Module Case Study Information A Module Case Study is a critical analysis and evaluation of a specific case or subject. For this course a Module Case Study must: Be two pages in length, double-spaced. Consist of a title (accurately reflective of the topic), an introductory paragraph, one to three body paragraphs, and a summary paragraph. Include information obtained from primary or secondary sources beyond those listed in the Module. Include proper APA (current edition) citations and references (with the references listed on a separate last page). Combined, Module Case Studies account for 25% of your final grade. For the grading standard for all Module Case Studies, review the Case Study Rubric in Module 1 (https://erau.instructure.com/courses/52743/assignments/809262) . File Format Either '.doc' or '.docx' file formats are acceptable with any assignment throughout the course. For example purposes in the course activity instructions, '.doc(x)' will be used to indicate both of these file types. Turnitin Turnitin is enabled for all case study assignments. For Turnitin guidance please refer to: How do I submit a Turnitin Assignment? (https://community.canvaslms.com/docs/DOC-3119) How do I view Turnitin results for my assignment submission? (https://community.canvaslms.com/docs/DOC-3120) Chapter 14 Human Factors Introduction 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 14-1] 14-1 Human Factors Mental State Emotional State Human Capabilities Physical State Human Limitations Human-Machine Interface Environmental Conditions Figure 14-1. Human factors and how they affect people are very important to aviation maintenance. 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 to many other threats to aviation safety, the mistakes of an aviation maintenance technician (AMT) can be more difficult to detect. Often times, these mistakes are present but not visible and have the potential to remain latent, affecting the safe operation of aircraft for longer periods of time. AMTs are confronted with a set of human factors unique within aviation. Often times, they are working in the evening or early morning hours, in confined spaces, on platforms that are up high, and in a variety of adverse temperature/humidity conditions. The work can be physically strenuous, yet it also requires attention to detail. [Figure 14-2] Because of the nature of the 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 14-3] Human factors awareness can lead to improved quality, an environment that ensures continuing worker and aircraft safety, and a more involved and responsible work force. More specifically, the reduction of even minor errors can provide measurable benefits including cost reductions, fewer missed Figure 14-2. Aviation maintenance technicians (AMTs) are confronted with many human factors due to their work environments. 14-2 Elements of Human Factors Human factors are comprised of many disciplines. This section discusses ten of those disciplines: Clinical Psychology, Experimental Psychology, Anthropometrics, Computer Science, Cognitive Science, Safety Engineering, Medical Science, Organizational Psychology, Educational Psychology, and Industrial Engineering. [Figure 14-5] Figure 14-3. AMT documenting repair work. 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 to include the most direct link to aviation maintenance human factors which can be found at https://hfskyway.faa.gov. What is Human Factors The term human factors has grown increasingly popular as the commercial aviation industry realize that human error, rather than mechanical failure, underlies most aviation accidents and incidents. Human factors science or technologies are multidisciplinary fields incorporating contributions from psychology, engineering, industrial design, statistics, operations research, and anthropometry. It is a term that covers the science of understanding the properties of human capability, the application of this understanding to the design, development, and deployment of systems and services, and the art of ensuring successful application of human factor principles into the maintenance working environment. The list of human factors that can affect aviation maintenance and work performance is broad. They encompass a wide range of challenges that influence people very differently as humans do not all have the same capabilities, strengths, weaknesses, or limitations. Unfortunately, aviation maintenance tasks that do not account for the vast amount of human limitations can result in technical error and injuries. Figure 14-4 shows some of the human factors that affect AMTs. Some are more serious than others but, in most cases, when you combine three or four of the factors, they create a problem that contributes to an accident or incident. The study and application of human factors is complex because there is not just one simple answer to fix or change how people are affected by certain conditions or situations. Aviation maintenance human factors research has the overall goal to identify and optimize the factors that affect human performance in maintenance and inspection. The focus initiates on the technician but extends to the entire engineering and technical organization. Research is optimized by incorporating the many disciplines that affect human factors and help to understand how people can work more efficiently and maintain work performance. By understanding each of the disciplines and applying them to different situations or human behaviors, we can correctly recognize potential human factors and address them before they develop into a problem or create a chain of problems that result in an accident or incident. Clinical Psychology Clinical psychology includes the study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development. It focuses on the mental well-being of the individual. Clinical psychology can help individuals deal with stress, coping mechanisms for adverse situations, poor self image, and accepting criticism from coworkers. Experimental Psychology Experimental psychology includes the study of a variety of basic behavioral processes, often in a laboratory environment. These processes may include learning, sensation, perception, human performance, motivation, memory, language, thinking, and communication, as well as the physiological processes underlying behaviors, such as eating, reading, and problem solving. In an effort to test the efficiency of work policies and procedures, experimental studies help measure performance, productivity, and deficiencies. Anthropometrics Anthropometry is the study of the dimensions and abilities of the human body. This is essential to aviation maintenance due to the environment and spaces that AMTs have to work with. 14-3 Poor instructions Boring repetitive jobs Lack of spare parts Unrealistic deadlines Substance abuse Smelly fumes Personal life problems Poor tool control Poor training Fatigue Loud noises Poorly designed testing for skill and knowledge Slippery floors Snow Incomplete or incorrect documentation Lack of tools and equipment Poor communication Figure 14-4. A list of human factors that affect AMTs. For example, a man who is 6 feet 3 inches and weighs 230 pounds may be required to fit into a small crawl space of an aircraft to conduct a repair. Another example is the size and weight of equipment and tools. Men and women are generally on two different spectrums of height and weight. Although both are equally capable of completing the same task with a high level of proficiency, someone who is smaller may be able to perform more efficiently with tools and equipment that is tailored to their size. In other words, one size does not fit all and the term \"average person\" does not apply when employing such a diverse group of people. Computer Science The technical definition for computer science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and 14-4 application in computer systems. How this relates to aviation maintenance is a lot simpler. As mentioned earlier, AMTs spend as much time documenting repairs as they do performing them. It is important that they have computer work stations that are comfortable and reliable. Software programs and computer-based test equipment should be easy to learn and use, and not intended only for those with a vast level of computer literacy. Cognitive Science Cognitive science is the interdisciplinary scientific study of minds as information processors. It includes research on how information is processed (in faculties such as perception, language, reasoning, and emotion), represented, and transformed in a nervous system or machine (e.g., computer). It spans many levels of analysis from low-level Industrial Engineering Clinical Psychology Experimental Psychology Anthropometric Science Human Factors 0 Not Com plex Flig ht 10 Exer cise Organization Psychology Caut ion 20 Endangerment Low Risk Educational Psychology Area of Co ncer n 30 Safety Engineering Cognitive Science Medical Science Computer Science Figure 14-5. Human factor disciplines. learning and decision mechanisms to high-level logic and planning. AMTs must possess a great ability to problem solve quickly and efficiently. They constantly have to troubleshoot a situation and quickly react to it. This can be a viscous cycle creating an enormous amount of stress. The discipline of cognitive science helps us understand how to better assist AMTs during situations that create high levels of stress so that their mental process does not get interrupted and effect their ability to work. Medical Science Safety Engineering Organizational Psychology Safety engineering assures that a life-critical system behaves as needed even when the component fails. Ideally, safety engineers take an early design of a system, analyze it to find what faults can occur, and then propose safety requirements in design specifications up front and changes to existing systems to make the system safer. Safety cannot be stressed enough when it comes to aviation maintenance, and everyone deserves to work in a safe environment. Safety engineering plays a big role in the design of aviation maintenance facilities, storage containers for toxic materials, equipment used for heavy lifting, and floor designs to ensure no one slips, trips, or falls. In industrial work environments, the guidelines of the Occupational Safety and Health Administration (OSHA) are important. Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness. Disposition and physical well-being are very important and directly correlated to human factors. Just like people come in many shapes and sizes, they also have very different reactions to situations due to body physiology, physical structures, and biomechanics. Organizational psychologists are concerned with relations between people and work. Their interests include organizational structure and organizational change, workers' productivity and job satisfaction, consumer behavior, and the selection, placement, training, and development of personnel. Understanding organizational psychology helps aviation maintenance supervisors learn about the points listed below that, if exercised, can enhance the work environment and productivity. Rewards and compensations for workers with good safety records. Motivated workers that want to do well and work safely. 14-5 Unified work teams and groups that get along and work together to get the job done right. Treat all workers equally. Educational Psychology Educational psychologists study how people learn and design the methods and materials used to educate people of all ages. Everyone learns differently and at a different pace. Supervisors should design blocks of instruction that relate to a wide variety of learning styles. Industrial Engineering Industrial engineering is the organized approach to the study of work. It is important for supervisors to set reasonable work standards that can be met and exceeded. Unrealistic work standards create unnecessary stressors that cause mistakes. It is also beneficial to have an efficient facility layout so that there is room to work. Clean and uncluttered environments enhance work performance. Another aspect of industrial engineering that helps in the understanding of human factors is the statistical analysis of work performance. Concrete data of work performance, whether good or bad, can show the contributing factors that may have been present when the work was done. History of Human Factors Around 1487, Leonardo DiVinci began research in the area of anthropometrics. The Vitruvian Man, one of his most famous drawings, can be described as one of the earliest sources presenting guidelines for anthropometry. [Figure 14-6] Around the same time, he also began to study the flight of birds. He grasped that humans are too heavy and not strong enough to fly using wings simply attached to the arms. Therefore, he sketched a device in which the aviator lies down on a plank and works two large, membranous wings using hand levers, foot pedals, and a system of pulleys. [Figure 14-7] Today, anthropometry plays a considerable role in the fields of computer design, design for access and maintainability, simplicity of instructions, and ergonomics issues. Figure 14-6. Vitruvian Man, one of Leonardo DiVinci's famous In the early 1900s, industrial engineers Frank and Lillian Gilbreth were trying to reduce human error in medicine. [Figures 14-8 and 14-9] They developed the concept of using call backs when communicating in the operating room. For example, the doctor says \"scalpel\" and the nurse repeats \"scalpel\" and then hands it to the doctor. That is called the challenge-response system. Speaking out loud reinforces what tool is needed and provides the doctor with an opportunity to correct his/herself if that is not the necessary tool. This same verbal protocol is used in aviation today. Pilots are required to read back instructions or clearances given by air traffic Figure 14-7. Leonardo DiVinci's rendering of a flying device 14-6 drawings about anthropometry. for man. control (ATC) to ensure that the pilot receives the correct instructions and gives ATC an opportunity to correct if the information is wrong. Frank and Lillian Gilbreth also are known for their research on fatigue. Also in the early 1900s, Orville and Wilbur Wright were the first to fly a powered aircraft and also pioneered many human factors considerations. While others were trying to Devil Hills, near Kitty Hawk, North Carolina, to develop the first practical human interactive controls for aircraft pitch, roll, and yaw. On December 17, 1903, they made four controlled powered flights over the dunes at Kitty Hawk with their Wright Flyer. [Figure 14-10] They later developed practical in-flight control of engine power, plus an angle of attack sensor and stick pusher that reduced pilot workload. The brothers' flight demonstrations in the United States and Europe during 1908-1909, awakened the world to the new age of controlled flight. Orville was the first aviator to use a seat belt and also introduced a rudder boost/trim control that gave the pilot greater control authority. The Wrights' flight training school in Dayton, Ohio included a flight simulator of their own design. The Wrights patented their practical airplane and flight control concepts, many of which are still in use today. Figure 14-8. Frank Gilbreth - Industrial Engineer. Figure 14-10. The Wright Brothers on December 17, 1903, flying over the dunes at Kitty Hawk with their Wright Flyer. Prior to World War I, the only test of human to machine compatibility was that of trial and error. If the human functioned with the machine, he was accepted, if not he was rejected. There was a significant change in the concern for humans during the American Civil War. The U.S. Patent Office was concerned about whether the mass produced uniforms and new weapons could effectively be used by the infantry men. Figure 14-9. Lillian Gilbreth - Industrial Engineer. develop aircraft with a high degree of aerodynamic stability, the Wrights intentionally designed unstable aircraft with cerebralized control modeled after the flight of birds. Between 1901 and 1903, the brothers worked with large gliders at Kill Evolution of Maintenance Human Factors With the onset of World War I (1914-1918), more sophisticated equipment was being developed and the inability of personnel to use such systems led to an increased interest in human capability. Up to this point, the focus of aviation psychology was on the pilot, but as time progressed, the focus shifted onto the aircraft. Of particular concern was the design of the controls and displays, the effects of altitude, and environmental factors on the pilot. The war also brought on the need for aeromedical research and the need for testing and measurement methods. By the end of World War I, two aeronautical labs were established, one at Brooks Air Force Base, Texas, and the other at Wright Field outside of Dayton, Ohio. 14-7 Another significant development was in the civilian sector, where the effects of illumination on worker productivity were examined. This led to the identification of the Hawthorne Effect, which suggested that motivational factors could significantly influence human performance. With the onset of World War II (1939-1945), it was becoming increasingly harder to match individuals to preexisting jobs. Now the design of equipment had to take into account human limitations and take advantage of human capabilities. This change took time as there was a lot of research to be done to determine the human capabilities and limitations that had to be accomplished. An example of this is the 1947 study done by Fitts and Jones, who studied the most effective configuration of control knobs to be used in aircraft flight decks. Much of this research transcended into other equipment with the aim of making the controls and displays easier for the operators to use. In the initial 20 years after World War II, most human factors research was done by Alphonse Chapanis, Paul Fitts, and Arnold Small. The beginning of the Cold War led to a major expansion of Department of Defense supported research laboratories, and many of the labs established during the war started expanding. Most of the research following the war was military sponsored and large sums of money were granted to universities to conduct research. The scope of the research also broadened from small equipment to entire workstations and systems. In the civilian industry, the focus shifted from research to participation through advice to engineers in the design of equipment. The Pear Model There are many concepts related to the science and practice of human factors. However, from a practical standpoint, it is PEOPLE most helpful to have a unified view of the things we should be concerned about when considering aviation maintenance human factors. A good way to gain this understanding is by using a model. For more than a decade, the term \"PEAR\" has been used as a memory jogger, or mnemonic, to characterize human factors in aviation maintenance. PEAR prompts recall of the four important considerations for human factors programs, which are listed below. People who do the job. Environment in which they work. Actions they perform. Resources necessary to complete the job. People Aviation maintenance human factors programs focus on the people who perform the work and address physical, physiological, psychological, and psychosocial factors. [Figure 14-11] It must focus on individuals, their physical capabilities, and the factors that affect them. It also should consider their mental state, cognitive capacity, and conditions that may affect their interaction with others. In most cases, human factors programs are designed around the people in the company's existing workforce. You cannot apply identical strength, size, endurance, experience, motivation, and certification standards equally to all employees. The company must match the physical characteristics of each person to the tasks each performs. The company must consider factors like each person's size, strength, age, eyesight, and more to ensure each person is physically capable of performing all the tasks making up the job. A good human factors program considers the limitations of humans and designs the job accordingly. An important Physical Physical size Sex Age Strengh Sensory limitations Psychological Nutritional Factors Health Lifestyle Fatigue Chemical dependency Figure 14-11. People who do the job. 14-8 Physiological Workload Experience Knowledge Training Attitude Mental or emotional state Psychosocial Interpersonal conflicts element when incorporating human factors into job design is planned rest breaks. People can suffer physical and mental fatigue under many work conditions. Adequate breaks and rest periods ensure the strain of the task does not overload their capabilities. Another \"People\" consideration, which also is related to \"E\" for \"Environment,\" is ensuring there is proper lighting for the task, especially for older workers. Annual vision testing and hearing exams are excellent proactive interventions to ensure optimal human physical performance. Attention to the individual does not stop at physical abilities. A good human factors program must address physiological and psychological factors that affect performance. Companies should do their best to foster good physical and mental health. Offering educational programs on health and fitness is one way to encourage good health. Many companies have reduced sick leave and increased productivity by making healthy meals, snacks, and drinks available to their employees. Companies also should have programs to address issues associated with chemical dependence, including tobacco and alcohol. Another \"People\" issue involves teamwork and communication. Safe and efficient companies find ways to foster communication and cooperation among workers, managers, and owners. For example, workers should be rewarded for finding ways to improve the system, eliminate waste, and help ensure continuing safety. Environment There are at least two environments in aviation maintenance. There is the physical workplace on the ramp, in the hangar, or in the shop. In addition, there is the organizational environment that exists within the company. A human factors program must pay attention to both environments. [Figure 14-12] Physical The physical environment is obvious. It includes ranges of temperature, humidity, lighting, noise control, cleanliness, and workplace design. Companies must acknowledge these ENVIRONMENT conditions and cooperate with the workforce to either accommodate or change the physical environment. It takes a corporate commitment to address the physical environment. This topic overlaps with the \"Resources\" component of PEAR when it comes to providing portable heaters, coolers, lighting, clothing, and workplace and task design. Organizational The second, less tangible, environment is the organizational one. The important factors in an organizational environment are typically related to cooperation, communication, shared values, mutual respect, and the culture of the company. An excellent organizational environment is promoted with leadership, communication, and shared goals associated with safety, profitability, and other key factors. The best companies guide and support their people and foster a culture of safety. A safe culture is one where there is a shared value and attitude toward safety. In a safe culture, each person understands their individual role is contributing to overall mission safety. Actions Successful human factors programs carefully analyze all the actions people must perform to complete a job efficiently and safely. Job task analysis (JTA) is the standard human factors approach to identify the knowledge, skills, and attitudes necessary to perform each task in a given job. The JTA helps identify what instructions, tools, and other resources are necessary. Adherence to the JTA helps ensure each worker is properly trained and each workplace has the necessary equipment and other resources to perform the job. Many regulatory authorities require the JTA serve as the basis for the company's general maintenance manual and training plan. Many human factors challenges associated with use of job cards and technical documentation fall under \"Actions.\" A crystal clear understanding and documentation of actions ensures instructions and checklists are correct and useable. [Figure 14-13] Physical Weather Location inside/outside Workspace Shift Lighting Sound level Safety Organizational Personnel Supervision Labor-management relations Pressures Crew structure Size of company Profitability Morale Corporate culture Figure 14-12. Environment in which they work. 14-9 ACTIONS Steps to perform a task Sequence of activity Number of people involved Information control requirements Knowledge requirements Skill requirements Altitude requirements Certification requirements Inspection requirements Figure 14-13. Actions they perform. Resources The final PEAR letter is \"R\" for \"Resources.\" [Figure 14-14] Again, it is sometimes difficult to separate resources from the other elements of PEAR. In general, the characteristics of the people, environment, and actions dictate the resources. Many resources are tangible, such as lifts, tools, test equipment, computers, technical manuals, and so forth. Other resources are less tangible. Examples include the number and qualifications of staff to complete a job, the amount of time allocated, and the level of communication among the crew, supervisors, vendors, and others. Resources should be viewed (and defined) from a broad perspective. A resource is anything a technician (or anyone else) needs to get the job done. For example, protective clothing is a resource. A mobile phone can be a resource. Rivets can be resources. What is important to the \"Resource\" element in PEAR is focusing on identifying the need for additional resources. produces, it becomes extremely troublesome. Training, risk assessments, safety inspections, etc., should not be restricted to attempt to avoid errors but rather to make them visible and identify them before they produce damaging and regrettable consequences. Simply put, human error is not avoidable but it is manageable. [Figure 14-15] ETY HUM AN E Human Error Human error is defined as a human action with unintended consequences. There is nothing inherently wrong or troublesome with error itself, but when you couple error with aviation maintenance and the negative consequences that it SAF RRO R Figure 14-15. Safety awareness will help foresee and mitigate the risk of human error. RESOURCES Procedures/work cards Technical manuals Other people Test equipment Tools Computers/software Paperwork/signoffs Figure 14-14. Resources necessary to complete the job. 14-10 Ground Handling equipment Work stands and lifts Fixtures Materials Task lighting Training Quality systems Types of Errors Unintentional An unintentional error is an unintentional wandering or deviation from accuracy. This can include an error in your action (a slip), opinion, or judgment caused by poor reasoning, carelessness, or insufficient knowledge (a mistake). For example, an AMT reads the torque values from a job card and unintentionally transposed the number 26 to 62. He or she did not mean to make that error but unknowingly and unintentionally did. An example of an unintentional mistake would be selecting the wrong work card to conduct a specific repair or task. Again, not an intentional mistake but a mistake nonetheless. Intentional In aviation maintenance, an intentional error should really be considered a violation. If someone knowingly or intentionally chooses to do something wrong, it is a violation, which means that one has deviated from safe practices, procedures, standards, or regulations. Kinds of Errors Active and Latent An active error is the specific individual activity that is an obvious event. A latent error is the company issues that lead up to the event. For example, an AMT climbs up a ladder to do a repair knowing that the ladder is broken. In this example, the active error was falling from the ladder. The latent error was the broken ladder that someone should have replaced. The \"Dirty Dozen\" Due to a large number of maintenance-related aviation accidents and incidents that occurred in the late 1980s and early 1990s, Transport Canada identified twelve human factors that degrade people's ability to perform effectively and safely, which could lead to maintenance errors. These twelve factors, known as the \"dirty dozen,\" were eventually adopted by the aviation industry as a straight forward means to discuss human error in maintenance. It is important to know the dirty dozen, how to recognize their symptoms, and most importantly, know how to avoid or contain errors produced by the dirty dozen. Understanding the interaction between organizational, work group, and individual factors that may lead to errors and accidents, AMTs can learn to prevent or manage them proactively in the future. Lack of Communication Lack of communication is a key human factor that can result in suboptimal, incorrect, or faulty maintenance. [Figure 14-16] Communication occurs between the AMT and many people (i.e., management, pilots, parts suppliers, aircraft servicers). Each exchange holds the potential for misunderstanding or omission. But communication between AMTs may be the most important of all. Lack of communication between technicians could lead to a maintenance error and result in an aircraft accident. This is especially true during procedures where more than one technician performs the work on the aircraft. It is critical that accurate, complete information be exchanged to ensure that all work is completed without any step being omitted. Knowledge and speculation about a task must be clarified and not confused. Each step of the maintenance procedure must be performed according to approved instructions as though only a single technician did the work. A common scenario where communication is critical and a lack thereof can cause problems, is during shift change in an airline or fixed base operator (FBO) operation. A partially completed job is transferred from the technician finishing his or her workday to the technician coming on duty. Many steps in a maintenance procedure are not able to be seen or verified once completed due to the installation of components hiding the work. No steps in the procedure can be omitted and some steps still to be performed may be contingent on the work already completed. The departing technician must thoroughly explain what has occurred so that the arriving technician can correctly complete the job. A recounting of critical steps and any difficulties encountered gives insight. A lack of communication at this juncture could result in the work being continued without certain required operations having been performed. The approved steps of a maintenance procedure must be signed off by the technician doing the work as it is performed. Continuing a job that has been started by someone else should only occur after a face-to-face meeting of technicians. The applicable paperwork should be reviewed, the completed work discussed, and attention for the next step should be drawn. Absence of either a written or oral turnover serves as warning that an error could occur. It is vital that work not be continued on a project without both oral and written communication between the technician who started the job and the technician continuing it. Work should always be done in accordance with the approved written procedure and all of the performed steps should bear the signature of the technician who accomplishes the work. If necessary, a phone call can be made to obtain an oral turnover when technicians cannot meet face-to-face at the work area. In general, the technician must see his or her role as part of a greater system focused on safe aircraft operation and must communicate well with all in that system to be effective. 14-11 THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Communication Lack of Teamwork Lack of Assertiveness Complacency Fatigue Stress Lack of Knowledge Lack of Resources Lack of Awareness Distraction Pressure Norms Maintainers must communicate with one another and explain what work has and has not been completed when changing shifts. MITIGATING THE RISK Properly use logbooks and worksheets to communicate work accomplishments. Ensure that maintenance personnel are discussing exactly what has been and needs to be completed to the next shift. Never assume that the work has been completed. Figure 14-16. Lack of communication. Complacency Complacency is a human factor in aviation maintenance that typically develops over time. [Figure 14-17] As a technician gains knowledge and experience, a sense of self satisfaction and false confidence may occur. A repetitive task, especially an inspection item, may be overlooked or skipped because the technician has performed the task a number of times without ever finding a fault. The false assumption that inspection of the item is not important may be made. However, even 14-12 if rare, a fault may exist. The consequences of the fault not being detected and corrected could cause an incident or accident. Routine tasks performed over and over allow time for the technician's mind to wander, which may also result in a required task not being performed. When a technician finds him or herself performing work without documentation, or documenting work that was not performed, it is a sign that complacency may exist. THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Communication Lack of Teamwork Lack of Assertiveness Complacency Fatigue Stress Lack of Knowledge Lack of Resources Lack of Awareness Distraction Pressure Norms People tend to become overconfident after becoming proficient in a certain task, which can mask the awareness of dangers. MITIGATING THE RISK Always expect to find something wrong. Never sign off on something that you did not fully check. Always double check your work. Figure 14-17. Complacency. Approved, written maintenance procedures should be followed during all maintenance inspections and repairs. Executing the proper paperwork draws attention to a work item and reinforces its significance. To combat complacency, a technician must train oneself to expect to find the fault that created the inspection item in the first place. He or she must stay mentally engaged in the task being performed. All inspection items must be treated with equal importance, and it must never be assumed that an item is acceptable when it has not been inspected. A technician should never sign for any work that has not been performed. Prior to the pen touching the paper for a signature, the technician should read the item before signing and confirm it has been performed. Lack of Knowledge A lack of knowledge when performing aircraft maintenance can result in a faulty repair that can have catastrophic results. [Figure 14-18] Differences in technology from aircraft to aircraft and updates to technology and procedures on a single aircraft also make it challenging to have the knowledge required to perform airworthy maintenance. 14-13 THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Communication Lack of Teamwork Lack of Assertiveness Complacency Fatigue Stress Lack of Knowledge Lack of Resources Lack of Awareness Distraction Pressure Norms In a world of ever changing technology, maintainers must remain up to date on current equipment and how to fix it. MITIGATING THE RISK Only fix parts that you are trained to fix. Ensure that the maintenance manual you are using is up to date. If you do not know how to fix something, ask for help from someone who does. Figure 14-18. Lack of knowledge. All maintenance must be performed to standards specified in approved instructions. These instructions are based on knowledge gained from the engineering and operation of the aircraft equipment. Technicians must be sure to use the latest applicable data and follow each step of the procedure as outlined. They must also be aware that differences exist in the design and maintenance procedures on different aircraft. It is important for technicians to obtain training on different types of aircraft. When in doubt, a technician with experience on the aircraft should be consulted. If one is not available, or the consulted technician is not familiar with the procedure, a 14-14 manufacturer's technical representative should be contacted. It is better to delay a maintenance procedure than to do it incorrectly and cause an accident. Distraction A distraction while performing maintenance on an aircraft may disrupt the procedure. [Figure 14-19] When work resumes, it is possible that the technician skips over a detail that needs attention. It is estimated that 15 percent of maintenance related errors are caused by distractions. THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Communication Lack of Teamwork Lack of Assertiveness Complacency Fatigue Stress Lack of Knowledge Lack of Resources Lack of Awareness Distraction Pressure Norms A distraction could be anything that takes your mind off the task that is being done. Any distraction while working can cause us to think we are further ahead in the process than we actually are. MITIGATING THE RISK Once returning to the job, go back through all of the steps to ensure where you left off. Use a detailed checklist. Never leave tools or parts lying around. Secure them before leaving the area. Figure 14-19. Distraction. Distractions can be mental or physical in nature. They can occur when the work is located on the aircraft or in the hangar. They can also occur in the psyche of the technician independent of the work environment. Something as simple as a cell phone call or a new aircraft being pushed into the hangar can disrupt the technician's concentration on a job. Less visible is a difficult family or financial matter or other personal issues that may occupy the technicians thought process as work is performed. This can make performance of the required maintenance less effective. Regardless of their nature, numerous distractions may occur during the course of maintaining an aircraft. The technician must recognize when attention to the job at hand is being diverted and assure that work continues correctly. A good practice is to go back three steps in the work procedure when one is distracted and resume the job from that point. Use of a detailed step-by-step written procedure and signing off each step only after it is completed also helps. Incomplete work can be marked or tagged, especially when the technician is pulled from the work by a distraction, and it is unknown 14-15 when work will be resumed and by whom. Disconnect any connector and leave it plainly visible if an installation is not complete. There is a tendency to think a job is finished when a component is \"hooked up.\" Similarly, when a step in the maintenance procedure is complete, be sure to immediately lock wire or torque the fasteners if required. This can be used as an indication that all is well up to that point in the procedure. Lack of Teamwork A lack of teamwork may also contribute to errors in aircraft maintenance. [Figure 14-20] Closely related to lack of communication, teamwork is required in aviation maintenance in many instances. Sharing of knowledge between technicians, coordinating maintenance functions, turning work over from shift to shift, and working with flight personnel to troubleshoot and test aircraft are all are executed better in an atmosphere of teamwork. Often associated with improved safety in the workplace, teamwork involves everyone understanding and agreeing on actions to be taken. A gear swing or other operational check involves all the members of a team working together. Multiple technicians contribute to the effort to ensure a single outcome. They communicate and look out for one THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Communication Lack of Teamwork Lack of Assertiveness Complacency Fatigue Stress Lack of Knowledge Lack of Resources Lack of Awareness Distraction Pressure Norms Personality difference in the workplace must be left at the door. Organizations should emphasize that a lack of teamwork can ultimately effect the safety of maintenance work. MITIGATING THE RISK Ensure that lines of communication are open between personnel. Figure 14-20. Lack of teamwork. 14-16 Discuss specific duties when jobs require more than one person to eliminate any questions. Always look out for co-workers with safety in mind. another as they do the job. A consensus is formed that the item is airworthy or not airworthy. The technician primarily deals with the physical aspect of the aircraft and its airworthiness. Others in the organization perform their roles and the entire company functions as a team. Teams can win or lose depending on how well everyone in the organization works together toward a common objective. A lack of teamwork makes all jobs more difficult and, in maintenance, could result in a miscommunication that affects the airworthiness of the aircraft. Fatigue Fatigue is a major human factor that has contributed to many maintenance errors resulting in accidents. [Figure 14-21] Fatigue can be mental or physical in nature. Emotional fatigue also exists and effects mental and physical performance. A person is said to be fatigued when a reduction or impairment in any of the following occurs: cognitive ability, decision-making, reaction time, coordination, speed, strength, and balance. Fatigue reduces alertness and often reduces a person's ability to focus and hold attention on the task being performed. THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Communication Lack of Teamwork Lack of Assertiveness Complacency Fatigue Stress Lack of Knowledge Lack of Resources Lack of Awareness Distraction Pressure Norms Occupations that require an individual to work long hours or stay up overnight can lead to fatigue. Fatigue can cause a decrease of attention and a decreased level of consciousness, which can be very dangerous when conducting maintenance. MITIGATING THE RISK Be aware of the symptoms and look for them in yourself and coworkers. Forfeit complex tasks if you know you are exhausted. Eating healthy, exercising and regular sleep patterns can prevent fatigue. Figure 14-21. Fatigue. 14-17 Symptoms of fatigue may also include short-term memory problems, channeled concentration on unimportant issues while neglecting other factors that may be more important, and failure to maintain a situational overview. A fatigued person may be easily distracted or may be nearly impossible to distract. He or she may experience abnormal mood swings. Fatigue results in an increase in mistakes, poor judgment, and poor decisions or perhaps no decisions at all. A fatigued person may also lower his or her standards. Tiredness is a symptom of fatigue. However, sometimes a fatigued person may feel wide awake and engaged in a task. The primary cause of fatigue is a lack of sleep. Good restful sleep, free from drugs or alcohol is a human necessity to prevent fatigue. Fatigue can also be caused by stress and overworking. A person's mental and physical state also naturally cycles through various levels of performance each day. Variables such as body temperature, blood pressure, heart rate, blood chemistry, alertness, and attention rise and fall in a pattern daily. This is known as one's circadian rhythm. [Figure 14-22] A person's ability to work (and rest) rises and falls during this cycle. Performance counter to circadian rhythm can be difficult. Until it becomes extreme, a person may be unaware that he or she is fatigued. It is easier recognized by another person or in the results of tasks being performed. This is particularly dangerous in aviation maintenance since the lives of people depend on maintenance procedures performed at a high level of proficiency. Working alone when fatigued is particularly dangerous. Alertness Level Multiple Sleep Latency Test (MSLT) The best remedy for fatigue is to get enough sleep on a regular basis. The technician must be aware of the amount and quality of sleep obtained. Caution or time off is justified when too little sleep has occurred and errors are probable during maintenance. Countermeasures to fatigue are often used. Effectiveness can be short lived and many countermeasures may make fatigue worse. Caffeine is a common fatigue countermeasure. Pseudoephedrine found in sinus medicine and amphetamines are also used. While effective for short periods, a fatigued person remains fatigued and may have trouble getting the rest needed once off the job due to this drug use. Suggestions to help mitigate the problems caused by fatigue include looking for symptoms of fatigue in one's self and in 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 the 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 change is a problem that 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 one'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 performancea dangerous situation. The technician must be aware that shift work is the norm in aviation. Avoidance of fatigue is part of the job. Title 14 of the Code of Federal Regulations (14 CFR) part 121, section 20 1-3 AM Peak alertness 15 Slightly impaired 10 Reduced alertness 5 Dangerously drowsy 0 9 12 15 18 21 24 3 Time of Day Figure 14-22. Many human variables rise and fall daily due to one's natural circadian rhythm. 14-18 6 9 377, 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 his or her sleep habits to avoid fatigue. Lack of Resources A lack of resources can interfere with one's ability to complete a task because there is a lack of supply and support. [Figure 14-23] 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 not needed for flight but suddenly becomes needed, this could create a problem. Parts are not the only resources needed to do a job properly, but all too frequently parts become a critical issue. AMTs can THE DIRTY DOZEN Twelve human factors for aircraft maintenance proficiency Lack of Communication Lack of Teamwork Lack of Assertiveness Complacency Fatigue Stress Lack of Knowledge Lack of Resources Lack of Awareness Distraction Pressure Norms When there is a lack of resources available to properly fix something, a decision should be made to cease maintenance until the proper parts are available. MITIGATING THE RISK Maintain a sufficient supply of parts and order any anticipated parts before they are required. Never replace a part with one that is not compatible for the sake of getting the job done. Preserve all equipment through proper maintenance. Figure 14-23. Lack of resources. 14-19 When and where the event occurred? Were there any indications prior to failure? 14-20 Circadian Rhythm Disruption and Aviation It's All About the Rhythm and Blues Our body's biological functions work much like a finely tuned watch: Every part works in unison to keep the body in homeostasis (maintenance of the internal environment within tolerable limits). However, when one working part doesn't function normally, it tends to disrupt many other vital parts and can upset homeostasis. Often, we bring disruptions on ourselves with such things as self-imposed stress, and then we must try to get everything back to normal. Managing your circadian rhythm is no different. It must be maintained to operate within normal working parameters, or a variety of negative effects will occur, and some of these could become a safety-of-flight issue. An Internal Biological Clock Our circadian rhythm is best described as an internal biological clock that regulates our body functions, based on our wake/sleep cycle. Circadian rhythms are not only important in determining sleep cycles but also in feeding patterns. There are clear patterns of brain wave activity, hormone production, cell regeneration, and other biological activities linked to these daily cycles. Origin Circadian rhythms are believed to have originated in the earliest cells, with the purpose of protecting replicating DNA from high ultraviolet radiation during the daytime. As a result, replication was relegated to the dark, and a basic pattern of day/night cycle was engrained within the cell and passed down to subsequent generations. At some time in the distant past, the days may have been longer, because when we are deprived of time clues, we gravitate toward a 25-hour circadian cycle. The Internal Works of Our Biological Watch In your brain, there is a type of \"pacemaker\" located within the suprachiasmatic nuclei. This area regulates the firing of nerve cells that seem to control your circadian rhythm. Scientists can't explain precisely how this area in your brain \"keeps time.\" They do know your brain relies on \"outside\" influences called zeitgebers (German for time givers) to keep it on a normal schedule. The most obvious zeitgeber is daylight. When daylight hits your eyes, cells in the retinas signal your brain. Other zeitgebers are ambient temperature, sleep, social contact, physical activity, and even regular meal times. They all send \"timekeeping\" clues to your brain, helping keep your circadian rhythm running on schedule. Circadian Rhythm Disruption Any time that our normal 25-hour circadian rhythm is altered or interrupted, it will have physiological and behavioral impacts. This is better known as circadian rhythm disruption, or CRD. Normal circadian rhythms are naturally altered as one ages including changes in sleep pattern with respect to earlier onset of sleepiness, early-morning awakenings, and increased need for daytime napping. Sleep Disorders and CRD Several chronic sleep disorders can lead or contribute to circadian rhythm disruptions, including: Delayed Sleep Phase Syndrome. This disorder causes a delay in the normal sleep onset time by two or more hours. People affected by this disorder complain of late-evening insomnia and/or excessive early-morning sleepiness, have difficulties falling asleep before 2:00 a.m., have short sleep periods during weekdays, and prolonged (9-12 hours) sleep periods during the weekends. These individuals tend to experience depression and other psychiatric disorders. Advanced Sleep Phase Syndrome. This is a disorder where sleepiness occurs well before the desired sleep schedule. The resulting symptoms include evening sleepiness, an early sleep onset, and an morning awakening that is earlier than desired. A person feels the urge to go to sleep between 6:00 and 8:00 p.m. and wakes up between 1:00 and 3:00 a.m. the following morning. This disorder can have a negative impact on an individual's personal or social life because of the need to leave early-evening social activities to sleep. Evening sleepiness may also represent a driving hazard. Non 24-Hour SleepWake Disorder. This disorder is the result of an inadvertent delay of the sleep onset time, followed by unsuccessful attempts to sleep at the desired sleep schedule. People affected by this disorder constantly delay sleep onset times that interfere with circadian rhythms. They have a normal sleep duration pattern but live in a freerunning \"biological clock\" of 25 hours instead of the community-accepted 24-hour clock. The sleep cycle is affected by inconsistent insomnia that occurs at different times. Those affected will sometimes fall asleep at a later time and wake up later; or fall asleep at an earlier time and wake up earlier. Even if you do not have a chronic sleep disorder, there are several measures that can help you get a good night's sleep. Among these are: Mental\tor\tphysical\trelaxation\ttechniques\t(reading, meditation, yoga). If\tyou\tdon't\tfall\ta\tsleep\twithin\t30\tminutes\tof\tgoing\tto\tbed, get out of bed and try an activity that helps induce sleep such as reading, listening to relaxing music, watching something boring on TV, etc. Ensure\tyou\tare\tin\tan\tenvironment\tconducive\tto\tsleeping (dark, quiet, comfortable temperature and mattress). Exercise\tregularly,\tbut\tnot\ttoo\tnear\tbedtime. A\tnutritious,\tbalanced\tdiet. Shift Work and CRD Shift work almost always causes a circadian rhythm disruptionthe internal body clock is at odds with the shift schedule. Shift-work problems are well documented, ranging from performance issues to accidents and health problems. Recognizing Circadian Rhythm Disruption Pilots or passengers who are suffering from CRD may experience one or more of the following symptoms: Difficulty\tfalling\tand\tstaying\tasleep,\tlate-night\tinsomnia. Increased\tdaytime\tsleepiness. A\tgeneral\tlack\tof\tenergy\tin\tthe\tmorning. An\tincrease\tof\tenergy\tin\tthe\tevening\tor\tlate\tat\tnight. Difficulty\tconcentrating,\tbeing\talert,\tor\taccomplishing mental tasks. Oversleeping\tand\ttrouble\tgetting\tup. Increased\tnegative\tmoods. The most debilitating symptom of CRD is, of course, fatigue. Fatigue is typically characterized by: General\tdiscomfort. Sleepiness. Irritability. Apathy\tor\tloss\tof\tinterest. Decreased\tconcentration. Loss\tof\tappetite. Impaired\tsensory\tperceptions. Mood\tchanges. Impaired\tdecision-making. Fatigue, itself, is a very dangerous condition for any pilot attempting to operate an aircraft. Realizing the cause of the fatigue (in this case, CRD) is the first and most important step in treating it. Jet Lag is a CRD! Of all the stressors in aviation, jet lag, or rapid time zone change syndrome, seems to have the biggest impact. This syndrome consists of symptoms that include excessive sleepiness and a lack of daytime alertness in people who travel across time zones. Other Symptoms: Fatigue, insomnia, disorientation, headaches, digestive problems, lightheadedness. Jet lag is more evident if you fly from west to east because it is more difficult for your body to adjust to \"losing time\" when you journey east than to \"gaining time,\" when you fly from east to west. Tips to Help Minimize Jet Lag Adjust your bedtime by an hour a day a few days before your trip. This will adjust your sleep pattern to match the sleep schedule you will keep at your destination. Reset your watch to the destination time at the beginning of your flight to help you adjust more quickly to the time zone you will be visiting. Drink plenty of water before, during, and after your flight. The air you breathe on airplanes is extremely dry, and some experts believe that dehydration is a predisposing cause of jet lag. Virtually everyone agrees that dehydration can make jet lag worse. Eat lightly but strategically. What you eat can have a direct influence on your wake/sleep cycle. Remember that highprotein meals are likely to keep you awake, while foods high in carbohydrates can promote sleep, and fatty foods may make you feel sluggish. Relax on the first day at your destination. If you have the luxury of arriving at your destination a day or two before you have to engage in important activities that require a lot of energy or sharp intellectual focus, give yourself a break and let your body adjust to the time change a little more gradually. As a Passenger: m Avoid drinking alcohol or anything with caffeine in it during your flight (includes many soft drinks, coffee, and tea.) Both alcohol and caffeine increase dehydration. m Sleep on the plane if it is nighttime at your destination. Use earplugs, headphones, eye masks, or other sleep aids to help block out noise and light, and a travel pillow to make you more comfortable so you can sleep. m Stay awake during your flight if it is daytime at your destination. Read, talk with other passengers, watch the movie, or walk the aisles to avoid sleeping at the wrong time. CRD Affects Your Flying Skills CRD-induced fatigue that goes untreated or ignored will have both physiological and psychological ramifications that not only can jeopardize your personal health but can also become a safety-of-flight issue. A few of the more well known undesired personal affects are