Abstract: An aircraft fuel tank system including a fuel tank compartment for containing liquid fuel and having a float-activated valve arranged to become positively buoyant when immersed in liquid fuel so that the float moves up to a raised position which causes the valve to close and prevent liquid fuel from flowing out of the fuel tank compartment through the valve. The float is also arranged to move down to a lowered position in response to a level of the liquid fuel in the fuel tank compartment dropping, the movement of the float to the lowered position causing the valve to open and permit liquid fuel to flow out of the fuel tank compartment through the valve. A pressure-activated valve may be used as an alternative to the float-activated valve.

Abstract: An aircraft fuel tank system including a fuel tank compartment for containing liquid fuel and having a float-activated valve arranged to become positively buoyant when immersed in liquid fuel so that the float moves up to a raised position which causes the valve to close and prevent liquid fuel from flowing out of the fuel tank compartment through the valve. The float is also arranged to move down to a lowered position in response to a level of the liquid fuel in the fuel tank compartment dropping, the movement of the float to the lowered position causing the valve to open and permit liquid fuel to flow out of the fuel tank compartment through the valve. A pressure-activated valve may be used as an alternative to the float-activated valve.