Abstract: A vehicle control surface, such as an aircraft horizontal stabilizer, is hydraulically controlled using solenoid operated valves (SOVs) controlling directional control valves and/or rate control valves with small numbers of ports, e.g. a four port three position directional control value and/or a four port two position rate control valve.

Abstract: Systems and methods are provided for a hydraulic stabilizer trim actuator (HSTA). The HSTA may operate one or more movable control surfaces.

Abstract: Systems and methods are provided for a hydraulic stabilizer trim actuator (HSTA). The HSTA may operate one or more movable control surfaces. The HSTA operate responsive to commands issued by the pilot and/or by a controller and may include hydraulic architecture that minimizes the probability of an un-commanded movement or movement in the opposite direction of such commands.

Abstract: Systems and methods are provided for a hydraulic stabilizer trim actuator (HSTA). The HSTA may operate one or more movable control surfaces. The HSTA operate responsive to commands issued by the pilot and/or by a controller and may include hydraulic architecture that minimizes the probability of an un-commanded movement or movement in the opposite direction of such commands.

Abstract: A method for detecting freewheeling skew failures in the wing flaps of an aircraft includes measuring the outputs of flap skew sensors when the aircraft is in flight (IF) and the flaps are extended to a selected position, and when the aircraft is next on the ground (OG) and the flaps are extended to the selected position. The respective differences between the IF and OG outputs of symmetrical pairs of the flap skew sensors are computed, and then the respective difference between the computed IF output difference and the computed OG output difference of each symmetrical pair of the sensors is computed. The computed IF and OG difference of each symmetrical pair of the sensors is then compared with each of predetermined maximum and minimum threshold value to determine whether a freewheeling skew failure exists in any of the flaps of the aircraft.

Abstract: A method for detecting freewheeling skew failures in the wing flaps of an aircraft includes measuring the outputs of flap skew sensors when the aircraft is in flight (IF) and the flaps are extended to a selected position, and when the aircraft is next on the ground (OG) and the flaps are extended to the selected position. The respective differences between the IF and OG outputs of symmetrical pairs of the flap skew sensors are computed, and then the respective difference between the computed IF output difference and the computed OG output difference of each symmetrical pair of the sensors is computed. The computed IF and OG difference of each symmetrical pair of the sensors is then compared with each of predetermined maximum and minimum threshold value to determine whether a freewheeling skew failure exists in any of the flaps of the aircraft.