OliV2
What powers the fuel pumps - engine, right?
Without the electric fuel pumps in the tanks operating, the engine driven fuel pumps would have been sucking fuel from the tanks. It's not a problem on descent but if you were to climb with that situation, you run the risk of cavitation as gas bubbles come out of the fuel in the lower atmospheric pressure.
another superlame, Ram Air Turbines (RATs) are only fitted to twin engined aircraft as four engined aircraft are deemed to have enough redundency to not require one. They didn't take into account flooding of all GCU's.
Speculation about starting the APU for electrical power has a couple of issues:
1. The B744 APU is not certified to start in the air.
2. The APU starter motor would draw a huge current from both the Main and APU batteries and if the start attempt failed then there would be even less battery power available for the essential items to get the aircraft on the ground.