screen capture of demo

Using Vice Last updated: 2023-04-08

vice is an air traffic control simulator, focused on TRACON. Its goal is to provide a training experience similar to a VATSIM sweatbox with an instructor, just without the instructor, making it possible to better prepare for sweatboxes and to practice vectoring and traffic handling techniques without being on the network. It presents a STARS-like interface, but with simulated traffic and other controllers.

vice currently supports departure and arrival control scenarios in the N90 TRACON (KEWR, KJFK, KLGA, KPHL, Liberty Departure) and in the F11 TRACON (KJAX, KMCO, KSFB, KISM, KORL, ...). Adding scenarios at more airports is a matter of writing JSON configuration files that describe them; see below for documentation about how scenarios are described and please join the vice discord if you'd like to contribute!

There is a short video overview that gives a tour of vice. (Note: this video was recorded with an older version of vice, so some details are different in the latest version.)

Getting Started

The radar client interface that vice provides is based on STARS, by way of reimplementing most of the functionality in vSTARS. In general, all of the keyboard and menu commands that are available in vSTARS are available in vice (though quicklook and CRDA are not yet implemented). See the vSTARS Command Reference for a summary of the commands supported. The appearance of vice can be similarly configured using the DCB buttons at the top of the window.

The first time you launch vice, a window is shown for configuring the simulation. (After the first time, the window can be brought up by clicking the "replay" button in the menubar: .) A number of scenarios are available, some departure-only and some including both departures and arrivals. Here is the configuration window for KLGA:

configuration dialog box

Scenarios may offer one or more control positions; for example, KLGA offers both approach and departure. Once a control position is chosen, you can choose a specific runway configuration.

In the configuration window, you can set the average departure rate (ADR) for all of the airports that may have departures in the scenario as well as the average arrival rate (AAR) for all of the arrival airports. (The KLGA scenario only includes Laguardia Airport, though other scenarios include both a primary airport as well as satellites.) Both of these rates are specified in terms of aircraft per hour, so an ADR of 30 corresponds to one aircraft departing every two minutes (on average). If you'd like an arrival-only scenario, for example, just set all of the departure rates to zero.

The "Sequencing challenge" slider controls how challenging the departure sequence is—the higher it is, the more likely it is that successive departures will be to the same gate or to the same fix. For arrivals, the "Go around probability" slider allows setting the probability that each arrival goes around.

After you have configured the simulation, click "Ok" and you will have a STARS scope and flight strip window to work with. Use the usual STARS commands as appropriate (to initiate track, accept handoffs, handoff to other controllers, etc.), and the additional ATC commands below to issue control commands to aircraft.

To adjust the amount of space used for flight strips, right click the line separating the flight strips from the radar window and drag left or right with your mouse.

A number of buttons are available in the menu bar at the top of the window:

  • / : pause or resume the simulation.
  • : opens the window to select a new scenario and set its parameters.
  • : open a window that allows changing various settings. The most useful one is the simulation rate: you can speed up time during boring times or to increase the challenge.
  • : open this webpage to review vice's documentation
  • : display information about the version of vice you have installed.
  • : join the vice Discord.

When you exit vice, it remembers everything going on—all of the aircraft in flight, the instructions they have been given, etc. The next time you launch vice, it loads all of that back in and you can continue where you left off. If you'd like to start something new, just click and configure a new scenario.

When vice is paused, you can hover the mouse above a radar track to see information about the instructions the aircraft has been given so far—for example, altitude and speed assignments, whether it has been sent direct to a fix, the approach it has been assigned, etc. An example is shown below. This information is especially useful when resuming a vice session after you have been away from it for a while.

configuration dialog box

ATC Commands

In order to issue control commands to aircraft, type the appropriate command from the table below and click on an aircraft's track. After you issue a command, the virtual pilot's readback is shown at the top of the window. The aircraft will then start following that instruction, to the best of its abilities. Unlike VATSIM, the pilots will always do exactly what you tell them to.

If you'd like to issue multiple commands to an aircraft, enter the commands one after another with a space between them and then click on the appropriate aircraft.

Command Function Example
Hheading Directs the aircraft to fly the specified heading. It will turn in whichever direction gets it to that heading most quickly. H050
Lheading Directs the aircraft to turn left to the specified heading. L130
LdegreesD Directs the aircraft to turn the specified number of degrees to the left. L10D
Rheading Directs the aircraft to turn right to the specified heading. R210
RdegreesD Directs the aircraft to turn the specified number of degrees to the right. R20D
Dfix Directs the aircraft to proceed direct to the given fix. (The specified fix must be in the aircraft's flight plan, including on the approach assigned to it.) DWAVEY
Calt Directs the aircraft to climb to the specified altitude, which is given in hundreds of feet. C170
Dalt Directs the aircraft to descend to the specified altitude, given in hundreds of feet. D20
Sknots Gives the aircraft a speed restriction. If the restriction is given after an aircraft is cleared for an approach, the speed restriction is in effect until 5 mile final. S210
Eapproach Tells the aircraft to expect the specified approach. This command must be used before an aircraft is cleared for an approach and it also adds the approach fixes to the end of the aircraft's route. EI2L
Capproach Clears the aircraft for the specified approach. The aircraft must have been told to expect the approach before it is cleared for it. CI2L
X Deletes the specified aircraft from the simulation. This command is useful when one starts going down the tubes. X


vice is able to indicate when aircraft are outside of the departure or approach airspace, if it has information about the airspace boundaries. (This information is currently only available for KPHL.) If an aircraft is outside of its assigned airspace, a red "AS" error will be printed at the top of its datablock, as shown below. The valid altitudes for the aircraft are shown as well, if there are any valid altitudes at its current location. For example, the aircraft below is at 5,000' but should be between 10,000' and 12,000' (or should be at a different location!)

configuration dialog box

Two commands are available to draw the boundaries and altitude ranges of the departure and approach airspace. (Note that the placement of the drawn altitude labels is not always ideal.)

Command Function
DA Draw the approach airspace, or stop drawing the approach airspace if it is currently being shown.
DD Draw the departure airspace, or stop drawing the departure airspace if it is currently being shown.


Departure and arrival scenarios are available in both the New York N90 TRACON and the Jacksonville F11 TRACON. For all of these, the identifiers used for approaches with the "expect approach" and "cleared approach" commands are the same as the ones used for scratchpads. (Thus, you can practice scratchpad assignment while you're at it!)

F11 TRACON Scenarios

Scenarios are available for both North and South Operations at Orlando (MCO). You control both departures and arrivals for KJAX, KMCO, KSFB, KISM, and KORL and departures for KMLB.


8 I8 RZ8
14 I14 R14
26 I26 R26
32 R32


17L I7L R7L
17R I7R R7R
18L I8L R8L
18R I8R R8R
35L I5L R5L
35R I5R R5R
36L R6L
36R I6R R6R


7 I7 R7
25 I25 R25


9L I9L R9L
9R I9R R9R
27L R7H
27R I7G R7G


6 R6
15 I15 R15
33 R33

N90 TRACON Scenarios


Two scenarios are available at KABE, N90's training TRACON, one landing/departing runway 6 and the other landing/departing runway 24. The following approaches are available:

6 I6 R6
13 I13 R13
24 I24 R24
31 R31


Scenarios are available for all of the usual airport configurations, at both KEWR and KTEB. The following approaches are available at KEWR:

4L I4L R4L
4R I4R R4R
11 I11
22L I2L
22R I2R
29 X: R29, Y: RY9, Z: RZ9

And these are the KTEB approaches:

6 I06 X: RX6, Y: RY6, Z: RZ6
19 I19 X: RX9, Y: RY9, Z: RZ9
24 R24


Scenarios are available for all of the usual JFK configurations. It is also possible to include KFRG arrivals, KLGA departures to the Southwest and to water gates, and KISP departures to the North gate, if desired. The "intra-TRACON" arrivals are flights from nearby airports that don't arrive via STARS but are instead inbound from COL, ZIGGI, and DPK.

4L I4L R4L
4R I4R R4R
13L I3L R3L
13R R3R
22L I2L R2L
22R I2R R2R
31L I1L R1L
31R I1R R1R

These are the supported KFRG approaches:

1 R1
14 I14 R14
19 R19
32 R32


Scenarios are available for both departure and arrival configurations at LGA. The following approaches are available:

4 I4
22 I22
31 R31


vice offers scenarios at KPHL for both West and East ops. There is also a "KPHL 27R Final" scenario that has flows of traffic from the North and South that need to be merged in the approach.

As with the other airports, the identifiers used for the "expect approach" and "cleared approach" commands correspond to the scratchpad labels used at KPHL. For now only the ILS approaches are available (except for runway 35, where there is no localizer.) They are summarized for reference below:

9L I9L
9R I9R
17 17Z
26 I26
27L 27L
27R 27R
35 G35

Liberty Departure

Not surprisingly, the Liberty departure scenarios only include departures. Departures from KEWR, KJFK, and KLGA can be simulated.


Installing vice is straightforward, at least on Windows and Macs; on Linux, you need to do a little more work.


To install vice on Windows, download and launch the installer below. After installation, vice will be available in the Windows Start menu and a shortcut will be added to your desktop.

Your browser may warn about the installer being from an unknown publisher and when you run the installer, Windows will put up a window informing you that it has protected your PC and prevented the installer from running. Click "More Info" and then "Run anyway" to proceed with installation.

Download Vice v0.8.1 for Windows


On a Mac, download the zip file below; it contains a universal binary that runs on both Intel and Apple CPUs. Note that MacOS Big Sur or a more recent version of OSX is required. After opening the zip file, drag to your Applications folder to install it.

Download Vice v0.8.1 for Mac


On Linux systems, it is necessary to install vice from source. See the directions on building vice on Linux in the source code distribution for details.

Reporting Bugs

If you encounter bugs in vice, apologies! It would be of great help if you would send in a report if vice crashes or if you see mistakes in how it simulates aircraft or the STARS interface.

The best way to report bugs is via the "bugs" channel on the vice discord. Alternatively, if you have a github account, you can file bugs directly in vice's issue tracker.

Release History

  • 0.2.1: Initial release
  • 0.3.1: Added KJFK approach scenarios, improved aircraft flight model, routes, and airlines.
  • 0.4.0: Added KPHL scenarios, airspace warnings, and KFRG arrivals and intra-TRACON arrivals for KJFK.
  • 0.4.1: Fixed bugs in datablock positioning, added "turn left/right X degrees" commands.
  • 0.4.2: Fixed a crash at first launch, updated syntax for "turn left/right X degrees" commands.
  • 0.4.3: Allow specifying JSON config on the command line, to make it easier to develop new scenarios.
  • 0.5.0: Added new scenarios for EWR and LIB departure (thanks to Adam Bolek!)
  • 0.5.1: Fixed bug with RNAV approaches not descending, improved JFK arrival spawn and route details.
  • 0.6.0: Added scenarios in the F11 TRACON (KMCO, KSFB, KISM, KORL...). Thanks to Mike K!
  • 0.6.1: Fixed a crash related to handed off aircraft and sped up launching vice.
  • 0.6.2: Added go arounds and ABE TRACON scenarios.
  • 0.6.3: Added KJAX scenarios for F11. Updated PHL scenarios for arrival changes.
  • 0.6.4: Fixed a bug with intercepting the localizer that occasionally led to aircraft hanging in the air for a while before proceeding.
  • 0.6.5: Fixed another bug with intercepting the localizer.
  • 0.6.6: Small KJAX scenario fixes and added ISP and HVN arrivals/departures to the JFK scenario.
  • 0.7.0: Added LGA scenarios (thanks to Arya T!), and various small bug fixes.
  • 0.8.0: When you quit vice, now it remembers all of the aircraft; when you launch it again, you can resume right where you left off. When the sim is paused, hovering the mouse on a radar track displays information about its routing and assignments. Many additional small bugfixes.
  • 0.8.1: fixed a bug where the STARS window wouldn't show anything.

Facility Engineering

All of the configuration of vice is via JSON-formatted files. Extending vice to include more airports or additional scenarios is a matter of generating additional JSON that provides the necessary information.

In the following, the use of terms like "element", "object", "member", "array", etc., correspond to their use in the JSON specification. See this page for reference.

Scenarios are directly included in vice when a release is made. See the scenarios/ directory in the vice source code for the scenarios that are currently available and the videomaps/ directory for the video map definitions. Files in those directories with names ending with a "zst" suffix have been compressed using zstandard; in order to examine their contents, you'll want to install zstandard or another decompression program that supports that format.

When developing scenarios, you might make a copy of an existing scenario's JSON file and modify it in order to add more configurations, or you or might specify completely new scenario and video map files if you're working on support for a new TRACON. While you're doing this, there are two ways to point vice at the file you're working on:

  • Via the command-line: if you open a command prompt and run vice from the command line, there are two options make it possible to specify additional files for testing:
    • The -scenario command line option takes a single filename. The scenario specified file is loaded at startup time; if it has the same name as an existing scenario, it replaces that scenario's definition.
    • In a similar manner, the -videomap command line option also takes a single filename that specifies a file with video map definitions.
  • Alternatively, select the "Settings..." menu item in vice and then expand the "Developer" section. You can select a scenario file and or a video map file to use.

When you're working on a new scenario, you may omit the "video_map_file" specifier in its JSON file. In this case, vice will automatically use the video map file you specified via -videomap or via the UI.

Specifying Locations

Throughout the vice configuration files, it's often necessary to specify various locations on the Earth. vice has a built-in database of all of the airports, VORs, NDBs, and fixes in the United States (courtesy of the FAA), which allows using these directly for specifying locations. Locations can also be specified via latitude-longitude positions, given as strings. For convenience, multiple latitude-longitude formats are supported.

Encoding Description Example
Name of VOR/NDB/fix A string giving the name of an airport, VOR, NDB, or fix in the United States. "JFK"
Decimal value pair A pair of decimal numbers where the first specifies the longitude and the second specifies the latitude. "40.6328888,-73.771385"
Degrees, minutes, seconds A pair of values with position specified in degrees, minutes, and seconds, separated by periods. "N" and "S" are used to distinguish North and South latitudes and similarly for "E" and "W" with longitudes. "N40.37.58.400, W073.46.17.000"
ISO6790 Annex H A more compact degrees/minutes/seconds representation; see the Wikipedia page for details. "+403758.400-0734617.000"

(In all three examples above, the location specified is the same—the JFK VOR.)

In vice, if you hold down the control and shift keys and click on a point on the video map, the corresponding latitude-longitude position is copied to the clipboard—this can be very useful when developing new scenarios!


vice uses a custom syntax for specifying the routes of aircraft, both for arrivals and departures. In addition to the lateral positions along the route, it is possibly to specify speed and altitude restrictions, handoff points, and headings to fly.

Here is an example route from a JFK departure. The first two waypoints are custom fixes at the start and end of the KJFK 31L runway, specified via the "fixes" object in the scenario group, while the next three are standard fixes. The "#223" at the end leaves the aircraft on a 223 heading as it departs RNGRR. It will maintain that heading until it is further vectored by the controller. If there's are further fixes after such a heading, the aircraft may be sent direct to one of those fixes by the controller.


Altitude and speed restrictions can be specified at fixes. Here's an example from a JFK arrival. The "@a3000" after CATOD specifies a 3,000' altitude restriction at the crossing and "@s210" specifies a 210 kts speed restriction.

  "PZULU [email protected]@s210 [email protected] [email protected]",

Finally, a handoff point can be specified using a single "@". When an aircraft reaches that point in the route, it is handed off from the virtual controller to the user. Here is an example from the CAMRN4 arrival at KJFK. Immediately after the aircraft reaches KARRS it will be handed off from the virtual controller that is tracking it (NY_CTR in this case) to the user's control position. The aircraft will continue to CAMRN and then fly a 041 heading until the user gives it vectors.

  "N039.46.43.120,W074.03.15.529 KARRS @ CAMRN #41"

Airlines and Aircraft

Both departures and arrivals need to know about which airlines fly their routes and which aircraft they use for them. Airlines are specified via their ICAO strings (e.g., AAL for American Airlines). See the file openscope-airlines.json for the database of possible airlines. In that file, each airline may have one or more aircraft fleets specified, in its "fleets" member. If no fleet is specified, vice randomly chooses an aircraft type from the "default" fleet, but if a particular fleet's aircraft is a better match to a route, you may want to use it. For example, AAL's "long" fleet would be a good choice for trans-Atlantic flights.

For reference, the available types of aircraft and their performance characteristics are available in the openscope-aircraft.json file.

As is probably obvious, both of these databases are by way of openScope, which made them available under the MIT license.

Video Maps

Video maps are specified separately from the rest of the configuration since they require fairly large files and are not normally edited by hand. Video map files are simply JSON files with a series of members, each one of which stores an array of strings giving latitude-longitude positions. Each successive pair of positions specifies a line to be draw when rendering the video map. The following shows an excerpt from the ZNY video maps file that gives a sense of the format.

  "ABE": [
  "ABE - MVA": [

There is a utility program for extracting video maps from VSTARS configuration files; it is available from the vstars2vice releases page. Binaries for both Windows and Mac are available. It is a command-line program: the first argument should be the path to a VSTARS configuration file and the second a path to an output file.

Scenario Groups

vice offers users a variety of ATC scenarios, where a scenario consists of one or more airports being controlled, a control position (departure, approach, etc.), and airport configurations—the runways that are active at each airport. Scenarios are organized in scenario groups, which generally collect multiple control scenarios at a single airport. Each scenario group is specified by its own JSON file; see the scenarios/ directory in the vice source code distribution for examples.

These are the elements of a scenario group:

Element Type Description
"airports" Object Defines all of the airports that are included in the scenarios. See the airports section for details.
"airspace" Object Defines the extent of controllers' airspace; see airspace for details.
"arrival_groups" Object Defines the possible arrival routes; see arrivals.
"center" String Default radar scope center (as a latitude-longitude position.)
"control_positions" Object Information about all of the controllers that are used in the scenarios in the group. Each member specifies a controller with the corresponding callsign. For each controller, the following members should be specified:
  • "frequency": the controller's radio frequency, expressed as an integer (e.g., 125325 for 125.325)
  • "scope_char": a string giving a single character to use on radar scopes for tracks owned by this position (e.g., "C")
  • "sector_id": the controller's sector id, as used for handoffs, etc. (e.g., "N56")
"default_controller" String A default to use for the initial selected control position when the scenario group is chosen. There must be at least one scenario for this controller in "scenarios".
"default_scenario" String A default to use for the initial scenario when the scenario group is chosen. Must match one of the members in "scenarios".
"fixes" Object Each member associates a name with a latitude-longitude location. These names can be used when specifying routes for departures and arrivals. (Note that they cannot be used when specifying other locations in the scenario group configuration.) For example, this associates a useful name with the point at the end of runway 22R at JFK: "_JFK_22R": "N040.39.00.362,W073.45.49.053".
"magnetic_variation" Number Number of degrees difference between true North and magnetic North. Around New York, for example, this value is approximately 13.
"name" String The name for the scenario group. This name cannot be the same as the name for any of the other scenario groups.
"nm_per_latitude" Number Number of nautical miles per degree of latitude in the area around the scenario group's center point. On Earth, this should be 60.
"nm_per_longitude" Number Number of nautical miles per degree of longitude in the area around the scenario group's center point. This value depends on the center point's latitude; it's around 45 around KJFK, for example.
"primary_airport" String The main airport for the scenario. This is used to determine which airport's altimeter and winds to include at the top of the SSA list in the STARS radar scope.
"radar_sites" Object Specification of all of the radar sites. (A good source of data for these is the RadarSites section of your ARTCC's vSTARS configuration file.) Each object member describes a radar site; the member's name gives the site's identifier. Each radar site has the following configuration values:
  • "char": a single character string identifier for the radar
  • "elevation": an integer giving the radar site's elevation in feet
  • "position": the radar's lateral position
  • "primary_range": an integer giving the range in nautical miles at which the radar can pick up a primary track (typically, 60)
  • "secondary_range": an integer giving the range in nautical miles at which the radar can pick up a secondary track (typically, 120)
  • "silence_angle": the spread angle in degrees of the radar's "cone of silence"—the volume above it where aircraft cannot be tracked (typically, 30)
  • "slope_angle": the angle in degrees with respect to the ground that the base of radar coverage increases as a function of distance from the radar site (typically, 0.175)
"range" Number Default radar scope center range in nautical miles. If unspecified, a 50 mile range is the default.
"scenarios" Object This defines all of the ATC scenarios that are available in the scenario group. See the scenarios section for details.
"scratchpads" Object Each member specifies a scratchpad entry that is assigned when a departing aircraft has a given exit fix. Example: "MERIT": "MER"
"stars_maps" Array of objects These objects specify the available video maps in the STARS scope; the first 6 are shown in the main DCB and all are available under the "MAPS" sub-menu. Each one has three member values:
  • "group": either 0 or 1, to denote map group "A" or "B". (STARS allows setting the brightness of these separately.)
  • "label": a short string giving the map's label to show in the STARS DCB (e.g., "JFK4")
  • "name": a string giving the name of the map in the video map file (e.g., "N90 JFK - 4s")
"video_map_file" String Filename of the video map file from which the maps specified in "stars_maps" are found (e.g., "videomaps/zny-maps.json.zst")

Airports and Departures

The airports in a scenario group are specified via the "airports" member of the scenario group. Each airports is a separate member, named according to the airport's ICAO code (e.g., "KJFK"). The airport object then has the following member variables:

Element Type Description
"approaches" Object Defines all of the approaches to the airport that may be used by aircraft. Member names give the abbreviated name of the approach, as used in vice's ATC commands. Each approach is then defined by the following members:
  • "full_name": a string giving the full name of the approach (e.g., "RNAV Z Runway 13L")
  • "runway": a string describing the runway the approach ends at (e.g., "13L")
  • "type": a string indicating the type of the approach; it must be either "ILS" or "RNAV"
  • "waypoints": an array of one or more strings giving the approach's route.
Multiple strings can be provided for "waypoints" for approaches with multiple IAFs (e.g. an RNAV "T" configuration). Arriving aircraft are removed from the simulation when they reach their last approach waypoint. Thus, for all of the routes specified, the last waypoint should generally be at the runway threshold with a ground-level altitude restriction.
"departure_routes" Object Each member is an object that defines routes for the specified a departure runway. These routes are followed by aircraft departing that runway, organized by exit fix. See below for documentation of the per-runway departure route object.
"departures" Array of objects Each object in the array defines a departure to a destination, including one or more airlines that fly that departure, the type of aircraft flown, and information about the aircraft's path. See below for details of the departure object.
"departure_controller" String If specified, gives the virtual controller initially controlling the aircraft.
"elevation" Number The airport's elevation in feet
"exit_categories" Object Each member corresponds to a fix used as an exit for departures in the scenario group and allows associating a string category name with each exit. (These categories are used so that users can control the mix of exits used in a scenario.) Example: "ARD": "Southwest"
"location" String The airport's location
"tower_list" Number Gives which of the three STARS tower lists the airport should be associated with, if any. If present, should have the value 1, 2, or 3.

There are two pieces for specifying departures: their initial route leaving the airport, which depends on the active departure runway, and their subsequent route out of the TRACON, which does not. These two parts are specified separately.

The "departure_routes" object gives the initial routing for departures, based both on the runway they are departing as well as their exit fix. Here is an excerpt from the KJFK departure routes:

  "departure_routes": {
    "13R": {
        "cleared_altitude": 5000,
        "route": "JFK5",
        "waypoints": "_JFK_13R _JFK_31L #185"

The members of "departure_routes" are strings identifying the departure runway; each departure runway's routes are then represented by an object with one or more members that specify comma-separated lists of exit fixes. (Thus, the specification above applies to departures with exit ARD, DIXIE, RBV, or WHITE, departing runway 13R.) The departure route specification has three members:

  • "cleared_altitude": the initial altitude that aircraft are cleared to
  • "route": a string naming the route that is added to the start of aircraft's route as shown in flight strips, etc.
  • "waypoints": the initial series of waypoints that the aircraft follows. (Here, the first two are custom fixes specified at the ends of the runway.

On departure the aircraft will fly the specified waypoints and then the waypoints specified in the route to its destination. In this case, aircraft will remain on a 185 heading until vectored by the controller (as explained in Routes, above.)

The other half of specifying departures is the array of objects stored in "departures". Each one describes a departure to a particular destination. Here is a KJFK departure to Paris Charles de Gaulle:

      "airlines": [
          "fleet": "long",
          "icao": "AFR"
      "destination": "LPFG",
      "exit": "HAPIE",

Four things must be specified with each departure:

  • "airlines": The airlines that fly the route and which part of their fleet of aircraft is used; see airlines and aircraft below for more information
  • "destination": the ICAO airport code for the destination. This is only used in flight strips and for the aircraft's datablock on the radar scope; it does not affect its routing.
  • "exit": the exit fix for the departure. In conjunction with the departure runway, this is used to determine the aircraft's route leaving the airport using "departure_routes".
  • "route": the aircraft's route to the destination. This is mostly used so that flight strips have plausible routes, though vice does its best to have the aircraft follow the given route after it reaches the exit fix.


Arrivals are specified via the "arrival_groups" variable, which allows specifying one or more STARs that bring aircraft to the TRACON. Members of "arrival_groups" give the names of arrival groups; each one stores an array of one or more arrival objects.

Because arrival rates are specified per-arrival group rather than per-STAR, vice can simulate center controllers sequencing multiple STARs into a single arrival flow rather than spawning arrivals on two STARs that follow nearby routes and thus should be sequences.

Each object stored in an "arrival_groups" array corresponds to a STAR. These objects have the following members:

Element Type Description
"airlines" Object Destination airports and airlines for the arrivals. See example below.
"cleared_altitude" Number The altitude to which the aircraft is descending when first spawned.
"cruise_altitude" Number The aircraft's final cruise altitude. (This is only used in the aircraft's flight strip.) If unspecified, vice tries to choose a reasonable cruise altitude based on the distance and direction of flight.
"initial_altitude" Number The aircraft's altitude when first spawned.
"initial_controller" String The callsign of the controller who is initially tracking the aircraft.
"initial_speed" Number The aircraft's initial speed when first spawned.
"route" String Route to show for aircraft in flight strips. Not used for navigation.
"runway_waypoints" Object This specifies runway-specific waypoints. After an approach is assigned to an aircraft, the corresponding runway waypoints are added to its route. Note that the first waypoint in each entry in "runway_waypoints" must match the last waypoint in "waypoints". (See the example below.)
"speed_restriction" Number If present, gives a speed restriction in knots
"waypoints" String The series of waypoints that aircraft should fly. New aircraft are spawned at the first waypoint. These waypoints should include a "@" directive at the point where the aircraft should be handed off from the virtual controller to the user.

STARs are sometimes able to deliver aircraft to multiple airports. Therefore, the "airlines" member is an object with airport names as members. Each of the airports is associated with an array of objects that specify departure airports, airlines, and (optionally) airline fleets. Here is an excerpt from the CAMRN4 arrival group at KJFK:

  "airlines": {
    "KFRG": [
        "airport": "KDCA",
        "icao": "EJA"
    "KJFK": [
        "airport": "MMMY",
        "fleet": "long",
        "icao": "AMX"

We can see that CAMRN4 applies to both the KFRG and KJFK airports, though with different airlines and different departure airports for the arrivals. The specified departure airports (here, KDCA and MMMY) are only used so that flight strips and data blocks on the scope are realistic, but the specified airlines are used to select the type of aircraft from their fleets. As elsewhere, a value for "fleet" may be specified to limit which types of aircraft may be chosen.

The "runway_waypoints" member can be used for STARs that have different routes depending on the runway. When the user instructs the aircraft to expect a particular approach then the corresponding waypoints are added to its route. As an example, the specification of the KPHL JIIMS4 arrival starts with the following string for "waypoints": "HEKMN N039.27.43.645,W074.56.38.400 @ [email protected]". (The second point is used to set the handoff point to be between HEKMN and JIIMS.) It then has the following "runway_waypoints", corresponding to the runway-specific routes. Note that all start with JIIMS, the same fix at the end of "waypoints".

  "runway_waypoints": {
    "27L": "[email protected] ZMRMN CHPMN PSOUT MKORD #87",
    "27R": "[email protected] ZMRMN CHPMN PSOUT MKORD #87",
    "17": "[email protected] SNEDE #312",
    "35": "[email protected] SNEDE #312",
    "9L": "[email protected] WUDRR WEVVE ERNYY #268",
    "9R": "[email protected] WUDRR WEVVE ERNYY #268"


Airspace volumes may optionally be specified using the "airspace" object in the scenario group. These volumes may be assigned to controllers in scenarios, in which case vice will show an alert when aircraft are outside of the controller's airspace. The airspace object has two members:

Element Type Description
"boundaries" Object Defines all of the airports that are included in the scenarios. See the airports section for details.
"volumes" Object Defines all of the airports that are included in the scenarios. See the airports section for details.

Each member in "boundaries" names a polyline of one or more line segments. Polylines are specified by arrays of locations. The first and second points specify the first line, the second and third points specify the second line, and so forth. Here is an example from the KPHL airspace:

  "PHL_DQO27_33": [

Note that the first point and the last point are at the same location and thus, "PHL_DQO27_33" is a closed polygon. Airspace boundaries do not have to be polygons like this; because boundaries are generally shared between different volumes of airspace, it's often useful to define boundaries just as polylines and to assemble multiple boundaries to define the lateral extent of a volume of airspace.

Given the boundaries, "volumes" specifies full 3D volumes of airspace. Airspace volumes have three members; "boundaries" is an array of strings that names the boundaries that give the airspace's lateral extent, and "lower" and "upper" specify the altitude range of the airspace. Here is an example from KPHL that uses the boundary defined above:

  "PHL_DU_APP27": [
      "boundaries": [
      "lower": 5000,
      "upper": 6000


Scenarios pull together components from the definitions in scenario groups in order to present specific control scenarios to the user. The scenarios object's members are the names of the scenarios. Each of these scenarios may have the following members:

Element Type Description
"approach_airspace" Array of strings If airspace has been specified in the scenario group, then these strings give the names of the airspace volumes that arrivals should remain inside.
"arrival_runways" Array of objects Each object has two values that specify an airport and one of its runways
  • "airport": string that gives an airport name
  • "runway": string that specifies a runway at the given airport
The specified airport must be present in the "airports" member of the scenario group, and the specified runway must be one of its runways.
"arrivals" Object Each member specifies an arrival group and is an object that contains one or more members that specifies an airport name and a default arrival rate for the arrival group to the airport. It can be useful to specify an arrival rate of zero—in this case, the arrival group will still be included in the UI shown to the user, which allows the user to enable it.
"callsign" String The callsign for the user's control position. (This must be present in "control_positions" in the scenario group.)
"controllers" Array of strings Callsigns of the other controllers who are online. (These also must be in "control_positions".)
"default_map" String The name of the initial video map that should be selected when this scenario is selected.
"departure_airspace" Array of strings Similar to "approach_airspace", if present, this gives the names of airspace volumes that departure aircraft must remain inside.
"departure_runways" Array of objects Each object specifies information about departures at a runway at an airport in the scenario.
  • "airport": string giving the airport's name
  • "runway": string specifying one of the airport's runways
  • "rate": number giving the number of departures per hour
  • "category": an optional string that specifies an exit category. If present, then only departures that have an exit that is associated with the category will be launched from this runway.
"wind" Object This specifies the current winds for the scenario. Winds are included in the simulation and affect aircraft similarly to how they do in the real world.
  • "direction": the wind's direction, expressed as a number giving the heading
  • "speed": the wind speed in knots
  • "gust": if present, gives the wind gust speed