FUEL Panel

Question 1

Describe the layout of the fuel tanks.

Answer 1

• The fuel tank layout depends on the specific aircraft.
  - Fuel is stored in a center tank and wing tanks:
  - On some aircraft the wing tanks are divided into inner tanks, outer tanks, and vent tanks.
  - On some aircraft the wing tanks are not divided into inner and outer tanks, but still have vent tanks.

Question 2

Generally, what is the total fuel capacity?

Answer 2

 42,000 lbs (41,285)

Question 3

Why is it possible for there to be a value higher than 42,000 lbs indicated on the ECAM FOB?

Answer 3

 The fuel can expand by 2% without venting overboard

Question 4

How many fuel pumps are on the aircraft and where are they located?

Answer 4

• There are seven total fuel pumps: two center tank pumps, four wing tank pumps, (two in each wing) and one APU fuel pump. On some aircraft, the center tank pumps are jet pumps, which transfer fuel from the center tank into the wing tanks.
  - The APU pump is used when fuel feed pressure is low (due to loss of tank pumps or loss of normal AC electrical supply)

Question 5

On an aircraft without jet pumps, explain the flow of fuel from before engine start to climb (assume full tanks).

Answer 5

- At engine start the fuel is fed from the wing tanks
- After both engines are started, the center tank pumps turn on and continue
to run for 2 minutes.
- If slats are selected within those 2 minutes, the center tank pumps will
continue to run until the time has elapsed, then they will stop.
- If the slats are extended at any other time, the center pumps will shut off.
- At takeoff, the engines feed fuel from their respective wing tanks.
- When slats are retracted to zero, the fuel is fed from the center tank.
- When the center tank runs low, the pumps continue to run for 5 min.

Question 6

What does a fault light in one of the L(R) TK PUMPS pushbuttons indicate?

Answer 6

 Low delivery pressure

Question 7

What does a fault light in the MODE selector indicate?

Answer 7

- Failure of the AUTO mode
- Center tank has more than 550 lbs and either wing tank has less than
11,000 lbs

Question 8

How would a pilot know that fueling is in progress?

Answer 8

REFUELG message appears on the ECAM. This does not mean the fuel is entering the tanks, merely that the refueling door is open.

Question 9

Describe IDG cooling and how it relates to the FADEC.

Answer 9

• Some of the fuel supplied to each engine goes from the high-pressure fuel line in that engine, through the integrated drive generator (IDG) heat exchanger (where it absorbs heat), to the fuel return valve, and back to either the wing tank or outer tank, depending on the aircraft.
  - This operation ensures IDG cooling when the oil temperature is high or when at low engine power.
  - The FADEC controls the fuel return valve. The rate of return is approximately 660 lbs per hour during low IDG temperature and 1,100 lbs per hour during high IDG temperature.

Question 10

On aircraft without jet pumps, what happens if returned IDG cooling fuel fills the wing tanks while the center tanks are feeding?

Answer 10

The center tank pumps will cut off until the wing tank quantity is reduced by 1,100 lbs.

Question 11

What is the approximate fuel capacity of each outer fuel tank, when installed?

Answer 11

 Approximately 1,500 lbs

Question 12

When do the wing outer tanks drain into the inner tanks?

Answer 12

 When the inner tank quantity reaches approximately 1,650 lbs.

Question 13

If only one inner tank reaches 1,650 lbs, what happens to the other transfer valve?

Answer 13

 All four transfer valves open.

Question 14

Once opened to transfer fuel, how are the fuel transfer valves closed?

Answer 14

 Automatically at the next refueling operation.