ACAS (TCAS Training for ATCOs)

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ACAS (TCAS Training for ATCOs)

36TH ANNUAL CONFERENCE, Taipei, Taiwan, 17-21 March 1997

WP No. 150

ACAS (TCAS Training for ATCOs)


TCAS training was included in the work programme of SC4 at the 1996 Tunis Conference. IFATCA Technical Policy page 3212 “urges national administrations to assemble, disseminate, administer and maintain a comprehensive ACAS training package for ab-initio and refresher training”


The use of ACAS in the form of TCAS has been implemented worldwide by airlines. In the USA it is mandatory for most public transport aircraft and it will become mandatory in Europe, Australia and possibly elsewhere by the year 2000. In most countries there is a lack of suitable ATC training as far the use of TCAS is concerned. Therefore controllers are not familiar with TCAS dynamics, and particularly with reference to manoeuvres performed by pilots as a result of resolution advisories. (RA)

Existing IFATCA policy emphasises that “the primary means of collision avoidance within a controlled airspace environment must continue to be the air traffic control system”. Therefore controllers should be fully aware of their functions and responsibilities connected with the use of TCAS. Pilots, also, should be more conscious of all possible outcomes caused by aircraft not complying with as ATC clearance when following a TCAS advisory.

In most countries ACAS information is almost non-existent. This is not as adequate situation as far as the controller’s functions and responsibilities are concerned. Controllers should be provided with guidelines, familiarisation and training programmes en the use of ACAS. This programme should cover the following subjects:

  • Official Definition of ACAS (TCAS);
  • Technical Description and Cockpit Displays;
  • Pilot Responsibilities and Reactions to Traffic Advisories and Resolution Advisories;
  • Controller Reactions and Legal Responsibilities;
  • Phraseologies used in TCAS Communications;
  • Experience of Simulated ACAS (TCAS) events either in a Simulator or by Video presentation.


Air Traffic Controllers require training in the technical and operational aspects of ACAS (TCAS) in order to fulfil their duties and responsibilities. Controller training packages should contain, at a minimum, the elements described above.


That the IFATCA Policy Manual Page 4352 be amended as follows;


5.5. Airborne Collision Avoidance Systems (ACAS)

5.5.1. Controllers should be trained in the technical capabilities of ACAS (TCAS) systems, actions taken by pilots in response to advisories, and controller actions and responsibilities as follows:

a)  Definition of ACAS (TCAS).

b)  Technical Description and Cockpit Displays

c)  Pilot Reactions to Traffic Advisories and Resolution Advisories

d)  Controller Reactions and Legal Responsibilities

e)  Phraseologies

f)  Experience of simulated ACAS (TCAS) events in an Aircraft Simulator or on Video.

Last Update: September 28, 2020  

March 5, 2020   404   Jean-Francois Lepage    1997    

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