Not only that, but the engine pumps will feed the engines up to about FL 280 for an un-modified 747 classic, and up to FL 350 with some Boeing mod they cooked up years ago.
(Not sure if the above is true on take-off power, but at least in cruise that is the story)
Wonder how much those guys could see that early in the morning?
Every time I have take off with flowers from Bogota it has been pitch black and I sure as hell would not be able to pick out a field to "land" in.
Had a few compressor stalls just after t/o from Bogota in the dark, and they scared the crap out of me, can't imagine the joy of loosing 2 engines just after t/o between those hills.
Hat off to the crew, hell of a job....