Hydraulic Systems
Each engine has one engine driven hydraulic pump. Engines 1 and 4 each have a pump which pressurizes the green system, engine 2 drives the pump for the blue system, and engine 3 drives the pump pressurizing the yellow system.
There are 3 ELEC pbs controlling 3 hydraulic electrical pumps (1 for each system).
Normally, high pressure air from engine 2 pressurizes the hydraulic reservoirs.