So why at least are the ATC supervisors not aware that the weather at one of the airports in their area of responsibility has gone bad?
According to the report, it all came about as a result of changes to the AIP and MATS in 2009. Prior to the changes, ATC notified pilots about all SPECI reports and amendments to forecasts. After the changes, pilots were not to be alerted to the availability of a SPECI the could be obtained from an ABS. The reason for the change was the introduction of more automatic weather stations, which resulted in a flood of AUTO SPECI reports to ATC, all of which required review and broadcast to relevant traffic. That caused a huge increase in controller workload and conflicted with ATC's primary role of providing a traffic separation service.
The report states that these changes to MATS were subject to a Safety Case Assessment and Reporting Determination (SCARD). The SCARD determined that:
"...a safety case was not required as there was no change to the Air Traffic Services Provider Certificate. The size of the change was assessed as ‘small’ and the magnitude of the change as ‘reasonable’. In assessing the magnitude of the change, Airservices identified a potential failure of ‘the pilot does not obtain in-flight information’, with the effect that the ‘pilot is not aware of significant weather information’. The overall assessment was considered ‘minor’ and approved by the relevant managers."
In a nutshell, it became a pilot's responsibility to check the weather by requesting the information from ATC or by using other means such as the ABS; the information won't be provided automatically by ATC. Indeed, the controllers themselves may not know about deteriorating weather conditions, because the SPECIs are not automatically sent to them either. As an aside, this is not unique to Australia; the report notes that the US, Canada and New Zealand all have similar systems, whereby it is the pilot's responsibility to obtain the relevant weather information by requesting it if necessary.
Following this incident, the report says Airservices is working with BoM to "explore feasible options to provide information on significant deteriorations in weather conditions". Airservices has also updated MATS to ensure that information continues to be disseminated by ATC in cases where the ABS is out of service.
I certainly hope that the Airservices managers who assessed the 2009 changes as 'minor' now feel suitably chastised.