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 14-13] Physical The physical environment is obvious. It includes ranges of temperature, humidity, lighting, noise control, cleanliness, and workplace design. Companies must acknowledge these 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 good workplace and task design. ENVIRONMENT 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 that 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.” Clearly understandable documentation of actions ensures instructions and checklists are correct and useable. [Figure 14-14] Resources The final PEAR letter is “R” for “Resources.” [Figure 14-15] It is sometimes difficult to separate resources from the 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 14-13. Environment in which they work. 14-11 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 • Procedures/work cards • Technical manuals • Other people • Test equipment • Tools • Computers/software • Paperwork/signoffs • Ground Handling equipment • Work stands and lifts • Fixtures • Materials • Task lighting • Training • Quality systems Figure 14-14. Actions they perform. RESOURCES Figure 14-15. Resources necessary to complete the job. 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. Another major human factors tool for use in investigation of maintenance problems is the Boeing developed Maintenance Error Decision Aid (MEDA). This is based on the idea that errors result from a series of factors or incidents. The goal of using MEDA is to investigate errors, understand root causes, and prevent accidents, instead of simply placing blame on the maintenance personnel for the errors. Traditional efforts to 14-12 investigate errors are often designed to identify the employee who made the error. In this situation, the actual factors that contributed to the errors or accident remain unchanged, and the mistake is likely to recur. In an effort to break this “blame and train” cycle, MEDA investigators learn to look for the factors that contributed to the error, instead of the employee who made the error. The MEDA concept is based on the following three principles: • Positive employee intent (In other words, maintenance technicians want to do the best job possible and do not make intentional errors.) • Contribution of multiple factors (There is often a series of factors that contribute to an error.) • Manageability of errors (Most of the factors that contribute to an error can be managed.) When a company is willing to adopt these principles, then the MEDA process can be implemented to help the maintenance organization achieve the dual goals of identifying those factors that contribute to existing errors, and avoiding future errors. In creating this five-step process, Boeing initially worked with British Airways, Continental Airlines, United Airlines, a maintenance worker labor union, and the FAA. The five steps are: 1. Event: the maintenance organization must select which error that caused events will be investigated. 2. Decision: was the event maintenance related? If the answer is yes, then the MEDA investigation continues. 3. Investigation: using the MEDA results form, the operator conducts an investigation to record general information about the airplane—when the maintenance and the event occurred, what event initiated the investigation, the error that caused the event, the factors contributing to the error, and a list of possible presentation strategies. 4. 5. Prevention strategies: the operator reviews, prioritizes, implements, and then tracks the process improvements (prevention strategies) in order to avoid or reduce the likelihood of similar errors in the future. Feedback: the operator provides feedback to the maintenance workplace so technicians know that changes have been made to the maintenance system as a result of this MEDA process. The implantation and continuous use of MEDA is a longterm commitment and not a “quick fix.” However, airline operators and maintenance facilities frequently decide to use the MEDA approach to investigate serious, high visibility events which have caused significant cost to the company. The desire to do this is based upon the potential “payback” of such an investigation. This may ultimately be counterproductive because a highly visible event may not really be the best opportunity to investigate errors. Those involved in the process may be intimidated by the attention coming from upper management and various regulatory authorities. By using the MEDA process properly, the organization can investigate the factors that contributed to an error, discover exactly what led to that error, and fix those factors. Successful implementation of MEDA will allow the organization to avoid rework, lost revenue, and potentially dangerous situations related to events caused by maintenance errors. The “SHEL” model is another concept for investigating and evaluating maintenance errors. [Figure 14-16] As with other human factors tools, its goal is to determine not only what the problem is, but where and why it exists. SHEL was initiated SHEL Software • Hardware • Environment • Liveware S (Procedures) H (Machines) Worker E (Ambient) L (Personnel) Figure 14-16. SHEL model. by Professor Elwyn Edwards (Professor Emeritus, Aston University, Birmingham, U.K.) in 1972. It was later modified slightly by the late Capt. Frank Hawkins, a Human Factors consultant to KLM, in 1975. The acronym SHEL represents: • Software • Hardware • Environment • Liveware The model examines interaction with each of the four SHEL components, and does not consider interactions not involving human factors. The term “software” is not referring to the common use of the term as applied to computer programs. Instead it includes a broader view of manual layout, checklist layout, symbology, language (both technical and nontechnical), and computer programs. Hardware includes such things as the location of components, the accessibility of components and tooling. Environment takes temperature, humidity, sound, light, and time of day factors into account. Liveware relates technician interaction with other people, both on the job and off. These include managers, peers, family, friends, and self. No discussion of human factors is complete without reference to James Reasons’ Model of Accident Causation. This diagram, which was introduced in 1990, and revised by Dr. Reason in 1993, is often referred to as the Swiss cheese model and shows how various “holes” in different systems must be aligned in order for an error to occur. Only when the holes are all aligned can the incident take place. 14-13 There are two types of failure which can occur—active and latent. An active failure is one in which the effects are immediate. An example of this type would be an aircraft slipping off one of the lifting jacks due to improper placement by the technician. In this example, the aircraft jack is the approved item of ground support equipment, and it has been properly maintained. A latent failure occurs as a result of a decision or action made long before the incident or accident actually occurs. The consequences of such a decision may remain dormant for a long time. An example of a latent failure could also involve the aircraft slipping off a joint, but in this case, it could be an unapproved jack being used because funding had not been approved to purchase the correct ground support equipment (GSE). The field of human factors, especially in aviation maintenance, is a growing field of study. This section of this chapter has presented only a small segment of the numerous observations and presentations about the topic. If the technician desires to learn more, numerous books exist and a review of Internet data will provide an abundant supply of information. A good place to start researching would be the FAA’s own website at http://hfskyway.faa.gov/. This site, titled “Human Factors on Aviation Maintenance and Inspection (HFAMI)” provides access to products of the Federal Aviation Administration Flight Standards Service Human Factors in Aviation Maintenance and Inspection Program. Many aviation maintenance industry trade magazines include a section or at least a page devoted to human factors. “The Human Factors and Ergonomics Society” is a national organization composed of 22 technical groups, including one devoted to aerospace systems, which address both civilian and military issues of safety and performance. Human Error Human error is defined as a human action with unintended consequences. When you couple error with aviation maintenance and the negative consequences that it produces, it becomes extremely troublesome. Training, risk assessments, safety inspections, etc., should not be restricted to an 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 14-17] Types of Errors Unintentional An unintentional error is an accidental wandering or deviation from accuracy. This can include an error in your action (a slip), opinion, or judgment caused by poor reasoning, 14-14 Figure 14-17. Safety awareness will help foresee and mitigate the risk of human error. 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, it is 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 purposely deviated from safe practices, procedures, standards, or regulations. 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 straightforward 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 14-18] 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 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 14-18. Lack of communication. 14-15 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 drawing to the next step. 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 those in that system to be effective. Complacency Complacency is a human factor in aviation maintenance that typically develops over time. [Figure 14-18] 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 might be 14-16 made that inspection of the item is not important. However, even 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. 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 be trained 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 14-20] Differences in technology from aircraft to aircraft and updates to technology and procedures on a single aircraft also make it challenging to obtain the knowledge required to perform airworthy maintenance. 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 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 14-21] When work resumes, it is possible that the technician skips over a 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 14-19. Complacency. detail that needs attention. It is estimated that 15 percent of maintenance related errors are caused by distractions. process as work is performed. This can make performance of the required maintenance less effective. 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 technician’s thought Whatever their nature, numerous distractions can 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 from when distraction occurred and resume the job from that point. Using of a detailed step-by-step written procedure and signing off each step only after it is completed also helps. Incomplete 14-17 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 14-20. Lack of knowledge. work can be marked or tagged, especially when the technician is pulled from the work by a distraction, and it is unknown 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. 14-18 Lack of Teamwork A lack of teamwork may also contribute to errors in aircraft maintenance. [Figure 14-22] Closely related to the need for 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 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 14-21. Distraction. 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 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. 14-19 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 differences in the workplace must be left at the door. Organizations should emphasize that a lack of teamwork can ultimately affect the safety of maintenance work. MITIGATING THE RISK Ensure that lines of communication are open between personnel. Discuss specific duties when jobs require more than one person to eliminate any questions. Always look out for co-workers with safety in mind. Figure 14-22. Lack of teamwork. [Figure 14-23] Fatigue can be mental or physical in nature. Emotional fatigue also exists and affects 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, or balance. Fatigue reduces alertness and often reduces a person’s ability to focus on the task being performed. 14-20 Symptoms of fatigue can also include short-term memory problems, channeled concentration on unimportant issues while neglecting more important ones, 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. 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 decreased attentiveness 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 maintaining regular sleep patterns can prevent fatigue. Figure 14-23. Fatigue. 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 circadian rhythm. [Figure 14-24] A person’s ability to work (and rest) rises and falls during this cycle, and 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. 14-21 Alertness Level Multiple Sleep Latency Test (MSLT) 20 1-3 AM Peak alertness 15 Slightly impaired 10 Reduced alertness 5 Dangerously drowsy 0 9 12 15 18 21 24 3 6 9 Time of Day Figure 14-24. Many human variables rise and fall daily due to one’s natural circadian rhythm. 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. Time off is justified when too little sleep has occurred and errors are probable during maintenance. Countermeasures to fatigue are often used, but their effectiveness can be short lived and many can make fatigue worse. Caffeine is a common fatigue countermeasure. Pseudoephedrine found in sinus medicine and amphetamines are also used. While they can be effective for short periods, the underlying fatigue remains and due to this drug use, the person may have trouble getting the rest needed once off the job. Suggestions to help mitigate the problems caused by fatigue include looking for symptoms of fatigue in oneself 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 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 14-22 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 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 his or her 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 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 try to be proactive by checking suspected areas or tasks that may require parts at the beginning of the inspection. Aircraft on ground (AOG) is a term in aviation maintenance indicating that a problem is serious enough to prevent an aircraft from 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 14-25. Lack of resources. flying. In these cases, there is a rush to acquire the parts to put the aircraft back into service and prevent further delays or cancellations of the planned itinerary. AOG applies to any aviation materials or spare parts that are needed immediately for an aircraft to return to service. AOG suppliers refer qualified personnel and dispatch the parts required to repair the aircraft for an immediate return to service. AOG also is used to describe critical shipments for parts or materials for aircraft “out of service” (OTS) at a location. If the status of an aircraft is AOG and materials required are not on hand, parts and personnel must be driven, flown, or sailed to the location of the grounded aircraft. Usually the problem is escalated through an internal AOG desk, then the manufacturer’s AOG desk, and finally competitors’ AOG desks. All major air carriers have an AOG desk that is manned 24 hours a day, 7 days a week by personnel trained in purchasing, hazardous materials shipping, and parts manufacturing and acquisition processes. 14-23 Within an organization, making sure that personnel have the correct tools for the job is just as important as having the proper parts when they are needed. Having the correct tools means not having to improvise. For example, an aircraft that had received a new interior needed to be weighed prior to being released to fly. Two days before the planned release, the aircraft was weighed without the proper electronic load cells placed between the aircraft jack and the aircraft. Because the correct equipment was not used, the aircraft slipped off of one of the load cells and the jack point creased the spar. The cost of improvising can be very steep. The right tools for the job need to be used at all times, and if they are broken, out of calibration, or missing, they need to be repaired, calibrated, or found as soon as possible. Technical documentation is another critical resource that can lead to problems in aviation maintenance. When trying to find out more about the task at hand or how to troubleshoot and repair a system, the needed information often cannot be found because the manuals or diagrams are not available. If the information is unavailable, personnel should ask a supervisor or speak with a technical representative or technical publications department at the appropriate aircraft manufacturer. Most manuals are in a constant state of revision and, if organizations do not identify missing information in the manuals, then nothing is done to correct the documentation. Resources such as publications departments and manufacturers’ technical support are available and should be used rather than ignoring the problem. Another valuable resource that the maintenance department should rely on is the flight crew. Organizations should encourage open communication between flight crews and maintenance crews. The flight crew can provide valuable information when dealing with a defective part or problem. Figure 14-26 shows a number of questions that flight crews can be asked to help resolve and understand maintenance issues. When the proper resources are available for the task at hand, there is a much higher probability that maintenance will do a better, more efficient job and higher likelihood that the job will be done correctly the first time. Organizations must learn to use all of the resources that are available and, if the correct resources are not available, make the necessary arrangements to get them in a timely manner. The end result saves time and money, and enables organizations to complete the task knowing the aircraft is airworthy. Pressure Aviation maintenance tasks require individuals to perform in an environment with constant pressure to do things better and faster without making mistakes and letting things 14-24 When and where did the event occur? Were there any indications prior to failure? Did the system surge or flicker? How often does the system cycle? What was the range of transmission or reception? What was the time of retractions or extensions? Were there noises in the aircraft or headsets? Were there vibrations or stiffness of system controls? Was irregular trim required? Was there ease or lack of control? Were smoke or fumes present? Was there a loss of amperage and/or voltage? Figure 14-26. Questions that technicians can ask flight crews in an effort to resolve and understand maintenance issues. fall through the cracks. Unfortunately, these types of job pressures can affect the capabilities of maintenance workers to get the job done right. [Figure 14-27] Airlines have strict financial guidelines, as well as tight flight schedules, that pressure mechanics to identify and repair mechanical problems quickly so that the airline industry can keep moving. Most important, aircraft mechanics are responsible for the overall safety of everyone who uses flying as a mode of transportation. Organizations must be aware of the time pressures that are put on aircraft mechanics and help them manage all of the tasks that need to be completed so that all repairs, while done in a timely manner, are completed correctly with safety being the ultimate goal. Sacrificing quality and safety for the sake of time should not be tolerated or accepted. Likewise, AMTs need to recognize on their own when time pressures are clouding their judgments and causing them to make unnecessary mistakes. Self-induced pressures are those occasions where one takes ownership of a situation that was not of their doing. In an effort to combat self-induced pressure, technicians should ask for help if they feel overwhelmed and under a 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 Pressure to get things repaired is always present in aviation. Maintainers must not let the pressures of time constraints get in the way with safely finishing a repair. MITIGATING THE RISK Ensure that the pressure is not self-induced. Communicate if you think you will need more time to complete a repair rather than rush through it. Ask for extra help if time is an issue. Figure 14-27. Pressure. time constraint to complete a repair. Another method is to have someone check the repair thoroughly to ensure that all maintenance tasks were completed correctly. Lastly, if given a repair with a specific time limitation that you feel is unrealistic or compromises safety, bring it to the attention of the organization’s management and openly discuss a different course of action. Lack of Assertiveness Assertiveness is the ability to express your feelings, opinions, beliefs, and needs in a positive, productive manner and should not be confused with being aggressive. [Figure 14-28] It is important for AMTs to be assertive in issues relating to aviation repair rather than choosing not to or not being allowed to voice their concerns and opinions. Not being 14-25 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 Lack of assertiveness in failing to alert others when something does not seem right can result in many fatal accidents. Do not let something that you know is wrong continue by ignoring it. MITIGATING THE RISK Provide clear feedback when a risk or danger is perceived. Never compromise your standards. Allow co-workers to give their opinions and always accept corrective criticisms. Figure 14-28. Lack of assertiveness. assertive could ultimately cost people their lives. The following are examples of how a lack of assertiveness can be offset: 1. Address managers and supervisors directly by stating the problem. Example: “John, I have a concern with how this repair is being rushed.” 2. Explain what the consequences will be. Example: “If we continue, the result will be that the part will break sooner rather than later.” 3. Propose possible solutions to the problem. Example: “We could try doing things another way or you may want to try this way.” 14-26 4. Always solicit feedback and include other opinions. Example: “John, what do you think?” When being assertive with co-workers or management, deal with one issue at a time rather than trying to tackle a number of problems at once. It is also important to have documentation and facts to back up your argument, which can give people a visual account of what you are trying to explain. A lack of assertiveness in failing to speak up when things do not seem right has resulted in many fatal accidents. This can easily be changed by promoting good communication between co-workers and having an open relationship with supervisors and management. Maintenance managers must be familiar with the behavior styles of the people they supervise and learn to utilize their talents, experience, and wisdom.
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