The transfer pumps transfer fuel from the outboard tanks to their respective Nacelle tank, and should be on during all operations when there is fuel in the outboard tanks.

Electric Boost Pumps are on the Hot Battery Bus (always powered), and should be on whenever the engines are running, and until 10% or less N1 speed is reached upon shutdown.

In the default position, the Fuel Quantity Switch will show the total fuel aboard the airplane. When in the NACELLE position, only the fuel currently in the Nacelle tanks will be displayed by the fuel gauges.

The Transfer Test switch allows us to test the No Transfer sensing system.

The Crossfeed switch has three positions: Closed, Auto and Open. Auto is the normal mode of operation for flight, which will allow the crossfeed valve to open automatically in the event of a boost pump failure. This will allow one side's fuel supply and boost pump to provide head pressure for the high pressure fuel pump on the side of the failed boost pump. This mode of operation can be overridden by placing the switch in the Closed position.

Capacitance-type fuel gauges indicate the quantity of fuel in the selected tanks (Outboards plus Nacelles when quantity switch is in the default position, Nacelles only when fuel quantity switch is in the NACELLE position) in pounds. Do not take off if fuel levels are less than 265 lb/side, or in the yellow arc.