Position Overview

2.1 Choosing your ATC position [S]

When first getting introduced to Virtual Controlling the various positions and call signs used can look very intimidating at first glance. The easiest manner to decipher these is to divide them into three distinct categories:

While the exact terminology varies from country to country, there are generally three different types of ATC.

  • Control Towers
  • Approach controllers
  • Centre controllers

As a new member to VATSIM and depending on the local restrictions in use at your vACC, Student Controllers will usually start controlling at a Ground or Tower position and then move up to Approach and Departure positions and from there to Area Control positions and eventually once the required rating has been achieved will be able to control the Euro Control Areas if interested.

 

2.1.1 Tower Positions [S]

The primary method in real life of controlling the immediate airport area is by means of visual observation from the control tower. The tower is a tall, windowed structure located on the airport. Tower controllers are responsible for the separation and efficient movement of aircraft and vehicles operating on the taxiways and runways of the airport itself, and aircraft in the air near the airport.

Radar displays are also available at some airports (on VATSIM at all airports). Tower uses radar to display airborne traffic on final approach and for departing traffic once they are airborne.

Some airports (on VATSIM all airports) also have radar designated to display aircraft and vehicles on the ground. This is used by Ground controllers as an additional tool to control ground traffic.

The areas of responsibilities for tower controllers fall into three general operational disciplines:

  • Clearance Delivery
  • Ground Control
  • Local Control (Actual Tower position)

The following provides a general concept of the delegation of responsibilities within the tower environment.

Clearance Delivery, the position responsible for verifying a flight plan and issuing IFR clearance.
Ground, responsible for controlling traffic on the airport “movement” areas, this generally include taxiways and holding areas and giving traffic information and suggestions (for example approving push-back) to traffic on aprons.
Tower, responsible for movements on the runways and traffic in the control zone, (CTR) which surrounds the aerodrome and normally extends around 5 to 10 NM from the aerodrome and from the ground up to normally, 1500-2000ft. The tower is the position that clears aircraft for take off or landing and ensures the runways are clear for these aircraft.

As in real life and in dense traffic, at certain large airports more than one of these positions may be opened, for example S or N for South or North.

 

2.1.2 Radar Positions [S]

Even though as described above Tower and Ground also use radar displays, we will refer to the following as Radar Positions since they rely 100% on radar in order to control and separate traffic. 

These positions are not located in the actual tower; these facilities on the other hand can be located in buildings adjacent to an airport or even in buildings totally separated from it. A radar position as the name implies uses Radar scopes to track and follow the movement of traffic in the air. These teams are in turn subdivided into:

Approach Control (APP)

  • Area Centre Position (ACC)
  • Flight Information Service (FIS)
  • Approach Position, the position responsible for controlling, separating and sequencing arriving and departing aircraft. APP is usually responsible for the terminal control area (TMA). At small airports, the TWR and APP position is often combined. On the contrary, at large airports or in complex TMAs, APP is usually divided into several sectors. APP positions may have different radio callsigns depending on the function, such as Departure, which as the name implies controls departing aircraft, Arrival or Director, which usually handle vectoring of arriving aircraft.
  • Area Control Centre, the position responsible for controlling traffic in the control areas (CTA) and upper control areas (UTA) within the centre’s area of responsibility. The area of responsibility is generally a FIR or part of a FIR, so ACCs cover large areas, and therefore may be divided into several sectors, both horizontally and vertically.
  • FIS, Flight Information Service is not used much in VATSIM and seldom in Europe, but should it be on line then it is responsible for providing traffic information, flight following and providing information to VFR flights. It is not a Control Position and can not give instructions to aircraft but only advisories and information. As FIS is not a standard Designator on VATSIM, controllers providing this service usually log in with XXXX_I_CTR call-sign

FIS in essence is the most basic form of air traffic service that is provided to aircraft.

However, the FSS suffix is used in Europe as part of the different Euro Control positions which even though they use FSS as part of the log-on to the net work are proper Control positions in the Upper Airspace from FL245 and above 




2.2. List of positions in VATSIM  [S]

  

Call sign

Designator

Short Description

Delivery (Clearance)

DEL

Responsible for issuing IFR clearances

Ground

GND

Responsible for movements on the ground on the manoeuvring area.

Tower

TWR

Responsible for traffic on the runways and in the CTR..

Departure

DEP

Responsible for separation and flow of departing traffic at certain airports.

Arrival/Approach

APP

Responsible for separating and sequencing arriving and departing traffic in TMA’s

Final/Director

APP

Responsible for final vectoring of arriving traffic at busy airports.

Control/Radar

CTR

Responsible for en-route traffic and traffic in CTA/UTA

Euro Control

FSS

Responsible for control of upper airspace from FL245 when no local CTR is on line.


Euro Control in VATSIM was created especially to ensure ATC cover over large geographical areas when no local ATC is on line.


A further position is AFIS

AFIS (Aerodrome Flight Information Service

TWR

Gives information about traffic and weather at some uncontrolled airports.


In VATSIM AFIS must log on with a TWR call-sign but the controller information (ATIS) will state when it is an AFIS

ESSA_DEL   : Arlanda Clearance Delivery
LTBA_GND
  : Ataturk Ground
EDDF_TWR
 : Frankfurt Tower
EPWA_DEP : Warsaw Departure
LIPZ_APP   :Venice Tessera  Approach
LEBL_CTR   :Barcelona Control


2.3 Visual Ranges [S]  

 

The VATSIM community relies on a network of computers interlinked to provide position updates to controllers and pilots alike. The network is donated by third parties. In an effort to avoid any wasting of bandwidth the following Maximum ranges have been imposed.

Position

Range

DEL/GND

10 to 20 nm

TWR

30 to 50 nm

APP/DEP

100 to 150 nm

CTR

300 to 600 nm

FSS

1500 nm

When a user logs on to network, it is important that the visual range slider be set to the appropriate range depending on the position being manned, the main reason is to limit the waste of bandwidth. Bear in mind that a user will receive information packets every few seconds, so a GND controller having a range of 400nm will also be receiving traffic information in a radius of 400nm from the position being manned this is an absolute waste of bandwidth and should be avoided at all cost.

Unfortunately some controllers forget to change their facility type when switching to another ATC position. Setting a correct facility type is important; since it affects the radio range of the controller. Therefore in some cases a wrong facility type could affect the text communication between a controller and a pilot.

RANGE is the visual range set by the controller in ASRC/VRC options using the range slider. There is one exception: visual range for FSS facilities is hard coded to 1500nm (since this is much more then the slider is allowed to be set to). This range defines from which distance the controller gets aircraft position reports, so which traffic is shown at the radar scope and which not. It’s obvious it should be adjusted to the service the controller is providing. The best situation is when controller is capable to see the traffic within his sector plus a small margin. Therefore the visual range should be adjusted to the size and shape of the sector

(NOTE that the visual range is calculated from the point where the radar scope is actually centered, unless the .vis command has been used to set a different visibility point).

If you use VRC as radar client, it is a good practice to configure it for the facility you are manning and then save the profile with its callsign to make sure that all settings are appropriate for your position. (i.e.: LEBL_TWR, EGKK_APP, etc.)

There are some situations, when extended range is justified, for example a very large or an irregular shaped sectors or some special operations.

(NOTE: for irregular shaped sectors, you can use multiple visibility points in order to have a “radar antenna” at the significant points of your sector, so that it’s not needed to increase range).