The criticisms of contemporary investigations come into three categories: • The investigation may be considered in some way inadequate, either
because all the relevant facts were not discovered, or because there are logical flaws in the analysis, or
• The investigation may be sound, but the report may be difficult to follow, or
• The investigation might still be considered a failure if valid corrective action is not taken.
(Taylor, 1998)
Proposed methods of investigation ought therefore to result in improved quality of investigations, more readily understandable reports, and valid corrective actions which are likely to be acted upon.
In terms of the quality of investigations, the proposed methods would represent an improvement if they are able to discover facts which the official
investigation missed, or new logical linkages of facts which may have been dismissed as unimportant, or logical deficiencies in the original reports. It is expected that MES will discover limitations in gathering facts, since that is one of its intended roles (Benner, 1994). Improvement in logical analysis can be achieved by the use of WBA, as shown by the case study by Gerdsmeier et al. (1997), the analysis of the Cali disaster (ACRC, 1996). It is expected that a similar improvement in logical analysis could be achieved in the present study.
Readability of reports is important, but it is necessarily subjective, and thus difficult to assess. It is generally accepted that reports in the recommended ICAO format (ICAO, 1994) are disjointed and difficult to read (Zotov, 2001). Part of the problem lies in the unsuitability of a written (serial) format to describe things which have been interacting in parallel (Johnson et al., 1995). MES, WBA and TOC analyses all result in graphical depictions of events and conditions, which should be easier to follow. The assessment of reports which are derived from the proposed methods will be discussed later.
Validity of corrective actions derives in part from the validity of the investigation. Where re-examination discloses new facts or logical linkages, it is expected that the need for different or further corrective actions will become apparent. Even more important is the possibility of discovering core problems, whereby a single corrective action may address a wide range of problems, since such actions may be more likely to be implemented. To the extent that the proposed methods disclose
would represent an improvement over those currently in use.
TOC is a 'change methodology'; its raison d'être is to make improvements in existing systems (Dettmer, 1997). It could therefore be expected that
recommendations devised with the use of the TOC would be more likely to be
implemented than is at present the case. However, while such recommendations might seem to be more persuasive, there cannot be a guarantee that they will prove so in practice, since at least some of the opposition to changes in the past has been irrational (see, for example, TAIC, 1992a). To gain a true assessment, it would be necessary to track the response to recommendations made in this way, from actual investigations. While this should certainly be done, to do so would be beyond the scope of the present study, which is a revelatory case study, concerned to see whether the TOC methodology can be applied to the information from a particular accident.
The extent to which revised recommendations are an improvement on those in the official report must be left to the reader. As Westrum has said (personal
communication, 2000) a case study must stand on its own merits.
Expertise
The New Shorter Oxford English Dictionary (1993) (OED) defines an expert as ‘A person with the status of an authority (in a subject) by reason of special skill, training or knowledge; a specialist’
1. A person… who has gained skill from experience.
Palmer, Stough, Burdenski & Gonzales (2005) reviewed the general expertise literature, before focussing their attention on expertise in teaching. They found that one or more marker categories were generally used, in determining whether someone could be considered an expert:
• Years of experience • Social recognition
• Performance-based criteria.
These criteria are in accord with the OED definition: ‘years of experience’ correlates with ‘gaining skill from experience’; social recognition’ correlates with ‘status as an authority’, as does ‘professional or social group membership’.
The OED stipulates that the status of an authority is ‘in a subject’: Palmer et al. (2005), in their review of the literature on expertise, found that “individual expertise is unique to a specific domain of activity” (p. 15). It requires thousands of hours of dedicated practice within that domain (Berliner, 1994).
Expertise is, in part, a social attribution (Agnew et al., 1997). “Individuals… are selected as experts because others consider them to be experts” (Palmer et al., 2005, p. 15). One form of social recognition is membership of a group, such as a learned society, or a University faculty.
Performance-based criteria would prima facie be the optimum way to discover who could be termed an expert, but may be more problematic to define. While those who consistently win competitions against opponents are considered experts
(Ericsson, 1996, cited in Palmer et al., 2005) in other fields performance criteria may have to be subjective. For example, while it might be possible to define elements of a musical performance which could be enumerated, these could not capture the quality of performance by a master.
Overall, Palmer et al. (2005) that identification of experts was somewhat idiosyncratic. They recommended a multi-gated approach, using as many different criteria as appropriate in a particular case.
Accident Investigator Criteria
Criteria for qualifying as an expert in accident investigation follow the principles outlined above, of years of experience, social recognition, professional or group membership, and performance-based criteria. General prerequisites are a high aviation professional qualification, followed by specialist training, and a minimum of five years of practical experience (Zotov, 1999). Most investigators work, initially at least, in an official investigation agency, and most become members of the
completion of 5 years of full-time experience as investigators. Performance is acknowledged in part by promotion to the role of Investigator in Charge of accident investigations, and in part by such matters as presentation of papers at international symposia.
The qualifications of the author as an expert accident investigator are detailed in Annex C.
Summary
This case study is intended to bring about a general improvement in the safety of air transport by showing how the analysis of data from an accident investigation can be improved, and more effective safety recommendations can be generated. The case study seeks to show:
1. How core problems can be derived from accident investigation data, 2. How effective safety recommendations can be developed, so as to
minimise the risk of other similar accidents.
This will be done by examining the data from a revelatory case, the Ansett (NZ) de Havilland Dash 8 accident near Palmerston North (TAIC, 1995). The
accident will be examined using three formal methods, MES, WBA and TOC, and the results compared with those produced by the official investigation using traditional methods. Success will be measured by the extent to which the proposed methodology better establishes the facts of the accident, or generates deeper insights into the structure of the accident, or generates safety recommendations more likely to be effective.