G3X Installation Manual – GSU 73 Page 4-7190-01115-01 Revision ADo not use shock mounting to mount the GSU 73. Shock mounts used for other types of inertial systemsare not acceptable for the GSU 73 AHRS. The mounting system must have no resonance with the unitinstalled. Excessive vibration may result in degraded accuracy.The supporting plate must be rigidly connected to the aircraft primary structure through strong structuralmembers capable of supporting substantial loads. Avoid areas that are prone to severe vibration.The GSU 73 should be mounted within 13 feet (4.0 meters) longitudinally and 6.5 feet (2.0 meters)laterally of the aircraft center of gravity. In cases where the longitudinal distance from the CG is plannedto be greater than 6.5 feet (2.0 meters), it is preferable to mount the GSU 73 forward of the aircraft centerof gravity if possible, to enable better acceleration outputs for autopilot use. The mounting location forthe GSU 73 should be protected from rapid thermal transients, in particular, large heat loads from nearbyhigh-power equipment.The GSU 73 must be leveled to within 3.0° of the aircraft level reference, and an aircraft leveling andoffset calibration procedure carried out prior to flight. (This procedure is described in Section 9.)Alternatively, if the GSU 73 can be guaranteed level to within 0.25° of the aircraft level reference, theaircraft leveling and offset calibration procedure is not required.Avoid placing the GSU 73 within 1 inch of magnetically mounted antennas, speaker magnets, or otherstrongly magnetic items.4.7 Unit InstallationFor final installation and assembly, refer to the outline and installation drawings shown in Appendix C ofthis manual.1. Assemble the wiring harness and backshell connectors.2. Assemble the pneumatic hoses and connectors.3. Mount the unit to a suitable mounting location using #10-32 pan or hex head screws (4 ea) perthe requirements in Section 4.6.4. Connect backshell connector and hoses.NOTEWhen mounting the GSU 73 to the airframe, it is important to ensure thatfastening hardware is tight for proper unit operation.
