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12 most important human factors to consider according to AS9100 Rev D

AS9100 Rev D contains a couple of requirements that include the consideration of human factors when designing the aerospace Quality Management System (QMS) for your company. These requirements include considering actions to prevent human error (clause 8.5.1g) and thinking about causes of nonconformity that come from human factors when processing corrective actions (clause 10.2.1b).

On the surface, this sounds simple; but, upon further discernment, the implications of these requirements may cause some confusion. What exactly are human factors, and what needs to be considered? Here is more information on where the concept of human factors comes from and why you should consider this in your management system.

For more information on what has changed in AS9100 Rev D, see this article: AS9100 Rev D vs. Rev C – What has changed?

Human factors: Originating in aircraft maintenance

The consideration of human factors in the aerospace industry first emerged in aircraft maintenance. The idea is that when we have a nonconformity due to human error, that is, a quality issue that was caused by a person doing something incorrectly, there is a deeper root cause of the occurrence. There are many factors that can cause a situation where a human error can occur, and these precursors or preconditions are referred to as human factors.

While there are a number of conditions that can result in human error (some lists include more than 300 human factors), the aerospace industry has found 12 that are the most common when discussing human factors. This list is sometimes called the “dirty dozen,” and includes:

1) Lack of communication. Was important information not communicated to the person, such as a process change that the operator didn’t know about? Was there information that was not transmitted from one shift to another? These little considerations should be investigated to see if there was a problem with communication leading to the human error.

2) Distraction. What could have drawn the person’s attention away from the task at hand? This could be something simple, such as being startled by a sound. However, you may also need to consider more complex distractions, such as the employee worrying about a situation they are dealing with at home.

3) Lack of resources. Sometimes an employee may not have everything needed to complete a task, but they will do their best to finish anyway. If there are only older tools available, or if a tool breaks during a task without a ready replacement, what problems could result when the task is completed in such conditions? When the resources are not optimal for the task, errors can be made.

4) Pressure. Poor judgement sometimes occurs when people make an assumption of what is expected. Sometimes deadlines on a project are tight, and employees may try to finish tasks faster in order to meet the schedule. Keep in mind that this could be as simple as an employee trying to finish a task before the end of their shift, because they need to leave on time due to family commitments.

5) Complacency. When people have been doing the same activity for a long time, they sometimes have less awareness of the danger presented, becoming complacent. This can also occur when people let their guard down after a big problem has been solved. Do operators do the same job over and over again with few breaks? Have you just had a very active time trying to solve a problem? This can lead to employees tuning out while they work.

6) Lack of teamwork. Issues with teamwork on group tasks can lead to problems occurring. Is this a new team that is learning to work together? Has an experienced team member, especially from a leadership position, recently left the team? Is there a team member who was sick when the error occurred?

7) Stress. Like pressure, people can feel stress from factors inside the work environment, or from outside the company. This stress can be a long-term source of pressure and can distract from their ability to perform their work.

8) Lack of awareness. When someone works in isolation, they may not be aware of how their actions affect others’ activities. This lack of awareness can make it difficult for others to perform tasks, leading to errors.

9) Fatigue. Fatigue can lead to stress and distraction, and it can even be a cause of human error by itself. This fatigue can be caused by work experiences, such as employees putting in a lot of overtime to deal with a program issue, or from outside factors such as an employee who was awake the previous night with a sick child.

10) Lack of knowledge. Does the employee have the training they need for the job? People often think that training is only needed for new employees. However, when an experienced employee starts a new job, or a job they have not done for a long time, they may not have the up-to-date knowledge needed for that particular task.

11) Lack of assertiveness. When a less-experienced employee makes a mistake under the direction of a senior person, that employee may have thought that what they were doing was incorrect, but they did not want to question the authority of the senior person. Even if they misunderstood the instructions, they may not have felt free to question what they thought they were told.

12) Norms. When employees perform their tasks according to accepted norms, they are acting on unwritten rules. This can lead to problems when an uncommon issue occurs that is not part of the norm, and therefore goes unnoticed or unaddressed.

For more on the aerospace-specific definitions in AS9100 Rev D, see this article on Five special aerospace terms in AS9100 Rev D.

Considering human factors in your QMS

The consideration of human factors can be important both during the investigation of the root cause of a human error, as well as when making plans to avoid these mistakes. Some common activities to avoid errors include using checklists to prevent communication problems between shifts, planning changes in teams to avoid teamwork problems, and ensuring breaks to avoid distraction and fatigue. Think about what you already have in place, and you will see that some of these issues have already been addressed – but, considering human factors can help you to prevent human errors in the future.

For more information on the steps to implement AS9100 Rev D in your company, download this free Project checklist for AS9100 Rev D implementation.

Advisera Mark Hammar
Mark Hammar
Mark Hammar is a Certified Manager of Quality / Organizational Excellence through the American Society for Quality and has been a Quality Professional since 1994. Mark has experience in auditing, improving processes, and writing procedures for Quality, Environmental, and Occupational Health & Safety Management Systems, and is certified as a Lead Auditor for ISO 9001, AS9100, and ISO 14001.