Abstract: A mechanism for varying the position of a plurality of nozzle vanes in a gas turbine engine. The mechanism includes a single double-acting hydraulic actuating jack disposed between two bell cranks for simultaneously applying force to a ring gear at two diametrically opposed connection points. The single actuating jack applies equal and opposite forces to the diametrically opposed connection points on the ring gear and reduces distortion producing stresses therein. The ring gear simultaneously engages a plurality of individual gear segments rotatable with each individual nozzle vane in the engine. Movement of the single actuator jack causes balanced rotation of the ring gear and simultaneous rotation of the nozzle vanes.