YS FLIGHT SIMULATOR Untested Version for Debugging Purpose


You can download test-version YSFLIGHT and Scenery Editor.  Since these files are test version, these haven't gone through pre-release test which I run before releasing an official version.  If you would like to use a stable official version, please download YSFLIGHT from here.

By the way, I really truly absolutely didn't run pre-release test at all for this test version at this time.  Usually I pick a few test items and try them before rolling out a test version, but this time I haven't.  All I did was I took off and made one traffic pattern with F-18E.  I suppose you will see a lot of bugs in this test version.  I appreciate your report so that I can fix them.

When you report me a problem, please describe the situation as much detailed as possible.  Please include at least in what operating system you are running the program, and in Windows which executable you are using, and if the problem is specific to a particular airplane or scenery, please include them.  If a problem is associated with a specific add-on, please let me know where I can download it from as well.

Thank you for your help!

for Windows

[YSFLIGHT] (2018/10/01)

[Scenery Editor] (2018/07/04)

for Intel Mac OSX

[YSFLIGHT] (2018/10/01) (Including YSFLIGHT for Linux)

[Scenery Editor] (2018/07/04)

for Linux 32-bit & 64-bit (Tested on Ubuntu 14 on Parallels Desktop)

[Scenery Editor] (2018/07/04)

Concept Mission

[AomoriWars.yfs] (2014/10/29)

Sound DLL Sample Source Files

[Sound DLL Source] (2012/02/19)

Voice DLL Source File Skeleton

[Voice DLL Skeleton Source] (2012/02/25)


[Practice IFR Appoach in YSFLIGHT (Draft)]

Auto-Test Script

[Auto Test Scripts (2018/08/03)]




  • Corrected OpenGL 2.0/ES 2.0 rendering error.
  • Support macOS 10.14.  Actually I had to make more-than-expected corrections in user-interface.  Please let me know if you find some strange behavior in the UI.


  • install_addon.py in the auto-test scripts looks into .acp files references in the ground object data files and correct capitalization.


  • I don't know if it is useful for someone, but I have uploaded a set of test scripts.  It is significant for me because more than half of pre-release test items are covered by this batch.  (Such as selecting random menu items or changing configurations and make sure the program does not crash)  Also I have automated installing the add-on packages to a test-environment and flip through airplanes and maps.  Actually that was fun.  I was impressed by the variety and the quality of the models.  I used to be randomly selecting a few packages before.  This revealed many mistakes in my code, which should be fixed shortly.
  • By the way, install_addon.py is free on BSD license.  Please feel free to customize and bundle with your add-on packages.  This might be useful.


  • I'm thinking to start pre-release test based on this version.
  • Fixed VOR OBS indication.  (I should make a Pittsburgh map so that I can positively check heading/OBS indications...)
  • Scenery Editor: Prevent Color-Palette Dialog disappearance.


  • I think this time I really fixed the magnetic heading and true heading consistency.  By the way, I made the sign back to the previous.  (In YSFLIGHT West is positive.)
  • ARTCC was not giving higher than 10000ft, which was awkward for a long cross country in a jet airplane.  Now it gives up to the altitude specified in the aircraft data.  (Actually, the descending instruction was supposed to be given +6000, +3000, and then +1500 of the destination airport, but for some reason the current ATC skips +3000.  I'm looking into the problem.)


  • Separated ILS view (default F6) and Tower view (default F8).
  • Looks like a standard definition of magnetic variation is West=minus and East=plus.  I was calculating opposite.  I reversed it to align with the standard.  Thank you for pointing it out!
  • Fly -> Select Aircraft -> Fly -> Retry Previous Flight was resetting the aircraft to the first player aircraft.  Now it will start in the last aircraft.
  • Auto-Test script


Oops, three months has passed while I was playing with my FM77AV.

  • Can put SRF models in FLD.  (Can be done from the Scenery Editor).  Very long time ago, FLD had this feature but the collision was checked against the bounding box.  In this update, the collision is checked per polygon.  I really wanted to add field-specific ground object, but anyway SRF in FLD is also needed for complex terrain.
  • Bug fix: If a DNM model defines rotation based on STATE 0, new data structure was not transforming it as intended.  Sorry, I was not clear about which of no-transformation or STATE-0 is the base orientation.  I was thinking to make it no-transformation, but looks like there are many models that are assuming STATE-0 is the base.  I'm leaning toward making STATE-0 as the base orientation.
  • Bug fix: Fireball renderer was not clearing Emissive color in D3D9 code.
  • I'm also experimenting with unit-test scripts.  So far I was able to automate selecting all items in Simulation menu, selecting all default fields, and some config items.  I need to automate testing file menus and network features.


  • Bug fix:  Change of "Default Field" in the config dialog was not updating the starting points.
  • Bug fix:  "NO CLOUD" option was ignored.
  • Bug fix:  Full-Screen setting was ignored after restart.
  • Bug fix:  Fly-Heading-Bug auto pilot was ignoring magnetic variation.
  • Bug fix:  ATC's heading instruction was ignoring magnetic variation.  (I think I fix it.  Hope I didn't break it.)
  • Bug fix:  Starting-Position search text box in New-Flight Dialog was not functioning.  Selection changes, but not really selected.
  • Bug fix:  Aircraft DNM not initialized in the aircraft-selection dialog.
  • Racing Mode (Still in the middle of making)
  • Implemented Endurance Mode, Intercept Mission, Ground-to-Air Mission, Close-Air-Support Mission as an extension.  The first goal is to reduce the running modes of the program into 5 modes: GUI, Flying, Replay, Server, and Client.  Those missions used to be an independent mode, which was making the program very difficult to maintain.  Eventually I want to make Server and Client as an extension, but that's the next stage.

    I learned a lot about C++ programming through YSFLIGHT.  That means in many places, I learned a better practice, which improved my research / work code, but it was too late for YSFLIGHT.  Also known as code debt.  I am cleaning those mess.

    With this change, I still have three additional modes to turn into an extension.  So, if you can help me debugging it, I'll appreciate if you can fly a few times of those missions.


  • Fixed shadow-map in the aircraft-selection screen.  (It took a while, but I just forgot enabling GL_DEPTH_TEST and unmasking GL_DEPTH_BUFFER after drawing widgets.)
  • Fixed NearZ in additional cockpit views.
  • Zoom/Unzoom with mouse wheel even when Windows reported rotation count smaller than the unit count.


  • Draws smoke trail (of airplanes and missiles) with particles if use-particle option is on.  If the new version is too slow due to massive particles, turn off this option to draw clouds with polygons.


  • Added Cessna 172.


  • Config: Draw runway lights during the day "only if the visibility is less than XX miles"
  • Draws flare and black smoke with particles.
  • Draws clouds with particles in YSFLIGHT on OpenGL 1.x and Direct X9
  • Vary point size for aircraft lights depend on the window size (it was fixed 3 pixels.)
  • I forgot copying sound DLLs for Linux.  Now it is in.
  • Sorry, I haven't been able to address all the bug reporst.  I'll try to get them done in the next update.
  • (Forgot mentioning. Description added 5/21) The fog-density calculation from visibility was wrong and is corrected.  You may feel the visibility is lower than earlier version, but if you want a better visibility, change in the weather settings.


  • Sorry, Shadow-Map was off in the package I uploaded yesterday.  It takes too much time for pre-releaste test.  So, I have been trying to automate some of them.  In the process, I accidentally disabled the shadow map.  The new package re-enables the shadow map.


  • Console Server for macOS
  • Maps are now drawn with depth-test turned on.  I think elevated maps are drawn correctly.


  • Multi-Language Input.  Except Linux.
  • Calculate transformation matrices in CPU in double precision.  This substantially reduces the shaking effect when the view point is far away from the origin without much performance penalty.  By the way, in early days, a major misunderstanding was that the matrix calculation was taking much of the computation in graphics.  It was wrong.  Z-Buffering was the major headache around 1990 to 2000.
  • YSFLIGHT on OpenGL 2.x uses shadow-mapping to draw shadow.  Now aircrafts and ground objects cast shadow nicely.  By the way, in the process of implementing, I have tried Cascaded Shadow Map, which turned out to be utterly useless.  Most of, probably more than 99%, of the recent graphics techniques cannot be used in the scene which covers 20 miles square.  I ended up coming up with my ad-hoc shadow-volume calculation, which I think worked out well.
  •  Start-Position search box in the new-flight dialog.

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