A formal and structured approach to the use of task analysis in accident modelling

摘要

Recent work (Telford & Johnson, 1996; Johnson, 1997), involving the application of formal notations to analyse accident reports has shown that the quality of these accident reports is poor, so much so that their conclusions can be misleading The proposed solution has been to use formal notations in combination with traditional analysis to produce a report, the conclusions of which can be verified by formal reasoning. However, there are weaknesses with the formal notations used up until now. Firstly, they have not allowed the representation of all aspects of an accident or incident. For example, human factors have either not been represented or not clearly delineated from system factors. In particular, there has not been an attempt to provide a task analysis of the incident. Secondly, the notations used do not easily facilitate the system engineering concepts of modularity, encapsulation or scalability. In consequence, it is difficult to model different aspects of an accident, compose these different aspects to build up the model or make changes to parts of the model without affecting the rest of the model. The purpose of this paper is to demonstrate how a formal object-oriented specification language can be used to provide the benefits offered by an engineering approach and in particular, by using this approach, how a task analysis model can be constructed. The task analysis incorporates Hollnagel's (1993) classification of erroneous actions, so that scenarios, deriving from human error, can be reasoned about. An air accident investigation report, issued by the UK Civil Aviation Authority, is used as a case study. (C) 1998 Academic Press. [References: 23]