Originally Posted by
Fursty Ferret
If Airbus thought it would help, they'd put it in the procedure. It's possible that the yellow pump is incapable of driving the flaps in flight.
I had asked this to Airbus. They do not have any objection. They replied that when windmilling RPM becomes low to cause Yellow system low pressure ECAM will ask to switch on yellow pump. Only thing is that the yellow Elec pump has fluid turn over of 65L/mt. as against 145L/mt of EDP so it is not capable of supporting the PTU.