Aviation Incident and Accident Investigation
Sue Baker Civil Aviation Authority, Gatwick, UK
Any discussion of aviation-related incident and accident investigation invariably prompts a number of questions, many of which raise fairly fundamental issues about the nature and purpose of the investigation process. For example, should time and resources be expended on the investigations of incidents rather than focusing all the effort on the major aviation accidents? What is the underlying purpose of investigations and who should conduct them and, if a full-scale field investigation is conducted, what benefits can be gained from this as against a more limited and less resource-intensive "desk-top" enquiry? One of the aims of this chapter is to attempt to answer these questions and to consider, in some detail, the practice and process of investigation in the aviation sphere. The information on which this chapter is based is drawn from firsthand experience of the investigation of air traffic control (ATC) related incidents and accidents in the United Kingdom, but it seems reasonable to assume that the points raised have a general application extending beyond the ATC area or any one state.
In order to convey an insight into what incident investigation is and what it does, it may be helpful to consider what incident investigation is not. First and foremost, it should not be an exercise in the apportioning of blame. The individual does not work in a vacuum. Mistakes are made in the context of the system, and unless the system itself is considered during an investigation, the whole process is likely to be of dubious value. Blaming and/or punishing an individual serves no valuable function for the person concerned. All this would do is to maintain the status quo and therefore the circumstances under which further errors may occur, doing little or nothing to rectify shortcomings or prevent future occurrences. A report published by the UK Air Accident Investigation Branch in 1990 illustrates the point. In the accident in question, a BAC 1-11 had been inadvertently fitted with the wrong sized windscreen retaining bolts during maintenance. At around 17,000 ft the affected windscreen separated from the aircraft, and in the ensuing depressurization the pilot was partially sucked through the gap. The accident gave rise to a number of human factors concerns regarding the maintenance procedures, which are outside the scope of this chapter. However, what