A320 Strange fuel consumption scenario!
 

Hi there, please check my hyperlink in below, and answer my questions if you can. This is happened few days ago in my flight, and all photos are taken at there real time.

https://onedrive.live.com/redir?resi...int=file%2cpdf

Hi hossein, I have read your document and your questions. Before starting to answer your questions I actually have one for you : what about applying the manufacturer's instructions when flying in normal / abnormal conditions ?

Hi hossein,

1. Is this happened because of any sensors or FQI fault?
Ans = No.

2. If so, is there any relation between these faults with HIGH EGT and HIGH OIL PRESSURE?
Ans = No.

3. How do FOB,F.USED and F/F showed such a these things? And which one is the most trustable reference?
Ans = They all seem reasonably reliable and sensible. (How much APU fuel was used?)

4. And if so, why we've had heavy left wing?
Ans = When you had the fuel X feed open, the fuel will be delivered from the tank with the pump giving the highest fuel delivery pressure (in your case the right tank pump).

5. If this flight had more than 1 hour duration, what should we expect more?
Ans = The right pump would continue to deliver all the fuel to both engines until you did the fuel imbalance procedure, which would involve turning the lighter (RHS) pumps off.

6. Is refilling a quiet amount of center tank for short flights being necessary?
Ans = No. I often see about 50 kgs fuel remaining in centre tank.

Applying the ECAM/QRH/FCOM procedures wouldn't be a bad idea too.

Oh dear :sad:

I can only echo above posts. If you do not understand how your aircraft works, please at least follow the instruction book :{

A320 Strange fuel consumption scenario!
 

Tnx for your quick reply dears,
Ofcourse we did all ECAM/QRH/FCOM PROC, even we're completely ready for worst case such as both engine flame out and all procedures through.
Maybe I didn't hit the point.
APU was INOP from start.
QRH FUEL IMBALANCE was done as you see in the picture.
The major question is why Left Wing Tank Quantity at detination is the same as we start from departure point. 3300 kg remains all the way on the left tank, no change, with consumption of Eng#1 ! Heavy left wing. Is it both left wing pump fault or what?

QRH fuel imbalance requires both pumps to be turned off on the lighter side, you still have one on.

QRH/ECAM etc. aside, with the pump setup as presented by Hossein I'd still expect fuel to be drawn from the LH tank...

What am I missing? Would there be any reason the remaining pump on the RH side had higher output pressure than the LH wing pumps?

As a side note, I've seen this happen to a CTR pump once. With Center tank in use we noticed a developing unbalance and eventually traced it down to LH CTR pump having lower output pressure than the corresponding wing pumps. There was no 'LO PR' fault, but the center fuel obviously didn't feed the LH engine.

Applying the "fuel auto feed fault" ECAM procedure didn't solve the issue. We eventually switched off the faulty pump and opened x-feed to enable the other CTR pump feed both sides...*

*After careful checking for possible leak

Hi hossein,
If "Total fuel on board 7600 kg
(3300kg each wing tank with NO IMBALANCE)"
Then you must have started with 1,000 kgs in centre tank, which was used once the Flaps/Slats were set to zero. Therefore you only used fuel from the Left Tank during Take off and early Climb (say 500 kgs).
You had at one stage 3440 Kgs in Left Tank (2730+710) which shows that the NRV (Non Return Valve) to the Left Tank was leaking slightly and that the pump output from the RHS pump was greater than the pump pressure of either of the two LHS pumps.

That is why all fuel plumbings have X feed valves etc. to prevent fuel migration from one side to the other. If you had turned both pumps off in the RHS, then only the fuel from the LHS would have been used.

Hossein.

You file an ASR, and make a tech log entry

If the engineers cant find anything, you/they ask for the FDR to be removed, downloaded, and sent to Airbus for analysis.

Then, you will get your answers.

When you build a pump, it will have a specified nominal output pressure, and an acceptable "range". If you fit 4 of these identical pumps to an aircraft, by definition, they will all have slightly different output pressures.

As above, the QRH balancing process is clear - you turn off BOTH pumps on the lighter side. You then MONITOR very closely the balance, and do not let it build up. If you just turn off 1 pump, you might as well toss a coin in the air as to which tank will supply the fuel: L, R, or both.

With a confirmed engine problem on climb out why did you not return to the departure airport? You also need to turn both pumps off to balance fuel.

Thanks NoD. So in this case the pump feeding both engines is whichever has the highest output pressure...

How about balaning fuel in case of engine failure? In my outfit we are taught to switch the x-feed on and keep all 4 pumps in to draw fuel from both tanks to the live engine. In the sim it works like a charm. How about real life? I suspect it may lead to situation similar to that described by the OP?

It only works that way in the simulator because the pumps are simulated by a piece of software which of course has all of them running exactly on spec which in turn means the same output pressure for each pump. As explained above that never works in real life as there is an acceptable range of output pressure. Simply keeping all pumps on and opening the crossfeed valve is therefore pretty stupid as the result will be kinda random, not controlled.

There were a few pilots who used the same "technique" in the simulator in my outfit. They were reminded about the error of their ways and in some stubborn cases failed and send back for retraining (a failed check will only lead to retraining and recheck, nothing more no matter how long it takes).

Follow the OEM guideline on that and everything will be fine.

Great question C* - We are taught exactly the same as you. Denti - where is this OEM information please re: eng fail case. Not doubting it at all, just wanting to read it!

Best pump wins...

Hi C_Star,
If you have an engine failure, and keep the fuel X feed closed, the fuel imbalance will still grow at the rate you are consuming fuel by your running engine.

If you open the fuel X feed (with no fuel leak), then the imbalance rate cannot be any worse (it may even be less if you have a stronger pump on the dead engine side). The benefit is all the fuel is now available to your only running engine. You won't starve the engine until all the fuel is exhausted.

Thanks Goldenrivett :ok:

Now it's perfectly clear - leaving x-feed on may not prevent imbalance, but won't hurt either and can prevent fuel starvation due to fuel mismanagement...

Not as stupid as flaming out with fuel available because your company refuses you to fly an approach with the crossfeed open with all pumps running.

Hi Denti,
Did you really fail some pilots for ensuring they didn't run out of fuel?

Which OEM guidelines are you referring to?

Look at fuel management QRH guidelines "Fuel Leak" ... Leak from engine/pylon confirmed."
After the engine is secured with:
TL ... IDLE
ENG Master (of affected engine)...OFF,
the next line advises:
"FUEL X FEED ... use as required,
If the leak stops, the crossed valve can be opened to rebalance fuel quantity, or to enable use of fuel from both wings."

After an engine is secured and no fuel leak confirmed, why can't you use the fuel from both wings simultaneously in your outfit?