FSLTL User Guide

This user guide and FAQ is an overview of using our tool, noting common limitations, issues and behaviours. Please read and check this section first for support. General FSLTL project FAQ's can be found on the homepage.

If this section does not help, please join our Discord and reach out through the available support channels.

For support regarding the FlyByWire Installer, please refer to the separate FlyByWire installer guide.

Video Tutorial by BobbyFuzzy

Recommended MSFS Traffic Settings

The FSLTL Injector can run alongside MSFS traffic but to ensure the best experience we recommend the following MSFS settings to avoid conflict and overlap.

  • Flight Conditions
    • Air Traffic set to "off"
  • General Options / Traffic tab
    • Aircraft Traffic type set to "off"
    • Ground Aircraft Density set to "0"

FSLTL Injector

The FSLTL Injector is the tool that brings traffic into the simulator. Ensure that you have installed this during the FlyByWire installation phase.

Our tool differs from other published injectors by ensuring continued use of the full MSFS experience: ATC is functional, jetways connect to AI planes, and baggage/catering trucks serve parked aircraft.

The injector aims to provide real-time traffic as close to real life as possible.

Running FSLTL

  1. Start MSFS and load it into a flight
  2. Open the FBW Installer if it is not open.
  3. Once the FBW Installer opens, in the left plane, click on the radar icon (3rd icon from the top). This will bring you to the FSLTL menu where you will see two separate options for FSLTL Traffic Base Models and FSLTL Traffic Injector.
  4. Click on FSLTL Traffic Injector and you should see a status of Not Running under the image header. To start the injector, click on Start to the right and you will see a command prompt window open stating that the injector has started and connected to the simulator.
  5. You will be prompted if you would like to change the values for the injector. If you would like to do so, enter Y, otherwise enter N.
  6. Happy flying amongst busy skies! To stop the installer, simply click Stop in the FBW Installer.

FSLTL Injector Options

On the launch of the injector, you will be presented with the ability to change various options which affect how traffic is depicted, below describes what these are and their effects.

  • Max Active IFR Aircraft - Sets the overall amount of IFR traffic ( number is actual number of aircraft ), default gives good coverage with minimal performance impact (you can go higher but expect slowdowns!). Disable IFR flights by entering 0. This value is then proportioned to air and ground traffic based on your altitude (AGL):
    • user on the ground - 50% for air, 50% for on the ground
    • user above 10000ft - 75% for air, 25% for on the ground
    • user above 20000ft - 100% for air, 0% for on the ground
  • Max Active VFR Aircraft - Sets the amount of VFR traffic ( number is actual number of aircraft ), default gives a few GA flights. NOTE: GA control is beta and not close to perfect. Disable VFR flights by entering 0.
  • Additional Parked Aircraft - Sets the amount of static parked traffic at airports based on historical data for the ICAO. 0 for none, 10 for max, 2-3 recommended. ( number is scale linked to percentage of parking )
  • Absolute Parked Aircraft Max per Airport - Sets an absolute number of aircraft that will be used as additional parked aircraft at each airport. The number of parked aircraft will be the lesser of this value and the value the injector calculates from the Additional Parked Aircraft setting. This is useful to limit extra parked aircraft at large airports. The default is 30 (recommend) with a max setting of 100.
  • Max Radius to Inject Aircraft in Air- by default aircraft in the air are injected up to 150km from the user - you can alter that distance with this option. Aircraft are removed at 10km past this distance.
  • Max Radius to Inject Aircraft on Ground- by default aircraft on the ground are injected up to 150km from the user - you can alter that distance with this option. Aircraft are removed at 10km past this distance. Reducing this radius can be useful in dense airport space like around KLAX or EGLL.
  • Blocked Aircraft Removal Time - a time in seconds at which to remove aircraft that should be moving but are not - this can be stuck in pushback, in taxi or just holding for too long. Recommended using 120 or 180 seconds to prevent aircraft awaiting takeoff from being removed too quickly.
  • FlightPlannerDB API - Configures injector to represent optional realistic flight plan following. Create an account at https://flightplandatabase.com and enter the API key from the settings page to use this feature. Optional but highly recommended.
  • Disable showing Blank liveries - does what it says! By default, the injector will show blank liveries for models we have but currently there is no suitable livery on your machine. This option allows disabling these blank liveries from being used
  • Disable showing Generic Models - does what it says! By default, the injector will show generic models if a suitable fallback cannot be found when an FSLTL model doesn't exist. This option allows disabling these generic models from being used.
  • Just Flight FS Traffic models - for those with Just Flight's FS Traffic installed on your machine. This setting allows you to toggle whether the FS Traffic models are given priority over the FSLTL models or not. By default FS Traffic will be below FSLTL in priority and behave like backfill in the way AIG does. If you enable this setting the role will be reversed and you will see FS Traffic's model with priority over the FSLTL version, and FSLTL will be backfill. If using this mode it is very important only the FS Traffic models are installed and the FS Traffic injection module is not active. To ensure this, we advise that only the justflight-aircraft-traffic-fleet folder be in your community folder and all other FS traffic folders be removed / disabled.

Changing FSLTL Options Manually

To update the options of FSLTL manually, browse the injector configuration file and make your alterations:

  • The FSLTL Traffic Injector is located here: %APPDATA%\fsltl-trafic-injector
  • Right-click on fsltl-trafficinjector-config.json and open in a text editor such as Notepad, Notepad++, or VS Code.
  • Enter the values you wish to change and save the file.

To remove the prompt for changing injector options when the injector is launching, add the following line to the config file mentioned above:

  • "silent":"yes"

In-Sim Running Control Options

While the injector is running, you can control a couple of aspects of its behaviour by using the inbuilt toolbar:

Reset Traffic Injection: Removes all existing aircraft and starts injecting again from scratch

Remove Nearby Traffic: Removes traffic that is active around you in an approx 5km radius - useful if aircraft are stuck in front of you on taxi or slow aircraft on final blocking your way!

The sliders allow you to update the injector settings (and have the new values written to the config file) in real-time. It can take a small amount of time until they fully update in the sim as aircraft are removed or added.

The Historic Parked setting is an exception to full real-time updates, existing parked aircraft won't be removed when you change this setting but new airports you come across will use the new setting.

Web API calls:

The injector exposes some rest API calls that allow you to trigger some of the functions of the toolbar from an external program or device.



FSLTL is fully usable with VATSIM but will require separate steps to run. The Injector tool should not be used whilst flying a VATSIM session.

Fallbacks for models not included in our solution and blank texture files for any airlines without livery are covered, however, you can use the FSLTL VMR alongside any custom model matching you may have or wish to use.

The FSLTL VMR file is titled FSLTL_Rules.vmr and can be found in the fsltl-traffic-base folder located in your MSFS Community folder.

Copy this file and place it in your vPilot folder. Within vPilot, add custom model matching and import the FSLTL VMR file. Order the file to the top to avoid overrides from any other VMR you may have.

Scope of Injector Input

  • The injector reads real-time data of aircraft location/type/departure/destination. NOTE: there is around a 30-second delay in this data.
  • You will get a lot more traffic than Asobo live traffic, just be mindful that this may affect performance. However, so far performance does appear good with the latest native models.
  • Flights are point-to-point when not using the FlightPlannerDB option
    • Example result: Origin airport to destination airport, linked to MSFS ATC so you will hear them communicate with ATC. ATC will control the take-off and landing of each flight.
  • We use SimConnect from Asobo which is still being improved. There are known issues with the API, and you might see crazy flight behaviour from some aircraft on occasion.
  • Once inserted into the sim, the injector no longer controls the movement of the aircraft - this is purely handled by MSFS. This is why ATC, TCAS, and other components know all details about aircraft.
  • Aircraft are actively removed that move out of range (around 200km) from the user's plane.
  • Injector removes aircraft that go around due to MSFS bug that they will then continue to circle forever. They are not removed immediately but after around 60 seconds when some distance away from the airport (to prevent immersion breaking of vanishing aircraft). They will then typically be parked at the destination airport a short time later assuming parking is available.
  • If enabled in settings the injector does insert static aircraft at airports based on real-world data collected over several months. The insertion is based on the percentage chance of seeing a livery/model combination at the real airport.
  • FSLTL injector tries to keep things moving at airports by culling aircraft that get stuck while taxing, we do this more aggressively than the default Asobo time frame.

Windows Firewall Settings

Upon the first run of the injector, you may get prompted that Windows Firewall has blocked some features on all public and private networks. In order for the Injector to communicate with FR24 external to your network, you will need to allow access. Failure to allow will prevent the injector from inserting aircraft based on live traffic data.

Known MSFS AI Limitations & Behaviors

A number of AI limitations and traffic behaviours exist in the sim which affects all AI solutions including FSLTL. These issues require fixes from Asobo which we hope to see in the future. If you wish to upvote the issue, then you can do so via the MSFS forums here.

Aircraft Limitations:

  • Aircraft can sometimes randomly disappear when at a gate.
  • Aircraft have only one ground contact point, causing them to 'jump' over gradient changes and in some cases appear to be floating or sunk into the ground.
  • Aircraft loiter on the runway before beginning their take-off roll and before they exit the runway after landing. This can cause excessive go-arounds.
  • Aircraft may land short or long of the runway in strong winds, when using high sim rates, or if an airport's ILS system is not set up correctly by the scenery developer.
  • Aircraft taxi slower than expected.
  • Aircraft taxi with their engines at 100% power.
  • Aircraft turn immediately after take-off to their first waypoint and do not follow a SID (Standard Instrument Departure).
  • Departure aircraft do not climb higher than the initial altitude to which they are assigned by ATC.
  • Only an extremely limited number of configuration options are active in the FlightModel.cfg, causing undesirable aircraft behaviour during all stages of flight.
  • The use of Slew mode may prevent aircraft from starting their pre-flight routine.
  • Aircraft take off on the incorrect runway (either not taking off into the wind or taking off from a runway not normally used in real-world operations).
  • Aircraft taxi routes are not correct at all airports.
  • Airports having incorrect gate sizes set (Al aircraft cannot use gates where the wingspan is set smaller than that of the aircraft).
  • Airports having incorrect taxiway set-ups, causing Al aircraft to get stuck and eventually disappear.
  • Airports not being correctly modelled and are missing taxiways or terminals or only have runways, preventing correct Al traffic operation. (This typically occurs at auto-generated airports in cities with newly constructed airports in the real world that are not yet created in MSFS, such as the new Istanbul Airport LTFM.)
  • Airports not having airline codes set at gates, causing airlines to use a random selection of gates.
  • Jetway animations are inconsistent when connecting to the aircraft, preventing the jetway from connecting flush to the aircraft on every occasion.

Other Limitations:

  • Al labels cannot be applied to Al created using SimConnect.
  • Callsign pronunciation varies between ATC and aircraft. The pilot may pronounce a callsign correctly, yet ATC may pronounce a callsign phonetically.
  • Changing the time, date or weather during a flight temporarily removes all airborne traffic.
  • MSFS Live Traffic and Multiplayer model matching may be inaccurate.
  • Multiplayer aircraft may spawn at the same gate as an FS Traffic aircraft.
  • When exiting a flight, Al aircraft models will sometimes appear inside the globe.

Please also note that when the injector reads real-time data of aircraft location/type/departure/destination, there is around a 30-second delay in this data, along with additional delays due to MSFS inputs. Positioning won't be 100% accurate but will be very close to real life.