Air Traffic Control Separation Monitoring Tool (ASMT)

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Air Traffic Control Separation Monitoring Tool (ASMT)

42ND ANNUAL CONFERENCE, Buenos Aires, Argentina, 17-21 March 2003

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 through 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, and at Cancun for the 2002 Conference new policy was incorporated but the subject was once again included in the Work Programme for SC4 as it was thought likely that further experience would be gained during the year following implementation by other Service Providers.


For convenience, the following is the current Provisional Policy as given on page 4126 of the IFATCA Manual:

2.10 IFATCA considers ASMT to denote a generic ATM Safety Monitoring Tool that extracts system data to detect infringements of parameters predefined within the system itself.

2.10.1  ASMT must be part of a safety management system and shall not be used as a punitive tool for disciplinary action.

2.10.2  Except for Aerodrome Control, the introduction of ASMT should 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.


The system in the UK is known as the ‘Separation Monitoring Function’ (SMF) whilst that proposed for the Maastricht UAC is entitled ‘Air Traffic Control Safety Monitoring Tool’ (ASMT) – the IFATCA acronym defined in Provisional Policy (2.10 above) encompasses both of these, together with the system introduced many years ago in the USA known as the ‘Operational Error Detection Patch’.

The Eurocontrol ASMT system was technically evaluated in Maastricht and introduced operationally within the ACC, initially as a statistical tool, from the 1st August 2002 under an agreement reached between staff and Director Maastricht that lead to the signing of a Memorandum of Understanding that included the following terms:

Under this agreement, incidents will not trigger any follow-up action, but will be passed on to an Operational Analysis Group (OAG) – consisting of Management, Operational Staff, Trade Union and Professional Association nominees as well as Operational Support Staff.

The data will be used to identify trends and potential ‘hot spots’ which, when evaluated, should lead to recommendations for safety improvements.

The parameters have been set at 4.9nm lateral and 600ft vertical where the separation standard is 5nm and 1000ft. However, the possibility of amending these to locate areas where ‘marginal separations’ are perhaps common has not been excluded.

There is to be no terminal in the Operations Room, the system will only be accessible to members of the OAG and technical maintenance staff, all of whom are bound by a confidentiality agreement.

The Maastricht Safety Monitoring Advisory Group (SMAG) will monitor the working of the OAG and study changes and/or enhancements of the system.

It has been stated that all staff are in complete agreement with these provisos and are confident that any possible mis-use of the tool will quickly be highlighted.

Concerns have also been expressed about possible uses at other locations as a capacity measurement tool as well as using the system data in Key Performance Indicator calculations. Managers are thought to be considering setting parameters and examining radar data where no incidents or losses of separation have occurred, purely to discover which staff are routinely (or occasionally) approaching minimum separation standards. Furthermore, individuals involved in the evaluation might not have suitable experience or knowledge of the ATC requirements and could, without an appropriate background or proper training, come to inappropriate conclusions when evaluating the recorded data.


Further potential use of ASMT has come to light such that the safety management characteristics could be misused.

The interpretation and evaluation of any ASMT derived data needs to be carried out in an objective manner, by professional staff suitably experienced and trained to do so, rather than rely on any computer software or other method to produce results.

The system is not suitable for, nor should it be used as, a capacity measurement/monitoring tool indicator.

The recommendation for additional Policy reflects these areas of concern.


Add to IFATCA Manual Page 4126 as Provisional Policy:

2.10.6.  The system should not be used as a performance monitor for individual controllers.

2.10.7.  Analysis of any derived data should be undertaken by appropriately experienced and trained ATM safety experts.

2.10.8 Data obtained from the system should not be used as a capacity measurement or monitoring indicator.


IFATCA Manual.

Last Update: September 29, 2020  

March 21, 2020   572   Jean-Francois Lepage    2003    

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