Boeing 777 Electrics
1 / 15
What does the green EXTERNAL POWER AVAIL light indicate?
2 / 15
During autoland, the busses isolate to allow three independent sources to power the three autopilots.
The left IDG powers the left AC transfer bus, the left main DC bus, and the captain’s flight instrument bus The right IDG powers the battery bus and AC standby bus through the main battery charger The backup system powers the right AC transfer bus, the right DC bus, and the first officer’s flight instrument bus.
3 / 15
The main battery provides standby power to the following:
4 / 15
How many main AC power sources are required to maintain the entire plane AC electrical load?
5 / 15
What is the secondary source of power for 'fly-by-wire' if one or more PMGs are unpowered?
6 / 15
Bus tie relays, controlled by BUS TIE switches, isolate or parallel the right and left main busses. When both BUS TIE switches are set to AUTO, the bus tie system operates automatically to maintain power to both main busses.
7 / 15
What provides DC power on the B777?
8 / 15
What is the primary source of DC power during normal flight?
9 / 15
Which one of the following is not true about the ram air turbine (RAT) generator?
10 / 15
Which bus operates only on the ground?
11 / 15
Which bus powers the main battery charger and the APU battery charger?
12 / 15
How are the busses powered if the right engine is started with the APU powering the left bus system and external power powering the right bus system?
13 / 15
The Electrical Load Management System (ELMS), manages load shed priority (galley first, utility bus second, then selected AC components).
14 / 15
What automatic switching will occur if you start the APU with external power on the BUS TIE system?
15 / 15
You have a cold airplane (no power connected). Which items will be powered if you push the BATTERY switch ON?
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