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Safeguard Magazine

Accident: What happened, and why?

The highest profile accident investigations involve ships, trains and planes. TIM BURFOOT outlines the standard investigation process.

The Transport Accident Investigation Commission (TAIC) is effectively a standing commission of inquiry. Its principal purpose is to determine the circumstances and causes of accidents with a view to avoiding similar occurrences in future, rather than to ascribe blame to any person.

Unlike ad-hoc royal commissions of inquiry, TAIC has four permanent part-time Commissioners and a team of permanent investigators for the air, rail and marine transport modes it is mandated to investigate. This means TAIC is ready to commence an investigation immediately after the event.

TAIC has a goal of no repeat accidents, ever! It is an aspirational goal – a philosophy or way of thinking when deciding which accidents it will investigate, how quickly it needs to get certain lessons learnt out there to industry, and what it will recommend to prevent similar accidents recurring.

EVIDENCE GATHERING

As soon as TAIC launches an inquiry, an investigator in charge is appointed and he or she is assigned a team to work with. The team is made up of investigators with subject matter experience. If TAIC does not have the appropriate expertise in-house, then it will contract it in.

The investigators begin gathering the evidence almost immediately, which typically involves the team travelling to the site to map and photograph the scene and document the evidence. Wreckage is not always confined to a single area. Sometimes it is spread over great distances. Interviews are held with people directly or indirectly involved (including witnesses to an event). The system in which the aeroplane, train or vessel operated is examined and documents associated with that system are collated.

Of course, evidence is never straightforward, and does not always align in a logical way leading to a logical conclusion. It is important to cross-reference one source of evidence with another – never to accept what is said at face value. Witnesses are notoriously unreliable. Two people observing the same event can give two totally different accounts of what they saw. This is normal because people process information in different ways. A good, open and unbiased style of interviewing technique is crucial to getting the right story. If a witness did not see anything, then so be it. Given the opportunity, a witness can be overly helpful and fill in the gaps with what they think the investigator wants to hear.

Increasingly, evidence is coming in the form of data from a variety of recorders. These range from dedicated on-board recorders (colloquially referred to as black boxes) down to the humble mobile phone, including anything in between. Navigation systems, machinery monitoring systems, CCTV footage – the list goes on – can be valuable sources of information. Investigators love this sort of evidence as it is more objective than subjective, although some care is needed in its interpretation.

TAIC has recently employed a recorders and data specialist investigator who works across all three modal teams. His job is to verify the data and present it in a usable format for the team to use. If TAIC does not have the capability to extract or interpret a dataset then we seek assistance from those who can, be it the equipment manufacturer or our colleagues working in similar accident investigation agencies overseas.

ALWAYS A TEAM EFFORT

On that note, it is important to acknowledge that TAIC does not work alone, nor do individual investigators work in isolation. It is often said that there are no new ways to have an accident. It has often happened before somewhere. Liaising with our international colleagues is an important source of information.

It is very important that one-person biases do not impede an open investigation process and lead it down a one-way path, particularly if it is the wrong path. I mentioned earlier that the investigator in charge is assigned a team. The team is not only made up of TAIC-trained investigators. There is a corporate support network of researchers, media and communications experts, legal counsel, finance, and then on up to the Commissioners themselves, who are the decision makers. It is the Commissioners who ultimately make the findings and recommendations. A failure in any one aspect of an investigation can detract from the end goal of learning and disseminating the lessons to those who can help prevent a recurrence.

Peer review is an important process during an inquiry. At TAIC this begins at the site in the form of team meetings, daily debriefings and early analysis of the facts gathered up to that point. Peer review continues for the life of the inquiry, through each phase of the investigation and each draft of the report.

Proper analysis of the facts is key to a well-run investigation. Establishing the facts will tell us what happened. Analysis will tell us why it happened and therefore what safety actions or recommendations are needed to prevent it happening again.

THE METHODOLOGY

There are several well-known methodologies for analysing evidence. TAIC has adopted what is known as the ATSB methodology, developed by our colleagues at the Australian Transport Safety Bureau, a similar agency to TAIC. I will try to summarise what is a reasonably complex methodology into a few paragraphs.

Timeline and event lines are developed from the evidence gathering phase. These are essentially what happened and in what order and when. Subject matter experts then analyse these as a team to identify unusual acts and/or omissions or unusual events or situations – things that are not considered normal. Then the question why was that? or why did that happen? is applied over and again for each scenario until we run out of answers, or the answers reach that point of diminishing returns. In this way we develop what is called an Acci-map, where the answers are categorised into types or “issues”.

If abnormal situations existed at the coal face of the operation, where things were really going wrong with the people, the vehicle and their immediate environment, then these are considered local conditions. Abnormal conditions that exist in the operating environment and above are an indication that there could be wider systemic issues that have contributed to the accident and that we need to look deeper.

This process gives an idea of what information is missing and what further lines of inquiry might need to be followed. Well-trained investigators begin this process at the site, even as a way of thinking. TAIC processes require this to be done formally as soon as possible on return from the site phase of the investigation. The whole team is involved, preferably involving someone from one of the other transport modes. They tend to ask those “dumb” obvious questions that keep the modal experts honest.

The process is repeated throughout the investigation until the team is satisfied that it has all of the relevant facts and has followed all relevant lines of investigation.

ALL GOOD THINGS TAKE TIME

Unfortunately if we are to prevent similar (repeat) accidents from occurring, time is not on our side. A thorough investigation that feeds a commission of inquiry process does take time. Processes must be followed and natural justice must be satisfied. If there is an international aspect to the inquiry, mainly in the air and marine modes, then the international requirements tend to extend the time taken to complete an inquiry and publish a report.

To overcome the timeliness issue TAIC has developed a strategy of publishing interim reports or urgent recommendations early in the investigation process, in order to get the message out there as soon as possible to prevent a repeat accident for similar reasons.

Interim reports satisfy the industry and public thirst for information soon after an accident. Urgent recommendations are made when an analysis session reveals a serious safety issue that cannot wait for the 12 to 18 months a typical inquiry takes to complete.

TAIC published an interim maritime report on the grounding of the container ship Rena on Astrolabe Reef in the Bay of Plenty in October 2011. The interim report contained no urgent recommendations, but the what happened was able to be established early in the investigation, and TAIC was able to share an understanding of what happened soon after this high-profile accident.

TAIC published urgent rail recommendations following the second of two similar accidents where metropolitan passenger trains collided with the stop block at the terminal station at Melling in 2014. These urgent recommendations were immediately accepted by the recipients, and a range of actions taken to reduce the likelihood and the consequence (the risk) of similar events. TAIC made further longer-term recommendations to address wider systemic safety issues in its full and final report.

In January 2012, a hot air balloon struck power lines near Carterton and caught fire. Eleven people died; at the time this was the second deadliest hot air balloon accident in the world. Early analysis identified safety issues and TAIC published an interim report with urgent recommendations. TAIC made further longer-term recommendations to address wider systemic safety issues in its full and final report.

RISK LEVEL

I mentioned the word risk. There is of course risk in everything we do. Determining what is an acceptable level of risk for any particular transport operation or activity is important. When a potential safety issue is identified, TAIC assesses what level of risk is apparent. If the risk is deemed unacceptably high, then TAIC will either encourage or recommend someone takes action to lower the risk to an acceptable level.

People don’t wake up and decide today they will have an accident. They are usually unexpected and happen for a variety of reasons. Very rarely will there be one single cause. Accidents are a culmination of several, often many, factors at different levels in the system. By finding out why they happen and getting that message out there, we think TAIC can influence the system to help prevent repeat accidents – to make the system safer.

Tim Burfoot is chief investigator with the Transport Accident Investigation Commission.

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