On 29 July 2011, at 0756 Eastern Standard Time, a loss of separation occurred between a Boeing Company 737-838 aircraft, registered VH-VZC (VZC), and a Boeing Company 737-8FE aircraft, registered VH-VOT (VOT), in the holding pattern at BLAKA, an IFR reporting point south-west of Brisbane, Queensland. The aircraft were inbound to Brisbane on the same air route, with a requirement to hold at BLAKA for sequencing.
The air traffic controller, who had been recently endorsed on the control position, did not identify that the sequence in which the two aircraft entered the holding pattern had changed, and twice assigned VOT descent through the flight level of VZC. The flight crew of VZC identified the confliction and queried the controller, who then took action to recover the compromised separation situation. Separation reduced to 3.9 NM (7.2 km) and 400 ft. The required separation standard was either 5 NM (9.3 km) or 1,000 ft.
What the ATSB found
The Australian Transport Safety Bureau (ATSB) identified that the controller received a reduced amount of on-the-job training, was allocated multiple training officers, and was required to intermittently staff another control position during and immediately following their training on the Gold Coast en route sector. As a result, the controller probably had not consolidated effective control techniques for the sector, particularly for high workload situations.
The ATSB also found that, even though the quality of the controller’s training had been affected by several factors, the controller’s planned on-the-job training period had been reduced from 6 weeks to 4 weeks. More importantly, there was no requirement for a systematic risk assessment to be conducted and documented when the planned amount of training for a controller was reduced.
What has been done to fix it
Airservices Australia advised that it would develop a training variation form to systematically assess risk associated with amendments to the planned length of controller training programs, and completion of the form required the involvement of the controller’s line manager and the Operational Training Manager. Airservices also indicated several other proposed enhancements to its controller training.
In order for the training of operational personnel to be managed safely and effectively, organisations should have a structured risk assessment process in place to evaluate proposed changes to a training program.