Frequently asked questions
Thank you for your interest in FlightGear! This FAQ lists some of the most commonly asked questions. Please create a topic at our forum 
if you cannot find the answer on your problem(s).
Distribution
Where can I get FlightGear?
The official download page is https://www.flightgear.org/download/. Precompiled binaries and disk images are available for Windows and MacOS, and most Linux users will find that most distributions have a packaged version of FlightGear (the package name could be fgfs or flightgear.)
How do I install FlightGear on Linux?
Many distributions include FlightGear in their repositories. In addition, in the Download Center you will also find AppImage, which will run on almost any modern distribution. If you can't find a packaged version for you, consider downloading and compiling from sources.
Where can I find the latest development source code?
The latest development code is available for everyone through our Git repository.
Where do I get the scenery? What is available?
While the base package only comes with scenery for the San Francisco Bay area, you can currently fly just about anywhere in the world. Currently TerraSync is the best option: it downloads the latest scenery while flying. See its page for usage information.
Where can I get additional planes?
The latest official aircraft can be downloaded and installed with a single click through the aircraft tab in the built-in launcher (see FlightGear Qt launcher). Some other aircraft can be found in 3rd party FlightGear hangars (see Howto:Install_aircraft).
How current is the data in FlightGear compared to the real world?
We use the same navaid and airport dataset that X-Plane uses. The current dataset can be found in the $FG ROOT/Navaids/ and $FG ROOT/Airports/ directories.
Why don't you charge money for this?
FlightGear can be downloaded for free from many locations including the FlightGear website. We encourage other groups to redistribute it for their users, especially within an operating system distribution which makes installation even faster and easier for new users.
Occasionally you may see FlightGear for sale on auction sites or commercial websites under some other name. This can be done quite legitimately as long as the terms of the license are upheld and might be worth the cost if some value-added features such as additional scenery, aircraft or after-sale support are included. Unfortunately, most cases seen to date appear to be just someone trying to make money selling something that is free and providing no real added value.
If you would like to support official project infrastructure, such as download servers or domain registrations, you are invited to make an optional donation.
How can I get started with FlightGear?
There's no better place than the page New to FlightGear!
Compiling
How do I compile FlightGear from source?
See Building FlightGear. There are explanations to compile in Windows, Linux and even scripts to automatically download and compile the whole thing.
Why won't FlightGear compile?
Well, that depends. First make sure you are using the appropriate versions of FlightGear, SimGear, plib, zlib. If any of the packages are out of sync with the others, compilation may fail. See also Building FlightGear
The FlightGear Downloads page should tell you what versions you need if you are trying to compile the latest stable release. If you are using a development snapshot, make sure all three packages are up-to-date.
Also ensure that you have some implementation of OpenGL with glut support with the appropriate header files. Linux users with nVidia cards should make sure you have the latest drivers from nVidia. Other Linux users make sure you have Mesa3D (https://mesa3d.org/) and your X server installed correctly.
If your problems persist, ask in the FlightGear forum , on IRC or subscribe to our FlightGear-Users mailing list and let us know what problem you're having.
What is SimGear, and why do I need it?
SimGear is a library of supporting code. SimGear is only needed if you plan on compiling FlightGear — it is not needed to run precompiled binaries. Note: When compiling FlightGear it is very important to have the matching version of SimGear.
Configuring and running
How do I start FlightGear?
The easiest way is using Qt Launcher. Otherwise, you can run it from the command line, with the proper options.
How do I install new scenery?
If you really don't want to/can't use TerraSync, the scenery archive files (ie. w100n30.tar.gz) should be decompressed into the Scenery/Terrain directory in your $FG_ROOT. More at Howto: Install scenery.
How do I setup my joystick(s)?
FlightGear supports wonderfully many joysticks/yokes out of the box. However if you're having problems see Input device.
What is fgfsrc? What format should my personal .fgfsrc file be in?
.fgfsrc is a file that can contain a list of Command line options with one option per line. The file is not an XML file. Note that also Windows installations have this file.
How do I get to see options, help etc?
You probably can not see the main menu. To make it show press F10.
Flying
Why won't my engine(s) start?
Aircraft vary in their starting procedure. Some may have an auto-start sequence menu entry or instructions in the aircraft help menu (press ? key) and/or at the aircraft's wiki. Please consider reading the FlightGear Manual, or see this quick small guide.
Where is the moving map?
In game, you can go into the menu "Equipment > Map", but there won't be any aeronautical chart. MPmap is an online map for multiplayer. Mapping provided by the OpenStreetMap project, is available through Phi or JMapView.
There is a nice article, Understanding navigation, and a lot is very well explained into the FlightGear Manual. Other resources are:
- http://www.navfltsm.addr.com/ is a very good site for learning techniques for navigation.
- See How It Flies a very nice book by John S. Denker, freely accessible online
What is the difference between Aileron and Rudder?
There is a bit of info on aileron vs. rudder in the very same book...
Is there support for multi-player flying?
Yes, sure we have it! See Howto: Multiplayer. Both the Windows and *nix versions of FlightGear are capable of multi-player flying on FlightGear servers. Also voice communication is supported, with FGCom.
A map showing players aircraft online in real time is available as MPmap.
Where are the best places to fly in FlightGear?
FlightGear scenery covers the whole world, but thanks to the FlightGear user community, certain airports and areas are more detailed than others. As a general idea:
- There are a lot of high-quality scenery models around Paris, France.
- EHAM Amsterdam Schiphol, EGKK London Gatwick and LFPG Paris Charles de Gaulle are some of the highest quality airports.
- LOWI Innsbruck is both developed in scenery and airport.
- TNCM St. Maarten is a popular destination, and the surrounding islands (Anguilla, St. Eustatius, Saba, St. Barthélemy, St. Kitts, and Nevis) are all well-modeled.
Furthermore, see Suggested Flights, Suggested Airports and Suggested custom scenery.
Where can I find airport info and aeronautical charts online?
See Getting aeronautical charts.
Is there support for any military scenarios like dog fighting or bomb dropping?
Yes. Check out the Bombable add on and the Bombable topic on the forum . There are also aircraft that support built-in multiplayer damage, such as General Dynamics F-16.
Flying issues
Why are my controls returning to a particular position?
There are several possibilities that can lead to this:
- If your aircraft's autopilot is enabled, it will take over (some of) your controls. Switch the autopilot off to regain control.
- Some laptops have an onboard gravity sensor that might be detected as a joystick. See how to solve that at Troubleshooting input devices.
There are lots of other aircraft flying around
FlightGear has a so-called AI Traffic system. This system generates other, computer-controlled aircraft based on real flight plans to make the FlightGear world look more alive. To disable artificial traffic, go to menu "AI" > "Traffic and Scenario Settings" and uncheck the "Enable AI traffic" option.
If on the contrary you can't see any aircraft other than yours, consider contributing to add traffic to your favourite place!
I can't make this plane fly straight, it keeps turning left!
Yes, FlightGear is a real flight simulator and simulates that too. Exactly, that's how real propeller aircraft behave. See Understanding Propeller Torque and P-Factor.
Also, doublecheck your weight distribution. Try adding a 180 lb copilot in the "Equipment > Fuel and payloads" menu and see if the turn goes away.
Contributing
For anyone who's willing to contribute, we have dedicated to you the Developer portal and a Volunteer page that explains all the nice things you can do.
What language is FlightGear written in?
Mostly C++ with some supporting C code that's primarily contained within SimGear. For more details on the used languages:
- FlightGear programm
- SimGear
- FlightGear data (aircraft, sounds etc.)
As you seem to be interested in core development, you should really check out Howto:Start core development.
How do I design a flight dynamics model for a new aircraft?
FlightGear supports various flight dynamics models (FDMs), but just two of them are commonly used:
- JSBSim: see http://jsbsim.sf.net/.
- YASim: if you want a simpler FDM to work with, try your hand at YASim. For a guide on creating YASim aircraft, look in the FlightGear base package for $FG_ROOT/Docs/README.yasim.
See the Aircraft development portal.
How do I design or modify a 2D panel?
See the $FG_ROOT/Docs/README.xmlpanel file on your computer.
How do I place objects, like buildings, into FlightGear?
The most up to date solution is using the UFO. See Howto:Place 3D objects with the UFO. The UFO will give you the interface to choose one of the available objects and place it to some grade of precision into FG world, and then export that data to be uploaded to the official scenery, or for personal use. For more, see the Scenery development portal.
Where can I learn 3D programming and how do I get involved?
If you'd like to create a 3D cockpit for FlightGear, or to create buildings, external aircraft models, etc., your help is desperately needed. Try to go easy on the triangles, so that your work will be enjoyed by as many people as possible. The most commonly used tools here are Blender, AC3D, Gimp.
If, on the other hand, you really want to get your hands dirty with C++ coding, you'll have to buy a good OpenGL book eventually. However, FlightGear uses OSG, a high performance 3D graphics toolkit. To get started with 3D C++ coding, you can take a look at the OSG documentation and learn only as much OpenGL as you need, when you need it.
How do I add an airport?
This process includes creating the airport layout in WorldEditor, testing it (you might want to generate part of the scenery, but this is not mandatory) and then, if your data sources are GPL compatible, use WorldEditor to upload it to the gateway. The airport will be available in the next full rebuild of the scenery, unless you want to generate your own scenery. More at Howto:Make an airport.
Can I generate my own scenery?
Yes, though it can be a difficult task. FlightGear's scenery generation is handled by a sister project, TerraGear. The good news, though, is that once you have set everything up it's quite easy (although might be time consuming), and above all that you can easily share it.
Problems
Network or DNS errors while downloading terrain
If network/DNS errors are encountered, enter --prop:/sim/terrasync/http-server= your server in the additional settings in launcher (e.g., --prop:/sim/terrasync/http-server=http://flightgear.sourceforge.net/scenery), or click the "Show more" button on the right and select a DNS server.
There is a forum post: Network errors occurred
X doesn't work / is broken / is wrong / won't run
FlightGear is a very complex program. If you need help in general usage of the game you'll find it at the User portal and on the FlightGear forum .
If your problem is instead software crashes, you're getting errors, etc..., please consider following the indications in Troubleshooting problems.
Some of the most common issues are however listed below. If you can't solve the problem on your own and need the help of someone, please remember that we're all here for fun, developers included, and that any help is an act of generosity. So try to be nice, even if the problem is frustrating you.
What happened to the panel, keyboard, etc?
The problem is almost certainly that your base package is out of sync with FlightGear. Many configurable parts of FlightGear are defined in XML files contained in the base package.
Why is FlightGear so slow?
If it seems just slow, see if you can fiddle with graphics settings here: Howto: Improve Framerates.
If things are pathologically slow (i.e. ~1 frame per second), maybe 3D hardware acceleration is not activated. Make sure you have OpenGL libraries installed and configured properly and make sure you have the latest drivers for your video card. Also, be ready because some cards are not well supported.
How do I see the Frame Rate?
On the in-sim menu select "View" > "View Options", then check the box that says "Show frame rate".
How do I toggle 2D cockpit settings?
To show/hide the 2D panel, use the key combination ⇧ Shift+P. To show/hide the HUD, press ⇧ Shift+H. You can also enable the alternative HUD by pressing ⇧ Shift+I (press I to return to the default one). Use the ⇧ Shift+H key to adjust the brightness of the HUD.
Stuck upside down after "crash"?
In his infinite wisdom the FlightGear Grand Master decided that planes were too valuable to allow them to be destroyed by novice pilots who seemed to crash a lot. The fact that nobody has bothered to model crashes may have something to do with it too. :-)
The result of this as you have noticed is that with a little practice an ingenuity you can trim the ship to fly inverted along the ground. The quick answer is to reset the sim, via the File > Reset menu. This will place your aircraft back at its starting location.
For the stubborn people out there: The trick to learn is to roll back to normal (non inverted) do this by nursing the elevator to get to about 500 feet or so and use the ailerons to snap roll 180*. This is all good avionics except for the plane not destroying itself. Remember the controls work in reverse when you are inverted and keep that airspeed up!!!
Why won't the latest versions of some aircraft work in my (older) version of FlightGear?
Often new aircraft development keeps pace with the latest FlightGear code development. New or newly modified aircraft may rely on files (such as new instrument files) or features, only available with newer versions of FlightGear. If you are stuck with an older version of FlightGear, you can try downloading an earlier version of the aircraft from the corresponding official FlightGear aircraft hangar.
When I start FlightGear I see an error mentioning "SQLite". What do I do?
Since FlightGear v2.10 (released in February 2013), the navdata cache was introduced to improve the FlightGear start times. This cache is a SQLite database that is a little fragile at times. If the database is corrupted FlightGear will refuse to start.
To fix this you simply need to delete the $FG_HOME/navdata.cache file. The first time FlightGear starts after deletion of the file the navdata cache will be rebuild. As this process is time consuming, FlightGear will take more time to start.
Some will resort to delete the entire $FG_HOME directory or even reinstall FlightGear. However neither is needed and may cause you to lose any custom preferences you have set up.
A further SQLite related problem indicator is the error message.
Sqlite error:attempt to write a readonly database (8) while running:
INSERT OR REPLACE INTO stat_cache (path, stamp) VALUES (?,?)
In this case a previously started FlightGear instance might still be running and locking the navdata.cache file. Check for a running fgfs process and terminate it.
My aircraft has grey windows?
The problem of opaque grey/gray windows that cannot be seen through is most often due to a version mismatch between the FlightGear program and the aircraft. Or it could be due to a window effect that is not compatible with the Rembrandt or ALS rendering systems. The technical cause is that the renderer and declared effect for the window are incompatible. Some solutions include:
- If you are using a stable FlightGear release, please download the aircraft from the official FlightGear hangars matching your FlightGear version.
- If you are using a cutting-edge nightly build or a version controlled copy of FlightGear, or you wish to use a cutting-edge aircraft, please see FGAddon#Obtaining aircraft.
- If you are using an aircraft from one of the 3rd party hangars, it is best to contact the original aircraft author or the person in charge of the 3rd party hangar.
- If you are using Rembrandt, try turning this rendering system off. Aircraft that use
model-default.efffor the windows (at the simple expense of doing nothing) rather thanmodel-transparent.eff,model-combined-transparent.efforglass.eff(which instruct Rembrandt to not use deferred rendering for the glass) will have grey windows when using Rembrandt.
My screen becomes completely red right after starting FlightGear
The red screen is the visualization of the "Redout" effect. If it occurs right after starting FlightGear, it might be caused by a problem with scenery loading. FlightGear loads scenery on the fly and if scenery cannot be loaded, eg. due to network problems, there might be no ground for the aircraft to be located on. As a result, the aircraft falls through the non existing ground starting to tumble. This in turn causes the readout effect. For verifying the problem you should start your flight in KSFO, whose scenery is already included in the base package.
The menubar font size could be adjusted via editing the data file. See menubar#How to Change the Default Menubar Font Size for details.
The FAQ
Who do I contact if I have comments about this FAQ?
Add your comment to this FAQ's discussion page.
How old is this document?
Check its history.
What other important documentation should I read?
- FlightGear manual
- New to FlightGear
- Also see the FlightGear/docs-mini/ directory in the source distribution for various other helpful documents.