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About Vice Last updated: 2023-10-10

vice is an air traffic control simulator, focused on TRACON. It presents a STARS-like interface, but with simulated traffic and other controllers. It also supports multiple users, where each person controls a different position at a facility.

vice supports departure and arrival control scenarios in a number of TRACONs: A80 (ATL), A90 (BOS), C90 (ORD, MDW), D01 (DEN, GJT), D10 (DFW), F11 (JAX, MCO, SFB, ISM, ORL), L30 (LAS), N90 (EWR, JFK, LGA, FRG, ISP, HVN), NCT (SJC, SFO, OAK, RNO, SMF, MRY, MER, MOD, SCK, SAC, LVK, SNS), P50 (PHX), S46 (SEA), SCT (BUR, LGB, ONT, PSP, SAN, SNA, VNY, WHP) as well as the AAC, ABE, ASE, AUS, BHM, CLE, CLT, COS, CYS, DAB, DCA, GSP, JAX, PHL, SAV, SDF, and TPA ATCT/TRACONs. New scenarios are regularly added. 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. For familiarity to VATSIM controllers, vice generally follows the keyboard command scheme implemented in CRC's STARS implementation; see the discussion of vice's STARS emulation below for more information.

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 LGA:

configuration dialog box

(Each scenario usually offers multiple runway configurations.)

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 LGA 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.

When the simulation starts, vice also displays a small window listing the active departures, arrivals, and approaches. For this LGA scenario, three arrivals are active but there is just one approach and one departure. Other scenarios may be more complex.

approach list

The approach code—here, "I22"— is used in vice's aircraft control commands like "expect approach" and "cleared approach".

To free up space, you can close this window by clicking on the "X" in the upper right corner. Clicking on the button in the menubar will show the window again.

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 slow times or to increase the challenge.
  • : show the window that lists the currently active departures, arrivals, and approaches.
  • : opens a window that shows a summary of vice's ATC commands and frequently-used STARS commands.
  • : open a window with controls for launching aircraft, either automatically or manually.
  • : 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 simulation.

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.

aircraft information

If you are signed in to Discord, vice can automatically update your activity status there with information about your current vice session (the number of arrivals and departures, the position you're controlling, etc.) When you first launch vice you are given the option to disable this feature if you would like. The settings window, available by clicking in the menubar, can also be used to enable or disable this feature afterward.

Drawing Routes

vice can draw the active departures, approaches, and arrivals for the current scenario. This can be helpful when studying those for an airport, since they are drawn directly on the radar scope with annotations that give the fixes, any altitude or speed restrictions, and procedure turns.

To toggle whether a route is drawn on the scope, click the checkbox on the left next to it in the scenario information window that is shown at the start or after clicking on the button in the menubar. For example, here is how the HVN RNAV Runway 2 approach is rendered:

manual aircraft launch window

We can see the procedure turn at PEPER and that it is both the IAF and the IF; altitude restrictions at both SALLT and PEPER, that SALLT is the FAF, and that arrivals from KEYED will not fly the procedure turn.

Launching Aircraft

When a new scenario starts, vice automatically launches new departures and arrivals based on the departure and arrival rates set in the "New Simulation" window. During a simulation, clicking on the departing plane icon in the menubar opens a window that allows more control over aircraft launches. (Note that when vice is used with multiple controllers in the same simulation, then only one controller may have this window open at a time.)

The rates for automatic launches can be adjusted in this window. Alternatively, aircraft can be launched manually. If manual launches are selected, the window shows all of the available departure runways and exits as well as all of the arrivals, as shown below. Clicking the aircraft icon for a departure or arrival causes the aircraft shown to be launched. If you'd like a different aircraft for the next launch (for example, to have a heavy aircraft), click the redo icon until you're happy with the selection. The window also shows the elapsed time since the launch of each type as well as how many miles in trail (MIT) there would be if the next aircraft was launched. To clear out all of the current aircraft and restart, click the trash icon: .

manual aircraft launch window

Multiple Controllers

With vice you can also have multiple controllers working aircraft together. Select "Create multi-controller" in the "New Simulation" window and you can select a scenario and set its parameters in more or less the same way that you do with a single controller. Here is the top part of the multi-controller configuration window; all of the settings that are the same as for single-controller aren't shown.

create multi-controller window

Each multi-controller simulation has a name associated with it; vice chooses a random one by default (above, it's "following-nature"). You're welcome to choose a different name if you prefer. These names can be used so that you can tell other people which simulation to choose in order to join you.

Selecting "Join multi-controller" shows a list of the simulations that are currently available, including how many controllers are signed into each one. Note that the simulation names are shown in the first column. After selecting one, you can choose one of the available control positions and join. vice also allows you to join a simulation as an observer, in which case you have no control capabilities.

create multi-controller window

ATC Commands

The commands below issue control commands to aircraft. To indicate which aircraft should be given a command, you can either enter a command and click on an aircraft's radar track or you can enter the aircraft's callsign, a space, the command, and then press the "enter" key. After you issue a command, the virtual pilot's readback is shown at the bottom 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. To open a window that shows the available ATC commands when using vice, click the button in the top menubar.

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. If no heading is given, the aircraft is instructed to fly present heading. H050, H
Lheading Directs the aircraft to turn left to the specified heading. L130
Rheading Directs the aircraft to turn right to the specified heading. R210
TdegreesL Directs the aircraft to turn the specified number of degrees to the left. T10L
TdegreesR Directs the aircraft to turn the specified number of degrees to the right. T20R
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
Dfix/Hheading Directs the aircraft to depart the specified fix at the given heading. (The specified fix must be in the aircraft's flight plan.) DLENDY/H180

Directs the aircraft to cross the specified fix at the given altitude and speed. Either one or both of A and S may be specified.

Altitudes may be given as single altitudes (corresponding to "at"), an altitude and a plus sign ("at or above"), an altitude and a minus sign ("at or below"), or a range of altitudes separated by a minus sign ("between").

Calt Directs the aircraft to climb to the specified altitude, which is given in hundreds of feet. If the aircraft is changing speed, both the speed change and climb are simultaneous. C170
TCalt Directs the aircraft to climb to the specified altitude, given in hundreds of feet, after it finishes speeding up or slowing down to meet a controller-specified speed. TC170
Dalt Directs the aircraft to descend to the specified altitude, given in hundreds of feet. D20
TDalt Directs the aircraft to descend to the specified altitude, given in hundreds of feet, after it finishes speeding up or slowing down to meet a controller-specified speed. TD20
ED Directs the aircraft to expedite the descent to its assigned altitude. ED
EC Directs the aircraft to expedite the climb to its assigned altitude. EC
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. If no speed is given, then the aircraft is instructed "cancel speed restrictions". Speed changes happen at the same time as any required altitude change. S210, S
TSknots Gives the aircraft a speed restriction to be applied after the aircraft climbs or descends to the most recent controller-specified altitude. As with S, speed restrictions are canceled at 5 mile final. TS210
SMIN Directs the aircraft to maintain its slowest practical speed. SMIN
SMAX Directs the aircraft to maintain its maximum forward speed. SMAX
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
Afix/Capproach Clears the aircraft for the specified approach when it passes the given fix. AROSLY/CI2L
CAC Cancels approach clearance for an aircraft. CAC
CSIapproach Clears the aircraft "straight in" for the specified approach. (This command is only useful for approaches that include procedure turns.) The aircraft must have been told to expect the approach before it is cleared for it. CSII6
I Directs the aircraft to intercept the localizer (at which point it will follow the localizer's lateral path but not descend until it is cleared for the approach.) I
CVS Directs a departure to "climb via the SID". CVS
DVS Directs an arrival to "descend via the STAR". DVS
TO Directs an arrival to contact the tower. TO
ID Instructs the aircraft to "ident". ID
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 not available at all airports.) 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.

STARS Emulation

vice attempts to present a reasonably accurate representation of the Standard Terminal Automation Replacement System. Its focus is to provide the STARS functionality that is useful for regular TRACON controlling; thus, obscure features like military operations area commands are not supported. If you are familiar with the actual STARS system, suggestions about how to improve vice's accuracy would be happily accepted! Head on over to the vice discord...

vice mostly follows the keybindings used in CRC STARS.

Differences from CRC STARS

vice supports the following features from STARS that are not present in CRC STARS:

  • vice supports the STARS "dwell" mode, which draws the datablock and leaderline of track under the mouse more brightly when it is enabled. Dwell mode can be configured by choosing "SHIFT" from the main DCB menu and then selecting the "DWELL" button, or via the following keyboard commands:
    • [multifunc] D E: enable dwell mode.
    • [multifunc] D L: lock dwell mode—the selected aircraft remains highlighted even if it or the mouse cursor moves.
    • [multifunc] D I: inhibit (disable) dwell mode.
  • vice supports displaying the current weather radar for the selected location.


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 v0.10.19 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 v0.10.19 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

0.10.19 (13 February 2024)

  • STARS: fixed bug with flickering airport weather list.

0.10.18 (12 February 2024)

  • Added new scenarios: SCT (Justin Nguyen and Eli Thompson), NCT and D01/GJT (Jud Lopez), and TPA (Connor Allen).
  • Smaller scenario updates: D10 and JAX (Mike K), AUS (Jace Martin), LGA, JFK, COS, CLE, ASE, DCA, F11.
  • STARS: more accurate simulation of the STARS weather radar display.
  • Added new syntax for issuing left/right turn in degrees: T10L, T20R, etc.
  • STARS: allow middle-click highlight of aircraft regardless of having their track.
  • STARS: fix LDB/FRB/PRI/POS brightness usage when drawing things (hopefully).
  • STARS: fixed bug where observers were unable to quicklook other positions.
  • Fixed a few cases where vice would crash when given an invalid scenario.
  • Improved calculation of the final approach course line, which fixed some bugs with bad approach intercepts.
  • Facility engineering changes/improvements:
    • Arc routes between fixes can now be specified without specifying a center point for the arc's circle: for example, WUPMA/arc7.5 ALABE has aircraft fly along the 7.5nm long arc between WUPMA and ALABE.
    • The "tower_list" property of airports is now used to prioritize tower list assignment rather than used directly. (Thus, if multiple airports have the same "tower_list" value, they no longer try to share the same tower list.)

0.10.17 (15 January 2024)

  • Added multiple new scenarios: D10 (Mike K), CYS, ASE, COS (Jud Lopez).
  • Fixed multiple bugs with handling of altitude and speed restrictions in departure routes.
  • Many small fixes to scenario routes and altitude/speed restrictions.
  • Increased acceleration and climb rate of departures to be more realistic.
  • Fixed bugs with point outs (couldn't be cleared, incorrect rendering in STARS).
  • Fixed bug in the STARS scope that required secondary scratchpads to be three characters.
  • When departures are handed off to center, they are only given direct to the exit fix if they are on a heading; otherwise they continue flying their route.
  • (Re-)added optional sound effect for accepted handoffs.
  • Airspace warnings are inhibited for aircraft flying approaches.
  • Fixed a bug where wind would affect aircraft on the ground and blow them off course.
  • STARS: allow control-left-click in place of the third mouse button to highlight aircraft.
  • STARS: don't allow scratchpads of arbitrary length.
  • STARS: actually use the LDB brightness setting for limited/partial datablocks.
  • STARS: fix incorrect error message after issuing "at fix, cleared approach".
  • Facility engineering changes/improvements:
    • Fixes in routes may have /flyover after them to indicate that aircraft must fly directly over the fix before starting their next turn.
    • It is no longer required to specify radar sites in scenarios; if no sites are given, then STARS Fused mode is always enabled.
    • Departure routes may be given with either "assigned_altitude" or "cleared_altitude". "cleared_altitude" implies "climb via SID": aircraft obey altitude restrictions and climb no higher than the given altitude, while "assigned_altitude" has them climb without restriction to that altitude.

0.10.16 (22 December 2023)

  • Added multiple new scenarios: S46, BHM, GSP (Aaron Flett), AUS (Jace Martin), P50 (Mike K)
  • Multi-controller servers can now be password-protected
  • Added "TO" command for "contact tower"
  • Various bugfixes with handoffs and approach navigation
  • Match real-world STARS alert sounds
  • Facility engineering changes/improvements:
    • The scenario group "nm_per_*" settings have been removed and no longer need to be specified.
    • Fixed crashes with the -scenario and -videomap command-line options
    • It is no longer required to specify "full_name" for approaches; a default name will be assigned using the specified approach type and runway if "full_name" is not given.
    • In "departure_routes", the "route" field has been renamed to "sid". It is optional to specify "sid"; if the aircraft isn't on a published departure it should be left blank.
    • In "arrivals", the "route" field has been renamed to "star".
    • Approaches now have a "tower_controller" field to specify which tower controller arrivals should contact. If an airport has a single controller named "(airport)_TWR", then "tower_controller" doesn't need to be specified.
    • Arrivals specified in "arrival_groups" now have an "assigned_altitude" field (and "cleared_altitude" has been removed.) If "assigned_altitude" is specified, it is treated as an altitude assignment from a previous controller and the aircraft will not descend further. For aircraft on a STAR that have been cleared to descend via the STAR, "assigned_altitude" should not be given.
    • For multi-controller scenarios, departure controllers can be specified per-runway (e.g., "KPHX/25R") or per-SID (e.g., "KJFK/SCORR5").

0.10.15 (19 November 2023)

  • STARS: fixed a bug where RBL lines for *T that included aircraft weren't drawn
  • Added an option to hide the flight strips (Settings window, Flight Strips section)
  • Fixed a bug where inbound handoffs wouldn't send a radio contact message
  • Sped up loading of video maps so that vice launches more quickly

0.10.14 (18 November 2023)

  • L30 TRACON (Las Vegas) added, thanks to Michael Trokel.
  • Added a combined N90 (JFK, LGA, EWR) scenario.
  • Important readbacks from pilots (e.g., "unable") are now highlighted in red.
  • Improved STARS *T to allow entering fix names and to show ETA.
  • Added support for charted visual approaches.
  • STARS allows control-shift click to initiate track (CRC style).
  • Secondary scratchpads are now supported.
  • Fixed bug that would cause arrivals to climb when vectored off of their STAR.
  • Fixed other minor navigation bugs.
  • Facility engineering
    • Scenarios can now have "center" and "range" specified; they override the scenario group valus, if present.
    • "default_map" in scenarios is now "default_maps"; an array of values can be given, allowing multiple maps to be initially shown.
    • Departures from different runways at an airport are sequenced better so that CAs on departure are less likely.
    • Added "tracon" to the scenario group definition; this is used to gather scenarios for a single TRACON in the UI.

0.10.13 (5 November 2023)

  • Fixed a bug that caused vice to sometimes crash after aircraft were given approach clearance.
  • Fixed a bug where descending aircraft would stop descending when given approach clearance.
  • Small fixes to the DCA scenario.
  • Polished up handling of early hand-offs of departures in the STARS scope

0.10.12 (31 October 2023)

  • Added a new DCA scenario.
  • Aircraft will now ident if given the "ID" command.
  • There is now a short delay (3-6 seconds) before aircraft start following heading instructions, to better model reality.
  • Control commands for aircraft can now be given without slewing on the aircraft: enter their callsign, a space, one or more commands, and then hit enter.
  • Point outs can be rejected by entering "UN" and slewing on the radar track of an aircraft being pointed out.
  • RNAV approaches can now be intercepted via a heading.
  • Fixed a bug where departures wouldn't follow altitude restrictions on SIDs.
  • Fixed a bug where aircraft that went around would always continue to do so on subsequent approaches.
  • Facility engineering updates:
    • The "multi_controllers" field in scenario definitions is now an object where each entry specifies a control position split. If more than one split is specified, then the user will be prompted to pick one of them when launching a scenario.
    • Also in "multi_controllers", a single departure controller is no longer specified using the Boolean "departure". Instead, there is a "departures" field that is an array of strings specifying airports and/or runways that a controller is responsible for.
    • Airports have an optional "name" field that is used in transmissions from aircraft when referring to the airport.

0.10.11 (10 October 2023)

  • Added the D01 (Denver TRACON) scenario to single-user vice (it was unintentionally not included in the installer).
  • Added support for updating your Discord activity based on your vice session (thanks to Samuel Valencia!)
  • Clicking the icon on the menubar opens a window that shows a summary of vice's keyboard commands.
  • Fixed a bug with aircraft descending too early when flying procedure turns.
  • Fixed a bug where some departures would try to re-fly their initial departure route after being handed off to a virtual controller.
  • Fixed multiple bugs with the handling of "at or above" altitude constraints.
  • Fixed a bug that left the default DCB brightness set to 0.

0.10.10 (1 October 2023)

  • Fixed a bug in the Windows installer that caused new scenarios (AAC, SAV, SDF) to not be installed locally.
  • Added the ability to draw active departure, arrival, and approach routes on the radar scope.
  • Facility engineering updates related to the above:
    • When specifying fixes in approaches, you can add /iaf, /if and/or /faf to specify that a fix is the initial approach fix, initial fix, or final approach fix. This is then drawn on the scope when the approach is shown but isn't used otherwise.
    • For arrivals under "arrival_groups", there is an optional string "description" field that will be shown in the UI. Similarly, for departures in "departure_routes", you can also give a "description" string.

0.10.9 (28 September 2023)

  • Many improvements to the AAC scenario's accuracy:
    • Added turboprop and piston departures and arrivals for AAC.
    • AAC jet arrivals now come in on the TULSA4; turboprops and pistons pass through their approach gate (at lower altitudes) and are routed direct TUL.
    • AAC departures now follow headings after takeoff (props 010 or 190, jets/turboprops 260/310, depending on departure gate.)
    • Inbound handoffs are now 45 miles out.
  • Fixed a bug where arrivals would sometimes climb after being cleared for the approach.
  • Facility engineering: when exits are specified in "departure_routes", additional text can be included after a period. This text is ignored when determining which exit an aircraft uses. This can be useful if for example piston aircraft and jets have different departure procedures; "COLIN.P" and "COLIN.J" departure routes could be specified with the used for piston aircraft and the second used for jets.

0.10.8 (26 September 2023)

  • When altitude and speed instructions are given, aircraft now do both at once. To give consecutive commands (e.g., "descend and maintain xxx, then reduce speed to yyy"), there is now a TS command for "then speed", and TA for "then altitude", or TC for "then climb", or TD for "then descend". (See the ATC command reference for details.)
  • Updates to the JAX, C90, and F11 scenarios and a new D01/KSAV/KSDF scenario (Thanks to Mike D and Samuel Valencia!)
  • Added a new scenario for KAAC/KJKE.
  • Facility engineering changes:
  • Various small bugfixes related to aircraft navigation and clearing approaches at fixes.

0.10.7 (8 September 2023)

  • Fixed a bug where arrivals would disappear in some scenarios (KJAX, KDAB, ...)

0.10.6 (not released)

0.10.5 (6 September 2023)

  • Added support for STARS fused mode (updates every second, round markers for radar tracks; choose "FUSED" in the "SITE menu.)
  • It is no longer allowed to issue control commands to departing aircraft before they have checked in.
  • Added multiple new ATC commands:
    • EC/ED: expedite climb/descent.
    • I: intercept the localizer (of the approach previously given with "expect approach").
    • SMIN: maintain slowest practical speed
    • SMAX: maintain maximum forward speed
    • Afix/Capproach: at the specified fix, cleared for the given approach.
    • More flexible altitude crossing restrictionsCfix/A100- is cross FIX at or below 10,000, CFIX/A120-150 is cross FIX between 12,000 and 15,000, etc.
  • Facility engineering changes:
    • Removed the "elevation" field for airports; it is no longer needed.
    • Radars must have an "elevation" value specified, unless their location is given using an ICAO airport code, in which the airport's elevation is used.
  • Minor fixes to the ABE scenario.

0.10.4 (16 August 2023)

  • Added support for STARS Converging Runways Display Aid (CRDA).
  • Made multiple improvements to aircraft flight modeling, including more accurate climbs at departure and better handling of wind.
  • Tuned up pilot radio communications, including adding initial contact messages.
  • Fixed a bug where after quitting and later resuming a simulation, some aircraft would forget their routing.
  • Added support for the STARS Maps system list.
  • Facility engineering changes:
    • Added "reporting_points" to scenarios: fixes aircraft may use when reporting their current position.
    • Added support for specifying volumes of space where collision alerts are inhibited.
    • Altitude restrictions at fixes are now more flexible: rather than just "at", they may be "between", "at or above," or "at or below."

0.10.3 (1 August 2023)

  • Added "quick look" support to the STARS implementation.
  • Added support for STARS dwell mode.
  • Fixed a rare crash when manually adjusting launch rates.
  • Various small improvements to the JAX and CLT scenario files.
  • Many additional small cosmetic and functionality improvements to the STARS radar scope.

0.10.2 (28 July 2023)

  • Added scenarios for the A80 (ATL) and A80 (BOS) TRACONs (thanks Mike K!).
  • Fixed a bug with drawing *J cones in the STARS scope.
  • Many improvements to the STARS DCB, including better rendering of the buttons, more support for configuring font size and brightness, as well as the ability to position the DCB on the top, bottom, left, or right edge of the screen.

0.10.1 (25 July 2023)

  • Updated the font used in the STARS radar scope.
  • Fixed a few bugs with drawing radar tracks in the STARS scope.
  • Fixed a rare crash with incorrect command input to the STARS scope.

0.10.0 (22 July 2023)

  • Vice now supports multiple controllers working in the same simulation. In the "New Simulation" window, choose "Create multi-controller" to create a new simulation or "Join multi-controller" to join an existing one.
  • Facility engineering changes:
    • Removed "default_controller" and renamed "callsign" in scenarios to "solo_controller". Scenarios now take an optional "multi_controllers" object to specify a multi-controller scenario. Added "full_name" to controller specifications for better radio readback text.
  • Launches of arrivals and departures can be controlled manually; click on the departing aircraft icon in the menu bar to open a window with launch controls. Alternatively, launch rates can be controlled during a session via that same window.
  • Various improvements to the accuracy of the STARS radar scope simulation.
  • Available approaches are now shown by vice at initial connection time and via the button in the menu bar.
  • Many small bug fixes to aircraft flight modeling.
  • New scenarios and improvements:
    • Added C90, including O'Hare East and West ops, MDW all configs
    • Added CLE TRACON, including final, feeder, and North/South scenarios
    • Added CLT TRACON, North and South configs
    • JAX: added DAB and the TEBOW1 arrival
    • N90: added multi-controller scenarios at JFK and PHL

0.9.2 (3 July 2023)

  • Fixed the behavior of *T to better match STARS: the line is now drawn to the mouse position after the first point is selected, without waiting for the second point.
  • Added more checks when loading scenario descriptions; in particular, misspellings and unused JSON objects are detected and an error is issued. This led to numerous small fixes in all of the the scenarios.

0.9.1 (20 June 2023)

  • Fixed a bug where arrivals wouldn't obey altitude restrictions in STARs(!).
  • Improved navigation: crossing restrictions beyond any at the immediately upcoming fix are now considered. Aircraft are now much better at starting altitude and speed adjustments in time to meet the crossing restrictions.

0.9.0 (15 June 2023)

  • All new flight modeling engine supports procedure turns (both racetrack and standard 45/180) and more accurate turns to intercept localizers, etc. The approaches in the existing scenarios have been updated to include their procedure turns, where appropriate.
  • A number of new aircraft control commands have been added:
    • Cancel speed restrictions
    • Cleared straight in approach
    • Cross fix at altitude and speed
    • Depart fix at heading
    • Fly present heading
  • When a departure is handed off to a virtual controller, the other controller won't climb it further until after it is clicked by the user to acknowledge the handoff.
  • Fixed very small fonts being used on Windows systems with high-DPI displays
  • Numerous other small fixes and improvements, including in the wind modeling and fixing a case where arrivals would fly faster than the aircraft is capable.
  • Facility engineering: In addition to new directives to specify procedure turns, there are a number of changes to how routes are specified.

Earlier Releases

  • 0.8.1: fixed a bug where the STARS window wouldn't show anything.
  • 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.
  • 0.7.0: Added LGA scenarios (thanks to Arya T!), and various small bug fixes.
  • 0.6.6: Small JAX scenario fixes and added ISP and HVN arrivals/departures to the JFK scenario.
  • 0.6.5: Fixed another bug with intercepting the localizer.
  • 0.6.4: Fixed a bug with intercepting the localizer that occasionally led to aircraft hanging in the air for a while before proceeding.
  • 0.6.3: Added JAX scenarios for F11. Updated PHL scenarios for arrival changes.
  • 0.6.2: Added go arounds and ABE TRACON scenarios.
  • 0.6.1: Fixed a crash related to handed off aircraft and sped up launching vice.
  • 0.6.0: Added scenarios in the F11 TRACON (MCO, SFB, ISM, ORL...). Thanks to Mike K!
  • 0.5.1: Fixed bug with RNAV approaches not descending, improved JFK arrival spawn and route details.
  • 0.5.0: Added new scenarios for EWR and LIB departure (thanks to Adam Bolek!)
  • 0.4.3: Allow specifying JSON config on the command line, to make it easier to develop new scenarios.
  • 0.4.2: Fixed a crash at first launch, updated syntax for "turn left/right X degrees" commands.
  • 0.4.1: Fixed bugs in datablock positioning, added "turn left/right X degrees" commands.
  • 0.4.0: Added PHL scenarios, airspace warnings, and FRG arrivals and intra-TRACON arrivals for JFK.
  • 0.3.1: Added JFK approach scenarios, improved aircraft flight model, routes, and airlines.
  • 0.2.1: Initial release

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.

See the resources/scenarios/ directory in the vice source code for the scenarios that are currently available and the resources/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 you can point vice at the file you're working on using 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.

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.

If you're working on multi-controller support for a scenario, you may want to run a vice server locally to debug it. A few command-line options are useful:

  • -runserver launches a vice server on your local system
  • -server specifies the IP address and port of a vice server to connect to. Specifying localhost:8000 will connect to a local server launched via -runserver.
  • -port allows specifying a custom port number for the server to listen to.

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 "/h223" after "RNGRR" specifies that the aircraft should fly a 223 heading as departing RNGRR. It will maintain that heading until it is further vectored by the controller. If there are further fixes after such a heading, the aircraft may be sent direct to one of those fixes by the controller.


A number of items like headings can be specified with a fix:

  • /arestriction: cross the fix with the specified altitude restriction (with altitudes specified in 100s of feet). The following options are available for specifying altitude restrictions:
    • low-high: cross at an altitude between low and high.
    • alt-: cross at or below alt
    • alt+: cross at or above alt
    • alt: cross at alt
  • /hheading: depart the fix at specified heading
  • /sspeed: cross the fix at the given speed
  • /ho: the aircraft should be handed off from the virtual controller to the user when it departs the fix
  • /iaf: indicates that the fix is an IAF (initial approach fix)
  • /if: indicates that the fix is the IF (intermediate fix)
  • /faf: indicates that the fix is the FAF (final approach fix)
  • /flyover: indicates that the fix is a flyover fix (as opposed to the default, fly-by). Aircraft must pass directly over flyover fixes before turning to the next fix, while they may turn early with fly-by fixes.

If the aircraft should follow an arc leaving a fix, /arc can be given after the fix. It can be used in two ways:

  • Both a radius in nautical miles as well as the fix at the center of the arc's circle can be specified. For example, HANAV/arc16OMN specifies a 16nm radius arc centered at OMN.
  • Alternatively, just the length of the arc may be given. For example, WUPMA/arc7.5 ALABE has aircraft fly along the 7.5nm long arc between WUPMA and ALABE.

For both uses, the direction of the arc is automatically determined based on the position of the following fix.

For approach fixes that have procedure turns, a number of additional items can be specified:

  • /hilpt: there is a hold in lieu of procedure turn (i.e., a racetrack procedure turn) associated with the fix. The default is right turns and a 1 minute limit for ILS approaches and a 4 nm limit for RNAV approaches. Different limits can be specified directly; for example /hilpt6nm gives a procedure turn with a 6 nm limit and /hilpt2min specifies a 2 minute limit. For left turns, add a l after the slash, like /lhilpt.
  • /pt45: specifies that there is a standard 45 degree procedure turn at the fix. (This has the same defaults— right turns, 1 minute (ILS) / 4 nm (RNAV)—as HILPTs. Alternative values are specified the same way.)
  • /ptaaltitude: if the aircraft should descend during the procedure turn, this can be used to specify the final altitude it should have at the end of the turn. (The altitude should be given in 100s of feet.)
  • /nopt180: specifies that aircraft approaching the fix in the 180 degree semicircle of directions aligned with the final approach course should not perform the procedure turn. (As an example, see the KJAX RNAV Z 8 approach; this applies for aircraft between heading 346 and 166 arriving at UDAQI.)
  • /nopt: when specified at a fix prior to one with a procedure turn, indicates that aircraft that pass that fix should not fly the procedure turn.

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 kindly 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 are utility programs available for extracting video maps from both vSTARS configuration files and from installed CRC ARTCCs.

  • vstars2vice is available from the vstars2vice releases page. 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.
  • crc2vice is available from the crc2vice releases page. See its README file for information about how to use it.

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 resources/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:
  • "full_name": the name of the control position, used in radio readbacks (e.g., "Philadelphia approach")
  • "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_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".

Fixes may be specified in relation to previously-specified fixes (or standard fixes from the FAA database) using the syntax FIX@HDG/DIST, where FIX is the name of a fix, HDG is a heading leaving it, and DIST is a distance along that heading given in nautical miles.

"inhibit_ca_volumes" Array of objects Each entry specifies a volume of space where collision alerts are inhibited. It can be useful to specify these around airports so that alerts aren't issued for aircraft arriving/departing on parallel runways. Each object has the following members:
  • "name": a string used to identify the volume in system lists.
  • "type": either "circle" or "polygon"
  • "floor": number giving the minimum altitude of the volume.
  • "ceiling": number giving the maximum altitude of the volume.
For "circle" volumes, there are two additional members:
  • "center": the location of the center of the volume.
  • "radius": the radius of the volume, in nautical miles.
For "polygon" volumes, an additional parameter specifies its extent:
  • "vertices": an array of locations specifying the outline of the volume.
"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.
"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 (Optional) Specification of all of the radar sites. (If not specified, then STARS Fused mode is the only radar mode available.) 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. (Not required if the position is specified using an airport ICAO code.)
  • "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.
"reporting_points" Array of strings Each entry specifies a fix that aircraft may use at initial contact when reporting their position ("AAL411, 5 miles Northeast of LENDY...").
"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")
"tracon" String Name of the ATCT/TRACON that the scenario group is associated with. This is used to show all scenarios for a given ATCT/TRACON together in the UI.
"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": (Optional) a string giving the full name of the approach (e.g., "RNAV Z Runway 13L"). If not specified and the approach is ILS or RNAV the approach's name is generated automatically using "runway" and "type".
  • "runway": a string describing the runway the approach ends at (e.g., "13L")
  • "tower_controller": (Optional) a string giving the name of the tower controller covering the approach. If an airport has a single tower controller named "(airport)_TWR", then this doesn't need to be specified.
  • "type": a string indicating the type of the approach; it must be "ILS", "RNAV", or "Visual"
  • "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.
"approach_regions" Object

Each member name specifies information about the region of space associated with a runway when CRDA is used and it is one of the converging runways. See the vSTARS Facility Engineer's Guide for details about their semantics. Note that if you have a vSTARS XML file for a facility with a CRDA specification, each of these corresponds to a value in the XML file.

The following members specify the lateral extent that an aircraft must be inside for a ghost aircraft to be generated for it:

  • "reference_point": position with respect to which the lateral and vertical extents are defined. (Often, the threshold of the runway.)
  • "reference_heading": heading that is opposite to the runway heading.
  • "reference_length": length in nm of the reference line.
  • "heading_tolerance": maximum difference between an aircraft's heading and the runway's heading for a ghost aircraft to be displayed.
  • "near_distance": distance from the reference point along the reference heading where the lateral volume begins.
  • "near_half_width": half of the width of the reference volume at the near distance.
  • "region_length": length of the lateral volume along the reference heading, starting from the near distance point.
  • "far_half_width": half of the width of the reference volume at the far distance.

These members specify the vertical extent that an aircraft must be inside to have a ghost aircraft:

  • "descent_distance": distance from the reference point in nm where aircraft are expected to start its final descent.
  • "reference_altitude": altitude of the reference point.
  • "descent_altitude": expected aircraft altitude when it's at the descent distance.
  • "above_altitude_tolerance": maximum distance in feet an aircraft may be above its expected altitude and still have a ghost be drawn for it.
  • "below_altitude_tolerance": maximum distance in feet an aircraft may be below its expected altitude and still have a ghost be drawn for it.
"converging_runways" Array of objects Each object specifies a pair of converging runways that will be included in the STARS CRDA list. Each object has the following members:
  • "runways": array of two strings referencing two runways specified in "approach_regions".
  • "leader_directions": array of two strings specifying the compass direction ("N", "NE", "E", ...) that will be used for leader lines for ghost aircraft from the two respective runways.
  • "tie_symbol": A single-character string giving the symbol to use on the STARS display for ghost aircraft when CRDA "tie" mode is used.
  • "stagger_symbol": A single-character string giving the symbol to use on the STARS display for ghost aircraft when CRDA "stagger" mode is used.
  • "tie_offset": number giving an offset in nautical miles to add to ghost aircraft's distance from the airport when "tie" mode is used.
"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.
"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.
"name" String (Optional) The name of the airport.
"tower_list" Number Gives the airport's priority for tower list assignments. 1 is the highest priority, then 2, etc. If "tower_list" is unspecified, the airport has the lowest priority. The 3 tower lists in the STARS scope are then assigned using this priority, with ties broken by airport name sorted alphabetically.

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,
        "sid": "JFK5",
        "waypoints": "_JFK_13R _JFK_31L/h185"

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 exit fix specifiers may include additional text after a period to allow specifying situation-dependent exits. For example, we might specify one route for "RBV.PISTONS", another for "RBV.TURBOPROPS", and a third for "RBV.JETS". vice treats all of these as going to the "RBV" exit. When departures are defined in "departures", they can then refer to the appropriate exit in their "exit" specifier.

The departure route specification has two required members:

  • "waypoints": the initial series of waypoints that the aircraft follows. (Here, the first two are custom fixes specified at the ends of the runway.
  • It then must have one of the two following members:
    • "cleared_altitude": the initial altitude that aircraft are cleared to. Aircraft given "cleared_altitude" are implicitly given "climb via SID": they will obey altitude restrictions in the departure route and climb no higher than the altitude given.
    • "assigned_altitude": the initial altitude that aircraft climb to. Aircraft given "assigned_altitude" do not obey any altitude restrictions in the departure route. (This option is mostly useful for hybrid SIDs that start with radar vectors and later have a pilot nav component; aircraft will not climb beyond this altitude until the "climb via SID" instruction is given to them.)

It also takes three optional members:

  • "sid": a string naming the SID that the aircraft is flying.
  • "description", a string: this description is shown in the UI for choosing routes to draw on the radar scope.
  • "handoff_controller": a string indicating which controller should receive the handoff if one of the fixes in the route has the /ho qualifier for a handoff. This is useful if a virtual controller has initial control, e.g., for a departure from a nearby airport.

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 JFK departure to Paris Charles de Gaulle:

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

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.

The "scratchpad" field is optional; if specified, it gives the aircraft's initial scratchpad. Otherwise, the scratchpad is set based on the exit, using the "scratchpads" dictionary in the scenario definition.


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.
"assigned_altitude" Number (Optional) If specified, the aircraft will be descending to the given altitude which it will then maintain until given further directions. If the aircraft should be descending via a STAR that includes altitude restrictions, leave this unspecified.
"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.
"description" String (Optional) If provided, this string is shown in the UI for drawing approaches on the radar scope to give further information about what the route is used for.
"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.
"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
"star" String Name of the STAR that the aircraft is flying.
"waypoints" String The series of waypoints that aircraft should fly. New aircraft are spawned at the first waypoint. These waypoints should include a "/ho" 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/ho JIIMS/a8000". (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": "JIIMS/a8000 ZMRMN CHPMN PSOUT MKORD/h087",
    "27R": "JIIMS/a8000 ZMRMN CHPMN PSOUT MKORD/h087",
    "17": "JIIMS/a8000 SNEDE/h312",
    "35": "JIIMS/a8000 SNEDE/h312",
    "9L": "JIIMS/a8000 WUDRR WEVVE ERNYY/h268",
    "9R": "JIIMS/a8000 WUDRR WEVVE ERNYY/h268"


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.
"center" String (Optional) If specified, this gives the initial radar scope center (as a latitude-longitude position.) It overrides the "center" value from the scenario group.
"controllers" Array of strings Callsigns of the other virtual controllers who are online. (These also must be in "control_positions".)
"default_maps" Array of strings The names of the initial video maps that should be displayed 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.
"multi_controllers" Object (Optional) If specified, this provides information about the control positions that are available for multi-controller scenarios. Each member specifies a controller split configuration. Each configuration is then an object where each member specifies a controller with the corresponding callsign. For each controller, the following members may be specified:
  • "arrivals": An optional array of strings specifying which arrival groups the controller is covering. (Used to determine where handoffs from center go.)
  • "backup": Specifies another controller in "multi_controllers" that covers the controller's position if the controller is not signed in.
  • "departures": An optional array of strings that determines which departing aircraft the controller is responsible for. Each string can be an airport name ("KJFK"), a slash-separated airport name and runway ("KJFK/22R"), or a slash-separated airport name and SID ("KJFK/SKORR5"). It is not allowed to mix different ways of specifying departures at a given airport.
  • "primary": Boolean value that indicates that the controller is the primary controller. Must be given for exactly one controller. If no other controllers are signed in, the primary controller covers all of the other control positions. The simulation pauses if the primary controller's position is not covered
"range" Number (Optional) If specified, gives the initial radar scope center range in nautical miles. This overrides the range given in the scenario group.
"solo_controller" String The control position to use for single-user. (This must be present in "control_positions" in the scenario group.)
"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