refueling rate
I remember the rate of fueling on B747-400 was about 2,000 lts/min from a refueling truck, so both sides 4,000lts / min initially when all refuelling valves are open, as tanks are filled the rate goes down as valves close, till the last tank to be filled the refueling rate is very low.
from SIN to LHR needed lots of fuel and a transit time of 70 minutes
pumping fuel for over 50 minutes and the need to check paper work, calculations, or check a tank is full by MLFI stick usually got a delayed departure.
had to make sure the refuelling tankers were there waiting and up to speed so as soon as aircraft stopped they would rush forward connect up hoses and pump fuel. not a slick as as a F1 pit stop but then there were not dozens of operaters.
fuel uplifts were 200000lts