ABSTRACT

The Human Factors Analysis and Classification System (HFACS) were specifically developed to define the latent and active failures implicated in Reason's "Swiss cheese" model so it could be used as an accident investigation and analysis tool. Specifically, HFACS describes four levels of failure, each of which corresponds to one of the four layers contained within Reason's model. These include: Unsafe Acts, Preconditions for Unsafe Acts, Unsafe Supervision and Organizational Influences. Skill-based behavior within the context of aviation is best described as "stick-and-rudder" and other basic flight skills that occur without significant conscious thought. As a result, these skill-based actions are particularly vulnerable to failures of attention and or memory. The chapter describes three conditions of operators that directly impact performance: Adverse mental states, adverse physiological states, and physical/mental limitations. It describes four categories of unsafe supervision: Inadequate supervision planned inappropriate operations, failure to correct a known problem, and supervisory violations.