching and DC bus tie closure will not occur
C. Generator drive disconnects

Back 1

B. Flight instrument switching and DC bus tie closure will not occur

Front 2

32. What does the APU Generator OFF light and APU GEN OFF EICAS message indicate?
A. APU drive disconnected manually
B. Ground handling bus powered
C. APU is running and the generator breaker is open because of a fault or the APU Generator
switch is selected OFF

Back 2

C. APU is running and the generator breaker is open because of a fault or the APU Generator
switch is selected OFF

Front 3

33. What items are powered from the ground service bus?
A. Two main battery chargers, aft #1 E/E cooling fan, left forward fuel pump and main deck
cargo lighting
B. Two main battery chargers, aft #1 E/E cooling fan, right aft fuel pump and main deck
cargo lighting
C. Two main battery chargers, aft #2 E/E cooling fan, left forward fuel pump and lower
forward and aft cargo lighting

Back 3

A. Two main battery chargers, aft #1 E/E cooling fan, left forward fuel pump and main deck
cargo lighting

Front 4

34. Standby Power selector in AUTO, if left main DC is lost, what occurs?
A. Ground handling bus powers standby DC
B. HDG is powered automatically
C. The battery or battery charger immediately takes over powering the battery bus and
standby DC

Back 4

C. The battery or battery charger immediately takes over powering the battery bus and
standby DC

Front 5

35. Standby Power selector in AUTO, if left main AC is lost, what occurs?
A. The right main DC bus powers the left main DC bus, standby DC bus and standby AC bus
through the static inverter
B. The right main DC bus powers the left main DC bus, standby AC bus and standby DC bus
through the static inverter
C. The left transfer bus powers the left main DC bus, standby DC bus and standby AC bus
through the ground handling bus

Back 5

A. The right main DC bus powers the left main DC bus, standby DC bus and standby AC bus
through the static inverter

Front 6

36. What are the possible power sources to the center busses?
A. Left main AC/DC or standby/battery system
B. Ground handling bus
C. F/O's flight instrument transfer bus

Back 6

A. Left main AC/DC or standby/battery system

Front 7

757 37. What busses are powered if both main AC busses fail?
A. Hot battery bus, battery bus and standby AC/DC busses
B. Left and right transfer busses, standby AC/DC busses and the hot battery bus
C. Standby AC/DC busses, battery bus DC, hot battery bus and the essential bus

Back 7

A. Hot battery bus, battery bus and standby AC/DC busses

Front 8

757 38. With the APU supplying both electrical and pneumatics, what occurs as the second engine is
started as it relates to utility bus load shed?
A. Both utility busses shed
B. No utility bus sheds
C. Only the respective utility bus sheds

Back 8

C. Only the respective utility bus sheds

Front 9

757 39. With the APU supplying both electrical and pneumatics, what occurs as the first engine is
started as it relates to utility bus load shed?
A. No load shedding occurs
B. Both utility busses shed
C. Only the respective utility bus sheds

Back 9

B. Both utility busses shed

Front 10

757 40. What is the normal source of power to the Captain's flight instruments?
A. Right main AC bus
B. Ground service bus
C. Left main AC bus

Back 10

C. Left main AC bus

Front 11

767 41. If both left and right AC busses are unpowered, what is the backup power source?
A. Air Demand Pump (ADP) only
B. Hydraulic Driven Generator (HDG)
C. Ground handling bus

Back 11

B. Hydraulic Driven Generator (HDG)

Front 12

767 42. Which busses are powered from the Hydraulic Driven Generator (HDG)?
A. Standby AC/DC busses, hot battery bus, battery bus DC, left and right transfer busses,
and Captain and First Officer's flight instrument transfer busses
B. Standby AC bus, ground handling bus, hot battery bus, left and right transfer busses
and Captain's flight instrument transfer bus
C. Standby AC/DC busses, hot battery bus, battery bus DC, left and right transfer busses
and Captain's flight instrument transfer bus

Back 12

C. Standby AC/DC busses, hot battery bus, battery bus DC, left and right transfer busses
and Captain's flight instrument transfer bus

Front 13

767 43. What is the power source for the Hydraulic Driven Generator (HDG)?
A. Hot battery bus
B. Air Demand Pump (ADP)
C. Ground service bus

Back 13

B. Air Demand Pump (ADP)

Front 14

767 44. APU supplying both electrical and pneumatics, what occurs as the second engine is started as
it relates to utility bus load shed?
A. Respective utility bus sheds
B. Both utility busses shed
C. There is no load shedding of utility busses during engine start

Back 14

A. Respective utility bus sheds

Front 15

767 45. The loss of which bus or busses will cause the Hydraulic Driven Generator (HDG) to operate?
A. The left main AC bus
B. Both AC and DC standby busses
C. The left and right main AC busses

Back 15

C. The left and right main AC busses

Front 16

1. What does the Engine Generator OFF light and EICAS message indicate?
A. Valve is open
B. Generator control breaker is open
C. Ground handling bus not powered

Back 16

B. Generator control breaker is open

Front 17

2. Cycling the Generator Control switch has what effect?
A. Audio Select Panel degrades
B. Ground handling bus powered in flight
C. Arms generator breaker to close automatically when generator power is available and
resets fault trip circuitry

Back 17

C. Arms generator breaker to close automatically when generator power is available and
resets fault trip circuitry

Front 18

3. What occurs if the Generator Drive Disconnect switch is pushed?
A. Approach mode is disabled
B. Disconnects generator and drive from engine and requires maintenance to reset
C. Allows the bus tie system to power left AC and DC, and the battery bus DC

Back 18

B. Disconnects generator and drive from engine and requires maintenance to reset

Front 19

4. What does the BUS OFF light and associated EICAS message indicate?
A. Respective AC bus is unpowered
B. ADP and HDG are inoperative
C. Ground handling bus is unpowered

Back 19

A. Respective AC bus is unpowered

Front 20

5. What are the priorities for powering the main AC busses?
A. Hydraulic Driven Generator (HDG), ground handling bus and ground service bus
B. Respective engine-driven generator, APU and opposite engine-driven generator
C. Respective engine-driven generator, ground handling bus and opposite engine-driven
generator

Back 20

B. Respective engine-driven generator, APU and opposite engine-driven generator

Front 21

6. What three conditions shed the utility busses on a B757?
A. Main Cargo Alert switch selected, power transfer and loss of the left engine-driven
generator
B. Engine start, generator loss and standby AC loss
C. Engine start, generator loss and overload

Back 21

C. Engine start, generator loss and overload

Front 22

7. When does the generator load shed protection arm regarding a generator loss?
A. Aircraft in flight or both thrust levers moved into the takeoff range
B. Following a generator failure
C. Power transfer

Back 22

A. Aircraft in flight or both thrust levers moved into the takeoff range

Front 23

8. Is it possible to manually reset the utility bus following an engine-driven generator loss in flight?
A. No, utility busses require two operating generators to automatically reset
B. Yes, only one generator required for utility bus reset
C. No, utility busses require the ground handling bus for reset

Back 23

A. No, utility busses require two operating generators to automatically reset

Front 24

9. During a multi-autopilot approach, APU operating, what occurs above or below 200' RA
following a failure of one engine-driven generator?
A. Electrical system remains isolated and APU powers ground handling bus
B. APU automatically powers the bus associated with the generator failure and electrical
system remains isolated
C. APU automatically powers the bus associated with the generator failure and ground
handling bus remains powered

Back 24

B. APU automatically powers the bus associated with the generator failure and electrical
system remains isolated

Front 25

10. What does the External Power AVAIL light indicate?
A. External power is plugged in and power is acceptable
B. External power is plugged in and power is not acceptable
C. External power is not plugged in and power is not acceptable

Back 25

A. External power is plugged in and power is acceptable

Front 26

11. What are the power sources for the ground handling bus?
A. Engine-driven generators, external power, and ground service bus
B. External power or APU
C. External power or right engine-driven generator

Back 26

B. External power or APU

Front 27

12. What is the normal power source for the ground service bus?
A. Right main AC
B. Left main AC
C. Ground handling bus in flight

Back 27

A. Right main AC

Front 28

13. What does the Battery DISCH light and MAIN BAT DISCH EICAS message indicate?
A. Battery is discharging
B. Battery is being charged
C. Left AC bus failure

Back 28

A. Battery is discharging

Front 29

14. What does the Standby Power Bus OFF light and STANDBY BUS OFF EICAS message
indicate?
A. HDG failed to operate
B. Standby AC and/or DC bus powered with Standby Power selector in AUTO
C. Standby AC and/or DC bus not powered and/or Standby Power selector in OFF

Back 29

C. Standby AC and/or DC bus not powered and/or Standby Power selector in OFF

Front 30

15. Which of the following will cause the Generator DRIVE light to illuminate?
A. Generator drive oil filter is clogged
B. Generator drive has overloaded
C. Generator drive oil temperature is high

Back 30

C. Generator drive oil temperature is high

Front 31

16. A Generator DRIVE light can indicate low generator drive oil pressure. True or False?
A. True
B. False

Back 31

A. True

Front 32

17. What can power a utility bus?
A. Respective main AC bus only
B. Respective main AC or opposite utility bus only
C. Respective main AC, opposite utility or AC bus

Back 32

A. Respective main AC bus only

Front 33

18. In flight, the left engine is shut down. What electrical busses are lost?
A. Only the left utility bus
B. Both utility busses
C. Both utility busses and the left DC bus

Back 33

B. Both utility busses

Front 34

19. If the right IDG fails above 200 ft with the APU operating, what occurs?
A. The right bus tie breaker closes, allowing the right AC bus to remain powered by the APU
B. Both BUS OFF lights and associated EICAS messages annunciate
C. HDG operates to protect the B757 main AC busses

Back 34

A. The right bus tie breaker closes, allowing the right AC bus to remain powered by the APU

Front 35

20. What busses power the autopilots during a coupled ILS approach (autoland) after selecting
APP (approach switch)?
A. Utility bus powers left and right autopilot and ground service bus powers the center
autopilot
B. Left main AC powers left autopilot, right main AC powers right autopilot and
standby/battery powers center autopilot
C. Left main AC powers left and center autopilot and standby/battery powers right autopilot

Back 35

B. Left main AC powers left autopilot, right main AC powers right autopilot and
standby/battery powers center autopilot

Front 36

21. How are both standby busses powered when the Standby Power selector is positioned to BAT?
A. Standby busses are powered by the ground service bus
B. Standby busses are powered from the main battery
C. Standby busses are unpowered

Back 36

B. Standby busses are powered from the main battery

Front 37

22. What occurs if Standby Power selector is positioned to BAT?
A. Disconnects main AC and DC power from the standby system
B. Disconnects hot battery bus and main AC/DC from the standby power system
C. Allows battery to power main AC busses

Back 37

A. Disconnects main AC and DC power from the standby system

Front 38

23. What does the AC Bus ISLN light indicate?
A. Ground handling bus is unpowered
B. Indicates fault or Bus Tie switch is OFF
C. Commands bus tie system to power HDG

Back 38

B. Indicates fault or Bus Tie switch is OFF

Front 39

24. What does the Utility Bus OFF light and associated EICAS message indicate?
A. Utility bus unpowered
B. Galley powered
C. Standby Power selector in BAT position

Back 39

A. Utility bus unpowered

Front 40

25. What is the purpose of the bus tie system?
A. Allows a bus to be shorted
B. Allows ground handling bus to power ground service bus via P6 Panel
C. Allows the right and left main AC busses to be isolated or connected

Back 40

C. Allows the right and left main AC busses to be isolated or connected

Front 41

26. What does the Generator DRIVE light and L or R GEN DRIVE EICAS message indicate?
A. No maintenance required
B. The IDG has already been disconnected from the drive
C. Low oil pressure or high oil temperature within the IDG

Back 41

C. Low oil pressure or high oil temperature within the IDG

Front 42

27. What components are powered from the ground handling bus?
A. Captain's flight instrument transfer bus, left AC/DC and right DC through the inverter
B. Lower cargo lights, refueling features and cargo handling
C. Left FMC and both clocks on the ground with OVRD selected

Back 42

B. Lower cargo lights, refueling features and cargo handling

Front 43

28. When is the ground handling bus powered?
A. In flight
B. Only on the ground
C. Either on the ground or in flight

Back 43

B. Only on the ground

Front 44

29. When is the ground service bus powered?
A. In flight only
B. Only on the ground
C. Either on the ground or in flight

Back 44

C. Either on the ground or in flight

Front 45

30. What occurs if a Bus Tie switch is manually opened?
A. Ground handling bus is powered
B. HDG automatically powers respective main AC/DC
C. Flight instrument switching will not occur

Back 45

C. Flight instrument switching will not occur