Frequently Asked Questions
This section provides answers to frequently asked questions on a range of common support topics and questions. The information here is designed to allow you to self-help and answer common questions without having to wait for an answer from our all-volunteer team.
If this FAQ does not cover your question, please head to our Support-Forum on Discord where you can search the topics for similar issues or raise a request of your own if you can't find an answer.
Known Issues w/ Asobo AI
A number of AI limitations and traffic behaviors exist in MSFS 2020 and/or 2024 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. (2020/2024)
- 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. (2020/2024)
- Even with SID and STAR features turned on in the FSLTL injector, Asobo decided the sim should take control of the aircraft flight plan when the aircraft is close to the airport. This often results in unrealistic AI flight maneuvers including unnecessary climbs, descents and backtracking to previous waypoints. (2020/2024)
- Departure aircraft do not always climb at a smooth rate to their assigned altitude and may linger at lower altitudes before continuing their climb. (2020/2024)
- Aircraft may utilize an incorrect runway for the current weather/wind conditions. (2020/2024)
- Departing and arriving aircraft may use a single runway at an airport, even with multiple parallel runways available (2024)
- Aircraft may utilize a runway not normally used for that aircraft type in real life. (2020/2024)
- The sim determines aircraft taxi routes to be the shortest route possible, not the most realistic. (2020/2024)
- Many default airports in the sim have incorrect gate sizes set which may prevent the correct aircraft types from using them (Al aircraft cannot use gates where the parking size is less than the wingspan of the aircraft). (2020/2024)
- Airports with incorrect or incomplete taxi paths and/or runways can cause Al aircraft to become stuck and eventually culled for non-movement. (2020/2024)
- Airline gate/parking assignments are configured in the airport scenery. Incorrect or missing gate/parking assignments will cause aircraft to be placed or parked in unrealistic locations of the airport. (2020/2024)
- Jetway animations are inconsistent when connecting to the aircraft, preventing the jetway from connecting flush to the aircraft on every occasion. (2020/2024)
- Aircraft landing is inconsistent with some aircraft making a low pass over the airport with gear up due to not entering a true landing state (2024)
- Aircraft taxi speed can be extremely slow, causing go-arounds for arriving aircraft as ground aircraft take too long to start takeoff roll or leave the runway after landing (2024)
- Arriving aircraft stop early at the gate/parking causing jetways to be too far away to connect (2024)
- Aircraft service vehicles (pushback tug, stairs, baggage loaders, etc) appear and disappear quickly, often not in the sim long enough to perform their function. (2024)
- Aircraft sounds may cut-out/cut-in based on their distance to the user/camera. Per Asobo, this is by design to fix a non-existent performance issue. (2024)
Other Limitations:
- Identification labels cannot be applied to Al aircraft created using SimConnect. (2020/2024)
- Callsign pronunciation varies between ATC and aircraft. The pilot may pronounce a callsign correctly, yet ATC may pronounce a callsign phonetically. (2020/2024)
- If using MSFS Live Traffic and/or Multiplayer (instead of FSLTL injector) model matching is completely controlled by the sim and may be inaccurate. (2020/2024)
- If using multiplayer aircraft while using FSLTL Injector, multiplayer aircraft may spawn at the same gate as AI aircraft. (2020/2024)
NOTE: 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. Initial positioning won't be 100% accurate but will be very close to real life. Because the sim is in control of injected AI aircraft, their position in the world may deviate from the real-world position as time progresses.
Installation
Make sure MSFS is closed when applying updates to FSLTL content.
Any errors encountered while using the FlyByWire installer app will be displayed along with instructions on how to proceed.
IMPORTANT: FSLTL is unable to support and troubleshoot issues with the FBW Installer app. Any and all errors in the FBW Installer app need to be reported to FBW directly. You can follow the instructions displayed with the error in the FBW Installer app, or contact them via their Discord server: FBW Discord.
FSLTL content MUST be installed or linked to the Community folder for the sim version you are using.
If you want or need to install FSLTL content on a different drive from your Community folder, you must use a symbolic link. More details on symbolic links can be found online, or you can use 3rd-party addons line Addon Linker to make the process easier.
The FSLTL team cannot assist with symbolic link creation or support.
By default, Chinese language versions of Microsoft Windows (and some other languages) do not support global language settings required for FSLTL to run correctly and can affect flightplan creation that will prevent AI aircraft from being imported into the sim.
Regardless of the Windows language you are using, the following language setting is a good troubleshooting tool if you have injection issues with non-English Windows installations (this is from the MSFS FAQ):
- In Windows: control panel->region->administrative tab->change system locale setting
- check the "Beta: Use Unicode UTF-8 for worldwide language support"
Overview
Let's take an airport and consider just the IFR and static counts.
An AI aircraft can be injected into the sim in two kinds of positions
- at a gate at its origin or destination
- or in the air at least 20km or so from its destination or origin (which is an MSFS limitation)
For in-the-air - the process is quite straightforward - if it's in the air in the received live traffic data, we will attempt to insert it in the air in the sim. If it's too close to its origin or destination, the sim will park that aircraft instead.
For aircraft that are at a gate by design, they come either from:
- being part of your static count which uses a proportion of available gates (based on your chosen injector settings) to add aircraft based on statistical probability from historic flight data (i.e. there is a 0.5% chance an ANZ A320 will be at this airport). They will only move if the below scenario occurs and we need an aircraft of that type and airline - in which case they will be repurposed as an active aircraft.
- or from being on the ground in the received live traffic data. Because SimConnect does not allow injecting AI aircraft during taxi, any live traffic aircraft on the ground, moving or not, will be placed at a gate/parking location by the sim. If live traffic data then shows the AI aircraft is in motion, above 3kts, the injector marks that aircraft for departure and the sim will start the preflight process. This can cause the perception of delayed traffic compared to the live data; it's just how long the sim takes before pushback for preflight. The FSLTL Injector console window will display the status changes of each aircraft as they happen within the sim.
The flight plan database API key is only relevant for IFR AI flights in the injector.
Without the API key, an AI flight flying from KLAX to KSFO, for example, will fly in a straight line from KLAX to KSFO. It will use an estimated cruise altitude. It will not have any altitude or speed constraints. On departure and arrival, MSFS will direct the aircraft for take off and landing before it flies in the straight line to the destination.
With an API key, an AI flight flying from KLAX to KSFO will query the flight plan database for a route and will fly (as example) : KLAX DERBB J1 AVE V137 ROM V485 RANCK KSFO, it will have a cruise of 35,000ft from the plan and will have stepped decent altitudes from AVE through to KSFO. You will see airways being used.
If you want something closer to reality for the enroute AI flights, use an API key.
What the API key won't do :
- Impact framerate
- Hugely increase your internet usage (its one API call per route per session)
- Change anything about your user aircraft flight
Troubleshooting
Logs for the FSLTL Injector can be found at the following location: %APPDATA%\fsltl-trafic-injector\Logs
Providing your FSLTL Injector log is required when requesting support. Use the #Support-Forum channel of our Discord server.
Sim CTDs are not uncommon and can be caused by a variety of issues. They are notoriously hard to find root cause. Below is a list of known CTD issues and tips to try and identify your cause.
Please note we are unable to support users running MSFS Sim Beta versions.
Known issues
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FSUIPC7: Fix as follows
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Go into fsuipc folder
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Find FSUIPC7.ini
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Add "ProvideAIdata=No" without the quotations
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- FSLTL Injector location: Some users may experience CTDs if your FSLTL Injector and Base models are both in your community folder, fix...
- Move the injector folder outside of MSFS Community.
- Self-Loading Cargo: Users have reported CTDs using SLC and FSLTL. No workaround has been found with this and the SLC product is no longer being developed. For now, we can only recommend not using both tools together if you experience CTDs.
CTD considerations and tracking
Log files showing us the injector has lost communication with the sim, unfortunately, cannot help determine the cause of a CTD. Conflict with other addons is usually a likely cause. To help track it down, follow the following steps:
- Temporarily move or unlink all non-FSLTL content from your community folder
- Re-run simulator. If CTD continues, open discord support case with your injector log, and note that you have a clean community folder or links disabled.
- If no CTD, gradually add back your addons to the community folder and test for CTDs to help identify the cause.
Bad nav data has been known to cause sim CTDs in the past. When the FSLTL Injector requests this corrupt nav data for an origin or destination airport of an AI aircraft, the sim can crash, giving the perception that FSLTL is the cause. In those instances, try a flight in another region. And if you're using 3rd party nav data add-ons (Navigraph, etc), be sure you are running the latest AIRAC/version.
Other considerations are your system capabilities. AI has always placed a high demand on CPU resources within ESP-based simulators (FSX/P3D etc). MSFS despite its advances still uses some legacy code in its AI management. If you experience CTDs while running complex addon aircraft at a detailed scenery area and complex airport with high AI injector settings, you are far more likely to experience sim-related CTDs. Tune down your simulator and injector settings to a level that is stable for your system and experience.
FSLTL injects traffic via SimConnect, an API that allows external applications to interact with MSFS. This API has been in place for many years within the MS Flight Simulator platform and some of its legacy limitations still exist. One of these limitations is a 1000 Sim Object limit for the simulator as a whole. This means that each object created in the sim by any external application uses one of those Sim Objects, but in addition Sim Objects associated to that object also count - for example all the ground vehicles for an AI aircraft.
The more Aircraft, Boats, Ground Vehicles, Marshallers etc you have in the sim, it becomes easier to hit this limit.
Once the limit is reached the simulator stops drawing objects, even though they are still created. So for AI aircraft you will still see them in Little Nav Map, the Injector Console etc but visually they won't appear in the sim.
To prevent this, you need to manage the objects being created and reduce the overal count. If you wish to see the count of objects in use we will explain how to do that at the base of this article, but you can just tweak your settings and experiment too.
Things to reduce:
- In MSFS Setting - Traffic settings reduce the Airport Vehicle Density and Worker Density sliders - do not set to 0 as this prevents pushback.
- FSLTL Injector Settings
- Additional Parked Aircraft - lower to 2 or 3 max.
- Abosulte Parked Aircraft Max per Airport - lower to 30 or less
- Max Acitve IFR Aircraft - lower to 80 or less
- Max Active VFR Aircraft - turn off if not required
- Other addons
- GSX Pro - disable 'Additional Ground Clutter' option in the GSX Pro configuration tool
- Boat / Ship Traffic addons - lower the number of boats injected
ADVANCED DIAGNOSIS! If you wish to actively monitor the object count - this can be done via the developer mode in MSFS.
- Firstly enable the develolper mode then select the Sim Objects option:
- Then enable 'Display summary on screen' in the dialog that appears. The total count in the number next to Nb as shown in the image. When this passes 1000 you will have the issue and need to reduce your settings.
With respect to native sound formats in MSFS, there appears to be a maximum sound limit that can play at once in the simulator. If you are using a complex aircraft, 3rd party scenery with ambient sounds and FSLTL, you may find some sounds do not play. There is no way to increase this limit. We have heard that for 3rd party scenery you can sometimes disable the sounds and this will help the overall sound limit in the sim.
In addition, in MSFS2024, there is a known issue starting around SU4, that causes aircraft sounds to abruptly cut-out/cut-in based on the distance of that aircraft to the user's aircraft or camera. Per Asobo, this is by design. Their reasoning for the change is performance; however, we very much disagree with their decision. We recommend you voice your opinion via the Asobo/MSFS forums.
Injector Errors & Crashes
This connection error is due to the FSLTL Injector attempting to connect to SimConnect but the simulator is not running.
We recommend you start sim and only start the FSLTL Injector once you've started your flight. The injector cannot inject aircraft until then anyway.
In rare instances, some users have reported injector crashes with the injector folder is located directly in the Community folder. While the FSLTL team cannot reproduce this issue, its been reported that moving the injector to a different folder resolves the issue.
You can use MSFS Addons Linker to then link that folder back to the community folder in order to keep the in-sim FSLTL toolbar icon working as expected and continue to use the FBW installer to apply FSLTL Injector updates.
The FSLTL Injector toolbar icon in the sim may be incompatible with older toolbar addons that have been abandoned by their developers or are not using current standards. Users have reported issues with the following:
- gs2020
- LukeAirTool-VRControls
While your experience may vary, if you experience sim issues and/or CTDs, we recommend temporarily removing all non-FSLTL content from your Community folder and then attempt to reproduce the issue.
This can be caused by a corrupt FSLTL Injector config .json file.
To resolve:
- Close MSFS
- Navigate to %APPDATA%\fsltl-trafic-injector\
- Delete the existing fsltl-trafficinjector-config.json file
- Restart MSFS and the FSLTL Injector. The injector will automatically create a new .json file with the default settings.
The FSLTL injector obtains the path to your Community folder by looking in a sim config file. The injector looks in one of these locations for a UserCfg.opt file, depending on the MS Store or Steam version installed of either MSFS 2020/2024:
MSFS2020:
- MS Store:
- %LocalAppData%\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache
- Steam:
- %AppData%\Microsoft Flight Simulator
MSFS2024:
- MS Store:
- %LocalAppData%\Packages\Microsoft.Limitless_8wekyb3d8bbwe\LocalCache
- Steam:
- %AppData%\Microsoft Flight Simulator 2024
If the injector finds a UserCfg.opt file in both locations for MSFS2020 or 2024, you will see a red error on injector start. This means you either have both versions installed, or you used to, and remnants are left behind.
With two different UserCfg.opt files telling the injector two different Community locations, the injector won't guess which is correct. Once you clean up the sim versions on your PC, the injector should start normally, but it is up to you to resolve this situation on your PC.
If you need to keep both versions of the sim installed, the workaround would be to manually rename the UserCfg.opt file for the version of the sim you don't want to use so the injector only finds the one you do want to use.
Livery Issues
While FSLTL Base Models includes over 2000 liveries, there are still many not yet included. As of May 2026, we have almost 1000 liveries on our to-do list, not counting special liveries, etc.
If you have a livery request, feel free to contact us in our Discord server, but chances are, its already on our list.
If you have aircraft liveries you have created yourself and would like to see them included in FSLTL Base Models, please reach out to us via Discord.
And as always, if you'd like to join the team as a livery artist, contact us here.
White liveries occur where the livery or models do not yet exist in the FSLTL package. This is a choice made by the FSLTL team to ensure traffic still exists in the simulation as opposed to empty ramps and skies.
While using the FSLTL Injector, if you do not want to see white liveries, configure the option to disable blank liveries and generic models when prompted to change settings when the injector starts.
Whilst we have over 2000 liveries in FSLTRL Base Models, not every airline and type is covered yet.
Please also note that if you are using a combination of FSLTL and AIG, both need to be in the community folder (or both outside and linked via the MSFS Add-ons Linker). Only having one of these in the community and the other outside will cause livery display issues.
For VATSIM users, these constraints remain the same but additional factors can apply. VATSIM clients and FSLTL VMR relies on users having the correct callsign in their pilot application. Using BA instead of the correct BAW for British Airways will result in a white livery. Also, a scenario where a VATSIM user may be using an aircraft livery on a type that is not operated by that airline may result in a white livery. For example, Vueling 737, for example, will show as a white 737 as Vueling operates an Airbus-only fleet.
Whilst it is possible to load into an airport where the traffic shown does not have liveries available, it's unlikely. A scenario where all aircraft are white normally indicates an issue with your installation. There are a number of possibilities here and things you can try.
- If you are using MSFS Add-ons Linker, check to make sure your FSLTL installation is checked and actively linked.
- You may have conflicting traffic add-ons that are causing issues. Try disabling these and then run FSLTL alone.
- Back up your community folder - and reinstall the injector and base models - so FSLTL is the only thing in the community. Re-run and see if liveries are still blank.
VA and historic liveries are really of concern to VATSIM users only. A selection of large VA's and some popular historic airlines that are frequently seen on VATSIM (Pan AM, etc.) are included in FSLTL.
We are also looking at an install selection to make these "optional" but limitations in the FBW Installer App don't yet allow for this.
FSLTL has partnered with VATSIM and any member of their VA Partner and Associate Virtual Airline programs can submit aircraft liveries to be included in the FSLTL package.
VA Partners and associate airlines should visit/contact VATSIM Virtual Airlines department channels detailing livery guidelines and requirements specific to MSFS and FSLTL standards. VA Partners and Associates must submit liveries to the VATSIM Virtual Airlines department, to be reviewed for inclusion FS Live Traffic Liveries.
If you run or manage a VA who is not part of the VATSIM VA partner or associate program and would love to see liveries represented, we encourage you to apply via your VATSIM portal. We have no plans to accommodate non-VATSIM-approved VAs.
VR has its own live traffic settings in addition to the standard traffic settings. If you are using VR, you must ensure that you turn off the in-sim live traffic settings within the VR options as well!
Most liveries within FSLTL Base Models are set to 4K resolution with Mip Mapping enabled.
FSLTL has no current plans to offer a separate lower resolution version of FSLTL Base Models.
For users with performance-limited computers and/or limited drive space that believe lower resolution liveries will be of benefit to them, there are resources online that allow you to make these modifications yourself. Please be aware that the FSLTL team cannot support custom modifications to the Base Models content.
Traffic Behaviour
The sim controls the runways AI aircraft will use.
This means the sim can decide to use runways that do not match real-world airport operations, do not match the runway you see being used when looking at real-world live traffic tracking sites, and/or do not match current weather conditions.
At this time, the FSLTL Injector is not able to work around this sim limitation.
FSLTL injects the traffic, MSFS handles the parking and movement of the aircraft.
Airline code assignment of gate/parking spots is a part of the airport scenery, and many default airport sceneries do not have these codes.
When FSLTL Injector injects an aircraft, the sim determines where in the scenery to place that aircraft. Without correctly sized and correct types of parking available, with airline codes assigned to that parking, where the sim places the aircraft in the scenery may not be realistic.
FSLTL cannot control or fix parking or the airlines codes assigned to that parking.
Third-party scenery add-ons, available online, free and paid, can add correctly sized, correctly typed parking with realistic airline code assignments which you can try.
Linked to the above item, this is controlled by the content of the airport scenery.
FSLTL Injector injects aircraft based on the live traffic data it processes from the live traffic data provider you chose.
However, once injected, the sim, for the most part, is now in control of that aircraft. Differences in pushback time, taxi speeds, runway usage, flightplan content, flightplan adherence, etc., can all mean the in-sim AI aircraft can deviate from where the real-world aircraft is located.
So, while most AI aircraft will be close, it will not be exact.
Arriving AI aircraft need appropriately sized and type gate/parking stands to be available in the airport scenery. When landing aircraft are unable to find a usable gate/parking spot, or no valid taxi path to parking is available, MSFS will remove the aircraft just after landing.
Scenery add-ons are available online for a wide range of airports that can fix parking and taxi routes of default sim airport scenery. FSLTL Injector cannot control or modify airport scenery.
Unlike departing traffic, landing traffic will take time to appear due to some MSFS issues.
MSFS will warp arriving injected aircraft straight to the gate if the aircraft are closer than 20-25km from the destination airport. Therefore, any traffic that will actually land are those aircraft injected more than 20-25km from the destination airport. It will take some time for those aircraft to arrive.
To troubleshoot:
- Download little nav map and set it to show AI aircraft
- Start injection with an IFR count of 300, VFR count of 0 and static count of 0
- Monitor the appropriate live traffic site to see what real aircraft are actually in the area; many times people assume there is more traffic in the area than there really is
- Watch little nav map and you should see aircraft farther away making there way to the destination airport - maybe 30+ km out - but they will be coming
If experiencing erratic behaviour or strange taxi flows, ensure you do not have overlapping scenery files, especially with Asobo hand-crafted airports or freeware.
For example, if you own Inibuilds EGLL or KLAX, you must delete the Asobo handcrafted from the content manager, otherwise, both may be active and cause AI problems.
A long-lasting bug in MSFS2020 can cause there to be no visible AI aircraft when you return to your original airport after a return flight (e.g. LHR-AMS-LHR).
The only workaround is to exit to the main menu of MSFS2020 and start you return flight as a new flight.
Unfortunately, since SU12 or so of MSFS2020, the sim will often ignore flightplan STAR and/or approach waypoints as the aircraft nears its destination airport. This can lead to AI aircraft making unrealistic turns, loops and backtracking before making its approach to the airport.
About FPS
When it comes to flight sim, do not fall into the trap of worrying about your FPS, this is not a first-person shooter, anything over 30 is good, 40 - 60 excellent.
Adding AI aircraft to your sim session is adding additional work for the sim and your computer to deal with. But don't focus on a magical FPS number... focus instead on smoothness in the sim and what feels right to you, and that's down to tuning your settings (Injector, sim, PC, other addons, apps, etc) to suit your PC capabilities and what you feel is most important for your sim experience.
Many users will experience no or minimal impact on their sim FPS experience however everyone is different and will have varied results. This section talks through how AI is handled by the sim and its potential impact.
MSFS AI is a legacy code from FSX, much like the ATC system. FSX users will recall the major impact of AI traffic; fortunately MSFS uses resources more efficiently. However, some users will still see an impact.
Handling AI requires some significant CPU calculations. Depending on your FSLTL injector and sim settings, the CPU is tasked with computing and placing the extra dynamic objects you've requested be added to your sim session, including those AI aircraft at a distance that you may not see.
Compared to static objects, this places a high demand on CPU loads. GPU is far less of a constraint here unless you are running a low-end card that relies on the CPU to back it up. CPU is the bottleneck when it comes to AI. Model detail and texture resolution are far less of a factor in FPS impact.
Well, the answer depends on you... your PC hardware and horsepower, system settings, sim settings, injector settings, other sim addons, other applications running on your PC, etc. There is no golden bullet here, and each user must find a balance to suit them and their system. No two people will have the same setup and variables, and each person will have their own wants and needs.
Given what we covered in the above sections, users reporting stutters or FPS hits with high injector and sim settings in busy areas such as London, New York and Frankfurt should not be surprised to see an impact. Your system will already be challenged drawing and managing a highly detailed area with lots of traffic. Add to that a detailed addon scenery product and a highly complex aircraft such as the Fenix A320 and your system will be affected.
Let's be clear, we cannot guarantee zero impact to users, although many do state they see little to no difference. As mentioned above, AI is hungry for CPU resources, and this is from the MSFS code, not the injector. FSLTL Injector just adds the correct model and airline, and MSFS manages the sim implementation and control.
High-end systems - Likely see no or minimal impact
Mid-range systems - Some impact, possibly 10-15 FPS, especially in high-demand scenarios
Low-End systems - likely mid to high impact - tune accordingly
Several things, again we stress the need to tune your sim and injector accordingly.
DX11 vs DX12 (MSFS2020)
Users have reported far worse performance with AI on DX12 versus DX11, even on higher-end systems. Try both to see if one works better for you.
Injector settings
Scale back your injector settings to find a good balance. Remember, more aircraft means more resources are needed for your CPU. Try lowering the IFR/VFR settings and/or injection radius settings to limit injection to those aircraft closer to you. Experimentation will be needed until you find a level you are happy with.
Sim Settings
Adjust your dynamic world settings, road traffic, airport ground vehicles, boats, clouds, water etc.
There are a 1001 different setting/FPS/Smoothness guides on YouTube, here are some example to watch which may help you.
Vatsim Model Matching
Verify you have set up the FSLTL VMR file correctly by following our User Guide page's "FSLTL in VATSIM" section.
Secondly, verify your base models are installed correctly or reinstall.
If the issue persists, run the FSLTL injector tool to check if injected AI aircraft appear as expected. If no aircraft appear with the injector either, please open a support post on our discord support forum sharing your log file (location contained within this FAQ).