Electrical (FM: 6.60) Flashcards
757/767: According to the graphic, the R UTILITY BUS OFF light is illuminated. What is the cause for its illumination?
a) The DC bus tie breaker is closed
b) The center number 2 ELEC HYD pump sheds
c) One or both galley busses shed or are unpowered
d) The associated utility bus is unpowered
D) The associated utility bus is unpowered
757/767: According to the graphic, the L GEN DRIVE DISC DRIVE light is illuminated. What is the cause for its illumination?
a) The IDG has automatically disconnected
b) Low oil temperature in the IDG
c) High oil pressure in the IDG
d) High oil temperature or low oil pressure
D) High oil temperature or low oil pressure
757/767: According to the graphic, the STBY POWER OFF light is illuminated. The aircraft is in flight. Which bus may not be powered?
a) HOT BAT bus
b) Left main DC bus
c) STANDBY AC bus
d) Right Transfer bus
C) STANDBY AC bus
757/767: According to the graphic, what is providing power to the standby busses?
a) Left main AC and DC
b) Left main DC bus
c) Right main AC and DC
d) Right Transfer bus
A) Left main AC and DC
757/767: When external power is connected, which bus is automatically powered?
a) Ground handling bus
b) Ground service bus
c) STBY AC bus
d) STBY DC bus
A) Ground handling bus
757/767: When the associated AC bus tie breaker is armed for automatic operation, the AC busses are powered according to the following system priorities:
a) Opposite Engine generator, associated Engine generator then APU generator
b) Associated Engine generator, APU generator then opposite Engine Generator
c) APU generator, associated Engine generator then opposite Engine generator
d) AC priority is not set when the BUS TIE switches are in AUTO
B) Associated Engine generator, APU generator then opposite Engine Generator
757/767: As the first engine is started with APU supplying electrical and pneumatic power, what load shed occurs?
a) Only the respective utility bus load sheds
b) Only the respective utility bus and all galley busses load shed
c) Both utility and all galley busses load shed
d) The utility busses remain powered but all the galley busses load shed
C) Both utility and all galley busses load shed
757 (as installed)/767: During flight, the Hydraulic Motor Generator (HMG) automatically starts and supplies AC power:
a) When the left hydraulic system pressure drops below a preset level
b) When the center and right hydraulic systems fail
c) When the HMG PWR switch is selected to ON
d) When primary AC power is lost on both main AC busses
D) When primary AC power is lost on both main AC busses
9) 757/767: The center busses transfer from the left main busses directly to the static inverter and the hot battery bus when:
a) At least two generators are operating and three autopilots are armed for an autoland approach
b) The right main AC bus fails during a coupled approach
c) Any one generator is operating and any two autopilots armed for an autoland approach
d) There is a failure of the left main AC bus and the airplane is above 200 feet RA
A) At least two generators are operating and three autopilots are armed for an autoland approach
757/763: On a three autopilot approach with a LAND 3 indication, what will the ASA indicate if an engine-driven generator is lost below 200 feet AGL without the APU running?
a) NO AUTOLAND
b) LAND 2 / NO LAND 3
c) LAND 2
d) LAND 3
D) LAND 3
757 (as installed): Once commanded to operate, are there limitations associated with how long the HMG can run?
a) Yes, 60 minutes or when power is restored to both Main AC busses
b) No, The HMG has no time limit
c) Yes, 30 minutes or when power is restored to the HOT BAT bus
d) Yes, 90 minutes is the maximum operating time
B) No, The HMG has no time limit
757/767: According to the graphic, what is providing power to the Ground Handling bus?
a) External power
b) An engine generator if operating on the ground
c) APU
d) The APU generator or an Engine generator if operating in flight
A) External power
The main aircraft battery and the APU battery are connected to their own respective battery chargers. Both battery chargers are powered by the:
a) Right Transfer bus on the ground or airborne
b) Ground service bus on the ground or airborne
c) Ground handling bus while airborne
d) BAT bus on the ground or airborne
B) Ground service bus on the ground or airborne
757/767: The Integrated Drive Generator (IDG) oil is cooled by:
a) A dedicated electric cooler powered by the STBY AC bus
b) A hydraulic / oil heat exchanger located in the right fuel tank (757) and left fuel tank (767)
c) A dedicated electric cooler powered by the main AC TIE bus
d) A fuel/oil heat exchanger
D) A fuel/oil heat exchanger
757/767: The main DC electrical system is powered:
a) Directly from the battery when the battery charger is available and supplying power
b) Directly from the associated engine DC generator
c) Directly from the battery bus
d) From the associated AC system through a transformer rectifier unit
D) From the associated AC system through a transformer rectifier unit
753/764: During HMG operations, what is the status of the IRUs?
a) After 5 minutes, the left and center IRU’s are no longer powered
b) Only the right IRU remains powered
c) Captains RDMI switches to the left IRU
d) All three IRU’s remain powered
D) All three IRU’s remain powered
752 (as installed)/763: HMG operation automatically switches the Captain’s RDMI to:
a) The center IRU
b) The right IRU
c) The left IRU
d) Any available IRU
A) The center IRU
757/767: In the case of a generator overload, which busses automatically load shed?
a) Only galley busses
b) Only utility busses
c) Both utility and galley busses
d) Associated utility and galley busses
D) Associated utility and galley busses
757/767: The ground service bus is normally powered by the:
a) Hot battery
b) Right main AC
c) Left main AC
d) Right utility
B) Right main AC
767: The left recirculation fan is powered by the:
a) Right utility
b) Right main AC
c) Standby AC
d) Left utility
D) Left utility
757/767: Either UTILITY bus has load shed due to a generator overload. What is required to restore power to the bus?
a) The crew must manually reset the switch
b) The bus cannot be reset and will remain unpowered
c) The bus will automatically reset when another AC power source is selected on
d) The bus can be reset by moving the associated BUS TIE out of AUTO
A) The crew must manually reset the switch
757 (as installed)/763: If primary AC power is lost on both main AC busses during flight, the HMG automatically starts and supplies AC power to the:
a) Standby busses only
b) Left and right AC transfer busses, standby AC bus, and Captains flight instrument transfer bus
c) Left and right main AC busses only
d) Standby flight instrument busses only
B) Left and right AC transfer busses, standby AC bus, and Captains flight instrument transfer bus
752/763: According to the graphic, which electrical busses are still being powered?
a) Battery and utility busses
b) Battery and standby busses
c) Battery, hot battery and STBY busses
d) Battery, left and right main DC busses
C) Battery, hot battery and STBY busses
757/767: According to the graphic, the DISCH light is illuminated. The main aircraft battery:
a) Is no longer powering the hot battery bus
b) Is operating normally
c) Is not being used
d) Is discharging
D) Is discharging
757/767: According to the graphic, the BUS TIE ISLN light is illuminated. This occurs when:
a) The bus tie breaker is closed due to a fault
b) AC power has been lost to the associated bus
c) The AC bus tie breaker is open due to a fault
d) DC power has been lost to the associated bus
C) The AC bus tie breaker is open due to a fault
757/767: What is the cause for the standby power bus off light to illuminate?
A) Battery and hot battery busses not powered
B) Standby AC, Standby DC, and/or the battery busses is not powered
C) Standby DC and left main DC buses not powered
D) Standby AC and right main AC busses not powered
B) Standby AC, Standby DC, and/or the battery busses is not powered
