Filthy Fifteen and PEAR Model

Human Error

A human action with unintended consequences.

Unintentional Error

The person did not mean to make the mistake; it is unknowing and unintentional.

Unintentional Error

Often results from a failure of attention (slips) or memory (lapses).

Intentional Error

An ____ is considered a violation in aviation maintenance.

Intentional Error

Involves knowingly or intentionally choosing to do something wrong.

Intentional Error

A conscious, purposeful deviation from established safe practices, procedures, or regulations.

Active Error

The specific, individual, and obvious event that occurs at the sharp end (e.g., flipping the wrong switch).

Latent Error

The organizational or company issues that lie dormant and predispose the system to failure (e.g., poor training, inadequate tooling).

Dirty Dozen

Developed by Gordon Dupont, a Canadian safety expert, in the 1990s.

Dirty Dozen

Identifies the 12 most common human error precursors in high-stakes environments (e.g., maintenance, aviation).

Error Chain

The phenomenon where factors rarely occur in isolation and stack up to cause an incident.

Re-entry Error

Forgetting where you left off when resuming the work.

Real Pressure (External)

Externally imposed, like a looming delivery deadline.

Perceived Pressure (Internal)

Self-imposed, often driven by pride or a desire to please.

Sloppy Norms

Unsafe work habits that become accepted practice within a group.

Filthy Fifteen

Expands upon Gordon Dupont's classic "Dirty Dozen" human factor error precursors by incorporating three modern organizational challenges (Not Admitting Limitations, Lack of Operational Integrity, and Lack of Professionalism) that compromise maintenance and operational safety.

PEAR Model

Developed by the Federal Aviation Administration (FAA), a structured human factors framework used to examine workplace variables and design error-tolerant systems.

Lack of Communication

Failure to transfer critical information clearly, accurately, and timely.

Lack of Communication

Includes poor shift handovers, vague verbal instructions, or incomplete documentation.

Lack of Communication

Failure to clearly transmit, receive, or confirm critical information, instructions, or shift handovers, leading to misalignments and missed procedural steps.

Distraction

An event (internal or external) that interrupts a critical task or procedure.

Distraction

Any mental or environmental interruption (e.g., noise, sudden calls, multi-tasking) that pulls focus away from the task at hand and causes technicians to skip essential checks.

Lack of Resources (Dirty Dozen)

Absence of necessary items: correct tools, spare parts, equipment, or even personnel.

Lack of Resources (Filthy Fifteen)

Inadequate or unavailable tools, equipment, documentation, replacement parts, or staffing required to perform a task safely and per specification.

Stress

The body's non-specific response to any demand for change (physical or psychological).

Stress

Mental, emotional, or physical strain caused by work demands, personal issues, or high-pressure environments, which impairs cognitive clarity and decision-making.

Complacency

An attitude of self-satisfaction leading to a relaxed level of vigilance.

Complacency

A false sense of security or overconfidence resulting from routine, repetitive tasks, leading individuals to skip inspections or assume systems are functional without verification.

Lack of Teamwork

Breakdown in coordination, cooperation, or mutual support within the work group.

Lack of Teamwork

Poor coordination, trust, or synergy among crew members, resulting in uncoordinated actions, duplicated work, or isolated working hazards.

Pressure

An intense expectation to complete a task quickly, often bypassing standard procedure.

Pressure

Real or perceived urgency to meet tight schedules, turnarounds, or deadlines, driving workers to rush and bypass mandatory procedures.

Lack of Awareness

Failure to accurately perceive the operating environment and comprehend its potential future state.

Lack of Awareness

Failure to recognize the broader operational picture, failing to anticipate hazards, environmental changes, or the downstream consequences of an action (loss of ____).

Lack of Knowledge

Insufficient training, experience, or familiarity with a specific system, tool, or procedure.

Lack of Knowledge

Performing a task without adequate training, experience, or technical familiarity with current procedures, aircraft models, or systems.

Fatigue

A physiological state leading to reduced mental and physical capacity.

Fatigue

Physical or mental exhaustion resulting from prolonged work hours, shift work, or sleep deprivation, which slows reaction times and degrades judgment.

Lack of Assertiveness

Inability or reluctance to voice concerns or challenge unsafe actions or decisions.

Lack of Assertiveness

Failure to express concerns, raise safety questions, or stop an unsafe operation due to fear of conflict, hierarchy, or peer pressure.

Norms

Unwritten, informal practices or workarounds ("the way we've always done it") that deviate from official published procedures and normalize risk over time.

Not Admitting Limitations

Reluctance to acknowledge personal boundaries—such as physical exhaustion, lack of experience, or cognitive overload—and failing to ask for help when needed.

Lack of Operational Integrity

Willingness to compromise standard operating procedures, quality standards, or regulatory rules, especially when unsupervised.

Lack of Professionalism

Failure to demonstrate accountability, pride in workmanship, self-discipline, and adherence to professional safety standards during daily operations.

People (PEAR Model)

Focuses on the individuals performing the work and their physical, physiological, psychological, and psychosocial characteristics.

Environment (PEAR Model)

Examines the physical workspace and organizational environment in which the work takes place.

Actions (PEAR Model)

Focuses on the specific operational tasks, steps, complexity, sequence, and behaviors required of the worker.

Resources (PEAR Model)

Includes all tangible and information-based support assets (hardware, equipment, information, material, time) needed to complete the task safely.