The FAA has had a formal involvement in this issue since 1988. That was the year the first Human Factors Issues in Aviation Maintenance and Inspection National Conference was conducted, and that effort reflects a working relationship between government research and industry activity. This yearly event includes airlines, suppliers, manufacturers, schools, and government agencies. There is also an FAA website for human factors at http://hfskyway.faa.gov/ which is a tremendous resource.
- Importance, Definitions, and Elements of Human Factors
- History of Human Factors
- The Pear Model
- Human Error and The “Dirty Dozen” (Part One)
- Human Error and The “Dirty Dozen” (Part Two)
- Human Error and The “Dirty Dozen” (Part Three)
- Where to Get Information
Importance of Human Factors
The greatest impact in aircraft safety in the future will not come from improving the technology. Rather it will be from educating the employee to recognize and prevent human error. A review of accident related data indicates that approximately 75–80 percent of all aviation accidents are the result of human error. Of those accidents, about 12 percent are maintenance related. Although pilot/co-pilot errors tend to have immediate and highly visible effects, maintenance errors tend to be more latent and less obvious. However, they can be just as lethal.
Definitions of Human Factors
Human factors are concerned with optimizing performance … including reducing errors so that the highest level of safety is achieved and maintained.
—Ron LoFaro, PhD, FAA
Human factors is the study of how people interact with their environments.
—FAA-H-8083-25, Pilot’s Handbook of Aeronautical Knowledge, dated 2003
Human factors are those elements that affect our behavior and performance, especially those that may cause us to make errors.
—Canadian Department of Defense (video)
Our focus is on human factors as it relates to improper actions. Note, however, that human factors exist in both proper and improper actions. [Figure 14-1] Since improper actions usually result in human error, we should also define that term.
Human error is the unintentional act of performing a task incorrectly that can potentially degrade the system. There are three types of human error:
- Omission: not performing an act or task.
- Commission: accomplishing a task incorrectly.
- Extraneous: performing a task not authorized.
There are also four consequences of human error:
- Little or no effect.
- Damage to equipment/hardware.
- Personal injury.
Why are human conditions, such as fatigue, complacency, and stress, so important in aviation maintenance? These conditions, along with many others, are called human factors. Human factors directly cause or contribute to many aviation accidents. It is universally agreed that 80 percent of maintenance errors involve human factors. If they are not detected, they can cause events, worker injuries, wasted time, and even accidents. [Figure 14-2]
Aviation safety relies heavily on maintenance. When it is not done correctly, it contributes to a significant proportion of aviation accidents and incidents. Some examples of maintenance errors are parts installed incorrectly, missing parts, and necessary checks not being performed. In comparison with many other threats to aviation safety, the mistakes of an aviation maintenance technician (AMT) can be more difficult to detect. Often, these mistakes are present but not visible and have the potential to remain latent, affecting the safe operation of aircraft for extended periods of time.
AMTs are confronted with a set of human factors unique within aviation. They can be working in the evening or early morning hours, in confined spaces, on high platforms, and in a variety of adverse temperature/humidity conditions. The work can be physically strenuous, yet it also requires attention to detail. [Figure 14-3] Because of the nature of maintenance tasks, AMTs commonly spend more time preparing for a task than actually carrying it out. Proper documentation of all maintenance work is a key element, and AMTs typically spend as much time updating maintenance logs as they do performing the work. [Figure 14-4]
Human factors awareness can lead to improved quality, an environment that ensures continuing worker and aircraft safety, and a more involved and responsible workforce. The reduction of even minor errors can provide measurable benefits including cost reductions, fewer missed deadlines, reduction in work related injuries, reduction of warranty claims, and reduction in more significant events that can be traced back to maintenance error. Within this chapter, the many aspects of human factors are discussed in relation to aviation maintenance. The most common human factors are introduced along with ways to mitigate the risk to stop them from developing into a problem. Several Federal Aviation Administration (FAA) human factor resources are provided, including a direct link to aviation maintenance human factors are at https://hfskyway.faa.gov.