The concern related to the potential of a loss of separation or loss of separation assurance as a result of a breakdown of coordination between Essendon tower and Melbourne tower.
The reporter expressed a concern that a breakdown in communication, which occurred in November between Essendon Tower and Melbourne Tower, may have resulted in a loss of separation assurance or potentially a loss of separation between aircraft operating at Melbourne and Essendon.
Airservices Australia (Airservices) appreciates the opportunity to respond to the reported concern regarding a breakdown in communication between Essendon and Melbourne.
Airservices confirms that the breakdown of communication was reported via Airservices Corporate Integrated Reporting and Risk Information System (CIRRIS).
The reported occurrence involved Melbourne Terminal Area Control who received coordination from Essendon Tower advising that they could not separate overshoots with Melbourne traffic due to the cloud base. The breakdown of communication occurred as the Melbourne Terminal Area Control passed the information to the Melbourne Approach Controller but failed to receive acknowledgement of the coordination resulting in the Approach Controller being unaware of the need to identify Essendon arrivals to Melbourne Tower.
A preliminary investigation confirmed that the documented procedure was not correctly followed in that the controller concerned failed to confirm acknowledgement of the coordination.
The investigation determined that no systemic issues existed and the potential safety impact that may have resulted from the breakdown of coordination was understood by the controller. Nonetheless, the Check and Standardisation Supervisors of the involved ATC group have been tasked with reviewing the coordination requirements with the aim of identifying potential opportunities to minimise the likelihood of a similar breakdown of communication reoccurring.
In the interim a temporary console display has been created to highlight separation responsibility for Essendon traffic arriving from terminal control unit (TCU) airspace.
With reference to the reporter's concern that the occurrence may have resulted in a loss of separation (LOS) or a loss of separation assurance (LOSA), Airservices can confirm that there was no LOS or LOSA occurrences during the time of the breakdown of communication.
We note that there was no loss of separation and CASA does not intend to take any direct safety action with regard to this matter; however CASA will use this information to complement other information that informs us of Airservices Australia safety risk profile.