Electric 747-400 Flashcards
Is it possible to switch off the HOT BAT BUSSES?
No. They are fixed to the batteries.
Is DC BUS 2 still powered with an open DCIR 2?
Yes. DC BUS 2 will be powered by the T/R unit 2. No connection to the tie bus.
What does the SSB light mean?
Different power sources feed the two halves of the synchronus bus.
Do the STBY BUSSES loose power when you switch the STANDBY POWER selector OFF?
Yes. It disconnects STBY BUSSES from all sources.
After the successful start of Engine 4, what powers the synchronous bus?
IDG 4 feeds the synchronous bus.
After engine start, do the IDGs supply all busses?
No.
The IDGs don’t power the GND HANDLING BUS, and Main deck cargo Handling bus.
What does an OFF light in the GEN CONT 3 switch mean?
The Generator control Breaker (GCB) 3 is open.
If the GEN CONT 3 OFF light is illuminated, which bus powers the CAPT X-FER BUS?
AC BUS 3.
If APU GEN 1 and APU GEN 2 are available, will they connect automatically to the synchronous bus, when the engines are cut?
No. Manual connection is required.
If the APU is on, and the Battery switch is turned off. What will happen if anything?
The APU will shut down without time delay.
After an automatic trip of a BYB (BUS TIE BREAKER) will the respective DCIR open too?
No. The DCIR remains closed.
What happens if you select the BATTERY switch to OFF in flight?
All busses remain powered.
Which AC busses have to fail, to start the APU STBY INVERTER?
AC BUS 1, and AC BUS 3 cause the APU STBY INV to start.
What does an OFF light on a utility bus that is ON mean?
That an ELCU disconnected at least one utility bus.
Both APU GENS supply the aircraft. What happens, if APU GEN 2 fails?
The SSB closes and all busses remain powered.
