We had the opposite from a jammed control - one that was far too loose. One of my partners spotted that the lower of the two rudder hinges was soon to come free from its attachment to the aft fuselage frame due to cracking. This would have left it attached by the top hinge only and the control cables. He spotted it because it was already displaced sideways and the elevators were fouling on it. Wouldn't have noticed it from the cockpit but he noticed it when lifting the elvators by hand during the walkround.