Narrative:

During flight #yy nrt-hkg on jul/xx/98, we had a major fuel imbalance situation which if not detected, could have resulted in the flameout of engines #1 and #4. There was plenty of accessible fuel in tanks #2 and #3 which would have allowed a restart and positive fuel flow for continued flight. The captain and first officer had different fuel pump configns in mind at engine start, both of which would have been acceptable. However only half of each confign was established. 3 out of 4 EICAS message advisories were never received. Human factors and distractions also were involved resulting in the imbalance. At engine start, I pushed the applicable fuel pumps on for tank to engine confign. As the fuel load was 121000 pounds, either the tank to engine or the fuel-override #2 and #3 pumps along with #1 and #4 xfeeds open, are acceptable configns. My captain was thinking of the override/xfeed confign and I was using tank to engine. Thus we encountered half the set up of each. The checklist has a challenge of 'xfeeds #1 and #4' of which there are two possible responses. My captain responded 'open' which was true and I should have stopped and asked: why? Rather, because this response is acceptable, I continued on. We should have received 3 EICAS advisory messages warning of this non standard confign, but never did and pushing the recall button displayed no applicable messages as well (1) fuel tank/engine, 2) xfeed confign, 3) xfeed fuel imbalance #1 and #4). The 4TH advisory did display halfway through the flight (low fuel quantity). At that time we placed the override pumps #2 and #3 on, which fed fuel into engines #1 and #4. The rest of the flight was uneventful with a normal landing in hkg. I noted the fuel quantity totals on the flight plan every waypoint which showed a consistent 2500 pounds under burn. The logbook arrival fuel was logged and a mechanic briefed. Human factors contributing to the imbalance were: 1) captain and first officer thinking of different fuel confign scenarios before engine start up, 2) distractions of a complex SID from nrt along with extensive briefing for approach and landing into the new hong kong airport, 3) the checklist was followed but did not address this scenario, 4) this was my first time in the cockpit for takeoff in 7 months. Mechanical factors were: 1) not receiving 3 EICAS advisory messages, 2) main pumps #1 and #4 having a higher output pressure than #2 and #3 main pumps resulting in fuel depletion (tanks #1 and #4) if #1 and #4 xfeeds open, 3) xfeed confign EICAS message displayed after complete engine shutdown in hkg. Other items to note are 1) the left FMC was reloaded with data due to previous failure just before our flight, 2) we have a temporary procedure of turning on the engine bleed valves just before start, 3) the fuel load of 121000 pounds allowed for either fuel confign set up, 4) late flap retraction due to noise abatement requirements in nrt, 5) cockpit operating manual does not solve this particular 'low fuel quantity' situation in tanks #1 and #4. Callback conversation with reporter revealed the following information: reporter stated that the fuel level was even at 120000 pounds total. The EICAS message indicated the fuel tanks of each wing tank should be to each respective engine. They got a fuel imbalance light and noted that tanks #1 and #4 differ by 6000 pounds. One tank got low enough to show fuel quantity. They carried extra fuel, but they did not check the fuel panel to assure how fuel was being used. When it was decided to rebalance the fuel, no one person was in charge. Each pilot decided which technique they would use and each pilot was doing something different than the other. The left FMC was inoperative which distracted the flight crew. Somehow, the fuel began to come within balance range in time for normal uneventful landing at destination.

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Original NASA ASRS Text

Title: THE FLC OF A B747-400 HAS PROBS TRYING TO BAL THE FUEL AS THEY FLY IN RCTP FOREIGN AIRSPACE.

Narrative: DURING FLT #YY NRT-HKG ON JUL/XX/98, WE HAD A MAJOR FUEL IMBALANCE SIT WHICH IF NOT DETECTED, COULD HAVE RESULTED IN THE FLAMEOUT OF ENGS #1 AND #4. THERE WAS PLENTY OF ACCESSIBLE FUEL IN TANKS #2 AND #3 WHICH WOULD HAVE ALLOWED A RESTART AND POSITIVE FUEL FLOW FOR CONTINUED FLT. THE CAPT AND FO HAD DIFFERENT FUEL PUMP CONFIGNS IN MIND AT ENG START, BOTH OF WHICH WOULD HAVE BEEN ACCEPTABLE. HOWEVER ONLY HALF OF EACH CONFIGN WAS ESTABLISHED. 3 OUT OF 4 EICAS MESSAGE ADVISORIES WERE NEVER RECEIVED. HUMAN FACTORS AND DISTRACTIONS ALSO WERE INVOLVED RESULTING IN THE IMBALANCE. AT ENG START, I PUSHED THE APPLICABLE FUEL PUMPS ON FOR TANK TO ENG CONFIGN. AS THE FUEL LOAD WAS 121000 LBS, EITHER THE TANK TO ENG OR THE FUEL-OVERRIDE #2 AND #3 PUMPS ALONG WITH #1 AND #4 XFEEDS OPEN, ARE ACCEPTABLE CONFIGNS. MY CAPT WAS THINKING OF THE OVERRIDE/XFEED CONFIGN AND I WAS USING TANK TO ENG. THUS WE ENCOUNTERED HALF THE SET UP OF EACH. THE CHKLIST HAS A CHALLENGE OF 'XFEEDS #1 AND #4' OF WHICH THERE ARE TWO POSSIBLE RESPONSES. MY CAPT RESPONDED 'OPEN' WHICH WAS TRUE AND I SHOULD HAVE STOPPED AND ASKED: WHY? RATHER, BECAUSE THIS RESPONSE IS ACCEPTABLE, I CONTINUED ON. WE SHOULD HAVE RECEIVED 3 EICAS ADVISORY MESSAGES WARNING OF THIS NON STANDARD CONFIGN, BUT NEVER DID AND PUSHING THE RECALL BUTTON DISPLAYED NO APPLICABLE MESSAGES AS WELL (1) FUEL TANK/ENG, 2) XFEED CONFIGN, 3) XFEED FUEL IMBALANCE #1 AND #4). THE 4TH ADVISORY DID DISPLAY HALFWAY THROUGH THE FLT (LOW FUEL QUANTITY). AT THAT TIME WE PLACED THE OVERRIDE PUMPS #2 AND #3 ON, WHICH FED FUEL INTO ENGS #1 AND #4. THE REST OF THE FLT WAS UNEVENTFUL WITH A NORMAL LNDG IN HKG. I NOTED THE FUEL QUANTITY TOTALS ON THE FLT PLAN EVERY WAYPOINT WHICH SHOWED A CONSISTENT 2500 LBS UNDER BURN. THE LOGBOOK ARR FUEL WAS LOGGED AND A MECH BRIEFED. HUMAN FACTORS CONTRIBUTING TO THE IMBALANCE WERE: 1) CAPT AND FO THINKING OF DIFFERENT FUEL CONFIGN SCENARIOS BEFORE ENG START UP, 2) DISTRACTIONS OF A COMPLEX SID FROM NRT ALONG WITH EXTENSIVE BRIEFING FOR APCH AND LNDG INTO THE NEW HONG KONG ARPT, 3) THE CHKLIST WAS FOLLOWED BUT DID NOT ADDRESS THIS SCENARIO, 4) THIS WAS MY FIRST TIME IN THE COCKPIT FOR TKOF IN 7 MONTHS. MECHANICAL FACTORS WERE: 1) NOT RECEIVING 3 EICAS ADVISORY MESSAGES, 2) MAIN PUMPS #1 AND #4 HAVING A HIGHER OUTPUT PRESSURE THAN #2 AND #3 MAIN PUMPS RESULTING IN FUEL DEPLETION (TANKS #1 AND #4) IF #1 AND #4 XFEEDS OPEN, 3) XFEED CONFIGN EICAS MESSAGE DISPLAYED AFTER COMPLETE ENG SHUTDOWN IN HKG. OTHER ITEMS TO NOTE ARE 1) THE L FMC WAS RELOADED WITH DATA DUE TO PREVIOUS FAILURE JUST BEFORE OUR FLT, 2) WE HAVE A TEMPORARY PROC OF TURNING ON THE ENG BLEED VALVES JUST BEFORE START, 3) THE FUEL LOAD OF 121000 LBS ALLOWED FOR EITHER FUEL CONFIGN SET UP, 4) LATE FLAP RETRACTION DUE TO NOISE ABATEMENT REQUIREMENTS IN NRT, 5) COCKPIT OPERATING MANUAL DOES NOT SOLVE THIS PARTICULAR 'LOW FUEL QUANTITY' SIT IN TANKS #1 AND #4. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE FUEL LEVEL WAS EVEN AT 120000 LBS TOTAL. THE EICAS MESSAGE INDICATED THE FUEL TANKS OF EACH WING TANK SHOULD BE TO EACH RESPECTIVE ENG. THEY GOT A FUEL IMBALANCE LIGHT AND NOTED THAT TANKS #1 AND #4 DIFFER BY 6000 LBS. ONE TANK GOT LOW ENOUGH TO SHOW FUEL QUANTITY. THEY CARRIED EXTRA FUEL, BUT THEY DID NOT CHK THE FUEL PANEL TO ASSURE HOW FUEL WAS BEING USED. WHEN IT WAS DECIDED TO REBALANCE THE FUEL, NO ONE PERSON WAS IN CHARGE. EACH PLT DECIDED WHICH TECHNIQUE THEY WOULD USE AND EACH PLT WAS DOING SOMETHING DIFFERENT THAN THE OTHER. THE L FMC WAS INOP WHICH DISTRACTED THE FLC. SOMEHOW, THE FUEL BEGAN TO COME WITHIN BAL RANGE IN TIME FOR NORMAL UNEVENTFUL LNDG AT DEST.

Data retrieved from NASA's ASRS site as of July 2007 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.