Electrics Flashcards
1
Q
If you disconnect an IDG in flight can it be reconnected?
A
- No requires maintenance action on the ground to reconnect
2
Q
Generator DRIVE light illuminates?
A
- Oil temp is high or:
- Oil press is low
3
Q
EXT PWR AVAIL light?
A
- External power is plugged in and power quality is acceptable
4
Q
ISLN light illuminates on the bus tie breaker?
A
- Fault has occurred automatically opening the AC bus tie breaker or:
- AC bus tie switch is OFF
5
Q
UTILITY BUS OFF light?
A
- Utility and galley buses are unpowered
6
Q
How can an IDG be disconnected from the buses?
A
- By pushing the GEN CONT switch to off or:
- By selecting EXT PWR prior to ENG shutdown
7
Q
What does the EICAS MSG L or R GEN DRIVE and the DRIVE light indicate and what should be done?
A
- High oil temp or:
- Low oil press
- The DRIVE can be disconnected but can not be deselected by flight crew
8
Q
Indication that EXT PWR is powering the main buses?
A
- ON light illuminates
9
Q
What is the source order for powering the LEFT and RIGHT main buses?
A
- Respective IDG
- APU GEN
- Opposite IDG
10
Q
How is the Battery bus powered?
A
- Main Battery: if no electrical power and BAT switch ON
- After establishing ELEC power: Left DC system, Main BAT provides a backup source of power
11
Q
During an Autoland what happens with the electrical system?
A
- Buses isolate to allow 3 independent sources to power three autopilots
- LEFT main system powers: left autopilot and captains flight instrument transfer bus
- RIGHT main system powers: Right A/P and FO’s flight instrument transfer bus
- BATERY/STANDBY system powers: Centre A/P
12
Q
Autoland ABV 200ft, loss of Generator results in?
A
- Both Tie breakers close
- Operating GEN powers L&R AC buses
- LEFT main AC system powers centre A/P
- NO LAND 3 appears on the Autoland status annunciator
13
Q
Below 200ft loss of a Generator results in?
A
- Both tie breakers remaining open
- A/P associated with a failed GEN is unpowered
- Flight instruments remain powered through the flight instrument transfer buses
- Auto-land continues using the remaining 2 A/P
14
Q
What gets shed first in Electrical load shedding
A
- Galleys then Utility buses
15
Q
AC Transfer buses?
A
- Left and right AC transfer busses power items considered necessary for ETOPS flights, which are not powered by the battery/standby system
- Transfer busses are normally powered by their associated main AC busses, but also can be powered by the Hydraulic Driven Generator when both AC busses are unpowered