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Head-up display

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This is a short description of FlightGears default Head-up display (HUD), it can be (de)activated with the [h]-key. To change the brightness, press [shift]+[h].

There are also two so called 'minimal' HUDs available which are accessible with [shift]+[i], to return to default HUD press [i].

Some of the HUDs options can be altered in the menu: View --> Adjust HUD Properties


HUD overview





Current speed relating to the ambient air in knot/knots (kt/kts) (1 kt = 1.852 km/h).



Current altitude relating to sea-level in feet (ft) (1 ft = 30.48 cm).


HUD autopilot

If autopilot is activ the direction of the next waypoint is displayed as well as the next two and the last waypoint of the Autopilot --> Route manager list.



Current altitude above ground in feet. Relating to the location of the aircrafts radio altimeter therefore it's not zero if the aircraft is on the ground.




Displays the g-force to the pilot in g - to avoid black-/redout.

The value riding on top of the Airspeed indicator.



Direction of the aircraft relating to the geographical North pole in degree (360 degree scale).




To change the coordinates-system, go to Autopilot --> Set Lat/Lon-format.


Like set with [Home]/[End].

It's the left marker of the Elevator indicator.

Pitch ladder

Displays the aircrafts pitch relating to the grounds level/horizontal in degree. It's used as an artificial horizon.

The big ladder like looking indicator at the HUDs centre.
Attitude indicator






Turn Coordinator

Further Information

The basic setup of the above described default HUD is defined at


There is also a 'Runway projection' available which is, because of some issues, disabled by default.

Documentation can be found at


Since FlightGear 0.9.10 there is also a newer and more flexibly HUD-system available. An example can be found at

$FG_ROOT/Huds/NTPS.xml and documentation at

Also have a look at $FG_ROOT/Huds/README.


While the instruments and their behaviour are set in the Huds-directory, the basic settings and the look regarding to any HUD are set in $FG_ROOT/preferences.xml. Search the file for <hud> and you will find a list of properties. For a short description of those have a look at property tree. But I'll give some of them a closer look:


The prefered thing one would like to customize is, I guess, the HUDs colour.

Discover your own settings is quite easy: Access the property tree via the Menu File --> Browse Internal Properties or via the Property server and your browser. Go to sim/hud/color, e.g. http://localhost:5500/sim/hud/color, edit a value and watch the result in FlightGears window instantly.

Once the decision is made copy one of the <color n="x">-tags and paste it on top of the colours within the <palette>-tag. ... Interrupted ... to be continued ...


Property tree

More information about FlightGears property tree and on how to access it can be found at its page: Property Tree.

Paths starting with '$FG_ROOT/' apply to the file system, the others are intra-property tree.

  current-color   (0|1|2...)    One out of /sim/hud/palette
  enable3d        (false|true)  hud n=0 3D off|on
  enable3d[1]     (false|true)  hud n=1 3D off|on
  frame-stat-type (tris|???)    ???
  path            (Huds/...)    Path to hud n=0
  path[1]         (Huds/...)    Path to hud n=1
  visibility      (false|true)  hud n=0 hidden|visible
  visibility[1]   (false|true)  hud n=1 hidden|visible
/sim/hud/color/                 Contains settings of current-color
    alpha         (0...1)       0=invisible, 1=nontransparent
    alpha-clamp   (???)         ???
    antialiased   (false|true)  Antialiasing off|on
    blue          (0...1)       
    brightness    (0...1)       0=dark/black
    green         (0...1)
    red           (0...1)
    transparent   (false|true)  Transparency off|on
    name          (*.txf)       One out of $FG_ROOT/Fonts
    size          (8)           Size of font
/sim/hud/palette/color/         Settings of predefined colors, nearly
/sim/hud/palette/color[n]/      the same options as in /sim/hud/color.