A320 Fuel leak procedure
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Both A320/321 have feeding presurized plumbing inside CTR/CTR TRANSFER tank. I think there is space for such scenario if double problem exists - leak from a feed line inside CTR tank and full sensor/transfer valve fault. In such situation can be fuel transfered from one inner to another via CTR tank and its tansfer system on 321...at least theoretically 
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capt937895565
What you stated is correct and I received the same reply from Airbus. Interesting thing is the question about the significance of 3Tons was asked by one of Airbus industry instructor himself and the answer given by them was that engineering cannot not find any significance about it so they plan to delete it. But they have not deleted even now after 7years. When I asked them this question they gave me detailed reply as yours. Then I asked them to remove the earlier one from FAQ. They replied that the respective department has been instructed. But they have not done it.
What you stated is correct and I received the same reply from Airbus. Interesting thing is the question about the significance of 3Tons was asked by one of Airbus industry instructor himself and the answer given by them was that engineering cannot not find any significance about it so they plan to delete it. But they have not deleted even now after 7years. When I asked them this question they gave me detailed reply as yours. Then I asked them to remove the earlier one from FAQ. They replied that the respective department has been instructed. But they have not done it.
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folks, talking about fuel... the newest A320 MSN have a maximum allowed fuel imbalance that is different between takeoff and in-flight/landing. Where does that come from ? On the "old" MSN the tables do not differentiate between different phases of flight.
Thanks
Thanks
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How do I correctly interpret the second case in the A320 fuel leak procedure, where it says "Leak from engine/pylon not confirmed or leak not located"?
This part of the procedure calls for the actions to be done to determine if the fuel leak is from the engine, wing, or center tank. If cabin crew and passengers or the Pilots themselves observe a fuel trail from the wing away from the engine and pylon; fuel SD page shows the respective side fuel decreasing, will I be right to say that we can safely assume that the fuel is leaking from the wing tank, without having to run this part of the procedure of shutting down the respective side engine etc? My instructor says we should still run this procedure regardless, but It seems obvious to me it's from the tank in this case. Unnecessary to apply this procedure to conclude the leak is from the wing. Any objections?
This part of the procedure calls for the actions to be done to determine if the fuel leak is from the engine, wing, or center tank. If cabin crew and passengers or the Pilots themselves observe a fuel trail from the wing away from the engine and pylon; fuel SD page shows the respective side fuel decreasing, will I be right to say that we can safely assume that the fuel is leaking from the wing tank, without having to run this part of the procedure of shutting down the respective side engine etc? My instructor says we should still run this procedure regardless, but It seems obvious to me it's from the tank in this case. Unnecessary to apply this procedure to conclude the leak is from the wing. Any objections?
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dream747
The fuel leak procedure is a bit ritualistic. The procedure LEAK FROM ENGINE/PYLON NOT CONFIRMED or LEAK NOT LOCATED also assumes that there is fuel in center tank. When there is no fuel in the center tank then it is straight forward case of leak from one side because the cross feed is always off and fuel imbalance will also be developing. But still leak can be from engine or tank. Even if leak is from engine it can be from upstream or down stream of fuel flow meter. In case of fuel leak down stream of FF meter the sum total of FU+FOB will match fuel at departure but the FF on that side will be high but in upstream leak case it will not match. So there are variables and to avoid too much thinking and hasty conclusion it is safer to run through the procedure.
The fuel leak procedure is a bit ritualistic. The procedure LEAK FROM ENGINE/PYLON NOT CONFIRMED or LEAK NOT LOCATED also assumes that there is fuel in center tank. When there is no fuel in the center tank then it is straight forward case of leak from one side because the cross feed is always off and fuel imbalance will also be developing. But still leak can be from engine or tank. Even if leak is from engine it can be from upstream or down stream of fuel flow meter. In case of fuel leak down stream of FF meter the sum total of FU+FOB will match fuel at departure but the FF on that side will be high but in upstream leak case it will not match. So there are variables and to avoid too much thinking and hasty conclusion it is safer to run through the procedure.
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Thanks Vilas for the insight.
Are we allowed to use the fuel cross feed after ascertaining that the fuel leak is from the wing tank? Procedure says do not apply fuel imbalance procedure, but does it mean we cannot use the crossfeed as well? The confusion I have stems from the fuel diagram which is not very clear to me. With the fuel crossfeed on, does fuel come from the good wing tank and goes into the opposite leaking tank, or just straight through into the Engine of the leaking side tank?
Are we allowed to use the fuel cross feed after ascertaining that the fuel leak is from the wing tank? Procedure says do not apply fuel imbalance procedure, but does it mean we cannot use the crossfeed as well? The confusion I have stems from the fuel diagram which is not very clear to me. With the fuel crossfeed on, does fuel come from the good wing tank and goes into the opposite leaking tank, or just straight through into the Engine of the leaking side tank?
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If fuel leak is identified but not stopped you cannot use cross feed. There is no inter tank transfer but I guess pipeline used is same. Most important thing after leak is identified is LAND ASAP. Select a diversion within a range without leaking side fuel quantity. Cross feeding is not required for balancing. Landing can be done with one side full and other side empty.
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Clarifying imbalance
One small note about the procedure:
It says that if fuel leak stops xfeed can be opened to rebalance fuel quantity or to enable use of fuel of both wings.
Opening xfeed for both wings feeding one engine:
Well the truth is opening the xfeed will further aggravate the imbalance
Let s imagine 5000 on left side and 2000 on the right side , once the xfeed is open you might end up in 5000 on left side and 0 on the right so a greater imbalance.
About rebalance:
I dont understand how Airbus can seriously call for a rebalance as imbalance procedure calls for switching off the fuel pumps on the heavier side
Now with one engine inoperative would you switch off the fuel pumps on the live engine just to rebalance?
And by just xfeeding imbalance will increase. So how rebalance is at all possible?
The only reason to xfeed should be to reach your airport if you need that fuel. As for rebalancing and xfeeding something is definitely wrong in the procedure.
Just to clarify things about imbalance, i will mention the famous never ending engine failure scenario we usually practice at v1.
The live engine has been operating on its respective wing tank side for a while, therefore the operating engine side has a lower fuel quantity that the inop side and xfeeding make sense and could hep
On the fuel leak scenario the good side has a higher fuel quantity than the "leaking" side therefore xfeeding will further increase the imbalance.
Therefore whenever the good side has a higher fuel quantity than the damaged side do not xfeed unless needed to reach an airport.
When the "live or good" side has a lower fuel quantity than the damaged side (engine failure case) xfeed will help to protect the good side
That was for xfeed.
As for imbalance procedure , in my opinion, this should only be considered with 2 "healthy" sides as it involves switching OFF pumps on the only remaining operative side.
It says that if fuel leak stops xfeed can be opened to rebalance fuel quantity or to enable use of fuel of both wings.
Opening xfeed for both wings feeding one engine:
Well the truth is opening the xfeed will further aggravate the imbalance
Let s imagine 5000 on left side and 2000 on the right side , once the xfeed is open you might end up in 5000 on left side and 0 on the right so a greater imbalance.
About rebalance:
I dont understand how Airbus can seriously call for a rebalance as imbalance procedure calls for switching off the fuel pumps on the heavier side
Now with one engine inoperative would you switch off the fuel pumps on the live engine just to rebalance?
And by just xfeeding imbalance will increase. So how rebalance is at all possible?
The only reason to xfeed should be to reach your airport if you need that fuel. As for rebalancing and xfeeding something is definitely wrong in the procedure.
Just to clarify things about imbalance, i will mention the famous never ending engine failure scenario we usually practice at v1.
The live engine has been operating on its respective wing tank side for a while, therefore the operating engine side has a lower fuel quantity that the inop side and xfeeding make sense and could hep
On the fuel leak scenario the good side has a higher fuel quantity than the "leaking" side therefore xfeeding will further increase the imbalance.
Therefore whenever the good side has a higher fuel quantity than the damaged side do not xfeed unless needed to reach an airport.
When the "live or good" side has a lower fuel quantity than the damaged side (engine failure case) xfeed will help to protect the good side
That was for xfeed.
As for imbalance procedure , in my opinion, this should only be considered with 2 "healthy" sides as it involves switching OFF pumps on the only remaining operative side.
Last edited by Citation2; 6th Sep 2017 at 20:12.
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Citation2
If you read the procedure wrongly then you wouldn't understand. The procedure calls for switching off lighter side fuel pumps and not heavier side. This is one of the simplest of procedures and it appears you have tied yourself in knots over it.
I dont understand how Airbus can seriously call for a rebalance as imbalance procedure calls for switching off the fuel pumps on the heavier side
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dream747
The fuel leak procedure is a bit ritualistic. The procedure LEAK FROM ENGINE/PYLON NOT CONFIRMED or LEAK NOT LOCATED also assumes that there is fuel in center tank. When there is no fuel in the center tank then it is straight forward case of leak from one side because the cross feed is always off and fuel imbalance will also be developing.
The fuel leak procedure is a bit ritualistic. The procedure LEAK FROM ENGINE/PYLON NOT CONFIRMED or LEAK NOT LOCATED also assumes that there is fuel in center tank. When there is no fuel in the center tank then it is straight forward case of leak from one side because the cross feed is always off and fuel imbalance will also be developing.
Having this fault in that particular scenario adds another intricacy to whole thing as, in theory at least, you might action case one first, which instructs you to shut down the leaking side engine which is always, you guessed it: the side with the live generator. This would leave you with just one gen alive (APU) and OEI for nothing as this is not where the leak is. What skipper and I decided to do was to read the rest of the procedure but not performing any actions to try and find some logic in the procedure before doing anything. After discarding the symptoms for a possible engine/pylon/wing tank, we just skipped case one altogether and went straight to case two, shut down the APU and that was it.
@citation2
One of the lines on ECAM after engine failure is "Imbalance... Monitor". It is my understanding that in the past that line used to say "Xfeed... Open". After several fuel advisories doing initial training (especially if after flying the EOSID we'd fly a single engine go around for another EOSID), if opening the Xfeed such advisory wouldn't pop up. Now, I'm not sure how it works since during the whole procedure you don't turn the receiving (not supplying) tank pumps off, but it works and it keeps the tanks balanced. Although it's not important on the A320, as vilas said, because you can land with one wing full and one wing empty without any issues
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The old qrh said open the x-feed after an engine failure after confirming no leaks. This procedure worked well on the sims. Sims are a bunch of electronics which meant both sides were giving equal fuel pressures. The real pumps have slightly different output pressures. On the real aircraft with all wing pumps running & crossfeed open it is possible that the live engine may be just using all the fuel from either wing. The (new) qrh procedure of monitoring the fuel imbalance makes better sense as long as it is not forgotten. Funny how long it took airbus to change the procedure however.
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On the real aircraft with all wing pumps running & crossfeed open it is possible that the live engine may be just using all the fuel from either wing.
Last edited by Goldenrivett; 8th Sep 2017 at 12:45. Reason: typo
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Villas , please next time you go the sim try to balance your tanks after a fuel leak and one engine shutdown. If you succeed in it I ll be happy to learn from you.
Again by opening the xfeed in a fuel leak there is no way to rebalance the tanks but simply increase the imbalance.
Very good thanks for spotting my mistake regarding the fuel imbalance , indeed the lighter side has to be switched off. So if you want to apply the imbalance procedure in a fuel leak you will switch off the fuel pumps on the "leaking lighter side " and send the fuel from the good side to the tank leaking ?
No way to rebalance . X feed is not made for that purpose but to consume from a dead side , thus further increasing an imabalance .
As for the engine failure scenario itself it is totally different as the "live side" has lower fuel than the dead side, as the live engine has been operating for a while on only one tank, then opening the xfeed will help to rebalance and consume from the dead side full of fuel.
My point is , if the live side has lower fuel than the dead side (engine fail at v1 only), xfeed will help
Fuel leak scenario , dead side has lower fuel than live side , xfeed will increase the imbalance.
Again by opening the xfeed in a fuel leak there is no way to rebalance the tanks but simply increase the imbalance.
Very good thanks for spotting my mistake regarding the fuel imbalance , indeed the lighter side has to be switched off. So if you want to apply the imbalance procedure in a fuel leak you will switch off the fuel pumps on the "leaking lighter side " and send the fuel from the good side to the tank leaking ?
No way to rebalance . X feed is not made for that purpose but to consume from a dead side , thus further increasing an imabalance .
As for the engine failure scenario itself it is totally different as the "live side" has lower fuel than the dead side, as the live engine has been operating for a while on only one tank, then opening the xfeed will help to rebalance and consume from the dead side full of fuel.
My point is , if the live side has lower fuel than the dead side (engine fail at v1 only), xfeed will help
Fuel leak scenario , dead side has lower fuel than live side , xfeed will increase the imbalance.
Last edited by Citation2; 9th Sep 2017 at 16:02.
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Citation2
I think you read the fuel leak procedure in a hurry . First you mistakenly assumed that the procedure requires to switch off heavier side. Now also you are mistakenly assuming that it asks you to balance the fuel if a leak is located and stopped with engine shut down. No! It doesn't. All it says is as below:
True you may have less fuel on the dead side because of fuel leak but nobody asks you to balance. Select your diversion and continue there. When live side fuel becomes less and if you need dead side fuel then open the cross feed and switch off lighter side pumps. The procedure is called imbalance procedure but in this case it is not for balancing. As for as the imbalance bogey is concerned FCOM below:
I think you read the fuel leak procedure in a hurry . First you mistakenly assumed that the procedure requires to switch off heavier side. Now also you are mistakenly assuming that it asks you to balance the fuel if a leak is located and stopped with engine shut down. No! It doesn't. All it says is as below:
If leak stops: ENGINE LEAK CONFIRMED
FUEL X FEED.............................................AS RQRD
DO NOT RESTART AFFECTED ENGINE
FUEL X FEED.............................................AS RQRD
DO NOT RESTART AFFECTED ENGINE
Note: There is no requirement to correct an imbalance, until the ECAM fuel advisory is displayed.
