28 Fuel

Question 1

Where is the vent surge fuel tank located?

Answer 1

Outboard of the outer tank in each wing

Question 2

When the fuel is filled to maximum capacity, how much can the fuel expand by without spilling?

Answer 2

2%

Question 3

What is the total usable fuel on the A321NEO (without ACT)?

Answer 3

18511kg

ACT = Additional Center Tank

Question 4

What is the total usable fuel on the A320NEO (without ACT)?

Answer 4

18623kg

Question 5

What is the total usable fuel on the A320?

Answer 5

18968kg

Question 6

What is the total usable fuel on the A319?

Answer 6

18729kg/19004kg

Question 7

How many fuel pumps are there on newer A320s and the A321?

Answer 7

Four (two in each wing), the centre “pumps” are jet pumps with transfer valves

Question 8

How many fuel pumps are there on A319 and older A320 aircraft?

Answer 8

Six (two in each wing, and two in centre tank)

Question 9

How many transfer valves are located in each wing?

Answer 9

Two

Question 10

Describe the fuel feed sequence

Answer 10

Centre tank first
Inner tank empties down to 750kg
Outer tank fuel transfers into inner tank

(A321NEO has no outer tank)

Question 11

Which electrical system supplies the APU fuel pump if the fuel feed pressure is low (due to loss of tank pumps or normal AC supply)?

Answer 11

The AC ESS SHED

If this fails, it runs off the AC STAT INV BUS

Question 12

What does the fuel system cool?

Answer 12

The Integrated Drive Generator

The fuel passes through the IDG heat exchanger (which absorbs heat), then to the fuel return valve and back to the outer fuel tank.

This ensure IDG cooling when oil temperature is high or at low engine power.

Question 13

What happens to the fuel from the fuel return valve (used for IDG cooling) if the inner tank is already full?

Answer 13

If the FUEL MODE SEL pb is in AUTO, and the centre tank pumps are feeding, the system selects CTR TK PUMPs off, and wing tanks pumps will automatically feed each engine until around 500kg has been used in each wing.

If the FUEL MODE SEL pb is in MAN, the CTR TK PUMPs will not be automatically switched off, which could lead to over flow of the wing tanks.

FCOM DSC 28-10-60

Question 14

What happens to the fuel from the fuel return valve (used for IDG cooling) if the outer tank is already full?

Answer 14

The fuel overflows to the inner tank through a spill pipe

FCOM DSC 28-10-60

Question 15

Why should you not change power supply during refuelling?

Answer 15

Electrical transients during automatic refuelling may stop the process, requiring a reselection of the Preselected Fuel Quantity in the panel

Question 16

How long does it take to refuel all tanks (around 19T)?

Answer 16

20 minutes (around 1T per minute)

Question 17

What causes a fluctuation in the inner tank fuel quantity indications after take off? How long does it take to return to normal?

Answer 17

For low fuel quantities below 7T, acceleration and high pitch angles causes the fuel to move in the tank. This can see the FOB reduce for 2 minutes after take off, then increase to accurate values about 6 minutes later during the climb. Maximum fluctuations can be up to 400kg (300kg in the go-around).

For higher fuel loads, a FOB increase up to 1000kg may occur after takeoff, this returns to accurate within a maximum of 6 minutes.

FCOM DSC 28-10-80

Question 18

What does the Fuel Tank Inerting System do? And how does it do it?

Answer 18

Reduces flammability in the fuel tanks which have a high flammability exposure (only the centre tank).

The system produces oxygen-depleted air that goes in the centre tank to replace the ambient air (around 12% oxygen level rather than 21% normally).

This isn’t installed on all aircraft, only later MSNs ( MSN 5019-9171).

FCOM DSC 28-10-90

Question 19

How long do the centre tank pumps run for at engine start if the MODE SEL pb is in AUTO?

Answer 19

2 minutes (they also run before or after engine start if the slats are retracted)

FCOM DSC 28-20

Question 20

How long do the centre tank pumps run for if the low level is reached?

Answer 20

5 minutes

Question 21

Which valve is displayed on the FUEL SD page immediately below the F.USED quantity at the top of the screen?

Answer 21

Engine LP valve

Question 22

What fuel temperature does an advisory appear at?

Answer 22

Above 45degC (inner cell)
Above 55degC (outer cell)
Below -40degC

Question 23

When does a fuel imbalance advisory appear?

Answer 23

When the difference in the two wings is greater than 1500kg

Question 24

Which fuel type do we usually use?

Answer 24

Jet A1

Question 25

What is the minimum fuel temperature?

Answer 25

-43degC

Question 26

What is the maximum fuel temperature?

Answer 26

54degC (55degC for NEO)

Question 27

What is the maximum allowable fuel imbalance for takeoff?

Answer 27

Inner tanks:
500kg if heavier tank is full
1050kg if heavier tank has 3000kg
1450kg if heavier tank has 1450kg
(Scale is linear)

Outer tanks:
370kg

Greater asymmetry allowed for flight and landing, see FCOM LIM FUEL

Question 28

What is the minimum fuel quantity for take off?

Answer 28

1500kg

Question 29

Can the aircraft be refuelled using batteries only? How?

Answer 29

Yes, using the BATT POWER toggle switch on the refuelling control panel.

Switching this on momentarily allows HOT BUS 1 to supply the FQI. It takes around 40 seconds for the FQI to complete tests before showing fuel quantities. The electrical supply is cut off after 10 minutes if no refuelling starts, or at the end of refuelling.

FCOM 28-20

Question 30

Where is the APU fuel feed line drawn from?

Answer 30

Left of the cross feed valve