For Pilots
ACARS for MSFS 2020 and 2024 Explained
An ACARS client is a program your virtual airline has you run on your PC alongside Microsoft Flight Simulator 2020 or 2024. It connects through SimConnect, the data interface built into MSFS, records your position, speed, fuel and engine state as you fly, and files the flight with your airline. Nothing gets installed inside the sim.
Jordan HavardFounder, Skyvex SoftwareIf your virtual airline (VA) flies Microsoft Flight Simulator (MSFS), its ACARS client talks to the simulator through SimConnect. Knowing roughly how that connection works makes setup quicker and most connection problems easy to fix.
How an ACARS Client Reads MSFS
SimConnect is the interface Microsoft ships with the simulator so that outside programs can read and control it. When MSFS starts, it opens a SimConnect server inside the sim. An ACARS client running on the same PC connects to that server, the same way a browser connects to a website.
Once connected, the client asks for a list of simulation variables, known as SimVars. These are named values the sim keeps for the loaded aircraft, such as PLANE ALTITUDE, GROUND VELOCITY, SIM ON GROUND and fuel quantity. MSFS then sends updated values back many times a second.
From those values the client works out everything else:
- Where you are from latitude, longitude and altitude.
- What phase you're in from ground speed, vertical speed, the on-ground flag and engine power.
- When you took off and landed from the on-ground flag changing.
- How much fuel you used from fuel on board at the start and end.
- How hard you landed from your height and descent rate in the last moments before touchdown.
The client also listens for SimConnect events, like the sim pausing or the flight being unloaded, so it knows when the data stops being trustworthy.
MSFS 2020 vs MSFS 2024
Both versions use SimConnect, and a client that supports both connects the same way. The differences that matter for ACARS are in the aircraft and the sim's menus, not the connection. MSFS 2024 changed how flights are started and how aircraft load, so a client written only for MSFS 2020 may need an update to read some values correctly in 2024. Check that your airline's client lists MSFS 2024 as supported before you fly it.
Do you need FSUIPC?
Not for SimConnect. Some older ACARS software relied on a separate add-on to read the simulator. Clients that connect to SimConnect directly don't need it, so check your client's requirements before installing anything extra.
What You Need Set Up
For a normal setup, with MSFS and the ACARS client on the same Windows PC:
- MSFS on PC. Any PC version works, whichever store you bought it from. The Xbox version doesn't offer the SimConnect connection that desktop ACARS clients rely on.
- Your airline's ACARS client installed on the same PC.
- A VA account and a booked flight, so the client knows your route and aircraft.
- Nothing in the sim. SimConnect is on by default. You don't need a community folder add-on for ACARS.
Then the order is simple: start MSFS, load into a flight at the departure gate, open the client, confirm it shows the sim as connected, and start tracking before pushback.
Running the client on a different computer
Some clients can connect to MSFS on another PC on your home network, for example a laptop next to a dedicated sim PC. That needs a small change to a file called SimConnect.xml on the sim PC so it accepts connections from other machines, and the sim PC's IP address and port entered in the client. Both computers must be on the same local network.
Common Problems and Fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Client says "not connected" | Sim still on the main menu or loading | Load into a flight and wait for the aircraft to appear |
| Never connects | Client and sim running at different permission levels | Run both normally, or both as administrator, not one of each |
| Connects, then drops | Another add-on crashed SimConnect, or the sim stuttered | Close other SimConnect tools, then reconnect |
| Wrong fuel or engine data | Add-on aircraft with custom systems | Check your airline's approved aircraft list |
| No connection to remote sim | Firewall or SimConnect.xml address | Allow the sim through Windows Firewall on private networks; set the address to accept network connections |
| Flight times look off | Tracking started late | Start tracking at the gate before pushback |
Add-on aircraft
Complex add-on aircraft sometimes model fuel, engines or lights in their own systems instead of the sim's standard variables. The ACARS client can only read what the aircraft reports, so a heavily customised aircraft might show odd fuel numbers or engines reported as off at idle. If one aircraft keeps giving strange PIREPs, mention it to your airline's staff. They may already know which aircraft report cleanly.
Pauses, menus and crashes
Opening the world map, sitting in the menu or pausing the sim interrupts the data. Good clients handle a short gap and carry on, but if the aircraft reappears somewhere else (you reloaded a save, or started a new flight), the client should stop and ask you what happened rather than record a jump. If MSFS crashes to desktop, reload at the same spot before resuming tracking.
Tips for Clean MSFS Flights
- Start the sim first, then the client.
- Spawn at a gate or parking spot rather than the runway, so the taxi out and takeoff roll are part of the record.
- Avoid slew mode and the "teleport" options once tracking starts.
- Keep simulation rate at 1x unless your airline allows time acceleration.
- Wait at the gate with engines off until the client registers that you've arrived.
Your first virtual airline flight walks through a whole flight from booking to PIREP. Flying X-Plane instead? See ACARS for X-Plane. For how your position reaches the live map, see flight sim flight tracking.
Frequently Asked Questions
Does ACARS work with MSFS 2024?
Yes, as long as your client supports it. MSFS 2024 uses SimConnect like MSFS 2020, so clients that support both connect the same way.
Can I use ACARS with MSFS on Xbox?
Generally no. Desktop ACARS clients need SimConnect, which the PC version of MSFS provides and the Xbox version doesn't.
Do I need SimConnect installed separately?
No. SimConnect comes with MSFS on PC. Some older tools need extra SimConnect files to run, but that's a requirement of the tool, not the sim.
Does ACARS slow down MSFS?
Barely. Reading flight data through SimConnect is a tiny load next to what the sim itself is doing.
Can I run ACARS on a Mac with MSFS?
MSFS runs on Windows, but a client that supports remote connections can run on a Mac on the same home network and connect to the Windows sim PC.
Where Stratos Fits
Stratos connects to MSFS 2020 and MSFS 2024 through SimConnect directly, with no FSUIPC needed, and detects the running simulator automatically. It can also connect to a sim on another PC on your network, including running Stratos on a Mac while the sim runs on Windows; the remote simulator setup guide covers the SimConnect.xml change. If the sim drops out, Stratos bridges short gaps and suspends tracking when the aircraft reappears somewhere implausible, until you're back where it left off.
Stratos, by Skyvex Software
Free ACARS for every pilot.
On Windows, macOS and Linux.
Stratos reads Microsoft Flight Simulator and X-Plane directly. Continuous telemetry, a landing score from the raw data, and the PIREP filed before you leave the cockpit.