A320 Transfer Valves Failure
CBs, SOPs, and FROST.
Yup, the CBs invariably did the trick in my day (1988-2001), but SOPs may frown on the practice nowadays?
I hope not, because - if you need the fuel - what else can you do?
There was another situation when we used them: to transfer the outer-tank fuel to the mains before the scheduled main-tank quantity. [I don't think that wing-bending relief is now a problem on the A320, but you had better check.] For the uninitiated, this was sometimes done before TOD (or after landing) into an airfield where it was cold and humid, to ensure that the outers would be refilled with fresh (warmer) fuel. That way you avoided or melted the (illegal) frost on the TOP surface of the outer wing, as well as the (normally acceptable) frost on the bottom.
We had official guidelines for the above procedure, but don't know if SOPs have changed...
I hope not, because - if you need the fuel - what else can you do?
There was another situation when we used them: to transfer the outer-tank fuel to the mains before the scheduled main-tank quantity. [I don't think that wing-bending relief is now a problem on the A320, but you had better check.] For the uninitiated, this was sometimes done before TOD (or after landing) into an airfield where it was cold and humid, to ensure that the outers would be refilled with fresh (warmer) fuel. That way you avoided or melted the (illegal) frost on the TOP surface of the outer wing, as well as the (normally acceptable) frost on the bottom.
We had official guidelines for the above procedure, but don't know if SOPs have changed...
Last edited by Chris Scott; 14th Mar 2008 at 21:06. Reason: Frost clarification.
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Originally Posted by zisis
How can i use the fuel from the outer tanks, when the transfer valves fail to open?
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Transfer Valves closed
What exact ECAM message is being seen? How much fuel was in the inners at the time? Which flight phase did it occur??? All these have a bearing to indicate if there is a hard or spurious fault!
The system is such that (in general) the forward L & R XFR valve are controlled by one set of low level circuits (in both L & R wing) and the aft set of L & R XFR valves controlled by another set of low level sensors (in left and right wing).
What does this mean in practice?? In short if you get to such that the low level sensors in the L or R inner tank (approx 750 kg) go dry then the related XFR valves for those sensors (either fwd or aft) on both wings opens.
The ECAM warning L(R) OUTER TK UNUSABLE should only occur at the point that the XFR valves are commanded open (due to the BITE logic). Also a failure in the control circuit (relay or otherwise) would only fail the forward or aft XFR valves. There will need to be a dual failure to fail the forward and rear on the left and right wings such that the ECAM indication L OUTER TK UNUSABLE and R OUTER TK UNUSABLE appear at the same time!!!
Airbus have released a TFU which covers XFR valve warnings that happen on both L & R wings at the same time - worth checking it out.
In short one of the recommendations for L & R XFR valve messages is to reset the FQIC (C/B's 1QT and 2QT). What this does is perform a Power on Bite of the fuel sstem which cycles the XFR valves, and clears the problem.
Hope this can give some guidance.......
The system is such that (in general) the forward L & R XFR valve are controlled by one set of low level circuits (in both L & R wing) and the aft set of L & R XFR valves controlled by another set of low level sensors (in left and right wing).
What does this mean in practice?? In short if you get to such that the low level sensors in the L or R inner tank (approx 750 kg) go dry then the related XFR valves for those sensors (either fwd or aft) on both wings opens.
The ECAM warning L(R) OUTER TK UNUSABLE should only occur at the point that the XFR valves are commanded open (due to the BITE logic). Also a failure in the control circuit (relay or otherwise) would only fail the forward or aft XFR valves. There will need to be a dual failure to fail the forward and rear on the left and right wings such that the ECAM indication L OUTER TK UNUSABLE and R OUTER TK UNUSABLE appear at the same time!!!
Airbus have released a TFU which covers XFR valve warnings that happen on both L & R wings at the same time - worth checking it out.
In short one of the recommendations for L & R XFR valve messages is to reset the FQIC (C/B's 1QT and 2QT). What this does is perform a Power on Bite of the fuel sstem which cycles the XFR valves, and clears the problem.
Hope this can give some guidance.......
Thanks, JetAGoblin. What I carelessly neglected to say, in my post above, was that you ALWAYS RE-SET the 4 CBs you have tripped (after 2 - 10 seconds). Also, it doesn't always work first time - perhaps if you reset too quickly?
I'm sure this is also what Dream Land and Silky meant.
I'm sure this is also what Dream Land and Silky meant.
