Human Factors, Just Culture & Non-Technical Skills

Human factors is the scientific discipline concerned with understanding how humans interact with the systems, environments, and other people around them — and how those interactions affect safety performance. In aviation, human error contributes to the majority of accidents and incidents.

Studying human factors does not mean assigning blame to individuals. It means understanding the conditions that shape human performance so those conditions can be improved.

Key categories of human error:

• Slip — correct intention, wrong execution (e.g. pressing the wrong button)
• Lapse — memory failure (e.g. forgetting a checklist item)
• Mistake — wrong plan or decision, correctly executed
• Violation — deliberate deviation from a rule or procedure

Understanding which type of error occurred is essential to designing the right fix. A slip requires a system change. A violation may require a culture conversation. Treating all errors the same produces ineffective responses.

The SHELL model is a conceptual framework used in aviation to describe how the human (Liveware) interacts with other components of the aviation system. It was developed by Elwyn Edwards and later refined by Frank Hawkins, and is referenced in ICAO Doc 9859 and AC 120-92B.

Accidents rarely result from a single failure. They occur when the interfaces between the central Liveware (the individual) and the other components become mismatched or break down. For example:

• L–S mismatch: A procedure is written in a way that is confusing or impractical — increasing the chance of a checklist error
• L–H mismatch: A cockpit control is positioned in a way that creates confusion between similar-looking switches
• L–E mismatch: High workload during a night approach in IMC degrades decision-making
• L–L mismatch: A crew member fails to speak up due to authority gradient

The "Dirty Dozen" is a concept developed by Gordon Dupont at Transport Canada to describe the 12 most common human factors that contribute to errors in aviation — particularly in maintenance operations, though they apply across all roles.

Individual errors rarely occur in a vacuum. Most accidents involve a chain of organizational factors that created the conditions for the error to happen. James Reason's "Swiss Cheese Model" describes how defenses in an organization have holes — and accidents occur when those holes align.

Organizational factors that directly influence safety performance:

• Safety culture — the shared values, beliefs, and behaviors around safety. A positive safety culture makes it safe to speak up, report errors, and raise concerns.
• Leadership behavior — safety culture flows from the top. When leaders prioritize schedule over safety, that message reaches every level of the organization.
• Resource allocation — inadequate staffing, time pressure, and missing equipment create the conditions for human error.
• Communication patterns — poor information flow between departments, shifts, or crew members is a systemic hazard.
• Authority gradient — steep hierarchy where junior personnel are unwilling to challenge seniors increases risk significantly.

At Gold Aviation Services, the Accountable Executive sets the tone from the top. The Director of Safety monitors the organizational safety environment through safety reports, audit findings, and Safety Board discussions. If you observe organizational pressures that are creating safety risks — that is exactly what the voluntary reporting system exists to capture.

A just culture is one that balances safety learning with individual accountability. It recognizes that punishing all errors indiscriminately destroys the reporting culture that safety depends on — while ignoring deliberate recklessness undermines safety standards.

The just culture model used at Gold Aviation Services distinguishes three types of behavior:

Just culture is not the same as a "no blame" culture. Accountability still exists — the distinction is between system-level accountability (fixing the conditions that led to an error) and individual accountability (addressing genuine recklessness). Both matter.

Non-technical skills (NTS) are the cognitive and social skills that complement technical knowledge and procedural skills. They are what allow individuals to perform safely under pressure, in complex environments, and as part of a team. They are taught through Crew Resource Management (CRM) training.

Threat and Error Management (TEM) is a framework that teaches crews to:

1. Identify threats proactively — weather, traffic, fatigue, unfamiliar airports
2. Manage errors before they become consequential — catch and trap errors early
3. Recover from undesired states — recognize when things have gone wrong and take corrective action