Fuel

Question 1

How are outer to inner tank transfer valves opened?

Answer 1

Automatically by a low level sensor in inner tank.

Question 2

Why are centre tank pumps switched off automatically when slats are extended for takeoff?

Answer 2

To ensure engines are fed from wing tanks for takeoff.

Question 3

What is the minimum fuel quantity for takeoff?

Answer 3

1500kg

Question 4

How is aircraft fueled?

Answer 4

Typically via the fuel coupling under the right wing.

A fuel cap on top of each wing allows wing tanks to be gravity fueled.

Question 5

How does fuel transfer from outer to inner tanks?

Answer 5

Two transfer valves are installed within each rib (separating inner/outer tanks), which permit fuel to gravity flow.

Question 6

What are the maximum fuel capacities?

Answer 6

Total: 18728kg
Centre: 6476kg
Inners: 5435kg x2
Outers: 691kg x2

Question 7

How are tanks protected from thermal expansion and overpressuring?

Answer 7

There is a vent surge tank which allows for thermal expansion without spillage through vent system.

Four overpressure relief ports (surge tanks and inner cells), with a carbon disc that will rupture in an overpressure condition. (White cross indicates disc intact).

Question 8

How is fuel measured if FQI system inoperative?

Answer 8

Magnetic level indicators on ground:
4/ inner cell, 1/outer cell, 1 in centre.

Question 9

All 6 fuel pumps are capable of producing the same amount of pressure. How does centre tank get priority to pressurise fuel manifold?

Answer 9

There are pressure reduction valves on the wing tank pumps.

Question 10

How can engines be fed if all fuel pumps fail?

Answer 10

Associated engine can be fed from wing tank by gravity suction valve.

*not from centre tank.

Question 11

Why do centre tank pumps switch off with flaps extended?

Answer 11

Allows each wing to supply its associated engine during takeoff, thus giving them independent sources.

Question 12

Fuel returning from IDG cooling goes to outer cell. What if it is full?

Answer 12

If outer cell full, it goes to inner cell through a return spill valve. If both full, centre pumps shut down to burn some from wings.

Question 13

What order does automatic refuelling fill tanks?

Answer 13

Outer cells first, then spills into inner cell through a spill pipe. Fuel is only introduced into centre tank if planned fuel load exceeds wing tank capacity.

Question 14

Why does centre tank have an inerting system and how does it work?

Answer 14

It has high flammability exposure.

System produces oxygen depleted air (<12%O2) into tank. Extracted bleed air goes through a separation module by tapping nitrogen molecules.

Question 15

How many fuel pumps are located in tanks?

Answer 15

6- 2 in centre and 2 in each inner.

Question 16

Where are engines fed from and in which sequence?

Answer 16

Centre, and both inners.

Sequencing preferentially flows from centre before its onside inner.

Question 17

How does crossfeed work?

Answer 17

Crossfeed connects both sides and one pump can supply both engines.

Question 18

Where is APU fed from?

Answer 18

Left side. APU LP Valve cuts off fuel when not running or APU FIRE pb used.

*APU pump not displayed on ECAM.

Question 19

Where are fuel drain valves located?

Answer 19

-2 under centre tank.
-1 under each inner tank.
-1 under each outer tank.

Question 20

What does an amber line across last 2 digits of fuel quantity mean?

Answer 20

Indication inaccurate.

Question 21

Some fuel is used to cool IDG. Where does this return to?

Answer 21

Outer tanks. If full flows to inner tanks. If these fill, centre pumps turn off until 500kg is burned from inner tanks.

Question 22

When do centre tank pumps stop after tank empty?

Answer 22

5 minutes after empty.

Question 23

When do transfer valves open to allow transfer fuel from outer to inner tanks?

Answer 23

When EITHER inner tank reaches a low level limit, transfer valves on BOTH sides open.