<version-desc>Display the current FlightGear version</version-desc>
<fg-root-desc>Specify the root data path</fg-root-desc>
<fg-scenery-descn="0">Specify the scenery path(s);</fg-scenery-desc>
<fg-scenery-descn="1">Defaults to $FG_ROOT/Scenery</fg-scenery-desc>
<fg-aircraft-desc>Specify additional aircraft directory path(s) (alternatively, you can use --aircraft-dir to target a specific aircraft in a given directory)</fg-aircraft-desc>
<download-dir-desc>Base directory to use for aircraft and scenery downloads (the TerraSync scenery directory may be specifically set with --terrasync-dir)</download-dir-desc>
<load-tape-desc>Load recording of earlier flightgear session. For <name>, if <name> ends with .fgdata it is treated as the local path of the recording file; otherwise we form the local path by prepending <name> with the tape directory and appending ".fgtape". For <url> (starting with http:// or https://) we download the remote recording (which must be a Continuous recording) in the background to a url-dependent filename while replaying it; if the url-dependent filename already exists it is assumed to be a truncated download and we only download any remaining data.</load-tape-desc>
<json-report-desc>Print a report in JSON format on the standard output, giving information such as the FlightGear version, $FG_ROOT, $FG_HOME, aircraft and scenery paths, etc.</json-report-desc>
<disable-hud-3d-desc>Disable 3D HUD</disable-hud-3d-desc>
<enable-hud-3d-desc>Enable 3D HUD</enable-hud-3d-desc>
<!-- Aircraft options -->
<aircraft-options>Aircraft</aircraft-options>
<aircraft-desc>Select an aircraft profile as defined by a top level <name>-set.xml</aircraft-desc>
<show-aircraft-desc>Print a list of the currently available aircraft types</show-aircraft-desc>
<min-aircraft-status>Allows you to define a minimum status level (=development status) for all listed aircraft</min-aircraft-status>
<vehicle-desc>Select an vehicle profile as defined by a top level <name>-set.xml</vehicle-desc>
<livery-desc>Select aircraft livery</livery-desc>
<!-- Flight Dynamics Model options -->
<fdm-options>Flight Model</fdm-options>
<fdm-descn="0">Select the core flight dynamics model</fdm-desc>
<fdm-descn="1">Can be one of jsb, larcsim, yasim, magic, balloon, ada, external, or null</fdm-desc>
<aero-desc>Select aircraft aerodynamics model to load</aero-desc>
<model-hz-desc>Run the FDM this rate (iterations per second)</model-hz-desc>
<speed-desc>Run the FDM 'n' times faster than real time</speed-desc>
<notrim-descn="0">Do NOT attempt to trim the model</notrim-desc>
<notrim-descn="1">(only with fdm=jsbsim)</notrim-desc>
<trim-descn="0">Trim the model</trim-desc>
<trim-descn="1">(only with fdm=jsbsim)</trim-desc>
<on-ground-desc>Start at ground level (default)</on-ground-desc>
<in-air-desc>Start in air (implied when using --altitude)</in-air-desc>
<wind-desc>Specify wind coming from DIR (degrees) at SPEED (knots)</wind-desc>
<random-wind-desc>Set up random wind direction and speed</random-wind-desc>
<turbulence-desc>Specify turbulence from 0.0 (calm) to 1.0 (severe)</turbulence-desc>
<ceiling-desc>Create an overcast ceiling, optionally with a specific thickness (defaults to 2000 ft).</ceiling-desc>
<aircraft-dir-desc>Specify the exact directory to use for the aircraft (normally not required, but may be useful). Interpreted relatively to the current directory. Causes the <path-cache> from autosave_X_Y.xml, as well as --fg-aircraft and the FG_AIRCRAFT environment variable to be bypassed.</aircraft-dir-desc>
<aircraft-model-options>Aircraft model directory (UIUC FDM ONLY)</aircraft-model-options>
<!-- Position and Orientation options -->
<position-options>Initial Position and Orientation</position-options>
<airport-desc>Specify starting position relative to an airport</airport-desc>
<parking-id-desc>Specify parking position at an airport (must also specify an airport)</parking-id-desc>
<carrier-desc>Specify starting position on an AI carrier</carrier-desc>
<view-offset-desc>Specify the default forward view direction as an offset from straight ahead. Allowable values are LEFT, RIGHT, CENTER, or a specific number in degrees</view-offset-desc>
<httpd-desc>Enable http server on the specified address. Specify the port or address:port to bind to.</httpd-desc>
<proxy-desc>Specify which proxy server (and port) to use. The username and password are optional and should be MD5 encoded already. This option is only useful when used in conjunction with the real-weather-fetch option.</proxy-desc>
<telnet-desc>Enable telnet server on the specified port</telnet-desc>
<jpg-httpd-desc>Enable screen shot http server on the specified port (replaced by --httpd)</jpg-httpd-desc>
<log-dir-desc>Log to directory DIR. The special value 'desktop' causes logging to the desktop (OS-dependent location). This option may be given several times, using a different value each time. Inside the specified directory, the written log file is named FlightGear_YYYY-MM-DD_<num>.log, where <num> takes the values 0, 1, 2, etc.</log-dir-desc>
