Help understanding the fuel system.

[sho69607 29]

I am slightly confused as to how the fuel system works in the Falcon 50. If I am operating with a low fuel load, the "XFR" button lights up on the center tank. Does this mean the boost pump and XFR switch are supposed to be off for the center tank?

Edited May 15, 2020 by sho69607

[ark 1,290]

2 hours ago, sho69607 said:

I am slightly confused as to how the fuel system works in the Falcon 50. If I am operating with a low fuel load, the "XFR" button lights up on the center tank. Does this mean the boost pump and XFR switch are supposed to be off for the center tank?

The expert on all this is Jim Barrett (he maintains Falcon a/c in real life) who hopefully will see this and comment, but the way I understand it is this:

The engines get fuel from the feeder tanks via the boost pumps, and the feeder tanks get fuel from the wing tanks via the XFR pumps once a feeder tank level drops down to about 600 lbs. So once a feeder tank drops down to about 600 lbs if should be getting fuel from the associated wing tank/XFR pump as long as the wing tank has fuel available. A feeder tank should not drop below 600lbs until the associated wing tank is out fuel. Once a wing tank is empty, you should turn off the associated XFR pump (yellow XFR pump light on).

Al

Edited May 15, 2020 by ark

[JRBarrett 3,070]

Turn booster pumps on (the lower three switches) prior to engine start. Once engines are running, turn the three XFR pumps on (The upper three switches).

The boost pumps pressurize the fuel lines going directly to the engines, supplied by the three feeder tanks. The XFR pumps replenish the fuel in the feeder tanks as it is consumed by the engines. The XFR pumps take fuel from the wing tanks.

In a nutshell, just be sure all 6 fuel pump switches (3 boost and 3 XFR) are on once engines are running, and the fuel system will take of itself.