Text-only reference. Published from the recorded official FAA General Chapter 14 PDF. Diagrams, photographs, and figure artwork are not reproduced here; use the official FAA PDF for those materials.
14-17 THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Teamwork Fatigue Lack of Resources
Pressure
Lack of Assertiveness
Stress
Lack of Awareness Norms Complacency Lack of Knowledge Distraction Lack of Communication MITIGATING THE RISK Always expect to find something wrong. Always double check your work. Never sign off on something that you did not fully check. People tend to become overconfident after becoming proficient in a certain task, which can mask the awareness of dangers. others. Have others check your work, even if an inspector sign off is not required. Avoid complex tasks during the bottom of your circadian rhythm. Sleep and exercise daily. Eight to nine hours of daily sleep are recommended to avoid fatigue.
AMTs in airline operations are part of a system in which most maintenance is performed at night. Fleet aircraft are operated primarily during daytime hours to generate company revenue. Therefore, shift work is required to maintain the fleet. It is already known that turning work over to other technicians during shift changes can lead to errors due to lack of communication. But shift work alone is a cause of fatigue that can degrade performance and also lead to errors. Shift work requires technicians to work during low cycles of their natural circadian rhythm. It also makes sleep more difficult when not on the job. Furthermore, regular night shift work makes a person’s body more sensitive to environmental disturbances. It can degrade performance, morale, and safety. It can also affect one’s physical health. All of these can be reflected in degraded maintenance performance—a dangerous situation.
The technician must be aware that shift work is the norm in 14-18 THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Teamwork Fatigue Lack of Resources
Pressure
Lack of Assertiveness
Stress
Lack of Awareness Norms Complacency Lack of Knowledge Distraction Lack of Communication MITIGATING THE RISK Only fix parts that you are trained to fix. If you do not know how to fix something, ask for help from someone who does. Ensure that the maintenance manual you are using is up to date. In a world of ever-changing technology, maintainers must remain up to date on current equipment and how to fix it. aviation. Avoidance of fatigue is part of the job. Title 14 of the Code of Federal Regulations (14 CFR) part 121, section 377, only requires 24 hours time off during a week of work. Since this is obviously not enough, it is up to companies and technicians to regulate shift work and time off to reduce the potential for errors. Most importantly, each technician must monitor and control their sleep habits to avoid fatigue.
Lack of Resources A lack of resources can interfere with a person’s ability to complete a task because of a lack of supplies and support. [Figure 14-25] Low quality products also affect one’s ability to complete a task. Aviation maintenance demands proper tools and parts to maintain a fleet of aircraft. Any lack of resources to safely carry out a maintenance task can cause both non-fatal and fatal accidents. For example, if an aircraft is dispatched without a functioning system that is typically nonessential for flight but suddenly becomes needed, this