An electromechanical actuator (10, 110, 210) comprising: a screw (12, 112, 212A) rotatable about a screw axis (11, 111, 211); a nut (14, 114A, 214A) mounted on the screw (12, 112, 212A), the nut (14, 114A, 214A) having an external toothed surface (16, 116, 216); a spline member (20, 120A, 220A) rotatable about a spline member axis (19, 119, 219), the spline member (20, 120A, 220A) including a splined surface (22, 122, 222) engaging the external toothed surface (16, 116, 216) of the nut (14, 114A, 214A); an actuator rod (18, 118A, 218A) coupled to the nut (14, 114A, 214A) for linear movement with the nut (14, 114A, 214A); a first motor (24, 124, 224A) connected to the screw (12, 112, 212A), the first motor (24, 124, 224A) being operable to rotate the screw (12, 112, 212A) about the screw axis (11, 111, 211) relative to the nut (14, 114A, 214A) to cause the nut (14, 114A, 214A) to travel linearly along the screw (12, 112, 212A); and a second motor (26, 126A, 226A) connected to the spline member (20, 120A, 220A), the second motor (26, 126A, 226A) being operable to rotate the spline member (20, 120A, 220A) about the spline member axis (19, 119, 219) to cause the nut (14, 114A, 214A) to rotate about the screw axis (11, 111, 211) relative to the screw (12, 112, 212A) such that the nut (14, 114A, 214A) travels linearly along the screw (12, 112, 212A); wherein the actuator rod (18, 118A, 218A) moves linearly by operation of the first motor (24, 124, 224A) alone and by operation of the second motor (26, 126A, 226A) alone, and characterised in that the actuator rod (18, 118A, 218A) moves linearly by simultaneous operation of the first motor (24, 124, 224A) and the second motor (26, 126A, 226A), and further comprises a no-back mechanism, wherein the first motor (24, 124, 224A) is connected to the screw (12, 112, 212A) by way of the no-back mechanism. a screw (12, 112, 212A) rotatable about a screw axis (11, 111, 211); a nut (14, 114A, 214A) mounted on the screw (12, 112, 212A), the nut (14, 114A, 214A) having an external toothed surface (16, 116, 216); a spline member (20, 120A, 220A) rotatable about a spline member axis (19, 119, 219), the spline member (20, 120A, 220A) including a splined surface (22, 122, 222) engaging the external toothed surface (16, 116, 216) of the nut (14, 114A, 214A); an actuator rod (18, 118A, 218A) coupled to the nut (14, 114A, 214A) for linear movement with the nut (14, 114A, 214A); a first motor (24, 124, 224A) connected to the screw (12, 112, 212A), the first motor (24, 124, 224A) being operable to rotate the screw (12, 112, 212A) about the screw axis (11, 111, 211) relative to the nut (14, 114A, 214A) to cause the nut (14, 114A, 214A) to travel linearly along the screw (12, 112, 212A); and a second motor (26, 126A, 226A) connected to the spline member (20, 120A, 220A), the second motor (26, 126A, 226A) being operable to rotate the spline member (20, 120A, 220A) about the spline member axis (19, 119, 219) to cause the nut (14, 114A, 214A) to rotate about the screw axis (11, 111, 211) relative to the screw (12, 112, 212A) such that the nut (14, 114A, 214A) travels linearly along the screw (12, 112, 212A); wherein the actuator rod (18, 118A, 218A) moves linearly by operation of the first motor (24, 124, 224A) alone and by operation of the second motor (26, 126A, 226A) alone, and characterised in that the actuator rod (18, 118A, 218A) moves linearly by simultaneous operation of the first motor (24, 124, 224A) and the second motor (26, 126A, 226A), and further comprises a no-back mechanism, wherein the first motor (24, 124, 224A) is connected to the screw (12, 112, 212A) by way of the no-back mechanism.