B744 ELECTRICAL Flashcards
Name some important items on the Main Hot Battery Bus:
Spar Valves
APU and Lower Cargo Fire Extinguishers
Engine Fire Extinguishers
Fire unlock switches
When I place the BAT switch to ON, what busses are powered? (DARK airplane)
- 2 HOT BAT Buses (Main and APU)
- 2 BAT Buses (Main and APU)
When I place the STBY PWR selector to AUTO, what Buses are powered & how?
Main and APU Stby Buses,
through the Invertors from the Main and APU Buses
What items are on the MAIN Stby Bus?
Primary EICAS Left FMS-CDU Left EIU Left ILS Left VOR
What items are on the APU Stby Bus?
Left PFD / Left ND / Left FMC
What powers the MAIN Stby Bus during normal operations?
AC Bus 3
What powers the APU Stby Bus during normal operations?
CA Xfer Bus
What is the source of power to the BAT Chargers?
Ground Service Bus
What is the main power source to the Grd Service Bus?
AC Bus 1
What is the purpose of the “Ground Service” switch located next to the L1 Door?
When AC Bus 1 is not powered, the Grd Serv Bus can be powered from the same source as the Grd Handling Bus by pushing the switch
What is the main source of power for the CA Xfer Bus? Backup?
AC Bus 3
AC Bus 1
What is the main source of power for the FO Xfer Bus? Backup?
AC Bus 2
AC Bus 1
When is the Ground Handling Bus powered?
On the ground, anytime APU 1 or EXT 1 is AVAIL or ON
What are some of the items on the Ground Handling Bus?
Lower Cargo Handling and Lights
Fueling system
AUX Hyd Demand Pump #4
When is the Main Deck Cargo handling Bus powered?
On the ground, anytime APU 2 or EXT 2 is AVAIL
What happens when you push a BTB switch?
Push OFF: opens the BTB and respective DCIR and resets Fault Logic circuitry
Push AUTO: arms the automatic AC bus tie circuitry and closes DCIR
What items are powered in flight with loss of all Normal AC Power (Loss of all Gens)?
Left FMC Left PFD Left ND Left VHF Comm Primary EICAS CA Pitot Heat NAI Dome Lights L and R interphone panels
Can I fly an ILS with loss of all Normal AC Power?
Yes, BUT no FD or A/P
Can I trim with loss of all Normal AC Power?
Yes, using Alternate switches (through a separate control channel)
Can I get the Gear & Flaps down with loss of all Normal AC Power?
Yes, the Gear through its normal Hydraulic mode and the TE Flaps through the Primary mode. The LE Flaps will NOT extend prompting a Flaps Drive message (25 Kt additive to VREF – QRH)
What about Reverse, Speedbrakes & Anti-Skid with loss of all Normal AC Power?
No Reverse, No Auto Speedbrakes (manual OK), and no Anti-Skid
