EASA Module 8 cheat sheet

Human factors is the study of human capabilities, limitations and behaviour, and how these interact with the aviation system.

Approximately 70–80% of aviation accidents are attributed wholly or partly to human performance factors.

The SHEL model comprises Software, Hardware, Environment and Liveware; its block edges represent the interfaces between components.

Murphy's law states that if anything can go wrong, it will; it justifies defensive design, checklists and independent inspections.

Maintenance and inspection errors are implicated in roughly 15–20% of commercial aviation accidents.

The 'dirty dozen' maintenance error precursors are fatigue, complacency, lack of knowledge, distraction, lack of teamwork, lack of resources, pressure, lack of assertiveness, stress, lack of awareness, norms and lack of communication.

Human factors training targets non-technical skills: communication, teamwork, situational awareness, decision-making and fatigue management.

A common corollary of Murphy's law is that the person who never makes a mistake rarely makes anything.

The fovea has the highest cone density and provides sharp colour vision; rods dominate peripheral and night vision.

Dark adaptation takes about 30 minutes; exposure to bright light resets it and forces readaptation.

The blind spot corresponds to the optic disc, about 15° nasal to the fovea, where the optic nerve leaves the retina.

Presbyopia is age-related loss of accommodation that reduces near vision, typically from about 40 years of age.

Human hearing spans roughly 20 Hz to 20 kHz, with maximum sensitivity between 2 kHz and 5 kHz.

Noise-induced hearing loss usually first appears as a notch at about 4 kHz.

Short-term memory holds about 7 ± 2 items for 15–30 seconds without rehearsal.

Attention is a limited resource; divided attention degrades when tasks compete for the same processing resource.

Claustrophobia and restricted physical access increase error rates during inspection and repair tasks.

Diffusion of responsibility occurs when individuals feel less accountable because responsibility is shared across a group.

Asch conformity experiments found that roughly one third of responses conformed to an obviously wrong majority.

Groupthink is a mode of thinking in cohesive groups where the desire for harmony suppresses dissent and alternative evaluation.

Safety culture components are a reporting culture, a just culture, a flexible culture and a learning culture.

A just culture consoles human error, coaches at-risk behaviour and sanctions reckless behaviour.

A steep authority gradient discourages junior team members from speaking up about safety concerns.

Effective supervision balances oversight with empowerment; a typical span of control is about 5–8 subordinates.

Hofstede's national culture dimensions include power distance, individualism, masculinity and uncertainty avoidance.

Yerkes–Dodson law: performance peaks at moderate arousal and degrades when arousal is too low or too high.

Blood alcohol concentration falls by about 0.015% per hour; hangover effects persist after BAC returns to zero.

Circadian low points occur around 03:00–05:00 and 15:00–17:00, increasing the risk of fatigue-related error.

Staying awake for about 17 hours impairs performance similarly to 0.05% BAC; 24 hours is comparable to 0.10% BAC.

Shift work disrupts circadian rhythm; forward-rotating shifts are generally better tolerated than backward-rotating shifts.

Underload causes complacency and vigilance decrement, while overload causes omissions and tunnel vision.

Many medications impair alertness; label warnings and aeromedical guidance govern fitness to work.

Sleep debt accumulates and requires recovery sleep; hydration, fitness and managed stress improve performance.

An 8-hour noise exposure above 85 dB(A) generally requires hearing protection; 90 dB(A) is a common occupational limit.

Detailed inspection tasks typically need 500–1000 lux, while general work areas need about 300–500 lux.

A comfortable working temperature is about 20–22°C; heat above about 30°C increases fatigue and error rates.

Whole-body vibration spans roughly 0.5–80 Hz; hand–arm vibration spans about 8–1000 Hz.

Relative humidity below 30% increases static and dust, while above 70% promotes condensation.

Poor illumination causes eye strain, headaches and reduced inspection reliability.

Motion sickness arises from conflict between visual, vestibular and proprioceptive inputs.

Carbon monoxide is colourless and odourless and binds haemoglobin about 200–250 times more strongly than oxygen.

Vigilance decrement: detection performance drops noticeably after about 20–30 minutes of monotonous monitoring.

Repetitive tasks cause musculoskeletal disorders; task rotation and micro-breaks reduce the risk.

Manual handling risk is reduced by correct posture, load limits and mechanical aids.

Visual inspection reliability is imperfect; independent second checks and good lighting raise defect detection rates.

Complex systems raise mental workload, and automation can induce complacency and skill fade.

Task analysis breaks a job into steps to identify hazards and error-likely conditions.

Error-likely conditions include unfamiliar, time-pressured, ambiguous or low-feedback tasks.

Communication requires a sender, message, channel, receiver and feedback; noise in any element causes loss.

Read-back or closed-loop communication confirms critical instructions such as ATC clearances.

Structured shift handover with open questions improves transfer of task status and responsibility.

Work logs and technical records must be legible, permanent, contemporaneous, accurate and signed.

Ambiguous or non-standard phraseology increases the risk of misunderstanding.

Currency requires recent experience and up-to-date documentation for the task being performed.

Dissemination ensures safety information reaches all affected staff, not only management.

Cross-team barriers include different jargon, competing priorities and hierarchical distance.

Reason's Swiss cheese model: accidents occur when holes in multiple defensive layers align.

Skill-based errors are slips and lapses; rule-based and knowledge-based errors are mistakes; violations are deliberate deviations.

Active errors have immediate effects at the point of work; latent errors lie dormant in management or design decisions.

Error management uses prevention to reduce opportunity, detection to capture errors, and containment to limit consequences.

The 'dirty dozen' lists common maintenance error precursors such as fatigue, pressure, distraction and norms.

Human error is normal and inevitable, so systems should be designed to be error-tolerant.

Violations are classified as routine, situational or exceptional.

MEDA (Maintenance Error Decision Aid) investigates the contributing factors behind maintenance errors.

A hazard is a potential source of harm; risk is the combination of the likelihood and severity of that harm.

A risk assessment matrix multiplies likelihood by severity to give a risk level and required action.

The hierarchy of control runs: eliminate, substitute, engineer, administrate, then personal protective equipment.

PPE is the last line of defence and never the first control measure.

Near-miss reporting reveals hazards before harm occurs.

A safety management system comprises safety policy, risk management, safety assurance and safety promotion.

Comply with local instructions, permits and lock-out/tag-out procedures before starting work.

Report hazards through the designated reporting system and record the corrective actions taken.