B-777 Electrical.txt

  1. The Static Inverter operates when what bus is not powered?
    Left Transfer Bus. The Static Inverter will also operate during autoland operations.
  2. What is the AC power priority to the Main Busses?
    • 1. Respective IDG
    • 2. APU
    • 3. Opposite IDG
  3. What is the power priority at the gate?
    • 1. PRI and SEC EXT power.
    • 2. APU
    • 3. IDG
  4. Which bus is basically hot wired to the PRI EXT or the APU?
    Ground Handling Bus, which is only powered on the ground.
  5. Where does normal DC power come from?
    The TRU's
  6. Name three backup DC sources.
    • 1. Main aircraft battery.
    • 2. APU battery.
    • 3. RAT, through TRU'S, C1 and C2.
  7. The ELMS will shed loads in what order?
    • 1. Galleys
    • 2. Utility Busses
    • 3. Individual components on the Main AC Busses.
  8. LOAD SHED message(s) is shown where?
    On the Electrical Synoptic.
  9. Loss of both AC Transfer Busses causes?
    • 1. The APU to start automatically regardless of switch position.
    • 2. The RAT to automatically deploy.
  10. The Backup Generators power what busses?
    AC Transfer Busses
  11. What causes an IDG to disconnect automatically?
    High oil temperature only.
  12. The APU can supply electrical power to what altitude?
  13. A Backup Generator will come online automatically under what conditions?
    • 1. Only one AC generator (including APU) is available.
    • 2. Power to one or both Main AC Busses is lost.
    • 3. APP mode is selected for autoland.
  14. Switching between what two power sources may cause some power interruption?
    PRI and SEC EXT power.
  15. Which bus powers the main aircraft battery charger and APU battery charger?
    Ground Service Bus
  16. Which bus powers the Left FWD fuel pump?
    Ground Service Bus
  17. When is the backup AC system tested?
    After each engine start. (Its respective side)
  18. Where do the TRU's get their power from?
    AC transfer busses.
  19. What normally powers the flight control system?
    4 PMG's
  20. The main battery charger normally powers?
    • 1. Battery
    • 2. Hot battery bus
  21. What is the purpose of TRU C1?
    To power the CA flight instrument bus.
  22. What is the purpose of TRU C2?
    To power the F/O flight instrument bus.
  23. Which backup generator provides power when needed?
    Which ever engine is ROTATING.
  24. Where does the RAT directly apply power to?
    TRU's C1 and C2.
  25. Where does the RAT switch get its power from?
    • 1. Hot battery bus
    • 2. APU battery bus.
  26. The main battery provides standby power where?
    • 1. Hot battery bus
    • 2. Battery bus
    • 3. CA flight instrument bus
    • 4. Standby Inverter
  27. If normal and secondary power sources to the PSA's have failed, which bus can power the left and center PSA's?
    Hot battery bus
Card Set
B-777 Electrical.txt
Questions about the electrical system.