A shut-off valve system includes a tank having an inlet and an outlet with a flow path defined therebetween. A float within the tank occludes the tank outlet at a first fluid level under positive G forces and unoccludes the tank outlet at a second fluid level under positive G forces. A flow restricting orifice and/or a hydraulic fuse is downstream of float and tank outlet to restrict fluid communication between tank outlet and an ejector pump. A method for restricting flow in an ecology fuel return system includes recovering fuel from engine components, communicating the fuel to an inlet of a fuel tank, pumping the fuel from an outlet of fuel tank to an inlet of an engine when a float within tank unoccludes the outlet of the fuel tank, and restricting fluid flow from tank outlet to an ejector pump with a flow restricting orifice and/or a hydraulic fuse.

A shut-off valve includes a float and a negative G control component. The float is configured to occlude a tank outlet at a first fluid level and 1 G and unocclude the tank outlet at a second fluid level and 1 G. The negative G control component is operatively connected to the float to limit fluid, e.g. liquid or gas, communication between a tank outlet and an ejector pump during negative G events. An ecology fuel return system includes a tank, an ejector pump, a float, and a negative G control component, as described above. The tank has an inlet and an outlet. The inlet is configured to be in fluid communication with components of an engine. The ejector pump is in fluid communication with the tank outlet and is configured to pump fuel from the tank to a fuel pump inlet of an engine.

A shut-off valve includes a float and a negative G control component. The float is configured to occlude a tank outlet at a first fluid level and 1 G and unocclude the tank outlet at a second fluid level and 1 G. The negative G control component is operatively connected to the float to limit fluid, e.g. liquid or gas, communication between a tank outlet and an ejector pump during negative G events. An ecology fuel return system includes a tank, an ejector pump, a float, and a negative G control component, as described above. The tank has an inlet and an outlet. The inlet is configured to be in fluid communication with components of an engine. The ejector pump is in fluid communication with the tank outlet and is configured to pump fuel from the tank to a fuel pump inlet of an engine.

A shut-off valve includes a float and a negative G control component. The float is configured to occlude a tank outlet at a first fluid level and 1 G and unocclude the tank outlet at a second fluid level and 1 G. The negative G control component is operatively connected to the float to limit fluid, e.g. liquid or gas, communication between a tank outlet and an ejector pump during negative G events. An ecology fuel return system includes a tank, an ejector pump, a float, and a negative G control component, as described above. The tank has an inlet and an outlet. The inlet is configured to be in fluid communication with components of an engine. The ejector pump is in fluid communication with the tank outlet and is configured to pump fuel from the tank to a fuel pump inlet of an engine.

A shut-off valve includes a float and a negative G control component. The float is configured to occlude a tank outlet at a first fluid level and 1 G and unocclude the tank outlet at a second fluid level and 1 G. The negative G control component is operatively connected to the float to limit fluid, e.g. liquid or gas, communication between a tank outlet and an ejector pump during negative G events. An ecology fuel return system includes a tank, an ejector pump, a float, and a negative G control component, as described above. The tank has an inlet and an outlet. The inlet is configured to be in fluid communication with components of an engine. The ejector pump is in fluid communication with the tank outlet and is configured to pump fuel from the tank to a fuel pump inlet of an engine.