Garmin G3X Touch Pilot’s Guide 190-01754-00 Rev. A212AFCSSystemOverviewFlightInstrumentsEISCNSInterfaceGPSNavigationFlightPlanningHazardAvoidanceAdditionalFeaturesAFCSAnnun/AlertsAppendixIndex9.1 AFCS OPERATIONWhen a GMC 305 is installed AFCS functionality is distributed across the followingLine Replaceable Units (LRUs):• GDU 460/465 Display Unit.• GSU 73/25 ADAHRS Unit• GMC 305 AFCS Mode ControlUnit• GSA 28 AFCS Pitch/Roll/YawDamper (optional) servos.The AFCS system can be divided into these main operating functions:• Flight Director (FD) — Flight director operation takes place within GDU460/465. Flight director commands are displayed on the PFD. The flight directorprovides:– Command Bars showing pitch/roll guidance– Vertical/lateral mode selection and processing– Autopilot communication• Autopilot (AP) — Autopilot operation occurs within the pitch, roll, and pitchservos. It also provides servo monitoring and automatic flight control in responseto flight director steering commands, Air Data and Attitude and Heading ReferenceSystem (ADAHRS) attitude, rate information, and airspeed.• Yaw Damper (YD) — The yaw servo (optional), is self-monitoring and providesDutch roll damping and turn coordination in response to yaw rate, roll angle, lateralacceleration, and airspeed. If installed the YD comes on when the autopilot is engagedand stays on after disengaging the autopilot. The YD can be turned on/off independentof the autopilot using the YD Key.• Manual Electric Trim (MET) — Manual electric trim may provide trim capabilityfor any properly configured axis (pitch, roll, or yaw) when the autopilot is not engaged.
