Narrative:

On taxi out; the flight attendants called to say a passenger reported fuel coming out of the right wing. This is not uncommon on this aircraft with high fuel loads. We discussed having one of the relief pilots go down to the main deck and check visually once we were had cleared both runways 1L and right. Crossing rwy 1L the tower told us he saw fluid coming out of the right wing. We stopped short of rwy 1R and immediately had a relief pilot investigate. He called on the interphone and reported a large stream of fuel coming out of the right wing. We shutdown engines 3 and 4 and also requested the fire department. All fuel pumps and crossfeeds for engines 3 and 4 were shut-off/closed. Fuel continued out of the wing. We started the APU and shut down all engines. Flight attendants were briefed that if the situation deteriorated; we would evacuate. Flight crew reviewed the evacuation checklist. Flight crew called and/or monitored the tower; dispatch; maintenance control; company operations; crash fire rescue equipment; and interphone. Maintenance brought out equipment to drain the right surge tank. Tank 2 quantity continued to decrease while tank 3 showed more fuel than in the flight manual.maintenance was unable to drain the surge tank fast enough and/or transfer any fuel. We advocated bringing out ground power and air so we could shut down the APU and have no fuel pressure in the system. After repeated attempts; this was refused. The city would not allow the aircraft to be towed while leaking fuel. After three hours city buses were brought out to deplane the passengers. The flight crew finally got off after almost four hours on the aircraft. We estimate that 12;000-15;000 pounds of fuel leaked out of the wing by the time we deplaned. Fuel was still leaking at the time we exited. Also maintenance agreed that it would not be safe to defuel on the left side until all passengers had deplaned. The fuelers began to defuel on the left side while passengers were exiting via stairs. They only stopped after I told them the flight crew would deplane and they would be responsible for the passengers' safety.my first officers did a tremendous job in helping reduce the workload and offer advice on how to deal with the situation. The previously dispatched first officer spent much of the time on the lower deck; monitoring the fuel leak and reporting to the cockpit. The remaining crew was in constant contact with maintenance control; dispatch; the purser; passengers; ATC; crash fire rescue equipment; and operations control. The communications workload was very high. Fortunately we did not have to evacuate and there were no injuries. Also of note is that the fueler transferred approximately 1;500 pounds of fuel at the gate. Whether or not this was a factor is not determined.

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Original NASA ASRS Text

Title: A passenger aboard a B747-400 alerted the flight crew of a substantial leak from the right wing during taxi for takeoff. The flight crew stopped the aircraft; shut down engines and called maintenance to secure the leak. Four hours later the passengers and crew were deplaned and approximately 16;900 LBS of fuel had been lost on the ramp.

Narrative: On taxi out; the Flight Attendants called to say a passenger reported fuel coming out of the right wing. This is not uncommon on this aircraft with high fuel loads. We discussed having one of the Relief Pilots go down to the main deck and check visually once we were had cleared both Runways 1L and R. Crossing Rwy 1L the tower told us he saw fluid coming out of the right wing. We stopped short of Rwy 1R and immediately had a Relief Pilot investigate. He called on the interphone and reported a large stream of fuel coming out of the right wing. We shutdown engines 3 and 4 and also requested the fire department. All fuel pumps and crossfeeds for engines 3 and 4 were shut-off/closed. Fuel continued out of the wing. We started the APU and shut down all engines. Flight attendants were briefed that if the situation deteriorated; we would evacuate. Flight crew reviewed the evacuation checklist. Flight crew called and/or monitored the Tower; Dispatch; Maintenance Control; Company Operations; CFR; and interphone. Maintenance brought out equipment to drain the right surge tank. Tank 2 quantity continued to decrease while Tank 3 showed more fuel than in the flight manual.Maintenance was unable to drain the surge tank fast enough and/or transfer any fuel. We advocated bringing out ground power and air so we could shut down the APU and have no fuel pressure in the system. After repeated attempts; this was refused. The city would not allow the aircraft to be towed while leaking fuel. After three hours city buses were brought out to deplane the passengers. The flight crew finally got off after almost four hours on the aircraft. We estimate that 12;000-15;000 LBS of fuel leaked out of the wing by the time we deplaned. Fuel was still leaking at the time we exited. Also Maintenance agreed that it would not be safe to defuel on the left side until all passengers had deplaned. The fuelers began to defuel on the left side while passengers were exiting via stairs. They only stopped after I told them the flight crew would deplane and they would be responsible for the passengers' safety.My First Officers did a tremendous job in helping reduce the workload and offer advice on how to deal with the situation. The previously dispatched First Officer spent much of the time on the lower deck; monitoring the fuel leak and reporting to the cockpit. The remaining crew was in constant contact with Maintenance Control; Dispatch; the Purser; passengers; ATC; CFR; and Operations Control. The communications workload was very high. Fortunately we did not have to evacuate and there were no injuries. Also of note is that the fueler transferred approximately 1;500 LBS of fuel at the gate. Whether or not this was a factor is not determined.

Data retrieved from NASA's ASRS site as of April 2012 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.