Electrical Flashcards
The Bus Power Control Units (BPCU) provide dynamic electrical load management when the airplane is operating on any available electrical power source.
A. True.
B. False.
A. True
If the permanent magnet alternator for the left engine EEC is not available, the EEC receives power from the:
A. F/O’s flight instrument bus.
B. 28v DC system and main battery.
C. Captain’s flight instrument bus.
D. Airplane’s115V ac system.
D. Airplane’s115V ac system.
When starting an engine using external power to energize the starters, a minimum of two electrical sources are required. One of these MUST be AFT external power.
A. True.
B. False.
B. False
The aft external power system can assist the forward system when starting the right engine first. To receive the benefit of the aft power source, both forward power sources must also be connected and the right engine must be started first.
The ground handling mode is powered __ if no other power source is available.
A. Automatically when both forward external power sources are in use (ON)
B. Automatically when either FWD external power is connected (AVAIL)
C. Only if the AFT external power is connected (AVAIL)
D. The battery switch is ON
B. Automatically when either FWD external power is connected (AVAIL)
The generator drive may disconnect automatically:
A. Only on the ground.
B. Anytime an engine is shut down in flight.
C. Only when due to bearing failure.
D. Depending on the fault condition detected.
D. Depending on the fault condition detected.
Circuit breaker status is always available:
A. On EICAS.
B. On the Status page display.
C. On the respective system synoptic.
D. On the CBIC (circuit breaker indication and control).
D. On the CBIC (circuit breaker indication and control).
The permanent magnet generators (PMGs):
A. Always power the Captain’s standby electrical system.
B. Provide a backup source for the hot battery buss and main battery charger.
C. Power the flight control electronics.
D. All the above.
C. Power the flight control electronics.
The main battery provides power to the following:
A. Electric braking (as backup source).
B. Captain’s flight instrument bus until RAT deployment
C. L VHF communications.
D. All of the above.
D. All of the above.
When the FWD or AFT external power switches are illuminated “AVAIL”, they indicate:
A. An unpowered external power plug has been plugged in.
B. External power is plugged in and power quality is acceptable.
C. DC bus synchronization has failed and external power is required.
D. The system is available for external power to be plugged in.
B. External power is plugged in and power quality is acceptable.
Thermal circuit breakers may be reset via CBIC as long as the pilots accomplish the Unannunciated Circuit Breaker supplementary procedure?
A. True.
B. False.
B. False
A TCB, if found in the open/tripped position (white cross-hatched), cannot be reset electronically.
The RAT will deploy automatically in flight if:
A. Three starter generators are lost simultaneously.
B. The L2 bus is lost in conjunction with BAT LOW EICAS message.
C. Any two starter/generators fail.
D. All electrical power to the Captain and F/O’s flight instruments is lost.
D. All electrical power to the Captain and F/O’s flight instruments is lost.
When on the ground prior to engine start and the Hydraulic Electric Demand pumps are selected to AUTO, the pumps do not operate. This function is called:
A. Load Shedding.
B. Non-essential circuit breakers will open as needed.
C. APU autostart.
D. Load Inhibit.
D. Load Inhibit.
If a total electrical failure occurs in flight, the PMGs provide Standby Power until RAT deployment.
A. True.
B. False.
B. False
The main battery provides standby power until RAT deployment.
During automatic load shedding, which of the following indications may display?
A. LOAD SHED is displayed next the affected equipment symbol on the appropriate system synoptic.
B. A list of affected airplane systems displays on the electrical synoptic.
C. “LOAD SHED” EICAS message displays.
D. Both A and B are correct.
D. Both A and B are correct.
If both FWD external power are powering the main AC buses, when the APU starter/generators become available:
A. The APU generator power is automatically applied when all external power sources are selected OFF.
B. The APU generators power R1 and R2 AC buses and FWD external powers the L1 and L2 buses.
C. APU generator power must be manually selected.
D. The APU generators automatically replace all external power sources.
D. The APU generators automatically replace all external power sources.
If a generator drive disconnect is initiated, either automatically or by selecting the respective Drive Disconnect Switch, with engines operating:
A. Select the RESET option in the electrical synoptic to reconnect the starter/generator.
B. The “ELEC GEN DRIVE” EICAS message displays.
C. The starter/generator is disengaged from the engine.
D. B and C are correct.
D. B and C are correct.
When the APU starter/generators are powering the main AC buses, and both FWD external power connectors are plugged in:
A. External power is automatically applied.
B. External power only becomes available after APU shutdown.
C. The APU generator powers the R1 and R2 AC buses & FWD external powers the L1 and L2 buses.
D. External power must be manually selected ON.
D. External power must be manually selected ON.
The electrical system can be powered by the APU and FWD external at the same time.
A. True.
B. False.
A. True
The 787 provides a “no break” power transfer when changing power sources.
A. True.
B. False.
A. True
The Towing Power switch when ON, provides power for the Captain’s ACP, Captain’s Flight Interphone, Nav lights, and brakes.
A. True.
B. False.
A. True
With the loss of a single engine generator, how is power provided to the associated main bus for that generator?
A. The lost main AC bus is now powered by another main AC bus.
B. All 3 powered AC buses share the load equally.
C. AC Standby Inverter powers the bus.
D. The PMGs will provide backup power to the associated bus.
A. The lost main AC bus is now powered by another main AC bus.
The Large Motor Power Distribution System (LMPS) powers:
A. CACs and Ram fans.
B. Hydraulic pumps.
C. Power for APU and Engine starting.
D. All the above.
D. All the above.
The PECS system provides:
A. Heat dissipation for the LMPS.
B. Cooling for the FD displays and indicators.
C. Cooling for the left and right CCRs.
D. Heat dissipation for the LMPS anytime the battery switch is on.
A. Heat dissipation for the LMPS.
The Starter/Generators (SGs):
A. Are variable frequency and utilize a CSD to provide stable output.
B. Are variable frequency and are directly connected to the engine gearbox.
C. Operate in pairs through a motor drive regulator.
D. Are variable frequency, and provide one primary and one backup output to each L and R main bus.
B. Are variable frequency and are directly connected to the engine gearbox.