Human Factors Models
Abbie Ijams
4/15/14

PEAR Model – Aviation Maintenance

The PEAR model recognizes four things: 1. The people who do the job 2. The type of environment in which they work 3. The actions that are taken 4. The recourses necessary to complete the job
People:
Most human factors programs are centered around people. They are the least reliable. However, they are necessary. There are four issues when considering the people in human factors. * Physical – physical size, age, strength, and sex. * Psychological – workload, experience, attitude, and emotional state. * Physiological – health, fatigue, lifestyle, and hunger * Psychosocial – interpersonal relations (people skills)
Environment:
There are two main locations in aviation maintenance – the ramp, hangar/shop and the relationship environment with the rest of the company. The first one can have issues with noise level, temperature, and other physical problems. The organizational factors with the rest of the company, however, has to do with communication, mutual respect, and cooperation.
Actions:
Human factors programs analyze the actions of individuals and the reasons they make the decisions that they do. Job Task Analysis (JTA) is used to determine what resources, instruction, and tools are needed to perform a task, as well as a person’s skill level and attitude.
Resources:
There are physical and non-physical kinds of resources. The physical types include things like tools, computers, test equipment, and manuals. The non-physical resources include time allotted for work, number and qualifications of workers, communication between everyone in the company.

Human Factors Analysis and Classification System (HFACS) Model

There are four levels of the HFACS Model: 1. Unsafe Acts 2. Precondition for Unsafe Acts 3. Usafe Supervisions 4. Organizational Influences

Unsafe Acts:
Unsafe acts are divided up into two categories. * Errors – unintentional behaviors * Violations – a willful disregard of the rules and regulations
Skill based, decision, and perceptual are all errors, which can be corrected. However, routine and exceptional violations are habitual and not as easily changed.
Precondition for Unsafe Acts:
Divided into three categories. * Environmental Factors – physical and technological factors which affect practices, conditions, and actions of an individual * Condition of Operators – adverse mental, physical, and physiological limitations that affect the environmental factors * Personnel Factors – crew resource management and personal readiness
Unsafe Supervision
Divided into four categories. * Inadequate Supervision – supervisor must provide guidance and be a helpful resource * Plan Inappropriate Operation – unacceptable during normal operation (risk management) * Fail to Correct Known Problem – supervisor knows of an issue but fails to take action to get it corrected * Supervisory Violation – rules are disregarded by supervisor
Organizational Influences:
Organizational influences is divided up into three categories. * Resource Management – refers to organizational decision making * Organizational Climate – the atmosphere at the company * Operational Process – rules that govern everyday activities and tasks

Threat and Error Management (TEM) Model

Threat and Error Management is a safety concept regarding aviation operations and human performance. It is a consequence of the constant desire to improve the safety of aviation. There are three main points/levels in the model. 1. Threats – events/errors that occur which must be managed to maintain margins of safety 2. Errors – actions or inactions that lead to deviations from intentions or expectations 3. Undesired States – result from ineffective threat and/or error management may lead to compromised situations and reduce margins of safety aviation operations a. Often considered the last stage before an incident or accident