Evidence analysis

Analysis involves sorting, corroborating, and linking evidence and facts to prove, disprove and weigh competing theories.

The chain of events leading to an incident or accident may appear to be clear, particularly those facts and factors closest to the occurrence. However, incidents and accidents rarely have a single cause; contributing factors are often complex and reach beyond the accident vehicle and its operation to wider systemic issues. For instance, a pilot may select a wrong control, leading to an accident. Contributing factors revealed in analysis could include the pilot’s training, the airline’s training system and its operation, the control design, and relevant regulations covering any of these aspects.

Testing the analysis

While the investigation team will come from a range of professional disciplines, often it will call on external experts to perform specialist examinations, offer opinions, or conference with other experts and the investigation team. These can include metallurgists, engineers, psychologists, medical disciplines, aircraft type experts, forensic data specialists, and so on, depending upon the inquiry needs. Commission staff who have not worked on the case are called on for the benefit of their fresh minds, enabling the larger group to consider the potential relevance of previous similar occurrences, including some from overseas. Sometimes we may need to gather further evidence.

Endorsing the analysis

The investigation team then presents its analysis to Commissioners who test it further and may direct further work. Their considerations include whether all the necessary facts have been gathered, the robustness of the evidence and analysis, and whether the safety issues have been properly identified. Analysis may also lead to consideration of whether any likely recommendations should be made urgently. Often the evidence available does not allow absolute findings to be made, and the Commissioners will have to make findings with a stated degree of probability.