Causal factor analysis contributing factors

Event and causal factors analysis includes charting, which depicts the logical sequence of events and conditions (causal factors that allowed the accident to occur), and the use of deductive reasoning to determine the events or conditions that contributed to the accident. 

Each company s management style and safety systems have strengths and weaknesses. These strengths and weakness tend to influence the types and severity of incidents that might occur. An analysis of incident investigation findings in terms of causal factors, immediate causes, contributing causes,... 

In both component and factor analysis, the properties of the system being observed are assumed to be linearly additive functions of the contribution from each of the m causalities that actually govern the system. For example, for airborne particles, the amount of particulate lead in the air could be considered to be a sum of contributions from several sources including automobiles, incinerators and coal-fired power plants, etc. 

The committee s analysis was conducted on several levels. First, members investigated the causal factors for each of the seven events listed in Tables 2-1 and 2-2. They then developed a notional causal tree for each of the two events in Table 2-2 that were analyzed in depth. For illustrative purposes, a causal tree developed by the committee for the December 3-5,2000, incident at JACADS appears at Appendix F. The tree is a standard tool in reliability analysis and is particularly useful in human reliability analysis where operator actions contribute either positively or negatively to an incident. Lastly, the committee provides a series of general and specific observations about the events. 

The procedure relies on building a tree structure as shown in Figure 36-3. At the top is the principal or top undesired event. The tree continues by breaking the event into contributing factors and further subdividing them into event causes. Fault tree analysis is a deductive process that moves from the general to the specific. A tree chart considers the causal chain of factors leading to the top event. Interactions between events and elements of the system are a vital part of this method. 

Causal factor chain. This is a cause and effect sequence where a specific action creates a condition that contributes to or results in an event. This creates new conditions that, in turn, result in another event, etc. Figure 12-1 summarizes a root cause analysis flow chart [2]. 

An organization that does not encourage employee participation and involvement and does not seek the advice of employees who have experience with the work being done do not benefit from the contributions they can make with respect to hazard identification and analysis and risk reduction, and thus improved efficienqr. Failure to involve employees sometimes results in known hazardous situations to remain in existence and become incident causal factors. 

The website http //www.ntsb.gov/events/aberdeeii/ppt presentations.htm includes presentations to the NTSB about the accident. There may be individual and team actions and failed defences that contributed to the incident, however these may never truly be known. As the speed of impact was near supersonic, it destroyed much of the physical evidence that could have provided a more definitive analysis of technical and human causal factors. 

Details of the contributing factors identilied in the case sriufy are included below. Figure 12.2 includes the ICAM Analysis Chart for the incident organizing the causal factors into the four ICAM elements of ... 

A generalised process model constitutes the backbone of our accident-analysis framework in Chapter 6. Process models help us in understanding how a production system gradually deteriorates from a normal state into a state where an accident occurs. Time is thus a basic factor. In contrast to causal-sequence models, process models make a clear distinction between the accident sequence on the one hand and the underlying causal or contributing factors on the other hand. 

Figure 21.2 illustrates how the starting point, the directions and the scope of each method fit into the accident-analysis framework of Chapter 6. Two of the methods. Fault tree analysis and Comparison analysis are deductive in that they start with the unwanted event. They proceed by analysing the underlying incidents and deviations (Fault tree analysis) or contributing factors (Comparison analysis). Several of the methods are mainly inductive in that they start with a deviation and proceed by studying the effects of this deviation. This applies to HAZOP, Failure mode and effect analysis. Event tree analysis and CRIOP, although they also have a component of causal analysis. Coarse analysis and Job-safety analysis start with the hazard and use a combination of inductive and deductive analyses. 

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