An apparatus for actuating a control surface includes a first spur gear, a
first drive assembly engaged with the first spur gear, a second spur
gear, a second drive assembly engaged with the second spur gear, and a
gear assembly capable of being coupled with the control surface and
engaged with the spur gears. The gear assembly includes a first screw, a
first gear engaged with the first spur gear, a thrust nut mounted to the
first gear and threadedly engaged with the first screw, a second gear
engaged with the second spur gear, a second screw mounted to the second
gear and mechanically coupled with the thrust nut and a translation nut
threadedly engaged with the second screw and capable of being coupled
with the control surface. The second screw and the thrust nut rotate
independently and translations of the thrust nut are transmitted to the
second screw.