Originally Posted by
B-HKD
Actually on the B777-300ER, when either main tank is below 23,900kg and the center tank is below 15,900kg. A scavenge pump will transfer fuel to the main tanks. All the crew would have to do is turn off the center fuel pumps early. With these conditions being met, transfer would begin immediately. Normally the center fuel pumps aren't turned off until ~1,000kg remaining.
Note, the last 100 or so deliveries have slightly different trigger values.
Perhaps a nit - but if I recall correctly, there are no scavenge pumps as such for the center fuel tank - rather it's an ejector type setup that uses the main tank pumps to scavenge the center tank.
Not sure if that setup would move fuel out of the center tank quicker than if you just kept sending it to the engines.