An outflow valve includes a valve closure mechanism that automatically closes the outflow valve in the unlikely event the outflow valve actuator becomes inoperable. The valve closure mechanism includes a pulley, a load plate, a cable, and a spring. The pulley is coupled to a valve element is the outflow valve and is configured to eccentrically rotate therewith. The cable has a first end coupled to the pulley, and a second end coupled to the load plate. The spring is disposed between the valve and the load plate and surrounds a portion of the cable. The spring is configured to supply a bias force, via the load plate and the cable, to the pulley that biases the valve element toward the closed position.