Human Factors in Aircraft Maintenance: Essential Principles

Posted on May 20, 2026 in Psychology and Sociology

1. Types of Memory (2023)

  • Sensory Memory: A recording of immediate events lasting a few seconds. It allows attention and perception processes to filter important information for short- and long-term retention.
  • Short-term Memory: Retains 5 to 9 items for approximately 30 seconds. Susceptible to distractions during maintenance tasks.
  • Long-term Memory: Virtually unlimited capacity.
  • Semantic Memory: Rules and contents necessary to function in an environment.
  • Episodic Memory: Stores specific situations and experiences.

2. Intentional Errors (2023)

Equivocation (Rules)

Deliberate actions violating established policies.

  • Example: Ignoring security procedures.
  • Strategies: Education, awareness, monitoring, and clear sanctions.

Equivocation (Knowledge)

Intentional actions based on incorrect knowledge.

  • Example: Misinterpreting requirements.
  • Strategies: Adequate training and a culture of continuous learning.

Violations (Routine)

Breaches due to complacency or convenience.

  • Example: Skipping safety steps to save time.
  • Strategies: Simplifying procedures and positive incentives.

Violations (Exceptional)

Disregard of rules in emergencies.

  • Example: Ignoring protocols in a crisis.
  • Strategies: Emergency training and ethical decision-making.

3. Types of Violations

  • Routine Violations: Deliberate breaches due to complacency.
  • Exceptional Violations: Intentional disregard of rules during emergencies.

4. Murphy’s Law and Complacency

Murphy’s Law

  • Principle: “Whatever can go wrong, will go wrong.” Anticipating problems prevents disaster.
  • Applications: First response and second reply.

Complacency

A risk factor developing over time. As technicians gain experience, they may develop false confidence, leading to overlooked tasks. Approved written procedures must always be followed.

5. Stress Factors in Aircraft Maintenance

Stressors

  • Physical: Heat, cold, noise, fatigue.
  • Psychological: Financial or health concerns.
  • Reactive: Time pressure, bullying, unexpected events.

Effects on Technicians

Decreased performance, safety risks, lack of situational awareness, loss of vigilance, task fixation, and decision-making errors.

6. Alcohol and Performance

Alcohol disrupts the sleep/wake cycle, causes sleep disturbances, and reduces attention and dexterity the following morning, leading to daytime sedative effects.

7. Alcohol, Sleep, and Fatigue

Alcohol fragments sleep, causes nightmares, and induces insomnia. While it may speed up falling asleep, it disrupts the REM/Non-REM cycle.

8. Types of Attention

Includes Selective, Divided, Focused, and Sustained Attention. Example: A technician monitoring engine start-up procedures remains alert to parameter deviations, which triggers an immediate response.

9. Critical Factor Norms

Technicians often use peer behavior as a frame of reference. Tacit standards (working habits) develop to solve ambiguous problems and eventually stabilize within the group.

10. Factors Affecting Visual Acuity

  • Physical eye health and age.
  • Ingested substances (medications, alcohol, tobacco).
  • Environmental factors (light, dust, fog).
  • Object characteristics (size, contrast, motion, distance, angle).

11. Peer Pressure

The influence exerted by peers to conform to group standards. Factors include culture, gender, self-esteem, subject knowledge, and group size.

12. Presbyopia and Maintenance

Age-related loss of visual acuity starting around age 35. The lens loses flexibility, making it difficult to focus on close objects (similar to hyperopia).

13. Characteristics of an Efficient Leader

  • Motivates the team regarding objectives.
  • Provides positive reinforcement.
  • Sets a clear example.
  • Builds team spirit.
  • Coordinates tasks and delegates functions.

14. Information Processing (5 Phases)

  1. Gathering: Sensory perception.
  2. Perception: Adding meaning via memory and expectations.
  3. Decision-making: Evaluating information to allocate attention.
  4. Action: Conscious or automatic response.
  5. Feedback: Correcting errors and refining responses.

15. Efficient Teamwork Characteristics

  • Common goals and balanced leadership.
  • Effective collaboration and shared mental models.
  • Clear communication and role definition.
  • Standardized procedures and conflict resolution.

16. Types of Stressors

  • Physical: Heat, cold, noise, fatigue.
  • Psychological: Real or imagined personal problems.
  • Reactive: Everyday events like time pressure or bullying.