Frequently Asked Questions
This section provides answers to frequently asked questions on a range of common support topics and questions.
Please self-help as much as possible to allow the FSLTL to focus on the future development of the tool.
Known Issues w/ Asobo AI
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 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 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.
- 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.
Firstly make sure MSFS is closed when applying updates. If it is closed and you still get an error code proceed with the below.
Errors with the FlyByWire installer have been reported by some users. FSLTL is unable to support and troubleshoot issues with the FBW Installer. However, FBW can so please head to their discord channel for support: FBW Discord.
Yes, you can install FSLTL on any drive. However, you will need to create a link for the sim to find it. FSLTL recommends using the MSFS Addons Linker tool for this purpose.
Of course, you will need to ensure you have enabled FSLTL within the linker tool for aircraft to show once the injector is running.
By default Chinese windows installs do not support global language settings required for FSLTL to run correctly, and for that matter for any flight plan to be imported from an external source like Simbrief into MSFS.
An additional windows setting must be made (this is from the MSFS FAQ):
- Go to control panel->region->administration->change system local setting
- check the "Beta: use Unicode UTF-8 to provide global language support"
Let's take an airport and consider just the IFR and static counts.
An aircraft be put into the sim in two kinds of positions
- at a gate at its origin or destination
- or in the air at least 30km 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 FR24 we will attempt to insert it in the air in the sim. If it's too close to its origin or destination - it may still appear parked at a gate based on the above limitation.
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 (2 or 3 tend to be sensible settings) to add aircraft based on history (that isn't from FR24) - this is just a probability mapping - 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 get reassigned to active.
- or from being on the ground in FR24. Because we can't inject already taxing traffic - anything on the ground in FR24 moving or not - will be put at the gate. If the aircraft then moves in FR24 above 4kts - we will mark it for departure and the sim will start the preflight. This is why people seem to think FR24 injection is 5 - 10 mins delayed - it's not - it's 30 seconds. It's just how long the sim uses before pushback for the preflight. Monitor the injection console and this is all displayed for you as things happen if you listen to the clearance channel in ATC you will hear lots of clearance calls almost straight away.
The maximum combination of aircraft in FR24 on the ground and in the air - but not part of the static set = your IFR count
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
Logs for the FSLTL Injector can be found at the following location:
If your log is too large to share, simply delete and re-run FSLTL in the sim to generate a new log.
Sim CTDs are not uncommon and can be caused by a variety of issues. They are notoriously hard to pinpoint the 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 update Beta.
FSUIPC7: Fix as follows
Go into fsuipc folder
Add "ProvideAIdata=No" without the quotations
- 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
- Remove or unlink all content in your community folder with the exception of FSLTL
- 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 in your addons to the community and test for CTDs to help identify the cause.
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, and 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 assocaited 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 easy 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 abient 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 overal sound limit in the sim.
Injector Errors & Crashes
This connection error is SimConnect trying to connect to the simulator if it's not running. If you are starting the injector before the sim you will get this error.
Start the injector once your flight has loaded. You can also connect when you are on the main menu screen of MSFS.
Some users may experience CTD's when the injector folder is located directly in the Community folder. The team is investigating, but in the meantime, 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 continue to use the FBW installer to update it.
Note that FSLTL may be incompatible with older toolbar addons that have been abandoned by their developers or possibly not using current standards. Users have reported issues with the following so far:
Your experience may vary, but please keep this in mind when submitting support requests on Discord.
This can be because of a corrupt cfg file. Delete %APPDATA%\fsltl-trafic-injector\fsltl-trafficinjector-config.json and try again.
If you still have issues, try launching MSFS with an empty community folder, close MSFS, add back your community items, launch MSFS and try the injector again.
We have 990 liveries at launch covering the majority of the major worldwide operators and the known popular flight areas as a priority. We have many more to come.
For the missing liveries, our team will target the biggest impact liveries in logical priority order.
At this stage we are not taking requests to allow the team to focus on the above. This may come at a later time when we feel we have large-scale coverage to help us close any overlooked gaps.
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 990 liveries at launch, not every airline and type is covered at this stage.
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.
MSFS generic A380 will be there unless you happen to have an A380 model from another AI product, this is due to that aircraft type not being available in the FSLTL package. Once FSLTL is able to bring the relevant model to our package this won't occur and won't use the default MSFS model anymore.
This also applies for any model. FSLTL will fall back to a similar model if we have one, a model from another AI product if you have one installed, etc. or if one doesn't exist, as a last resort we'll fall back to a generic MSFS model.
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".
For VA requests, we are in discussion with VATSIM to offer a solution for partner VA's to have their liveries represented.
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 live traffic within the VR options as well!
Base FSLTL liveries are set to 4K resolution with Mip Mapping enabled.
At this stage we do not intend to offer 2K resolution for the base liveries, some users have reported FPS benefits, but this is untested by us at present and is low on our priority list. The majority of users are CPU bound on performance, resolution has little impact on this.
Vatsim-specific liveries (Historic airline liveries, Aircraft not operated in RW or Virtual Airlines) are 2K resolution, purely for mod size considerations only. We aim to feature this as an optional install in the future at which point 4K will return.
Lets take an airport and consider just the IFR and static counts.
An aircraft be put into the sim in 2 kinds of position
- at a gate at its origin or destination
- in the air at least 30km or so from it destination or origin. (which is an MSFS limitation)
For in the air - the process is quite straight forward - if its in the air in FR24 we will attempt to insert it in the air in the sim. If its too close to its origin or destination - it may still appear parked at a gate based on the above limitation.
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 to add aircraft based on history (that isn't from FR24) - this is just a probability mapping - i.e. there is a 0.5% chance a 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 get reassigned to active.
- from being on the ground in FR24. Because we can't inject already taxing traffic - anything on the ground in FR24 moving or not - will be put at the gate. If the aircraft then moves in FR24 above 4kts - we will mark it for departure and the sim will start the preflight. This is why people seem to think FR24 injection is 5 - 10 mins delayed - its not - its 30 seconds. Its just how long the sim uses before pushback after preflight. Monitor the injection console and this is all displayed for you as things happen.
The maximum combination of aircraft in FR24 on the ground and in the air - but not part of the static set = your IFR count
A bug exists in MSFS that prevents traffic from pushing back if your in-game Airport Vehicle Slider setting is set to zero.
Set "Airport Vehicle Slider" to at least 1%.
As mentioned in the previous section, FSLTL does not inject aircraft already taxing on startup. MSFS put aircraft through a pre-flight sequence so pushback timing will not exactly mirror live timings, as such it can take 5-10 minutes for aircraft to start moving.
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 roughly 30-40 miles from your location on startup, as a result the traffic not warped has further distance to cover and land.
To see if you actually have an issue do this...
- 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 FR24 website to see if there actually any flying aircraft - so many times people tell us there is no traffic - WHEN THERE IS NO TRAFFIC IN REAL LIFE!
- Watch little nav map - and see all the aircraft that will be on approach - maybe 30 - 50 km out - but they will be coming
Another cause can be the max sim object limit that exists in MSFS. There is only so many objects MSFS can depict so the sim will cull above a certain setting. At busy airports with lots of parked aircraft, this can affect arrivals. To counter this reduce your sim ground vehicle settings (not lower than 1) and your parked aircraft setting in the injector.
To also help we have added an injection radius setting to the FSLTL injector. This can be configured by selecting Y when asked to change settings upon the injector launching. You can set a value between 50km and 200km to control injection range. This setting does not alter when aircraft are removed, which is fixed at 200km.
AI aircraft need parking stands or gates to be coded into the scenery file by scenery developers. Where this is missing, or there is no path to them from the runway, MSFS will remove the aircraft.
This is fixable by the community or the scenery developer with correct editing software, however, is not part of the FSLTL project.
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.
FSLTL injects the traffic, MSFS handles the parking and movement of the aircraft.
Parking code assignment is done by scenery content creators and FSLTL cannot control that. If a scenery developer has included accurate gate assignments to their scenery, then FSLT traffic will park at those gates. If the scenery creator did not accurate place gate assignments, then MSFS will park them randomly.
There is content at places like flightsim.to that includes content that tries to fix marking assignment codes across a wide range of airports.
Linked to the above item, this is controlled by accuracy of the scenery developer. In particular with default airports this can often be wrong. Using Little Nav Map you can review the radius of the airport parking and see if they are sized correctly.
Sadly, this is an MSFS issue as the sim takes over control of the aircraft once pushback is complete. FSLTL cannot control runways assigned to traffic by the sim.
This can also affect landing traffic including departing and arriving traffic on the same runway possibly in opposite directions.
FSLTL takes the live flight data from FR24 but the sim controls the traffic, so please do not expect a 1:1 location replica of the real world as there are too many sim factors at play (and the aforementioned Asobo AI bugs as well).
This can and often does include some time lag on the data. Generally, we can get close, but not spot on.
This issue is unfortunately due to MSFS and a bug likely introduced in SU10. It varies by individual airport if the issue will be present and depends on how the scenery was configured.
NOTE: This may also happen at times when using FlightRecorder to replay flights.
This issue is also unfortunately due to MSFS and a bug and occurs if you conduct a return flight back to origin, for example, LHR-AMS-LHR.
This affects all AI addons at this point. In order to avoid this, return to the main menu or restart your simulator between legs/sectors.
Unfortunately Asobo made a call with updates in SU12 to take over the final approach of the aircraft as it gets close to the airport, rather than following the full plan provided. This can lead to a STAR being followed until a certain distance from the airport then the aircraft starts to climb again or takes an incorrect path. This has been raised with Asobo to address, but at the moment they seem to believe it gives the best results - it clearly doesn't!
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 can still see an impact. If MSFS is your first experience in flight simming and with AI specifically, lets us explain some of the impacts of AI.
Handling AI requires some significant CPU calculations, Depending on your FSLTL injector settings the CPU is tasked with computing and placing over a hundred dynamic objects including those 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 your system and your injector and sim settings, there is no golden bullet here and each user must find a balance to suit them and their system.
Given what we covered in the above sections, users reporting 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 challenge drawing and managing a highly detailed area with lots of traffic, add to that equation a detail 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 no difference, as mentioned above AI is hungry for CPU resources and this is from the MSFS code, not the injector. Inject 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
Users have reported far worse performance with AI on DX12 versus DX11, even on higher-end systems. DX12 is still early on the MSFS dev curve so switch back to DX11 and compare.
Scale back your settings to find a good balance, remember more aircraft means more resources are needed for your CPU. Try changing the volume and distance settings. Experimentation will be needed until you find a level you are happy with.
Adjust your dynamic world settings, road traffic, airport ground vehicles, boats etc. Remember that "Airport Vehicle Slider" to at least 1% to avoid another known bug.
Check out this good guide from Q8Pilot
Visit https://www.fshud.com/#/site/manuals/application-settings to find instructions on setting the traffic settings for use with FSLTL.
Please note FSLTL just sends the base data for aircraft insertion to FSHud. All traffic movements, interaction with ATC and flight planning are managed by FSHud after that initial injection.
For FSHud support submit a ticket from the FSHud application or visit https://www.simforums.com/forums/fshud-air-traffic-control_forum59.html