The ground service bus is normally powered by the:
Right Main AC Bus
Whenever the right main bus is powered, the ground service bus is powered.
(T or F)?
TRUE
To allow for automatic landings with the lowest possible minimums, the electrical system configures so that each of the 3 autopilots is powered by a separate power source. (T or F)?
TRUE
If the ADIRU switch is left on after alignment and all electric power is switched off, the ADIRU continues to operate and the Nose Gear Horn sounds.
(T or F)?
TRUE
The primary electrical power sources for the flight control Power Supply Assemblies (PSAs) are the ____.
permanent magnet generators (PMGs)
The ground handling bus can be powered by:
primary external OR APU power
Voltage of the main battery is read on the ____.
ELECTRICAL synoptic
After the loss of AC power, when the RAT electrically load sheds or prior to RAT deployment, the ____ powers the standby power system.
main battery
If external power is not available, but the APU is running, the ground handling bus is powered.
(T or F)?
TRUE
What indicates that external power is connected to the airplane and is of usable quality?
The AVAILlight is illuminated.
When the APU is running and primary external power is on line, the APU powers ____.
the left main bus
Inflight, with both engines running, if both backup generator switches are selected ON and both OFF lights are illuminated, ____.
the converter has probably failed
If the RAT fails to deploy automatically, can the crew deploy it manually?
Yes, by the RAM AIR TURBINE switch located on the hydraulic panel.
Illumination of the Ram Air Turbine PRESS light on the hydraulic panel indicates that the ____
center system primary flight control hydraulic pressure is greater than 1500 psi
For primary electrical power system failures, the standby electrical system provides ____.
both AC and DC power
When the RAT deploys, if both hydraulic and electrical demands can be met, it will power the ____.
C1 and C2 TRUs
The RAT operates at _______airspeeds and altitudes
at ALL airspeeds and altitudes
What electrical components are powered by the RAT generator, if deployed?
The C1 and C2 TRUs.
Cargo Handling and Fueling/Defueling operations are powered by which electrical bus?
Ground Handling Bus.
What is the result of pushing a generator DRIVE DISC switch?
Disconnects the Integrated Drive Generator (IDG) input from the engine and can only be reset by maintenance on the ground.
What does an illuminated DRIVE light on the Integrated Drive Generator DISC switch AND an OFF light in the Generator Control switch represent?
Generator drive temperature is high and the IDG drive has disconnected.
What is the function of the bus tie system when AUTO is selected on the BUS TIE switches?
The bus tie system operates automatically to maintain power to both Main AC Buses.
Bus Tie relays isolate or link the right and left main buses.
During power source transfers on the ground the system is designed to prevent power interruption
Identify the condition(s) that will cause the Backup Generators to automatically power one or both AC Transfer Buses (Select all correct answer(s)).
When only one main AC generator (includes the APU) is available.
Approach (APP) mode is selected for autoland.
During the automatic system test after engine start.
Power to one or both of the Main AC buses is lost.
The Electrical Load Management System (ELMS) provides load management and protection to ensure power is available to critical and essential equipment.
(T or F)?
TRUE
An illuminated DRIVE light on the Integrated Drive Generator DISC switch represents (Generator Control Switch NOT illuminated)?
IDG oil pressure is low.
The Ground Handling Bus can be powered on the ground only by either, the APU Generator or the Primary External Power Source.
(T or F)?
TRUE
What is the purpose of the Permanent Magnet Generators (PMGs) housed within each Backup Generator?
To supply power to the PSAs/Flight Control busses.
What occurs automatically if both AC Transfer Buses lose power in-flight?
The Ram Air Turbine deploys and the APU starts automatically.
What does an illuminated AVAIL light in the Primary External Power switch indicate?
Primary external power is plugged in and power quality is acceptable.
What is the purpose of the Permanent Magnet Generators (PMG's) house within each Backup Generator?
Supply power to the flight control DC electrical system.
What is the function of the ON position of the Engine Generator Control (L/R GEN CNTRL)?
ARMS the generator breaker to close automatically when generator power is available.
Selecting the IFE/PASS SEATS switch to OFF removes power from the IFE and passenger seats, INCLUDING seat motor power and computer outlets.
True
What occurs when the CABIN/UTILITY power switch is selected OFF?
It removes power from the Cabin and Utility Systems, and turns on some of the cabin lighting
With the BATTERY switch ON, what remains powered inflight or on the ground when the AC power is removed or lost?
