Human Factors and Safety Culture in Aviation Maintenance and Inspection
Human Factors in Maintenance
Human factors (HF) in maintenance focus on the interaction between people, tasks, and the environment. Key concepts include the SHELL model (Software, Hardware, Environment, Liveware), the Dirty Dozen (the twelve most common human error preconditions, such as fatigue, complacency, and lack of communication), and the error management model (active failures vs latent conditions). Candidates must understand how HF contributes to maintenance errors and how to mitigate them through procedures, training, and design.
Safety Culture
Safety culture is the enduring value and priority placed on safety by all members of an organization. It includes reporting culture, just culture, flexible culture, and learning culture. A positive safety culture encourages reporting without fear of punishment for honest errors. Candidates should know how to assess safety culture and the role of leadership in promoting it.
Traps
A common trap is treating HF as only about individual performance; it also includes organizational and environmental factors. Another is confusing safety culture with safety climate (the latter is the perceived state at a given time). Also watch for the assumption that the Dirty Dozen are independent; they often interact.
Worked Example / Rule of Thumb
Rule: "Look beyond the individual; errors are symptoms of system weaknesses." Example: A mechanic installs the wrong part because two similar parts are stored together. The HF analysis identifies a design issue (look-alike parts) and a procedure issue (lack of verification step). Mitigation: separate storage and a required independent check.