The ATSB sought information from CASA regarding the circumstances under which the incorrect procedure was approved for use by the operator. Despite this request, no information was provided by CASA. Consequently, the ATSB was unable to determine whether the approval of incorrect information was an isolated human error or symptomatic of a systemic deficiency with the approval process.
A morally bankrupt organisation.
So is that because the ATSB is gutless, weak, incompetent or just plain old corrupt?
All of that, and confirmed by their actions.