Human Factors
What you must know
Human factors covers the SHELL model, error models (e.g. the Swiss cheese model), fatigue, stress, workload, situational awareness, communication, teamwork, and the physiological factors affecting maintenance personnel. You should understand the dirty dozen (complacency, distraction, fatigue, pressure, etc.), the importance of inspection and independent checks, and how documentation and shift handovers prevent error.
Traps to watch
- Fatigue: it impairs judgement and reaction time; questions often test that fatigue is a major contributor to maintenance error, not just a comfort issue.
- Complacency: repetitive, familiar tasks are the highest risk; the answer is usually to follow procedures and not rely on memory.
- Communication: ambiguous verbal instructions and shift handovers are classic error sources; written, confirmed communication is preferred.
- Situational awareness: loss of awareness often precedes an incident; distraction and pressure are key precursors.
- The dirty dozen are error precursors, not causes in themselves; questions may ask which one applies to a scenario.
Worked example
A technician is asked to complete a task quickly at the end of a long shift. The correct response is to recognise pressure and fatigue as error precursors, stop, and follow the approved procedure, possibly handing over to the next shift with a documented handover. Speed must never override procedure.
Rule of thumb
When a scenario involves rushing, fatigue, or familiarity, the correct answer is almost always to follow the procedure and use independent checks.