Aviation safety issues and actions

Controller scan of green radar returns

Issue number: AO-2012-131-SI-02
Who it affects: All Darwin Approach Supervisor, Approach and Planner rated Joint Battlefield Airspace Controllers
Issue owner: Department of Defence
Transport function: Aviation: Other
Background: Investigation Report AO-2012-131
Issue release date: 02 October 2014
Current issue status: Adequately addressed
Issue status justification:

The ATSB is satisfied that the action taken by the Department of Defence has adequately addressed the safety issue. Controller scanning of green radar returns is covered in the RAAF School of Air Traffic Control initial and approach controller training syllabi and included in the simulator scenarios of DoD air traffic units at all military aerodromes to which civil scheduled services operate.

Safety issue description

Darwin Approach controllers were routinely exposed to green (limited data block) radar returns that were generally inconsequential in that Approach control environment, leading to a high level of expectancy that such tracks were not relevant for aircraft separation purposes. Refresher training did not emphasise the importance of scanning the green radar returns. 

Response to safety issue:
In response to an internal recommendation for the Department of Defence’s 44 Wing to review radar control training programmes to ensure that they include a requirement for controllers to scan green codes, the Department of Defence (DoD) documented that:

The School of Air Traffic Control stated that they concentrate quite a lot of time towards scanning of green codes during the Initial Employment Training and the Approach training.

Planner students are required to continuously scan all unidentified aircraft to expand on their situational awareness. The subject of violations of controller airspace is also touched on with emphasis on the crew resource management aspect of scanning and assisting the approach controller in monitoring airspace.

During Approach training, unidentified aircraft are actively input in the scenario as violations of controlled airspace adding to the requirement of the controller scanning the radar picture. To ensure a non-standard solution, the exercises have multiple unidentified tracks outside of controlled airspace which never actually enter the airspace.

In addition, DoD documented that the majority of simulator-equipped air traffic control units had included green radar returns in their local training packages. The scenarios included unidentified radar returns that entered controlled airspace, with some requiring a traffic alert to be given and an ‘alternate separation solution implemented’.

ATSB comment:
The ATSB is not yet satisfied that the action taken by the Department of Defence has addressed the safety issue. Though the consideration of controller scanning of green radar returns has been covered in the initial and approach training syllabus of the School of Air Traffic Control, and included in the simulator scenarios of the air traffic units where there is such a capability, there is no evidence that there are provisions at those units to ensure that controllers complete the simulator-based refresher training. In this occurrence, the Darwin Approach cell personnel on duty reported that they had not completed any refresher training in at least a 12-month period, though Darwin was simulator-equipped.


Action number: AO-2012-131-SR-041
Action organisation: Department of Defence
Date: 02 October 2014
Action status: Released

The Australian Transport Safety Bureau recommends that the Department of Defence takes further safety action to address the limited provision of regular simulator-based refresher training that emphasises the importance of scanning green radar returns.

Additional correspondence

Response date: 19 December 2014
Response from: Department of Defence
Response text:

In accordance with Section 25A (2) of the Transport Safety Investigation Act 2003, I hereby advise the ATSB that Defence agrees with the two safety issues as outlined. As a proactive safety organisation, we will continue to implement changes to further enhance safety and reduce the likelihood of a similar occurrence in future.

In particular reference to the recommendations 041 and 042, Air Force has commenced work on a compromised separation recovery training package that will standardise training across all Air Base Air Traffic Service (ABATS) units. This package will include a training video and an annual exam requiring a 100% pass mark. Additionally, ABATS units that have a simulation capability have now included the scanning of green codes in their local training packages.

Response date: 10 March 2015
Response from: Department of Defence
Response text:

As advised in previous correspondence to the ATSB report, Defence has incorporated the scanning of 'green codes' within a number of training outcomes along each controller's training regime. The School of Air Traffic Control (SATC) exercises include significant training on scanning of green codes during initial employment training (IET) and post-IET radar approach control training. All 452SQN and 453SQN flights include the scanning of 'green codes' within their on-the-job training guides, and locations with dedicated simulator capability (Townsville, Darwin, Amberley and Williamtown, as well as Pearce using TAAATS at Perth TCU (noting that TAAATS equivalent of 'green code' is flashing blue and difficult to miss)) continue to include 'green codes' within their practical training packages.

Defence notes that the subject investigation isof one incident of a 'green code' being missed and resulting in a LOS, whereas the reporting evidence indicates that Defence ATC successfully detects 'green codes' on a regular basis and takes appropriate action to prevent safety occurrences. For example, Defence controllers reported 357 Airspace Infringements (AI), including 29 at Darwin, during 2012. The majority of AIs initially present as 'green codes', indicating the competency is business as usual and that the initial and refresher training is adequate.

Response date: 18 May 2015
Response from: Department of Defence
Response text:

Attached is the 'Because they rely on us' package. The 'Can you look away' package is a sub-set of 'Because they rely on us'. Huge effort by a number of personnel within the Wing and we are already seeing the 'Can you look away' principles being referred to in LOSA investigations within the Flights. The message has definitely got people talking.

Last update 20 July 2015