A relatively compact, lightweight outflow valve assembly includes suitable redundancy features that allow the valve assembly to meet regulatory requirements for certain postulated single point failures. The valve assembly includes a valve body that is constructed at least partially of a non-metallic material and has an outer surface and an inner surface that defines a flow passage having at least two flow ports. A sleeve is disposed within the valve body flow passage that is constructed at least partially of a metallic material. The sleeve has a flow passage formed therein that is in fluid communication with the valve body flow passage flow ports. A valve element is disposed within the sleeve flow passage and is moveable between at least an open position and a closed position. A plurality of brackets is mounted on the valve body outer surface and is coupled to the sleeve. When the valve assembly is installed in an aircraft, the plurality of brackets further couples the sleeve to the aircraft fuselage.