28-20-00  DISTRIBUTION Back

A. System Function

The distribution system has two sub-system. The refuel/ defuel sub-system and the fuel supply sub-system. The system has these functions:

• To fill the tanks with fuel to the correct level
• To supply fuel to the engine fuel system
• To remove the fuel from the tanks when it is necessary
• To show the flight crew and condition of the components of the system

B. System Components

The primary components (Ref. Fig. 1 thru Fig. 26) of the distribution system are the:

• Primary Jet pump and Scavenge jet pump
• Boost pump and canister
• Negative g tank
• Low pressure shut-off valve
• Motive-flow shut-off valve and Motive-line check-valve
• Crossfeed valve
• Refuel/ defuel coupling
• Refuel valve and Refuel valve solenoid
• Defuel valve
• High level sensor
• Manual defuel valve and Defuel check valve
• Check valve manifold
• Refuel control panel

C. System Operation

The refuel/ defuel sub-system fills the storage system with fuel, it also removes fuel from the storage system when necessary. The fuel supply sub-system supplies fuel independently from each wing tank to each engine. The two sub-systems give the flight crew indications of the condition of the components in the system.