Human Factors and Safety Management
Human Factors and Safety Management tests error prevention, fatigue and workload, communication, and SMS risk control. The exam expects you to distinguish individual error from organisational conditions.
Models and error
SHELL maps Software, Hardware, Environment and Liveware; mismatches at interfaces create error. Reason's Swiss cheese shows latent conditions and active failures aligning. Slips are execution errors, lapses are memory failures, mistakes are rule or knowledge errors; violations are deliberate deviations. Just culture distinguishes inadvertent error from reckless or intentional violation.
SMS
An SMS has four components: policy and objectives, risk management, assurance, and promotion. Risk = likelihood × severity; controls should reduce likelihood, severity or exposure. Reporting must be confidential and feedback looped; pilot error is a starting point, not a root cause.
Worked example
A hazard has severity 4 and likelihood 3 on a 5×5 matrix, giving risk 12 (high). Adding a warning light reduces likelihood to 2 (risk 8, medium) but does not reduce severity. A second independent barrier - a physical interlock - reduces likelihood to 1 (risk 4, low). The matrix is a prioritisation tool, not a substitute for engineering control.
Traps
Calling every deviation a violation; blaming the last person in the chain; treating a low risk score as acceptable without ALARP; and confusing safety assurance with safety promotion.