A320 Fuel Transfer Valves
 

Please can anyone technical help with this one?
I was led to believe that the A320 Fuel Transfer Valves were energised closed and 'relaxed' open in case of DC2 failure, but this appears from the FCOM not to be the case. There are 2 "Fuel Txfr" Cbs on 49VU. If all else fails, would pulling these CBs allow the Txfr Valves to open?
I have looked at the AMM but find it almost incomprehensible to a mere pilot.
Cheers
mcdhu

If I were designing the system I would want the valves to fail open , so,denying them electrical power by cb action would stop the transfer and this is I believe how Airbus designed the system.
The Cbs stop power to the two flscu which control the transfer..

Unfortunatelly each of four fuel transfer valves (two per side, so you can find next two C/B on panel VU 122 if I remeber location correctly) needs el. power for opening or closing. Valve itself is driven by electrical motor, which turns with valve via gearbox every time one quart of turn still in one direction to change from open to close and vice versa. It means there is no "fail safe" positon. But yes, on ground, you can open transfer valves by reseting C/Bs, as described in procedure for MEL (you can find it in AMM), if system is at least partialy powered. Don't know if such procedure is in QRH/FCOM for inflight use.

Is it an idle query or you want to do it? Before I pull any CBs that I am not allowed to open, I would wait for the inquiry report of Indonesia Air Asia flight 8501.

Thank you Vilas.
I am well aware of the danger of pulling CBs that are not in the Computer Reset section of the QRH. However it would be nice to know whether or not it is possible to use the outer wing tank fuel rather than running out in the event of DC1+2 fault.
I suspect it is not possible otherwise AI would have inserted it as a procedure.
So the answer to your question is - no, it is not an idle query but more of a technical exploration of the A320 so that I can answer the question when posed to me in the sim - where I live!
mcdhu

The majority of valves on large aircraft must be powered to actuate - on or off.

mcdhu
DC1+2 or DC1 or DC2 fail I don't see anything on transfer valves can you quote exact words?

vilas
FCOM DSC-28-40 Electrical supply, Intertank XFR Valves L2 & R2 are normally supplied by DC2, L1 & R1 supplied by DC ESS SHED bus.

The DC ESS SHED bus is only shed when you are in Emergency ELEC config & the RAT has dropped off line, leaving the buses only powered by the batteries.

Goldenrivett
As no.1 transfer valves are available when DC2 or DC1+2 fails ECAM and STATUS doesn't say anything about transfer valve. So obviously there is no fuel availability problem. I am not understanding the meaning of If all else fails. So where does CB pulling comes in?

Thanks guys. This came up in a CAE built sim the other day. Inserted DC1+2 Fault. Status said 'Outer Tank Fuel unuseable' so I was wondering how, if you were up against it, you might get that 1.5T of gas back. I agree that the FCOM for the aircraft I am involved with do not reflect that. Must be a sim thing!
It appears from the helpful answers above that you do need electrical power to motor the transfer valves open and closed.
Cheers
mcdhu

Valves have been known to stick, even if exercised regularly like these ones are. I had a low level ECAM a while back due to a stuck valve but as we were on final at the time there was no problem.

That this is even a question is worrying. There used to be the term "grease monkey" perhaps it's time for the term "stick monkey"

Yes, no matter what you post here, there's always one who seeks to mock.
Thanks for the sensible answers guys. I'm out.
mcdhu

There is a computer reset procedure related to the simultaneous triggering of the OUTER XFR CLOSED caution which basically asks you to reset the FQIC CBs rather than the CBs associated to the valves themselves.

sonic
This reset is for false warning of loss of fuel quantity indication or transfer valves closing when system display does not confirm it. it does not do anything to transfer valves themselves but resets the system.

Good Day All,

In a CAE built sim the other day. Inserted DC1+2 Fault. Status said 'Outer Tank Fuel unuseable' so I was wondering how, if you were up against it, you might get that 1.5T of gas back

Are you sure about the status?
On my Fcom, Status is: CTR TK UNUSABLE
From what I can see you'll get the 1.5 T of fuel on due time, according to the "logic" of the fuel system.

Note: Maybe, you though about the others Xtransfer valves for Fuelling/Refuelling purpose; but those ones are inhibited on ground (explaining your question about pulling CB's??)

Have a good one!

First off, congratulations replying to a 4 year old thread, a time in which airbusses have changed quite a bit. Not to mention, that that question was about simulator behaviour, some simulators do have quite a few differences from the real plane, or are on a very old standard of planes.

And then, of course, it depends on your MSN which message you get, some have after all CTR TANK USABLE BY GRAVITY in that case (well, except for the last 2T).

;) devil's advocate: Which did it say?

OUTR TK UNUSABLE
CTR TK UNUSABLE

Indeed, no way of remembering after all this time, but just imagine for a second the twilight inside SIM, the green font on a black background with reading glasses on .. OTR TK or CTR TK? Fuel page not in sight due to STS overlay on the SD.

https://cimg7.ibsrv.net/gimg/pprune....3298d869e5.jpg

The type of perception error I am perfectly capable of. Could have been wrong programming and OUTR shown instead of CTR as well. Same issue except on the side of the SW engineer.