Boeing 777 Electrics
1 / 15
During autoland, the busses isolate to allow three independent sources to power the three autopilot. In this case which one of the following is the power source for the right AC transfer bus, the right DC bus, and the first officer's flight instrument bus?
2 / 15
What is the source of standby electrical power if the RAT sheds electrical power because of low hydraulic pressure?
3 / 15
What is the primary source of standby power if all normal AC and DC power source fail?
4 / 15
Primary power for the flight control DC electrical system comes from permanent magnet generators (PMGs) housed within each backup generator. Variable frequency PMG AC power is used by individual power supply assemblies (PSAs) to provide DC power to the three flight control DC busses. To ensure a high level of system reliability, each PSA also has multiple AC power sources.
To ensure a high level of system reliability, each PSA also has multiple DC power sources (No AC power!). If primary PMG AC power is not available, secondary power for the left and right PSAs is provided by the related main DC bus. Secondary power for the center PSA is provided by the captain’s flight instrument bus. The hot battery bus provides additional backup power for the left and center PSAs only. Each PSA also uses a dedicated battery to prevent power interruptions to the related flight control DC bus. The batteries have limited capacity and are incorporated to supply power for brief periods during PSA power source transfers.
5 / 15
What is the primary power source for 'fly-by-wire'?
6 / 15
What is the primary source of DC power during normal flight?
7 / 15
Which one of the following is not true about the ram air turbine (RAT) generator?
8 / 15
How many total AC sources of power does the B777 accommodate?
Seven (2 IDG, APU, PRI and SEC external power, 2 BUG).
9 / 15
Which one of the following is not true about the Secondary External Power?
10 / 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?
11 / 15
The Electrical Load Management System (ELMS), manages load shed priority (galley first, utility bus second, then selected AC components).
12 / 15
What automatic switching will occur if you start the APU with external power on the BUS TIE system?
13 / 15
You have a cold airplane (no power connected). Which items will be powered if you push the BATTERY switch ON?
14 / 15
Which one of the following is not true about integrated drive generators (IDGs)?
15 / 15
The standby electrical system consists of:
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