A fuel deoxygenation system contactor-separator includes a fuel-gas mixture inlet section, a fuel outlet section, a gas outlet, a spiral contactor-separator, and a valve element. The fuel-gas mixture inlet section has a fuel-gas mixture inlet port. The fuel outlet section has a fuel outlet port. The gas outlet section has a gas outlet port. The spiral contactor-separator conduit has an inner wall and an outer wall that defines a spiral contactor-separator flow passage. The spiral contactor-separator conduit is coupled to, and is in fluid communication with, the fuel-gas mixture inlet section, the fuel outlet section, and the gas outlet section. The valve element is disposed between the fuel outlet port and the gas outlet port and is movable between a first position and a second position.