The field phase of an investigation is used to identify and validate perceived safety hazards. Competent safety analysis is required to assess the risks, and effective communications are required to control the risks. In other words, effective safety management requires an integrated and structured approach to safety investigations.
Some occurrences and hazards originate from material failures or occur in unique environmental conditions. However, the majority of unsafe conditions are generated through human errors. When considering human error, an understanding of the conditions that may have affected human performance or decision-making is required. These unsafe conditions may be indicative of systemic hazards that put the entire aviation system at risk. Consistent with the systems approach to safety, an integrated and structured approach to safety investigations considers all aspects that may have contributed to unsafe behavior or created unsafe conditions.
The logic flow for an integrated process for safety investigations is depicted in Figure 1 — Integrated Safety Investigation Methodology (ISIM). Using this type of model can guide the safety investigator from the initial hazard or incident notification through to the communication of safety lessons learned.
Effective investigations do not follow a simple step-by-step process that starts at the beginning and proceeds directly through each phase to completion. Rather, they follow an iterative process that may require going back and repeating steps as new data are acquired and/or as conclusions are reached.