Welcome back to VATSIM SOAR! In this edition we will discuss VATSIM’s top-down Control.

In the real world, there are different positions like Delivery, Ground, Tower, Approach/Departure, Area Control, and Flight Information Service. Controllers work at these positions around the clock in shifts and need special licenses. In big airports, they divide these jobs into smaller parts, like North Ground and South Ground for GND or Departure, Approach, and Arrival for Approach.

Since VATSIM is a network where people volunteer their free time to be controllers, we use a top-down model. This way, even if all controllers aren’t staffing all positions everywhere, pilots can still enjoy all aspects of Air Traffic Control under one controller.

So how does top-down work?

A Controller who has been rated for a certain position (eg, TWR) will provide services for positions which are underneath them as well (GND, DEL) if the controllers for those positions are offline. That means an aircraft spawned at an airport with only TWR online, will be able to request ATC clearance as well as pushback/startup and taxi clearance with the TWR controller.

The diagram below gives a good visual demonstration on VATSIM’s top-down structure.

Another example would be an Approach Controller (APP) providing services of DEL, GND, TWR for the airports coming under their control if the lower controllers for that airport are offline. 

Area/Enroute Controllers provide top-down services (DEL, GND, TWR, APP) for all controlled airports coming under their sector. The sectors being covered by an Area/Enroute Controller can be found on websites/applications such as simaware.ca, VATSpy, VATPrism, VATGlasses.uk. If you’re unsure if an airport is being covered by an Area/Approach controller, you can always ask them by messaging them through the pilot client! (vPilot, xPilot, SWIFT, etc)

Charts for specific airports often contain information about the coverage area of Enroute or Approach facilities. You can locate this information within the charts. Additionally, controllers may extend into adjacent sectors, even if it’s not displayed on most websites/applications. Often, you can find this information by double-clicking on the controller’s callsign on your pilot client.

The only exception to this rule is with respect to Flight Service Station (FSS) Controllers. They generally do NOT provide top-down service for Airports under their airspace, as their area of responsibility generally starts from FL245 onwards. This means aircraft have to contact FSS only if they’re passing above FL245.