Narrative:

Reference MEL 2821C. We were dispatched and I accepted a fuel load of 40.2 for flight ZZZ to ZZZ1. This was for economic ferry. The #1 center tank fuel pump was deferred. As per the MEL after takeoff checklist was completed we opened the xfeed and switched on the #2 center tank pump. At the time we did this the right wing tank was showing approximately 11700 pounds almost full. Shortly before cruise altitude I noticed the #2 center pump showed off. And we had been; during climb; burning only out off the left wing tank. We now had approximately a 2000 pound imbal between wing tanks with the right tank the high side. Also the fuel in the right wing tank still showed approximately 11700 pounds. I believed at the time; this was due to the operation of the logic of the automatic-feed system which was still in automatic. We turned off the center pump and then performed xfeed operation to balance the wing tanks. I wanted to get the right tank below 11000 pounds to allow us to start burning again from the center tank. This brought both wing tanks to approximately 9200 pounds. We secured from xfeeding. And then switched on the #2 center pump; it now showed on and flight continued to ZZZ1. My initial feeling was that this MEL may need to be examined as to large fuel loads like the one we had. No mention in the flight crew section of this MEL referred to the automatic system of the center tank pumps. Also while mention was made as to when to turn off the pumps when the center tank was empty no mention was made as to when to turn them off for landing while there was still fuel in the center tank. My understanding is you want to be back tank-to-engine with xfeed closed on approach and that is what we did. After landing I placed a call to maintenance with my concerns. And also to ask why with the xfeed open and the center pumps off did the left wing tanks override the right side and created an imbal. It seemed as if only the left tank pumps were feeding both engines at climb power settings. He stated that; he was aware of several recent problems with the automatic-feed system when one center tank pump was deferred and large economic ferry fuel loads. Thus the reason I write this report. At the least; the automatic-feed system with 1 center tank pump inoperative should be examined. If necessary this MEL should be changed as what to do with the automatic feed system and full wing tanks. Also reference to configuring the fuel system at landing with fuel still in the center tank and 1 center tank pump deferred. Or would limiting economic ferry fuel when this MEL is being used be appropriate. Carrying ferry fuel means you have more fuel than you should ever need and have larger than normal fuel load at touchdown.

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Original NASA ASRS Text

Title: AN A320 DISPATCHED WITH THE #1 CENTER FUEL TANK PUMP MEL'ED BUT WITH FUEL IN THE TANK; DEVELOPED A FUEL IMBALANCE BECAUSE ONLY THE LEFT WING TANKS WERE SUPPLYING FUEL TO BOTH ENGINES WHILE USING THE FUEL AUTO FEED SYSTEM.

Narrative: REF MEL 2821C. WE WERE DISPATCHED AND I ACCEPTED A FUEL LOAD OF 40.2 FOR FLT ZZZ TO ZZZ1. THIS WAS FOR ECONOMIC FERRY. THE #1 CTR TANK FUEL PUMP WAS DEFERRED. AS PER THE MEL AFTER TKOF CHKLIST WAS COMPLETED WE OPENED THE XFEED AND SWITCHED ON THE #2 CTR TANK PUMP. AT THE TIME WE DID THIS THE R WING TANK WAS SHOWING APPROX 11700 LBS ALMOST FULL. SHORTLY BEFORE CRUISE ALT I NOTICED THE #2 CTR PUMP SHOWED OFF. AND WE HAD BEEN; DURING CLB; BURNING ONLY OUT OFF THE L WING TANK. WE NOW HAD APPROX A 2000 LB IMBAL BTWN WING TANKS WITH THE R TANK THE HIGH SIDE. ALSO THE FUEL IN THE R WING TANK STILL SHOWED APPROX 11700 LBS. I BELIEVED AT THE TIME; THIS WAS DUE TO THE OP OF THE LOGIC OF THE AUTO-FEED SYS WHICH WAS STILL IN AUTO. WE TURNED OFF THE CTR PUMP AND THEN PERFORMED XFEED OP TO BAL THE WING TANKS. I WANTED TO GET THE R TANK BELOW 11000 LBS TO ALLOW US TO START BURNING AGAIN FROM THE CTR TANK. THIS BROUGHT BOTH WING TANKS TO APPROX 9200 LBS. WE SECURED FROM XFEEDING. AND THEN SWITCHED ON THE #2 CTR PUMP; IT NOW SHOWED ON AND FLT CONTINUED TO ZZZ1. MY INITIAL FEELING WAS THAT THIS MEL MAY NEED TO BE EXAMINED AS TO LARGE FUEL LOADS LIKE THE ONE WE HAD. NO MENTION IN THE FLT CREW SECTION OF THIS MEL REFERRED TO THE AUTO SYS OF THE CTR TANK PUMPS. ALSO WHILE MENTION WAS MADE AS TO WHEN TO TURN OFF THE PUMPS WHEN THE CTR TANK WAS EMPTY NO MENTION WAS MADE AS TO WHEN TO TURN THEM OFF FOR LNDG WHILE THERE WAS STILL FUEL IN THE CTR TANK. MY UNDERSTANDING IS YOU WANT TO BE BACK TANK-TO-ENG WITH XFEED CLOSED ON APCH AND THAT IS WHAT WE DID. AFTER LNDG I PLACED A CALL TO MAINT WITH MY CONCERNS. AND ALSO TO ASK WHY WITH THE XFEED OPEN AND THE CTR PUMPS OFF DID THE L WING TANKS OVERRIDE THE R SIDE AND CREATED AN IMBAL. IT SEEMED AS IF ONLY THE L TANK PUMPS WERE FEEDING BOTH ENGS AT CLB PWR SETTINGS. HE STATED THAT; HE WAS AWARE OF SEVERAL RECENT PROBS WITH THE AUTO-FEED SYS WHEN ONE CTR TANK PUMP WAS DEFERRED AND LARGE ECONOMIC FERRY FUEL LOADS. THUS THE REASON I WRITE THIS RPT. AT THE LEAST; THE AUTO-FEED SYS WITH 1 CTR TANK PUMP INOP SHOULD BE EXAMINED. IF NECESSARY THIS MEL SHOULD BE CHANGED AS WHAT TO DO WITH THE AUTO FEED SYS AND FULL WING TANKS. ALSO REF TO CONFIGURING THE FUEL SYS AT LNDG WITH FUEL STILL IN THE CTR TANK AND 1 CTR TANK PUMP DEFERRED. OR WOULD LIMITING ECONOMIC FERRY FUEL WHEN THIS MEL IS BEING USED BE APPROPRIATE. CARRYING FERRY FUEL MEANS YOU HAVE MORE FUEL THAN YOU SHOULD EVER NEED AND HAVE LARGER THAN NORMAL FUEL LOAD AT TOUCHDOWN.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.