Human Error Types
Rasmussen's SRK Model
Performance levels determine the type of error:
- Skill-Based (Automated): Routine tasks done without thinking (e.g., controlling pitch).
- Rule-Based (Procedural): Interpreting a situation and applying a learned rule (e.g., "If fire light ON, then shut down engine").
- Knowledge-Based (Novel): New situations requiring analytical thinking (e.g., complex failure with no checklist).
Error Classification (Reason/Norman)
- Slips (Action Error): Correct intention, wrong execution. Skill-based.
- Example: Selecting Flaps instead of Gear.
- Lapses (Memory Error): Forgetting to do something. Skill-based.
- Example: Forgetting to report passing an altitude.
- Mistakes (Planning Error): Wrong intention. The plan is flawed.
- Rule-Based Mistake: Applying the wrong rule or a bad rule.
- Knowledge-Based Mistake: Failure in reasoning/understanding the system.
Violations
Deliberate deviation from rules or procedures.
- Routine: "Corner cutting" accepted by the group.
- Situational: Breaking a rule to get the job done under pressure.
- Optimising: Breaking a rule for personal thrill/ego.