FUEL SYSTEMS

If there is any conflicting information, your FCOM shall be the overriding reference.

Please read the footnote at the end of this page.

Q1. What is the total fuel capacity of the A320?

A1. Total Fuel capacity of the A320 :-

In Volume : 23,858 Lts.

6302 UsG

In Weight : 18,728 Kgs

41,285 lbs

Q2. What is the type of fuel used for A320?

A2. Jet A-1.

Q3. What is the normal fuel feed sequencing?

A3. The Normal Fuel Feed sequencing is as follows :-

(a) The Center Tank

(b) The Inner Tanks : Each inner tank empties down to 750 Kgs.

(c) The Outer Tanks : Fuel transfers into the Inner Tanks.

Q4. During gravity feed, which tank fuel is used?

A4. Wing Tank.

Q5. Why gravity feeding is not possible from center tank?

A5. The Center Tanks are not fitted with suction valves. Therefore, gravity feeding is not possible from the Center Tank.

Q6. What is the maximum fuel imbalance between the left and right wing tanks (outer + inner) for the A320?

A6. Max. allowed wing fuel imbalance :-

Heavy Tank Content Max Allowed imbalance

Full 1320 Kg

4000 kg 1450 Kg

2350 Kg 2350 Kg

(Empty on other side)

Q7. How will you know that center tanks are supplying engines?

A7. “CTR TK FEEDG” appears in Green on the E/WD if at least one Center Tank pump is energized.

Q8. When there is a fuel in center tank with wing tanks full, why do you get CTR TK FEEDG memo during engine start {MODE SEL at AUTO}?

A8. With MODE SEL P/b at AUTO, the Center Tank pumps run at engine start for 2 minutes, this is why the CTR TK FEEDG Memo comes on.

Q9. What happens to the center tank pumps when SLATS are extended after engine start, when there is a fuel in center tank with wing tanks full (mode selector at AUTO)?

A9. When Slats are extended after engine start with MODE SEL P/b at AUTO, the Center Tank pumps are switched off.

Q10. If all criteria for center tank fuel usage have been met, when will the center tank pumps resume supplying after takeoff?

A10. After the Slats have been retracted.

Q11. After takeoff, “CTR TK FEEDG” appears on the E/WD. When did the center tank fuel begin feeding the engines?

A11. After Slat Retraction.

Q12. How can you know that the cross feed valve is fully open?

A12. On the Overhead FUEL panel,

OPEN Light comes on in Green when the valve is fully open.

On the ECAM FUEL page,

The X-feed indication is Green In-Line showing valve open.

On the E/WD,

FUEL X FEED Memo appears in Green if FUEL X FEED valve P/b s/w is ON & X FEED valve is not fully closed.

Q13. How will you detect a fuel leak?

A13. A Fuel leak may either be detected by :-

(a) The sum of FOB and F.used significantly less than FOB at departure, or decreasing, or

(b) Passenger observation (Fuel spray from engine or wing tip), or

(c) Total Fuel quantity decreasing at an abnormal rate, or

(d) A Fuel imbalance, or

(e) A Tank emptying too fast (leak from engine, or a hole in tank), or

(f) A Tank overflowing (due to a pipe rupture in a tank), or

(g) An excessive fuel flow (leak from engine), or

(h) A Fuel smell in cabin

(i) The destination EFOB turns to Amber on the F.PLN (or on the FUEL PRED) page, or “DEST EFOB BELOW MIN” appears on the MCDU scratchpad.

If visibility permits, a visual check from the cabin may enable identification of the leak source.

Q14. When and how the fuel is normally transferred from the outer to inner wing tanks?

A14. The Transfer valves automatically open when the inner tank fuel reaches the low level (about 750 kg), thus permitting fuel to drain from the outer to inner tanks. When open, the valves are latched open. They will automatically close at the next refuel operation. (MODE SEL at REFUEL position).

Q15. What are the indications when fuel from outer tank gets transferred to inner tank?

A15. On the ECAM FUEL Page,

The Transfer valve indication in Green shows open position.

On the E/WD,

OUTER TK FUEL XFRD appears in Green if at least one transfer valve is open in one wing tank.

Q16. During the descent “OUTER TK FUEL XFRD” appears. What causes this memo to appear?

A16. The transfer valves automatically open when the inner tank fuel reaches the low level (about 750 kg). The 750 kg value is based on a level aircraft attitude with no acceleration. During steep descents or accelerations/decelerations, the transfer valves may open with more than 750 kg of fuel in each inner tank and the low level warning may be triggered.

Q17. What is the “Fuel Recirculation System”?

A17. Some of the fuel supplied to each engine goes from the high pressure fuel lime in that engine, through the IDG heat exchanger (where it absorbs heat), to the fuel return valve, and to the outer fuel tank. This operation ensure the IDG cooling when the oil temp. is high or when at low engine power. The fuel recirculation system moves the warm fuel from the IDG cooling system back to the related wing tank.

Q18. If the fuel pumps in the left fuel tank were OFF, how would the APU obtain fuel?

A18. A special fuel pump supplies fuel for APU startup when fuel feed pressure is low (due to loss of tank pumps or loss of normal AC electrical supply). This pump normally runs off the AC ESS SHED bus, but runs off the AC STAT INV bus if the AC ESS SHED bus fails.

Q19. When do you get FAULT light in MODE SEL p/b for FUEL?

A19. Amber Fault Light come son in the MODE SEL P/b and ECAM caution comes when the Center tank has more than 250 kg of fuel and the left or right wing tank has less than 5000 kg.

Q20. What care do you have to take when applying “GRVTY FUEL FEEDING” Procedure?

A20. While applying “GRAVTY FUEL FEEDG” procedure, care should be taken to avoid Negative G Factor.

Q21. During flight an ECAM caution of FUEL L INNER TK LO TEMP is triggered. What are the crew actions?

A21. In Flight,

FUEL L INNER TANK LO TEMP

This is for crew awareness. Consider descending to a lower altitude and/or increasing Mach to increase TAT.

Q22. How about crew actions if same caution is triggered but in outer tank?

A22. Same as above.

Q23. What is the meaning of ECAM caution titled as FUEL AUTO FEED FAULT?

A23. The AUTO FEED FAULT indicates that the Automatic fuel feeding sequence is not working properly. The warning comes on when :-

(a) Fuel in one wing < 5000 Kg and in Center tank > 250 Kg.

(b) CTR TK Pumps running after Slat extension or LO Level in the center tank.

Q24. If CTR TK PUMPS keep running after slats extension, which ECAM will be triggered?

A24. FUEL AUTO FEED FAULT warning would be generated.

Q25. On FUEL ECAM page, if you see FOB half boxed in amber, what is the meaning?

A25. An Amber half box appears around FOB when the quantity shown is not all usable. (Inter-cell transfer valve failure or loss of center tank pumps).

Q26. On FUEL ECAM page, if you see an amber line appearing across the last two digits for FOB, what is the meaning? Which procedure has to be applied?

A26. An Amber line appears across the last two digits when the FQI is inaccurate. In case the FQI is in degraded mode, the ECAM FUEL page must be called on ECAM lower display to determine which tank is affected.

The loss of accuracy resulting from the loss of FQI normal mode is as follows :-

Wing outer cell affected : +20 Kg, -200 Kg

Wing inner cell affected : +/- 110 Kg

Center tank affected : +/- 130 Kg

All tanks affected : +390 Kg, -750 Kg

Q27. On FUEL ECAM page, if you see fuel quantity indication boxed in amber, what is the meaning?

A27. The Outer indication is boxed amber if both transfer valves fail to open when inner at low level.

The Center tank indication is boxed amber if both Center tank pumps are failed or switched off.

Q28. On FUEL ECAM page, if you see an amber line appearing across the last two digits for fuel quantity, what is the meaning? Which procedure has to be applied?

A28. An Amber line appears across the last two digits when FQI s inaccurate. In case the FQI is in degraded mode, the ECAM FUEL page must be called on ECAM lower display to determine which tank is affected.

The loss of accuracy resulting from the loss of FQI normal mode is as follows :-

Wing outer cell affected : +20 Kg, -200 Kg

Wing inner cell affected : +/- 110 Kg

Center tank affected : +/- 130 Kg

All tanks affected : +390 Kg, -750 Kg

Q29. Is refueling possible if the aircraft batteries are the only source of power?

A29. The aircraft can be refueled only when Battery power is available.

Q30. FOB on FUEL ECAM Page is boxed amber when quantity shown is not fully usable. When can this happen?

A30. This can happen when :-

(a) The center tank pumps have failed

(b) Both transfer valves fail to open when inner cell at low level.

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8 thoughts on “FUEL SYSTEMS”

  1. Hello
    i need a general question box of A320.
    If u have,please send it for my gmail.

    With best regards.
    Kouchaki

  2. Q1) Few variants have the following fuel capacity:

    18692 kg, 18968 kg, 19004 kg.

    Q2) A320 is certified for JET A1, JP 8, JET A, JP 5, RT, TS-1, JET B, JP 4 and N°3 JET.

    Q6) Max fuel imbalance given in A6 is for A321.

    For A320 it is as follows:

    A320 Non Sharklets:

    Max Inner tanks imbalance (Outer tank balanced), inner tank a) LH/RH Full – 1500 kg, b) LH/RH 4300 kg – 1600 kg, c) LH/RH 2250 kg – 2250 kg. No limitation below 2250 kg.

    Max outer tank imbalance : 690 kg provided a) Fuel content of one side (outer + inner) is equal to the fuel content of the other side (outer + inner) or b) On the side of the lighter outer tank, the inner tank fuel quantity is higher than the opposite inner tank quantity, up to a maximum of 3000 kg higher.

    A320 with Sharklets:

    Max inner tank imbalance at take off (outer tank balanced) : a) LH/RH Full – 500 kg, b) LH/RH 3000 kg – 1050 kg, c) LH/RH 1450 kg – 1450 kg.

    Max outer tank imbalance at take off (inner tanks balanced) : 370 kg.

    For landing same as for Non sharklets.

    Q29) Just to avoid confusion, ‘The aircraft can be refueled even if when only Battery power is available.’

  3. DEEPIKA SHARMA said:

    thank you all for this effort..
    i too would like to add a Question

    Q: FOB/F.used Disagree generates a Master caution . when is in inhibited?

    Ans:Inhibited only if Apu has been running for more than 30 mins after T/O

  4. Why a logic of 2 minutes cntr tank pumps run always during starting of engines?????

  5. Michael Kenslow said:

    Does the Airbus line use frame check valves in the fuel tanks, like Boeing Does?

  6. Mohamed a.alra said:

    Do u have any PDF copy from that and thanks a lot for this information

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