The investigation revealed that each controller had different expectations of the intentions of the other. The DN controller had expected the AN controller's Metro would continue on its current track, and that the two aircraft tracks would cross. Conversely, the AN controller expected to keep his aircraft inside the track of the departing B737. Neither the coordination nor communication between controllers was effective. The unexpected turn onto downwind by the Metro, towards the B737, reduced the distance available for the B737 to climb safely above the Metro. The DN controller attempted to stop the B737 at 6,000 ft, but that instruction, combined with the rate of climb of the aircraft, was unable to prevent a breakdown of the vertical separation standard.

1. Appropriate separation assurance techniques were not implemented by either controller.
2. Coordination between controllers was ineffective.

As a result of this investigation, and a number of similar occurrences, the Bureau of Air Safety Investigation undertook a systemic investigation into factors underlying air safety occurrences in Sydney Terminal Area airspace and issued report B98/90 on 18 August 1998. Nine recommendations were made in the report; the following three were considered relevant to this investigation.

R980157
"The Bureau of Air Safety Investigation recommends that Airservices Australia review the application of the "teams" concept within the Sydney Terminal Control Unit to ensure that teams are resourced appropriately and that there is an ongoing commitment to the provision of adequate training in order to achieve a high level of controller proficiency and standardisation."

R980158
"The Bureau of Air Safety Investigation recommends that Airservices Australia ensure that adequate refresher training is undertaken by controllers in order to provide for high levels of controller proficiency and standardisation so that the integrity of safety cases, in which refresher training is deemed to be a mitigating strategy for identified hazards, is maintained."

R980159
"The Bureau of Air Safety Investigation recommends that Airservices Australia reassess the human factor hazard analysis for both Stage One and Stage Two of the Long Term Operating Plan safety cases, so that the mitigating strategies applied to identified hazards adequately allow for the fundamental limitations of human performance. In reassessing this hazard analysis, BASI recommends that Airservices Australia seek the assistance of human performance expertise".

The following responses were received from Airservices Australia on 16 November 1998:

[R980157]
"A recent review of Sydney ATS has resulted in a "spill" of all management positions and a subsequent recruitment program which will be completed by 16 November 1998 to coincide with the Airservices' Business Transformation program.

The first step in this review has been to ensure that the management structure of the facility can operate effectively and that appropriate skills are available within the team. The manner in which the teams operate is the subject of a concurrent review process.

In support of these reviews, a consultant has completed a wide ranging review of supervision within air traffic services and its application within Teams.

Recommendations from these studies will be introduced into the Sydney rostering committee deliberations examining a better framework for TCU rosters. Sydney ATS management plan to introduce a revised roster in the TCU by 1 February 1999.

Team Leader training is recognised as vital to the success of teams and during October and November all Team Leaders will complete a series of Human Factors and Team Resource training modules. To further ensure that Team Leaders are better equipped to perform their duties a specific training programme for each Team Leader will be developed by 22 December 1998".

Response classification: CLOSED - ACCEPTED

[R980158] "Airservices provides familiarisation training in various forms before the introduction of new procedures and to maintain controller skill levels. This ongoing programme has been augmented by an additional period of refresher training which all TCU controllers will undertake during the remainder of this year".

Response classification: CLOSED - PARTIALLY ACCEPTED

[R980159]
"The LTOP Stage One and Stage Two Safety Cases have been subject to review by independent experts in the field as well as being the subject of a number of post implementation reviews. Recommendations arising from those reviews have been progressively evaluated and applied as appropriate.

Airservices will consider augmenting its review processes with human factors expertise in future".

Response classification: OPEN