xp2gdl90 is an X-Plane 12 plugin that broadcasts simulator data over UDP in GDL90 format for EFB apps such as ForeFlight, Garmin Pilot, WingX, and FltPlan Go.

The current codebase includes:

• Standard GDL90 heartbeat, ownship report, and ownship geometric altitude messages
• ForeFlight ID and AHRS extension messages
• ForeFlight auto-discovery with fallback to a manual target IP/port
• Traffic broadcasting from TCAS targets, with legacy multiplayer fallback
• An in-sim ImGui settings and status window
• Cross-platform builds for macOS, Windows, and Linux
• A unit test target and coverage script

Download the latest release from GitHub Releases, extract it, and copy the xp2gdl90 folder into:

X-Plane 12/Resources/plugins/

The packaged release layout is:

xp2gdl90/
├── mac.xpl
├── 64/
│   ├── win.xpl
│   └── lin.xpl
├── README.md
└── LICENSE

After launching X-Plane, open:

Plugins -> XP2GDL90 -> Settings...

You can also toggle broadcasting from:

Plugins -> XP2GDL90 -> Enable Broadcasting

Settings are stored in X-Plane's preferences directory as xp2gdl90.json, typically:

Output/preferences/xp2gdl90.json

For a basic manual setup:

1. Install the plugin.
2. Open Plugins -> XP2GDL90 -> Settings....
3. Set Target IP to the tablet or EFB device IP.
4. Leave Target Port at 4000 unless your app requires something else.
5. Keep NIC and NACp at 11.
6. Save the settings.
7. Confirm the Status tab shows packets being sent.

For ForeFlight, the plugin can also listen for discovery broadcasts on UDP 63093 and temporarily switch the broadcast target to the discovered host and port.

The repository uses the X-Plane SDK from SDK/ and Dear ImGui as a git submodule under third_party/imgui.

Clone with submodules:

git clone --recursive https://github.com/6639835/xp2gdl90.git
cd xp2gdl90

• CMake 3.16+
• C++17 compiler
• X-Plane SDK headers and libraries in SDK/ (already vendored here)
• OpenGL development libraries on Linux

Platform notes:

• macOS: Xcode Command Line Tools
• Windows: Visual Studio 2022 or a compatible MSVC toolchain
• Linux: GCC 7+ or Clang 6+ plus OpenGL development packages

Generic CMake flow:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --config Release

Expected output locations:

• macOS: build/mac.xpl
• Linux: build/lin.xpl
• Windows: build/win.xpl or build/Release/win.xpl depending on generator

Helper scripts are also included:

• macOS: ./build_mac.sh
• Linux: ./build_linux.sh
• Windows: build_win.bat

Enable the test target with:

cmake -S . -B build -DXP2GDL90_BUILD_TESTS=ON -DCMAKE_BUILD_TYPE=Debug
cmake --build build --target xp2gdl90_tests --config Debug
ctest --test-dir build --output-on-failure

A coverage helper is available at scripts/coverage.sh. It configures a separate coverage build under build/coverage, runs ctest, and reports line and function coverage for src/. On Clang-based setups it expects full coverage for those metrics.

The plugin currently sends:

• 0x00 Heartbeat at the configured heartbeat_rate
• 0x0A Ownship Report at the configured position_rate
• 0x0B Ownship Geometric Altitude at 1 Hz
• 0x14 Traffic Report at 1 Hz
• 0x65/0x00 ForeFlight ID at 1 Hz
• 0x65/0x01 ForeFlight AHRS at 5 Hz

Current behavior from the implementation:

• ForeFlight auto-discovery is optional and listens on the configured broadcast port
• Manual target_ip and target_port are used as the fallback target
• The effective callsign uses the aircraft tail number when available, otherwise the configured fallback callsign
• Ownship report altitude uses sim/cockpit2/gauges/indicators/altitude_ft_pilot when available
• AHRS heading can be transmitted as true or magnetic heading
• Traffic is sourced from TCAS target datarefs when available, otherwise from legacy multiplayer datarefs

Weather uplink data is not transmitted.

The on-disk settings file is JSON:

{
  "target_ip": "192.168.1.100",
  "target_port": 4000,
  "foreflight_auto_discovery": true,
  "foreflight_broadcast_port": 63093,
  "icao_address": 11259375,
  "callsign": "N12345",
  "emitter_category": 1,
  "device_name": "XP2GDL90",
  "device_long_name": "XP2GDL90 AHRS",
  "internet_policy": 0,
  "ahrs_use_magnetic_heading": false,
  "heartbeat_rate": 1.0,
  "position_rate": 2.0,
  "nic": 11,
  "nacp": 11,
  "debug_logging": false,
  "log_messages": false
}

Field reference:

The settings window currently exposes these tabs:

• Status
• Network
• Ownship
• Device
• Rates
• Accuracy
• Debug

The window supports Apply, Save, Revert, and Defaults.

Key X-Plane datarefs used by the plugin include:

• sim/flightmodel/position/latitude
• sim/flightmodel/position/longitude
• sim/flightmodel/position/elevation
• sim/cockpit2/gauges/indicators/altitude_ft_pilot
• sim/flightmodel/position/groundspeed
• sim/flightmodel/position/true_psi
• sim/flightmodel/position/theta
• sim/flightmodel/position/phi
• sim/flightmodel/position/psi
• sim/flightmodel/position/indicated_airspeed
• sim/flightmodel/position/true_airspeed
• sim/flightmodel/position/vh_ind_fpm
• sim/flightmodel/failures/onground_any
• sim/aircraft/view/acf_tailnum
• sim/cockpit2/tcas/targets/*
• sim/multiplayer/position/planeN_*

• Check X-Plane's Log.txt for lines prefixed with [XP2GDL90]
• Verify the plugin directory is Resources/plugins/xp2gdl90/
• Verify the correct platform binary exists inside the folder
• If building from source, make sure the ImGui submodule is present

• Make sure the X-Plane machine and EFB device are on the same network
• Confirm the target IP is correct if you are not relying on ForeFlight auto-discovery
• Keep NIC=11 and NACp=11
• Check the Status tab to confirm heartbeat and position packets are increasing
• Check Log.txt for UDP send errors

• Confirm ForeFlight auto discovery is enabled
• Confirm the discovery port matches the app environment; default is 63093
• Check that firewall rules allow UDP traffic
• Use a manual target IP/port as fallback

• Use Save, not only Apply
• Check whether xp2gdl90.json was created in the X-Plane preferences directory
• Check Log.txt for a settings write error

.
├── CMakeLists.txt
├── SDK/
├── docs/
├── include/xp2gdl90/
├── scripts/
├── src/
├── tests/
└── third_party/imgui/

This project is licensed under the MIT License. See LICENSE.

• Issues: GitHub Issues
• Actions: GitHub Actions