B777 Air Demand Pump Inop.
Dispatched with a center hydraulic air demand pump inop., MEL 29-11-03. The procedure required us to power the remaining ADP with the APU bleed for take-off by running the APU bleed and isolating the pump air supply with the L and R bleed isolate valves. After take off the APU was shut down and the bleed isolate valves are returned to their normal open positions.
This makes sense as it allows the remaining pump to provide hydraulic power for the gear retraction and flight controls (I believe primarily the TAC control of the rudder) in the event of an engine failure. What surprised us was that we were not required to re-configure the system for landing, What is different about a single engine go around than an engine out take off?
Any insight greatly appreciated.
Cropduster.