The Boeing Company
TRIM ACTUATORS FOR HORIZONTAL STABILIZERS AND METHODS OF CONTROLLING HORIZONTAL STABILIZERS

Abstract:

A trim actuator (102) for a horizontal stabilizer (210) comprises a power screw (106), a rotary actuator (104), configured to rotate the power screw (106), and a nut (108), configured to translate along the power screw (106) when the power screw (106) is rotated. Trim actuator (102) also comprises an anti-back-drive mechanism (114), configured to prevent the power screw (106) from rotating in a first rotational direction when a first force is applied to the nut (108) in a first axial direction and to prevent the power screw (106) from rotating in a second rotational direction, opposite the first rotational direction, when a second force is applied to the nut (108) in a second axial direction. Trim actuator (102) further comprises a sensor (120), configured to measure internal loading of the anti-back-drive mechanism (114) when the first force is applied to the nut (108) in the first axial direction or when the second force is applied to the nut (108) in the second axial direction.