Horizontal Stabilizer Trim Actuator

Our horizontal stabilizer trim actuators (HSTAs) maintain the most optimum horizontal stabilizer surface on the airplane, improving fuel efficiency and reducing pilot workload. With over 25 years of HSTA experience, Parker has strong heritage in electromechanical HSTAs for aerospace commercial applications. Our broad experience and HSTA pedigree includes business jet, regional jet, and transport markets.
Our HSTA designs meet the most stringent safety regulations driven by the certification authorities (FAA and EASA). In order to meet these safety requirements, the HSTA is designed as two actuators in one. The HSTA has two different load paths (ball screw and safety rod) connecting the stabilizer surface to the aircraft structure.
The ball screw is driven by two electric brushless DC motors via a torque sum gear train. The HSTA has primary-load-activated passive brake (skewed roller) and an electric fail-safe electromechanical brake. The position of the stabilizer surface is captured via two rotary variable differential transformers (RVDTs). In case of a primary load path failure, the primary load path is locked in place and the load is transferred to the secondary load path.