Coordination

OBJECTIVES:

  • Explain the necessity for coordination
  • Explain what the means of communication are on VATSIM
  • Explain what kind of coordination procedures exist
  • Explain transfer of control and transfer of communication

What is a Coordination?

  1. it is the negotiation between two or more ATCO's, Supervisors, etc... so as to agree how traffic will be transferred from one sector to the next
  2. one can only negotiate about situations affecting his own airspace
  3. once the agreement is reached, any change has to be coordinated again

Since we need to know how to clear aircraft before transfer to the next sector or position and, in return, because we like to know how we may expect aircraft to enter our airspace, coordinations are very important!

Coordination Procedures

There are 3 main ways of knowing how to transfer and receive flights:

  • Local Instructions
  • Letters of Agreement
  • Verbal coordination

Local Instructions

Between ATC positions within a Division, there may be pre-agreed procedures regarding separations, routes, levels, speeds etc. according to which aircraft have to be handed over from one position to the next.

By using these procedures, the receiving ATC knows how he may expect traffic to enter his sector without having to make a verbal coordination for each aircraft.

Example: when an aircraft is going to be handed over in a standard way and land on the runway that is in use, there is no need to coordinate each aircraft separately before passing it to the Tower controller. Since the aircraft is in his IvAc "In/Out" list, he knows what it's intentions are.

2

Letters of Agreement

In general, aircraft are transferred across FIR boundaries at flight levels and along pre-defined routes in accordance with the written agreements between Divisions, These documents are called the Letters of Agreement (LoA).

A flight may enter the other sectors airspace without verbal coordination if:

  1. it is following a standard route on its own navigation and
  2. it has been cleared to or is at an agreed level before transfer to the next frequency.

Example: http://nl.ivao.aero/downloads/ATC-files/LoA_EGTT-EHAA.zip

Verbal Coordination

Talking directly with the other controller to decide upon a course of action in short term, different from the standards.

Verbal coordination should only be used to coordinate a non-standard situation or for a particular request. It should be restricted to the minimum to prevent distraction. On VATSIM, chatting with other ATC positions via IvAc is also considered as a "verbal" coordination.

Example: one ATC could call another ATC and propose to send an aircraft on course to a certain point, navaid or intersection or at a particular level to avoid a possible conflict, e.g. if 2 aircraft are close together.

Means of Communication

Real-life coordinations between ATC Units and/or Centers are mainly done via direct telephone lines. These lines are often accessed via a digital interface panel by which you can call any adjacent ATC Unit or Center by simply pressing a single button. On VATSIM we simulate this by combining our home-made VATSAF ATC Intercommunication and Teamspeak, or by the use of chat in Euroscope.

Some modern ATC systems allow to send text messages between ATC positions and even other units. Real-life controllers will never use this for urgent or important messages since they may not be noticed in time or even distract them.

In our virtual VATSIM world, we have the option of using either:

  • ATC Intercom on Euroscope or on Teamspeak
  • Text Chat via an chat window on Euroscope

Verbal or text coodinations should always be kept to a strict minimum!

Transfer of Control

Transfer of Control of an aircraft from one ATC to the next, means that the receiving ATC can clear it further into his airspace without restrictions (turn, climb, descend, etc.). He may start to control it.

Even if a controller has received the aircraft on his frequency, he is not allowed to do anything with it, until the flight has reached a particular position or level as coordinated according 1 of the 4 methods stated above .

Transfer of Control normally takes place either:

  • at an agreed (reporting) point, or
  • at the FIR boundary, or
  • at or passing an agreed level, or
  • while climbing or descending to an agreed level

Conclusion: Only after the transfer of control, active control of the aircraft may start.

Transfer of Communication

Transfer of communication means that the pilot is instructed to contact the next controller so he can talk to the aircraft.

It can be given to the accepting unit at the same time as Transfer of Control or earlier.

As already mentionned above, Transfer of Communication can also be given to the accepting unit without Transfer of Control. The receiving sector can speak to the aircraft but can not change its heading, level or speed until the Transfer of Control has been reached. Only thereafter he assumes "control".