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 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
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
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.