Heading Indicator
Physical Heading Indicator (directional gyro) for the Cessna 172SP Six-Pack panel — bezel, compass card mechanism, heading bug, and X-Plane dataref mapping.
4 min read Updated 2026-06
Overview
The Heading Indicator (HI), also known as the directional gyro (DI), sits bottom-centre in the six-pack "T" arrangement. It shows aircraft heading on a rotating compass card against a fixed lubber line, with a heading bug used by the KAP 140 autopilot's HDG mode.
Construction
Like the other six-pack instruments, this gauge is built as a self-contained module:
- Bezel / Face Plate — 3D-printed bezel with a fixed lubber line marking
- Dial / Needle — rotating compass card in place of a needle
- Internal Mechanics — stepper motor driving the compass card; a second stepper (or a knob with encoder feedback) drives the heading bug for the autopilot
- Back Housing — 3D-printed enclosure mounting to the MIP frame's instrument cutout
- PCB & Controller — ESP32 driving the compass card and heading bug mechanisms
- Lighting — backlighting for night/IFR panel illumination
X-Plane Integration
sim/cockpit2/gauges/indicators/heading_electric_deg_mag_pilot
# Heading bug (shared with KAP 140 autopilot)
sim/cockpit2/autopilot/heading_dial_deg_mag_pilot
Status
Planning — design not yet started.