Elec Flashcards
The bus power control units provide electrical load management when the aircraft is operating on:
any available electrical power source.
If the permanent magnet generators are not available, the flight control electronics receive power from the:
28v DC system and main battery.
What is the minimum number of external power sources required for an external power ONLY engine start?
Two (L&R Fwd)
The ground handling mode is powered when _____ if no other power source is available.
either FWD external power is connected (AVAIL)
The generator drive may disconnect automatically _____.
depending on the fault condition detected
How can the flight crew determine circuit breaker status?
Check the CBIC display.
What is the purpose of the permanent magnet generators (PMGs)?
C. Powers the flight control electronics.
The main battery power to the following:
A. electric breaking (as backup source).
B. The Captains Flight instrument bus until RAT deployment
C. Towing and refueling operations
The illuminated “AVAIL” light on the FWD of AFT external power switches indicate:
External power is plugged in and voltage and frequency are within limits.
Which of the following is true with regard to loss of two Starter Generators (SG’s) in flight?
D. Some load shedding will occur.
Electronic Circuit Breakers can be operned or closed using CBIC on the ground or in flight.
A. True
Which circuit breaker types may be reset via CBIC?
B. Electronic
Which of the following conditions will cause the RAT to deploy automatically in flight?
Loss of all electrical power to the Capt and FO’s flight intruments
To remain within the capacity of the available power sources, ____ will occur.
( Mark it was not highlited so here are all the possible answers)
Load Inhibit
Non-essential circuit breakers will open as needed
APU autostart
Load Shedding
If a loss of all electrical power to Capt’s and FO’s flight instrument occurs in flight, the _____ provides Stanby Power until RAT deployment.
Main battery
Which of the following indications will display during automatic load shedding?
A. LOAD SHED is displayed next the affected equipment symbol on the appropriate system synoptic.
C. a list of affected aircraft systems on the electrical synoptic.
Inflight, with only one starter generator available _____?
power remains available to critical and essential equipment.
With the airplane unpowered on the ground, pushing the battery switch to ON:
begins the left CCR start-up process
If a drive disconnect switch is pushed, with engines operating:
A. The starter/generator is disengaged from the engine.
B. The “ELEC GEN DRIVE” EICAS message displays.
C. Maintenance action will be required to reconnect the starter/generator.
If both FWD external power are powering the main AC busses, when the APU starter/generators become available:
APU generator power replaces FWD external power
The APU and FWD external can power the aircraft at the same time:
A. True
Power source transfers are made without interruption when the aircraft is on the ground:
B. False
The Towing Power panel provides power for ___.
A. Capt’s audio control panel, Capt’s flight interphone.
B. Brakes, Navigation lights
How can crew members differentiate between an open Electronic circuit breaker (ECB) and an open Thermal circuit breaker (TCB)?
Open TCB’s are shown using a crosshatched diplay while ECB’s are solid white.
Inflight, when will the APU auto start?
With a loss of three or more starter/generators.
If any engine generator fails, how is power provided to it’s associated main AC bus?
The lost main AC bus is now powered be another main AC bus.
The Large Motor Power Distribution System (LMPS) powers _____.
A. CAC’s
B. Hydraulic pumps
C. power for APU and Engine starting
During an autoland approach with LAND 3 annunciated below 200ft, the R1 starter/generator fails. Which of the following occurs:
The ASA continues to display LAND 3.
The PECS system provides ____.
heat dissipation for the LMPS
After landing, PECS cooldown begind when ____?
packs AND hydraulic EMPS’s are shutdown
The Starter/Generators (SG’s) ____.
are variable frequency and are directly connected to the engine gearbox
The RAT provides:
A. stanby electrical power
B. backup hydraulic pressure
The standby electrical system consists of:
C. The Main battery and the RAT generator.
Primary and backup power for the brake system is provided by:
28vdc power for the primary system and the main battery for the backup source.
The main battery can supply DC power for:
A. engine and APU fire detection
B. the Left CCR.
C. Capt’s inboard and lower DU.
The APU generator OFF lights illuminate when:
The APU generator control breaker is open.
The benefit of using all three external power sources for engine start, is that aft external can assist the forward external if starting the right engine first.
A. True
The aft external power receptable is located:
D. on the left side of the fuselage aft of the wing.
