GSA 8X/GSM 85(A) Installation Manual
Page 1-1
190-00303-72
Revision R
1 GENERAL
DESCRIPTION
1.1 Introduction
This manual presents mechanical and electrical installation requirements for installing the GSA 80 or
GSA 81 servo actuator (referred to in this document as “GSA 8X”) and the GSM 85 or GSM 85A servo
gearbox (referred to in this document as “GSM 85(A)”) as part of the GFC 700 Automatic Flight Control
System, a sub-system of the Garmin Integrated Flight Deck. The GFC 700 system can be integrated into
a variety of airframes under an appropriate Type Certification (TC) or Supplemental Type Certification
(STC). Individual airframe installations may vary; use only approved (type or supplemental type) data for
specific installation instructions in a particular aircraft.
1.2
Equipment Description
1.2.1
GSA 80 and GSA 81 Servo Actuator
The GSA 8X 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 8X 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 8X 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.
Figure 1-1. GSA 81 Servo Actuator
