07 Electrical

Question 1

With all electrical power turned OFF, the main battery can power which items through the hot battery bus?

Answer 1

1) engine fire extinguisher bottles,
2) APU fire extinguisher bottle, and
3) Air Data Inertial Reference Unit (ADIRU).

The ADIRU switch must be turned ON.

Question 2

The C2 TRU powers?

Answer 2

The First Officers flight instrument bus which also provides secondary DC power to the Captains instrument bus.

Question 3

At the gate with PRI EXT PWR ON, after APU start the APU will power?

Answer 3

L MAIN AC bus. The ELMS automatically switches the APU to power the L MAIN AC BUS and the PRI EXT PWR to power the R MAIN AC bus.

Question 4

With both PRI and SEC EXT PWR ON, which buses are powered?

Answer 4

The ELMS will normally switch the PRI EXT PWR to power the R MAIN bus and the SEC EXT PWR to power the L MAIN bus.

Question 5

Prior to engine shutdown with the PRI EXT PWR ON, no APU and no SEC EXT PWR what powers the main busses?

Answer 5

Selecting the PRI EXT PWR ON removes the IDGs, closes both busses and the PRI EXT PWR powers both L and R MAIN busses.

Question 6

What condition causes the IDG to disconnect automatically?

Answer 6

High IDG temperature. Most IDG faults require manual disengagement of the IDG.