Air Traffic Control Separation Monitoring Tool (ASMT)

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Air Traffic Control Separation Monitoring Tool (ASMT)

41TH ANNUAL CONFERENCE, Cancun, Mexico, 15-19 April 2002

WP No. 158

Air Traffic Control Separation Monitoring Tool (ASMT)


At the IFATCA 1999 Conference at Santiago in Chile, EGATS tasked Committee C (and therefore SC4) with looking at possible policy on a Separation Monitoring tool known as ASMT that was shortly to be introduced at the Eurocontrol UAC located in Maastricht.

At Marrakech the next year, Provisional Policy was accepted based on Working Paper 153 presented by SC4, and although agreement was reached between the Chairmen of SC’s 1, 4 and 7 that the subject was more applicable to Standing Committee 1, no further development or transfer of responsibility took place.

At the 2001 Conference in Geneva, the item was again placed on the Work Programme for the newly constituted SC4.


For convenience, the following is the current Provisional Policy as given on page 4 1 2 6 of the IFATCA Manual:

2.10 Air Traffic Control Separation Monitoring Tool

2.10.1 IFATCA considers that the ASMT device is something that should be used for the analysis of the circumstances of any perceived loss of separation, rather than as a punitive tool that can be used directly by Management for disciplinary action.

2.10.2 The introduction of ASMT should be preceded by the introduction of STCA.

2.10.3 The criteria used to set up the separation parameters of an ASMT device must be carefully planned and monitored. To be effective, sufficient consideration must be given to restrict false or nuisance alerts.

2.10.4 If STCA is not part of the system, or is inoperable, then the legal liability of the ATCO needs to be clearly defined and established.

2.10.5 If ASMT is to be used, it must be part of a Safety Management programme.


Investigation shows that since the item was first raised at an IFATCA Conference, few Service Providers covering Member Associations have introduced the tool; these being the UK and the USA, although there are some countries where the triggering of any STC Alert facility is also given to management, and used as a pseudo ASMT notification.

The system used in the United States of America is used solely in the en-route phase and not the Terminal Area, whilst that in the UK is used throughout its Controlled Airspace.

The planned implementation of ASMT at the Maastricht UAC has still not taken place, and other units where the system was considered have also not yet implemented the facility. However, indications are that this will take place when appropriate parameters have been tested, and agreement reached with the relevant staff associations.


SC4 considers that new policy may be needed to cover the aspects of ASMT in Safety Management Systems, the recording of data on STCA for management use, and the applicability of Key Performance Indicators (KPI’s) to these areas. However, SC4 has not developed or even considered such policy, and asks Committee C to discuss the topics with a view to include any requirement in next years Work Programme.

It is likely that as many ATC Service Provider’s move towards incorporating such a tool as part of their Safety Management programme, policy should be upgraded to Policy Material from Provisional Policy. However, the current international scene indicates that little activity is taking place in this area, and that Provisional Policy is adequate for the needs of the majority of the Federation’s MA’s. It is considered prudent to develop policy further only when further experience has been gained, as the present guidance is considered appropriate for the relatively immature procedures of the developing system.

There is also a possible need to consider the development of policy (or inclusion into provisional policy on ASMT) for circumstances where ASMT does not exist as an addition to STCA, but the latter is used for management action or investigative purposes. Again, however, experience has highlighted few areas that are inadequately served by the Provisional Policy as stated in Para 2.1 above.


It is recommended to amend page 4 1 2 6 of the IFATCA Manual as follows:

2.10. ATM Safety Monitoring Tools (ASMT)

IFATCA considers ASMT to denote generic ATM Safety Monitoring Tools that extract ATM system data to detect infringements to parameters predefined within the system itself.

IFATCA Provisional Policy :

2.10.1. ASMT must be part of a Safety Management System and shall not be used by Management as a punitive tool for disciplinary action.

2.10.2. Except for Aerodrome Control, the introduction of ASMT shall be preceded by the introduction of STCA.

2.10.3. Implementation of ASMT must be preceded by a clear statement in which its goals are defined.

2.10.4. ATCO’s shall be involved in the definition of the ASMT role.

2.10.5. The criteria used to set up the ASMT parameters must be carefully planned and monitored. Sufficient consideration must be given to restrict false or nuisance reports.

Last Update: September 29, 2020  

December 21, 2019   269   Jean-Francois Lepage    2002    

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