Fuel level control system and method

A fuel level control system for an aircraft, comprising:

• an upper tank for storing fuel;
• a lower tank for storing fuel, the lower tank being disposed below the upper tank;
• a fuel transfer line connecting the upper tank to the lower tank;
• an upper fuel transfer line outlet in the lower tank and in fluid communication with the upper tank via the fuel transfer line, wherein an upper line outlet valve is associated with the upper fuel transfer line outlet for opening and closing the upper fuel transfer line outlet;
• a lower fuel transfer line outlet in the lower tank and in fluid communication with the upper tank via the fuel transfer line, wherein a lower line outlet valve is associated with the lower fuel transfer line outlet for opening and closing the lower fuel transfer line outlet;
• and
• a control shutoff valve disposed on the fuel transfer line for selectively limiting flow through the fuel transfer line;
• a wing tank for storing fuel;
• and
• a wing upper fuel transfer line outlet in the wing tank and in fluid communication with the upper tank via through the fuel transfer line, wherein a wing upper line outlet valve is associated with the wing upper fuel transfer line outlet for opening and closing the wing upper fuel transfer line outlet.

An aircraft fuel level control system, comprising:

• an upper fuel tank;
• a lower fuel tank disposed below the upper fuel tank;
• a fuel transfer line fluidly connecting the upper fuel tank and the lower fuel tank, the fuel transfer line including an upper branch line portion and a lower branch line portion, the fuel transfer line having an upper fuel transfer line outlet in the lower fuel tank disposed on the upper branch line portion with an upper line outlet valve for opening and closing the upper fuel transfer line outlet and having a lower fuel transfer line outlet in the lower fuel tank disposed on the lower branch line portion with a lower line outlet valve for opening and closing the lower fuel transfer line outlet;
• and
• a control shutoff valve disposed on the upper branch line portion and fluidly disposed between the upper fuel transfer line outlet and the upper fuel tank.

A fuel level control method for an aircraft, comprising:

• providing an upper tank for storing fuel;
• providing a lower tank for storing fuel that is disposed below the upper tank, the lower tank fluidly connected to the upper tank by a fuel transfer line including an upper branch line portion and a lower branch line portion;
• directing fuel from the upper tank to the lower tank through the upper branch line portion of the fuel transfer line via an upper fuel transfer line outlet having an upper line outlet valve;
• directing fuel from the upper tank to the lower tank through the lower branch line portion of the fuel transfer line via a lower fuel transfer line outlet having a lower line outlet valve;
• and
• selectively closing a control shutoff valve disposed on the upper branch line portion fluidly disposed on the fuel transfer line to selectively limit flow through the fuel transfer line.