Electrics

Question 1

The sources of main electrical power in flight

AC or DC?

Answer 1

Left and right IDG and APU

A/C

Question 2

How many main sources do you need to maintain full electrical power the plane

Answer 2

Any two main sources

Question 3

Sources of DC power

Answer 3

Main Battery
APU Battery
Flight Control DC Electrical System
Transformer-Rectifier Units

Question 4

What powers the Transformer-Rectifier Units?

Answer 4

Aircraft transfer busses

Question 5

With all power turned off the main battery can still power what times?

Answer 5

1.Engine Fire Extinguisher bottles
2.APU Fire Extinguisher bottles
3.ADIRUs- Air Data Inertial Reference Unit

Question 6

What can power the ground handling bus?

Answer 6

Ground Power or the APU

Question 7

What does the ground handling bus power?

Answer 7

Cargo handling, fueling/defueling, potable water and Lav servicing

Question 8

What has priority to power the ground handling bus? The APU or ground power?

Answer 8

Ground Power

Question 9

What does the Ground SERVICE BUS power?

Answer 9

Main Battery Charger
APU Battery Charger
Cabin Lighting and outlets
left forward fuel pump

Question 10

What are the main engine generators called?
How are they represented on the system synoptic?

Answer 10

IDGs

“DRIVE” Icons

Question 11

What does the Electrical Load Management System (ELMS) do?

Answer 11

-Provides load management and protection.
-It will load automatically load shed by priority if loads exceed power available

Question 12

If load shedding becomes necessary, what order does the ELMS shed reduce power?

Answer 12

Galleys, utility busses, individual equipment items on the main AIRCRAFT busses

Question 13

What does the backup electrical system power?

Answer 13

Essential aircraft equipment

Question 14

When would the backup electrical system by utilized?

Answer 14

If both IDGs and the APU generator are inoperative

Question 15

What busses power the essential aircraft equipment?

Answer 15

The L and R Transfer busses

Question 16

If power is lost to a main bus what would automatically power the associated xfer bus?

Answer 16

A backup generator

Question 17

Can one backup generator power both XFR busses?

Answer 17

yes

Question 18

What other time would a backup generator power are XFR bus?

Answer 18

Autoland operations

Question 19

What are the two different DC Electrical systems?

Answer 19

Main DC Electrical
Flight Control DC Electrical

Question 20

What powers the main DC electrical system

Answer 20

four Transformer-Rectifier Units (TRUs)

Question 21

What powers the TRUs

Answer 21

AC Transfer Busses

Question 22

What for the left and right TRU power and what do they provide secondary power for?

Answer 22

primary-The onside Main DC bus

secondary-The onside Power Supply Assembly and the opposite side main DC buss

Question 23

What does the C1 TRU power? (think CA’s side)
What does it provide secondary power for?

Answer 23

The CA’s Flight instrument bus and the Battery Bus

Center Flight Control PSA and the FO’s instrument bus

Question 24

What does the C2 TRU power? (think FO’s side)
What does it provide secondary power for?

Answer 24

The FO’s flight instrument bus

The CA’s Flight instrument bus

Question 25

When does the APU battery bus provide power to start the APU?

Answer 25

When sufficient Bleed Air duct pressure isn’t available for APU start

Question 26

What powers the APU Battary Bus? What recharges that?

Answer 26

The APU Battery The APU Battery charger

Question 27

If two main capacity generators are not available what powers the electrical system and dos it power everything?

Answer 27

The Standby Electrical System No-The Flight Control System and selected instruments, coms and Nav Systems are powered.

Question 28

If the three main generators and the two backup generators have faults or for some other reason, the left and right transfer buses are not powered what supplies electricity to the system?

Answer 28

The RAT will deploy automatically and provide standby power. It will also deploy for reasons other than electrical faults

Question 29

What two other things will cause the RAT to deploy?

Answer 29

-All three Hydraulic System pressures low -Dual engine failure and center Hydraulic low

Question 30

When being powered by the ram air turbine what takes priority? Hydraulic power or electrical power?

Answer 30

Hydraulic

Question 31

If the RAT sheds electrical loads what powers the standby power system?

Answer 31

Main Battery Power

Question 32

When the ram air turbine supplies electrical power which flight instrument buses are powered?

Answer 32

Both the CA and FO’s instruments

Question 33

When would the captains instruments be the only ones that are powered?

Answer 33

When down to battery power

Question 34

cAn you turn the battery power off in flight?

Answer 34

No. You can select it off but it is inhibited from actually being turned off

Question 35

What does "AVAIL" on the ext power switch mean?

Answer 35

External power is available and is of usable quality

Question 36

What does PRIMARY EXT PWR supply power to?

Answer 36

Both main A/C busses

Question 37

What side of the aircraft is the APU air inlet and exhaust?

Answer 37

Inlet is on the right, exhaust on the left

Question 38

Why do you need the main aircraft battery on to start the APU?

Answer 38

It powers the APU fire detection system, the fuel valve and the APU inlet door

Question 39

Does the APU have electrical priority over the external power sources?

Answer 39

Over the secondary, you can see this on the overhead schematic

Question 40

What does ELMS stand for?

Answer 40

Electrical Load Management System

Question 41

If one main generator is lost does the other power the entire sytem?

Answer 41

No. It still powers the opposite Main bus but the "failed side" backup generator takes over supporting the X-fer bus