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The GSA 81 servo actuator is an electromechanical unit that provides automatic control of a single flight axis (pitch, roll, or yaw), or their associated trims. The GSA 81 contains a motor-control and monitor circuit board, as well as a solenoid and a brushless DC motor, all enclosed in an extruded aluminum housing.
The GSA 81 receives serial RS-485 data packets from two GIA Integrated Avionics units, which contain data from the flight director, the GRS 77 AHRS, and the GDC 74 Air Data Computer. The motor-control board processes this incoming data and drives the brushless motor as necessary to obtain the desired aircraft response. The monitor board independently monitors the servo speed, monitors the output torque, and controls the engagement of the drive-clutch solenoid.
