The ATSB conducts different levels of investigation according to the anticipated scope and scale of the work required to determine the contributing factors to a safety occurrence.
Occurrence briefs
Occurrence briefs provide the opportunity to share important safety messaging and information with industry and the public in the absence of an investigation. They are a short factual summary to detail the circumstances surrounding an occurrence, which only uses information gathered during the initial notification, and from any follow-up information with relevant parties.
Because occurrence briefs are not investigations under the Transport Safety Investigation Act 2003, the information within them is de-identified. While they do not include any analysis, findings, safety issues, safety actions or recommendations, occurrence briefs do provide an additional opportunity to learn from the experiences of others.
Occurrence briefs can be produced by ATSB Transport Safety Investigators or members of our Safety Reporting Team (all of whom have significant transport industry experience).
Short investigations
Short investigations provide a summary and analysis of commonly occurring transport safety accidents and incidents. Investigation activity includes sourcing imagery and documentation of any transport vehicle damage and/or accident site, conducting interviews with involved parties, and the collection of documents such as procedures and internal investigations by manufacturers and operators.
Short investigation reports include a description of the sequence of events, limited contextual factual information, a short analysis, and findings. Findings include safety factors (the events and conditions that increased the risk of incident or accident happening) but only examine the actions and conditions directly relating to the occurrence and any proactive safety actions taken.
Defined investigations
Defined investigations look at transport safety accidents and incidents of a more complex nature than short investigations, and seek to identify systematic safety issues that reveal underlying causes of an occurrence. They involve several ATSB resources and may involve in-the-field activity or be an office-based investigation. Evidence collected can include recorded flight and event information, multiple interviews, analysis of similar occurrences, and a review of procedures and other risk controls related to the occurrence.
Defined investigation reports include an expanded analysis to support the broader set of findings within the report and may include safety factors not relating directly to the occurrence. Defined investigations may also identify safety issues (safety factors with an ongoing risk) relating to ineffective or missing risk controls. The report also identifies safety issues, along with proactive safety action taken by industry and ATSB safety recommendations.
Systemic investigations
Systemic investigations can involve in‑the‑field activity, and a range of ATSB and possibly external resources. They have a broad scope and involve a significant effort collecting evidence across many areas. The breadth of the investigation will often cover multiple organisations. Occurrences and sets of transport safety occurrences investigated normally involve very complex systems and processes.
In addition to investigating failed and missing risk controls, systemic investigations may also investigate the organisational processes, systems, cultures and other factors that relate to those risk controls, including from the operator, regulator, and certifying and standards authorities. Systemic investigations result in substantial reports, often with several safety issues identified.
Systemic investigations were previously known as 'complex' investigations. The change in terminology more accurately reflects the broad scope and systems-level complexities involved in these investigations.
Major investigations
In the event of a significant accident (potentially involving a large number of casualties), the ATSB would conduct a major investigation. Major investigations would likely involve significant ATSB and external resources and potentially require additional one-off government funding.