Electrical Flashcards
After starting engines 1 or 2 do and the GCU close giving power to the sync bus, do you need to push the APU Gen 1 switch to disconnect it?
No, auto disc
Which has priority ext pwr or APU gen?
Ext pwr
What’s a good way to think about what the ground hacking bus powers?
Basically the right side of the plane: Lowe cargo doors and lights, fuelling and hyd elec aux pumps 1&4
What’s a good way to look at what the ground service bus powers?
Things to get started from a dark ship:)
Lighting in the upper deck and cockpit (plus navs)
Upper deck doors
APU fuel pumps (2&3 aft)
And Battery chargers for both batteries so you don’t drain them while you’re getting everything fired up.
What’s a good way to think about what the cargo handling bus powers?
Anything main deck related:
To open and close doors
To use the equipment to move palates around.
Will the main deck cargo handling bus be powered if neither ext 2 or APU pwr avail lights are illuminated?
No, the cargo handling bus only receives power when one or both if them shows available
(Ext takes priority)
What systems do the D.C. busses powered?
Primarily various controllers for different systems:
Cabin pressure and pack temp controls
Wing and nacelle antiice control
Hydraulic pump controls
Fuel transfer and jettison valve control
What equipment does the APU HOT BATT BUS power?
Think of it this way: airplane is dark and you need to get power to it and get the IRS going.
D.C. power for IRU’s L/R outflow valves APU inlet door APU primary controller APU fire warning horn
What systems does the Main Hot Batt bus power?
Think of it this way: you’re having a bad day and you need protection for all your engines and APU from fire. “It’s the MAIN thing keeping you from dying”
Engine fuel spar valves Engine fire ext Lower cargo fire ext APU fire ext APU fuel shutoff valve
How is the D.C. system structured?
Normally each D.C. bus is powered by its AC bus which powers it’s D.C. bat bus and the D.C. hot batt bus. However if the power fails to that D.C. bus, the battery can feed the hot bat bus which feeds in reverse to the bat bus.
Where can you see batt voltages?
Secondary EICAS STAT
When does bus isolation stop on an auto land app?
Disconnect ap
Or TOGA
ELEC BUS ISLN 1,2,3,4
Bus tie is open due to improper voltage, phase or frequency for the synchronous bus.
ELEC AC BUS 1,2,3,4
ISLN
OFF
The AC BUS is not powered.
Objective: to reset the generator and then the bus tie. Also to reset the EEC’s if the bus is recovered.
Be careful to avoid icing conditions if AC Bus 1 or 4 are not powered due to loss of ice protection of pitot static. You will also be level 3 automation with no AT.
ELEC DRIVE 1,2,3,4
DRIVE
One of these occurs:
IDG oil press low
IDG oil temp high
Objective: to prevent damage to the IDG
Once the drive button is pushed, the GCU disc and you get:
>DRIVE DISC 2
ELEC GEN OFF 2
