An actuator system for controlling a control surface of an aircraft , comprising: a control structure configured to define the control surface wherein the control structure has an axis of rotation about which the control structure can rotate relative to the aircraft ; a first actuator assembly which has a first actuator arm ; and a second actuator assembly which has a second actuator arm , wherein: the first actuator assembly and the second actuator assembly are spaced apart from one another along the axis of rotation ; the first actuator assembly comprises a first cylinder member and a first piston positioned within the first cylinder member ; the second actuator assembly comprises a second cylinder member and a second piston positioned within the second cylinder member ; the first actuator arm is connected to the first cylinder member whereas the second actuator arm is connected to the second piston ; and the first actuator arm is connected to a first band member and the first band member is connected to the control structure on a first side of the axis of rotation and the second actuator arm is connected to a second band member and the second band member is connected to the control structure on a second opposing side of the axis of rotation , when viewed in an actuation direction of the actuator assemblies , crosswise to said axis of rotation . a control structure configured to define the control surface wherein the control structure has an axis of rotation about which the control structure can rotate relative to the aircraft ; a first actuator assembly which has a first actuator arm ; and a second actuator assembly which has a second actuator arm , wherein: the first actuator assembly and the second actuator assembly are spaced apart from one another along the axis of rotation ; the first actuator assembly comprises a first cylinder member and a first piston positioned within the first cylinder member ; the second actuator assembly comprises a second cylinder member and a second piston positioned within the second cylinder member ; the first actuator arm is connected to the first cylinder member whereas the second actuator arm is connected to the second piston ; and the first actuator arm is connected to a first band member and the first band member is connected to the control structure on a first side of the axis of rotation and the second actuator arm is connected to a second band member and the second band member is connected to the control structure on a second opposing side of the axis of rotation , when viewed in an actuation direction of the actuator assemblies , crosswise to said axis of rotation . the first actuator assembly and the second actuator assembly are spaced apart from one another along the axis of rotation ; the first actuator assembly comprises a first cylinder member and a first piston positioned within the first cylinder member ; the second actuator assembly comprises a second cylinder member and a second piston positioned within the second cylinder member ; the first actuator arm is connected to the first cylinder member whereas the second actuator arm is connected to the second piston ; and the first actuator arm is connected to a first band member and the first band member is connected to the control structure on a first side of the axis of rotation and the second actuator arm is connected to a second band member and the second band member is connected to the control structure on a second opposing side of the axis of rotation , when viewed in an actuation direction of the actuator assemblies , crosswise to said axis of rotation . <EOS>