Overview

Abflug.cloud is a multiplayer flight simulator system that allows pilots to see each other's aircraft positions in real-time. It works with Aerofly FS and other flight simulators that support ForeFlight UDP protocol.

Key Features

• Real-time position sharing via HTTP API
• Traffic display on interactive maps
• Observer mode for viewing traffic without flying
• API key-based authentication
• Rate limiting and security features

Architecture

The system consists of three main components:

1. Abflug Client (client/abflug_client_gui.py)

Receives GPS data from your flight simulator via UDP and forwards it to the server via HTTP API.

2. Server (abflug.cloud)

Receives position updates from all clients, stores active positions, and serves traffic data via HTTP API.

3. Rewinger (rewinger/rewinger.py)

Displays your aircraft position and nearby traffic on an interactive map. Queries the server for traffic data.

Data Flow

1. Aerofly FS → Sends GPS data via UDP (port 49002)
2. Abflug Client → Receives UDP, sends position to server via HTTP PUT
3. Server → Stores position, makes it available via HTTP GET
4. Rewinger → Queries server for nearby traffic via HTTP GET, displays on map

Preflight checks

Prerequisites

• Python 3.7+
• Aerofly FS configured to send UDP data on port 49002
• API key from Server here
• Download the python files here
• Computer performance for the Client is pretty basic - if you can run a flight sim, you can run the client and Rewinger.

Step 0: Check that Aerofly is set:

If you are using a separate machine to stream the data, you need to set Aerofly to send the data to the IP address either as broadcast (xxx.yyy.zzz.255) or to the IP address of the machine running Abflug Client.

Step 1: Extract abflug_v1.zip

you should see two folders:

• client
• rewinger

Move the folder somewhere safe, where you can access it easily via terminal.

Open the terminal application and change directory to "abflug_v1"

Hint: you may want to use python venv. Read how to at python.land

Launch the gui client using python:

Step 2: Run Abflug Client

Use the GUI application for easy setup:

Or use the command line tool:

The Aubflug Client waits for the Aerofly UDP data to be received on port 49002 and then sends the data to the server once online.

For this reason, please make sure that the UDP output is enabled in the Aerofly settings.

The Client will show a green dot if the UDP data is being received and a grey dot if the UDP data is not being received.

You don't have to set it to listen - the client will immediately starts to listen for Aerofly data after launch.

In this image, the Client is disconnected from Aerofly and from Abflug.cloud - called "No green configuration"

In this image, the Client is connected to Aerofly but not yet to Abflug.cloud.

Please paste your API key and fill out the Callsign.

In this image, the Client is connected to Aerofly and to Abflug.cloud - called "all green configuration"

Note: callsign is set but is not mandatory. If no callsign is set, the server will assign a random callsign.

Please check your flight plan and make sure that the callsign is set.

Abflug.cloud will identify across the network via an ICAO address generated from your API Key.

Step 3: Run Rewinger

Rewinger displays traffic on an interactive map. To connect to multiplayer:

Rewinger is launched and detected UDP connection. It's not automatically connected to the server. You need to fill the multiplayer section with the API key and click the "Connect" button to connect to the server.

In the "Multiplayer (HTTP API)" section:

1. Enter server URL: https://abflug.cloud
2. Enter your API key
3. Click "Connect"

In this image, Rewinger is connected to Abflug.cloud and is showing the traffic around you.

If the blue aircraft label changes from Aerofly FS 4 to the callsign of your aircraft, you are successfully connected to the server.

In this image, Rewinger is connected to Abflug.cloud and is showing the traffic around you. You can see the traffic from other aircraft in the area.

The traffic is displayed as orange aircrafts. The blue aircraft is your own aircraft.

The labels indicate the callsign and the altitude in feet.

Note that you don't need to set the callsign again as in the Abflug Client. The server will send your callsign to the Rewinger.

That means, if you want to change the callsign, you need to disconnect from the Client and change your callsign.

Step 4: Enjoy the multiplayer experience

Remember: this is a Beta version and the system is still under development.

If you find any issues, please report them to the developer at [email protected]

Observer Mode

You can also use the Observer Mode to view the traffic from other aircraft in the area. This is useful if you want to check the area around you without flying.

This mode is available only if you are not receiving GPS data from your flight simulator.
This means that you are not flying and you are just watching the traffic from other aircraft in the area.

You do not need the Abflug client - only Rewinger.

In this image, Rewinger is in Observer Mode and is showing the traffic from other aircraft in the area.
You are connected to the server and you are seeing the traffic from other aircraft in the area.

To use the Observer Mode, you need to set the latitude and longitude in the "Observer Position" field.

You can right click on the map to get the latitude and longitude of the clicked point.

You will get a small tooltip with the coordinates. Click on the coordinates and to receive a confirmation that lat/lon have been copied to the clipboard. Paste into the multiplayer section.

After, click the "Connect" button to connect to the server and you will see the traffic from other aircraft in the area.

Server will return the filtered traffic around the observer position via the radius you set in the multiplayer section.

if it shows Connected (observer) but grey, you may have forgot the position. As Abflug will return the filtered traffic around the observer position, you need to specify it via the radius you set in the multiplayer section.

Troubleshooting

General

Client or Rewinger cannot connect

• Check that Abflug Server is online. The health check requires no API keys.
• Please check your firewall and network connection. Business networks may limit the open ports.
• Check abflug.cloud if there is a new version
• Verify your API key does not contain quote marks!

Client Issues

"No data received" from Aerofly

• Check Aerofly is sending UDP data on port 49002
• Verify UDP output is enabled in Aerofly settings
• Check firewall isn't blocking UDP port 49002

"Connection refused" or "Server error"

• Verify server URL is correct (https://abflug.cloud)
• Check API key is correct
• Verify on the Abflug.cloud website if the server is up and running on the main page.

Rewinger Issues

"Not showing traffic"

• Verify you're connected to the server (check status label)
• Check you have GPS data or observer position set
• Increase traffic radius if needed
• Check server has active clients
• It could be that there is no traffic online. Check on a commonly used airport for traffic.

"Callsign not showing"

• Callsign comes from server (set by Client)
• Make sure Client is running with a callsign
• Wait a few seconds for traffic data to update
• IF you recently changed callsign, please close (not only disconnect) Client and Rewinger, then retry.

"Rewinger reports error 429: Rate limit exceeded"

This is a known issue and will be fixed in next releases.

API calls are limited to 1 per second. Sometimes the traffic timing loop is generating requests too fast.

Please disconnect, change the polling rate to 2 seconds, and retry.

"Rewinger reports error 50x: (different eror mesages)"

You are reaching Abflug, but the server is currently not running, probably maintenance.

Please wait a few minutes, Client and Rewinger will reconnect automatically.

Frequently Asked Questions (FAQ)

Service

Why two programs?

The idea is that the user may choose to have a different map viewer with richer data (e.g., navigational charts).

Also, it helps with development - allowing the Client to do functions that would not fit in Rewinger.

Does it work on mobile?

Not at the moment as the mobile version does not have the UDP functionality.

Can I connect other Simulators?

Other simulators are planned however they use navigation databases that are different than Aerofly.

Why not using Aerofly SDK?

Currently the SDK works only on Windows machines. On Mac and other platforms, this is not possible yet.

Do I see other aircraft in my Aerofly cockpit?

Unfortunately no. Aerofly doesn't currently support traffic injection. You'll see other pilots on the Abflug map/viewer.

Why am I the only aircraft showing?

During beta, there are few active users. You can write in the IPACS forums or Discord servers to coordinate flights with other players.

Can I change my callsign?

Yes! You need to disconnect the client and Rewinger, then choose the new callsign.

Is my position data private?

Your position, direction, altitude and callsign are shared with other Abflug users within a maximum distance of 500nm of game position for the duration of the session. Your API key, IP address and email address remains private. You can disconnect anytime by closing the client.

Does this work with VATSIM / IVAO?

They're complementary systems. Abflug focuses on casual coordination, and does not support radio just yet.

What about mobile (iOS/Android/Switch)?

Mobile support is not available. Currently PC/Mac only.

How much does this cost?

Free during beta and ideally will be always free for casual flights.

Certain future plans may be under subscriptions to pay for the ongoing server costs.

Disclaimer

This service is not affiliate with IPACS or Aerofly FS 4.

Rewinger uses components from "Aircraft Tracker" developed by Jugac64 released under MIT license.