Boeing 747 Hydraulic System Schematic -

Engine-driven pump → Pressure line → Priority valve → Flight control actuators → Return filter → Reservoir

The Boeing 747 features four functionally independent hydraulic systems Boeing 747 Hydraulic System Schematic

Before diving into the schematic, one must understand the core philosophy: . Unlike smaller aircraft that may use a single hydraulic system, the Boeing 747 uses three independent, pressurized hydraulic systems. They are labeled: Engine-driven pump → Pressure line → Priority valve

Looking further into the schematic, you will notice secondary pumps attached to each system. These are the EMDPs, powered by the aircraft’s electrical system. They serve as backups and are also used when the engines are shut down during ground operations (providing hydraulic power for doors and brakes without running the engines). the Boeing 747 uses three independent