time based flow management

professional tools for virtual ATC

About SimTraffic

This system simulates North American traffic management functions in support of the VATUSA and VATCAN divisions (part of the VATSIM network)

  • Time-Based Flow Management (TBFM)

    Implements system-wide TBFM between all major airports in the VATUSA and VATCAN divisions. Discover More

  • Expect Departure Clearance Time (EDCT)

    Provides a scheduling and display interface for issuance and compliance with EDCTs.

  • APIs

    An API that allows authorized read/write access to the scheduler and data methods. Discover More

  • Traffic Management Unit (TMU) Tools

    Emulates some of the FAA's traffic management user interfaces to include ladders, planview arrival displays, demand charts, and load graphs.

  • Traffic Metering

    Based on user-selectable arrival and departure rates, manages the flow of traffic to select high-demand airports.

  • Ground Handling/Alerts

    Emulates the FAA's Surface Movement Event Service (SMES) by providing detailed information on aircraft ground events.

Join Simtraffic today!

By design, the system includes all major airfields in the NAS. In order to get the most out of SimTraffic, your ARTCC staff should configure their airfields.

SimTraffic for Pilots

Tired of ground delays? So are we! Learn how SimTraffic is working to make the VATUSA and VATCAN event experience better.


What happens when there is too much traffic?

Center traffic management units (TMUs) set Airport Arrival Rates (AAR) and Airport Departure Rates (ADR) in conjunction with the ATC Command Center. These rates are based on airspace and airport design (how many runways) and controller availability/capability. When the demand exceeds capacity, traffic management initiatives meter the flow of air traffic.


How does TBFM work?

According to the FAA, TBFM provides time based metering applications to merge, space, and sequence flights to improve NAS efficiency. In other words, when we decide how many airplanes can fit in the airspace, TBFM provides a way for traffic managers to ensure that the flow of traffic remains at or below the maximum rate. SimTraffic implements a set of Traffic Management Tools to do this that are similar in function to the ones used by FAA TMUs.


What is a Departure Clearance Time?

One way that TBFM handles high traffic demand is to schedule a 'slot' for each aircraft and to hold the aircraft on the ground at their departure field until a controlled takeoff time. This is called a Ground Delay Program (GDP) and it works by issuing Expect Departure Clearance Times (EDCTs). If you are aligned with a virtual airline, they may be able to request an EDCT up to 48 hours before your scheduled departure time. If you are unaligned, ATC will request an EDCT for you when you request IFR clearance.

SimTraffic for Virtual Airlines

We're happy to offer departure scheduling and ground monitoring interfaces to our Virtual Airline partners via our API and GUI tools. Schedule and view departure clearance times (EDCTs) and get accurate push/taxi notification with our surfance movement event service (SMES). Empower your dispatchers today to improve network efficiency!

SimTraffic for Controllers

Our system provides a unique toolset for handling overwhelming air traffic demand, both during and outside of planned event periods.

Flight Planner

Our powerful flight planner computes the enroute time of each aircraft, from time of filing until touchdown, to accurately predict demand at metering fixes and runways.

Traffic Scheduler

The scheduler is the heart of traffic metering. When enabled, it ensures that an evenly-spaced flow of traffic arrives to each metering fix and runway, minimizing last-minute sequencing and stacks.

Demand Alerts

Wouldn't it be nice to know if you'll need more controllers 2 hours from now? Our demand alerts provide advanced warning of a traffic surge so you can put the call out for additional controllers early!