GFC 700 Autopilot
Physical GFC 700 autopilot control unit — 3D-printed bezel, encoder knobs, illuminated pushbuttons, and CockpitConnect integration.
Overview
The Garmin GFC 700 is the integrated autopilot fitted to the 172SP G1000. Its control unit sits on the glareshield and provides AP engage, flight director, altitude hold, heading, NAV, VNAV, approach coupling, and VS/FLC modes.
This page covers the physical build of the GFC 700 control panel — the bezel, button layout, encoder knobs, and integration with X-Plane via CockpitConnect. In the app it's part of the Cessna 172 G1000 Blueprint.
Panel Layout
X-Plane 12's G1000 Skyhawk binds its autopilot keys and its HDG and ALT knobs to the MFD's commands, sim/GPS/g1000n3_*, so this panel uses those.
| Control | Type | X-Plane 12 (sim/GPS/g1000n3_…) | Lamp (sim/cockpit2/autopilot/…) |
|---|---|---|---|
| AP | Illuminated pushbutton | ap | servos_on |
| FD | Illuminated pushbutton | fd | flight_director_mode |
| HDG | Illuminated pushbutton | hdg | heading_status |
| NAV | Illuminated pushbutton | nav | nav_status |
| APR | Illuminated pushbutton | apr | approach_status |
| VS | Illuminated pushbutton | vs | vvi_status |
| FLC | Illuminated pushbutton | flc | speed_status |
| ALT | Illuminated pushbutton | alt | altitude_hold_status |
| VNV | Illuminated pushbutton | vnv | vnav_status |
| BC | Illuminated pushbutton | bc | backcourse_status |
| NOSE UP / DN | Pushbuttons | nose_up, nose_down | — |
| HDG knob | Rotary encoder with push | hdg_up / hdg_down, push hdg_sync | — |
| ALT knob | Concentric rotary encoder | outer alt_outer_up / _down (thousands), inner alt_inner_up / _down (hundreds) | — |
The real GFC 700 shows its active and armed modes on the PFD rather than in its keys. Here each key's lamp lights while its mode is armed or engaged, from the autopilot's own status dataref.
Construction
The bezel is 3D-printed in PLA and painted to match the glareshield. Illuminated pushbuttons use 12mm momentary switches with integrated LEDs. One ESP32 drives the panel: the 12 keys sit on one MCP23017 I²C expander and the 10 key LEDs on a second (GPIO 21 SDA, 22 SCL). The encoder knobs are 3D-printed caps over 24-pulse rotary encoders on the ESP32's own pins: HDG on GPIO 25 and 26 with its push on 27, ALT outer on 13 and 14, inner on 16 and 17.
Status
Planning — bezel design not yet started. Wiring and X-Plane mapping defined.