B777 Electrical

Boeing 777 Electrics

Boeing 777 Electrics

1 / 15

What does the green EXTERNAL POWER AVAIL light indicate?

External power is connected to all the airplane's electrical busses.

External power is disconnected from the airplane.

External power is connected to the airplane, correct and ready to power the electrical busses.

Electrical power is available to the electrical busses but may not be correct.

2 / 15

What is the primary source of power for the transfer busses?

Ram Air Turbine.

Main DC busses.

Engine generators.

Backup generators.

3 / 15

On ground no power connected to the airplane. Which items will be powered if you push the BATTERY switch ON?

Only the main battery bus will be powered.

The APU controller and the DC fuel pump will be powered.

All statements are correct.

The hot battery bus will be powered.

4 / 15

The standby inverter converts DC power to AC power. The inverter powers the AC standby bus if the right transfer bus is not powered.

True.

False.

The standby inverter converts DC power to AC power. The inverter powers the AC standby bus if the left transfer bus is not powered.

5 / 15

How many main AC power sources are required to maintain the entire plane AC electrical load?

5

2

1

4

6 / 15

What is the secondary source of power for 'fly-by-wire' if one or more PMGs are unpowered?

DC busses.

Left transfer bus.

Main AC busses.

Hot battery bus.

7 / 15

Which bus operates only on the ground?

The ground handling bus.

The right transfer bus.

The left main AC bus.

The ground service bus.

8 / 15

How can you power the ground handling bus before shutdown if no external power is available?

Deploy the RAT.

Select the ground handling bus ON.

Start the APU.

The bus is powered as long as the right main bus is powered.

9 / 15

How many total AC sources of power does the B777 accommodate?

6

7

4

5

Seven (2 IDG, APU, PRI and SEC external power, 2 BUG).

10 / 15

Which bus powers the main battery charger and the APU battery charger?

Ground service bus.

Standby bus.

Left main bus.

Right main bus.

11 / 15

Which one of the following is not true about the Secondary External Power?

Secondary external power can only power the left main bus.

When the secondary external power source voltage and frequency are within limits, the secondary external power AVAIL (available) light illuminates.

If the BATTERY switch is ON and no other source is powering the main busses, pushing the SECONDARY EXTERNAL POWER switch ON connects secondary external power to both main busses.

If a single IDG powers both main busses, pushing the SECONDARY EXTERNAL POWER switch ON connects secondary external power to both busses and removes the IDG source.

12 / 15

The Electrical Load Management System (ELMS), manages load shed priority (galley first, utility bus second, then selected AC components).

False.

True.

13 / 15

Does electric power has priority over hydraulic power from the RAT?

yes

no

Hydraulic has priority, and if electric is shed, only the CA instrument bus is powered through the main battery

14 / 15

What automatic switching will occur if you start the APU with external power on the BUS TIE system?

The APU connects to the BUS TIE switches but does not power either main bus.

The APU connects to the BUS TIE and replaces secondary external power on the left main bus.

The APU connects to the BUS TIE swıtches and powers the maın bus.

The APU connects to the BUS TIE and replaces primary external power.

15 / 15

You have a cold airplane (no power connected). Which items will be powered if you push the BATTERY switch ON?

The hot battery bus will be powered.

The APU controller and the DC fuel pump will be powered.

Only the main battery bus will be powered.

Your score is

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