An Investigation of Systemic Factors Underlying Air Safety Occurrences in the Brisbane Area Approach Control Centre

Executive summary

The air traffic control safety net fails when human errors go undetected and uncorrected. These operational errors are generally more likely to occur in circumstances such as very high or very low workload situations, or events involving complex coordination. Predisposing or underlying factors relating to the ATC operational environment can influence the frequency, and the consequences, of operational errors. System safety can be improved by the identification and rectification of these predisposing factors.

Information from air traffic controllers from each sector within the Brisbane AACC. together with the results of interviews with the management from the Northern District and Central Office Air Traffic Services Division formed the basis of this investigation.

The investigation identified a number of local factors associated with the task and the environment which may increase the probability of errors by individual controllers. Task related issues included the operation of VFR aircraft in the Brisbane Terminal Area, and the relationship between the AACC and Brisbane and Archerfield Control Towers. Also highlighted within the AACC was what is referred to in the report as the 'service ethos', or the tendency for air traffic controllers to provide an. individualised service to aircraft at the expense of a regularised traffic flow. The level of awareness of human performance capabilities and limitations among the controllers interviewed was found to be minimal.

At the time of the investigation, training was under way for the implementation of teams and for transition to ICAO airspace (which was deferred shortly after interviews with the controllers were completed). This placed a considerable training burden on the AACC and there was a strong view among the controllers that too many changes were being introduced into the ATS system in too short a time frame. In addition, it was apparent that the management view of what the changes involved differed markedly from the understanding held by the controllers. It seemed that the human factors aspects of the change process (i.e. those involving the controllers) were not addressed by management to the same extent as were the "mechanical" aspects such as procedural and technical changes. Consequently, the recommendation is made that ATS Division devotes more attention and resources to the processes and mediums by which it leads its workface employees through the change cycle.

The effective two-way flow of information within a system is an important determinant of the "safety health" of that system. The introduction of teams at the Brisbane AACC in early October 1993 was a major step in facilitating improved information flow to and from the workface. Nevertheless, at the middle management level, significant deficiencies were identified in the communication network. These were the geographic separation of the office of the Manager AACC from the AACC itself, and a similar separation between the third and some of the fourth level management officers. This latter aspect will largely be overcome in April 1994 when the city office relocates to the airport. However, a Jack of suitable building space has prevented the Manager AACC from being co-located with the AACC and there are currently no plans for such a move. The investigation concludes that this aspect should be reassessed as a matter of urgency.

Communication was also identified as an issue at the corporate level. Liaison between the various managerial levels seemed to work effectively with regard to local and national initiatives formulated in Central Office. However, feedback to the workface concerning projects in which controllers were involved usually occurred at the conclusion of a project. This may result in controllers feeling they have little commitment to development, despite the involvement of district office representation.

Commitment of the workforce is a prerequisite to successful change. Evidence seems to indicate that in some respects this has been lacking despite the resources committed by management to the orientation of controllers. Change in the Australian ATS environment is inevitable and ATS Division therefore needs to re-examine the processes and mediums through which its educates its employees with particular reference to the implementation process for TAAATS. 


Type: Research and Analysis Report
Investigation number: BS/930154
Series number: Preliminary
Publication date: 11 April 1995
Publication number: BS930154
Last update 24 July 2019
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