COMMUNICATION - Keeping up to date, currency & Dissemination of information

Given the absolutely critical nature of aircraft maintenance there are numerous reasons for keeping accurate work records. The two with greater importance are safety and costs though, in a profession such as maintenance engineering, there are certain aspects of their professionalism and capability to provide certain services, which rely on aspects of recency and/or currency in performing a particular task. For example, an avionics engineer is unlikely to accept a task to swing an aircraft compass without the relevant training and having conducted a fourier analysis in the previous 12 months.

Reasons individuals may give for not keeping work records current are the time and the hassle involved. However, the small amount of time and effort involved in keeping an accurate record are far outweighed by the maintenance of safety standards and in turn the long-term costs associated with tasks not being completed or being left unfinished. Legal currency is met when the regulatory requirements for competency in a task is fulfilled. However, this does not always mean that practically a person will feel, or actually be, competent. Some tasks require specific currency or recency requirements in order to be undertaken safely, or supervision is required until proficiency is demonstrated. Disseminating information effectively often requires redundancy. This often involves repeating an idea so the receiver has more than one chance of grasping the meaning. Remember that the only message that matters is the one received. Humans are constantly subjected to a large number of potential messages. Visual, verbal, non-verbal stimuli surround them. So many messages compete for their attention that they must scan them and select those they wish to focus on. Often they tend to use just one channel (hearing) and ignore others (smell, taste, touch). Because they tend to focus on spoken communication, important information should be transmitted by this means. However, this is not to say that other means of communication are not to be used. In fact, they are also important so that the information has more than one chance of being received. Less critical information does not necessarily need to be spoken, but might be more appropriate if provided in another form, such as via written means. It is important to ensure that people do not overload others with information, so that they should limit how much information is passed in a spoken form.

HUMAN ERROR - SWISS CHEESE Error models and theories Swiss Cheese analogy derives from Professor James Reason Model. It is known throughout the world as Reason Model. Every layer of cheese represents a level of defense. Therefore, most organizations have many levels of defenses. The holes in the cheese represent defense breaches, so, as long as the holes in any layer of cheese are not aligned, accident/incident will not occur as that particular defense will stop the event. In Human Factor, we need to analyse the failures. There are 2 types of failures: Active and Latent Failure. In Active Failure, the result of unsafe acts (error and violation) committed in the sharp end of the system (traffic controller, pilots, maintenance engineer etc). Example would be a pilot raising the landing gear lever instead of the flap lever exemplifies this failure type. In Latent Failure, it is a hidden failure that is in the system waiting for the right condition to be evident. It is a failure in the organization committed either by manager, cleric officer, designer or manufacturer. It could be in the form of inappropriate choice of material, unfriendly system, unfavourable policy or typing error, such as, a decision to merge two companies without providing training to standardise aircraft maintenance and flight operation procedures. Failure in the system from incorrect action result breaches of all defenses causing accident to happen. This type of failure need to be identified before it becomes an incident/accident. There are two types of defense: Hard and Soft defense. For hard defense, fail safe design, automatic design, mechanical barrier etc is provided. An example is when the Technical personnel forget or refuse to install the ground lock pin, thus causing the landing gear to collapse. For soft defense, procedure, licensing, training, auditing etc is provided. A soft defense signoff may be breached with a typing error by a clerk where the document needs duplicate signatures which are otherwise omitted. In order to prevent any errors in the organisation, we need to change the culture by having more support from the top management, awareness safety policy, training, resources and workable procedure to maximise safety and a good working environment. A good example would be to use the MEDA programme to learn about past errors.

HUMAN ERROR Types of errors in maintenance tasks If any theory is going to be valid for the purposes of making changes to a system, someone needs to be able to distinguish between the different types of errors so that appropriate countermeasures can be put in place. It should be noted that Reason Model and active failures were covered previously hence, errors and error producing conditions will be concentrated upon instead. In the past, humans have been guilty of punishing individuals who commit any of the errors provided for in this system. That includes slips, lapses and mistakes. They should not have. Intentional violations are the only punishable errors in a just culture. Slip and Lapse are classified under Unintended Action. Slips are Attentional Failures which include intrusion, omission, reversal, misordering and mistiming. Lapses are Memory Failures and are common in humans. They include omitting planned items, place-losing and forgetting intentions Mistake and Violation are classified under Intended Action. Mistakes can be either rule-based or knowledge-based. Rule-based Mistakes are misapplication of good rule and application of bad rule. Knowledge-based Mistakes are many variable forms. Violations are unacceptable in any form. They can be classified as Routine Violations, Exceptional Violations and Acts of Sabotage. The next question is what causes humans to make all of these errors. The research effort then went into looking for the conditions under which these errors seem to become more prominent or more numerous. Error producing conditions are unfamiliarity with the task, time shortage and etc. These now provide some areas to target in the struggle to reduce the number and effect of error in the workplace. It should be note that many of them are in fact Human Factors elements. So it would be fair to say that this course, is in fact, a starting point for individuals to play a part in reducing the number and effect of errors in their own workplace as the years go on. It should also be expected that there would be re-enforcement of these principles through on-going training and courses as one progress in his or her chosen careers.

HUMAN ERROR Implications of errors (i.e accidents) There are some good legal reasons for wanting to minimise errors also. Much of this course was spent saying that humans commit errors and systems should be put in place to trap those errors before something goes wrong. Here is another reason. If an error was made, and something goes wrong, someone could be in trouble with the law. Professionals are liable for the work that they do. That includes maintenance engineers. If the person could reasonably have been expected to do a job right and he or she did not, the person may be criminally negligent. There are differences around the world about how much liability individuals should accept. The fact is that maintenance engineers are liable for the work that they do and the inspections they sign off. In general terms, a professional would be deemed to be criminally negligent if the person failed to complete work that he or she could reasonably have been expected to do given his or her employment and that resulted in someones death either in the workplace or on an aircraft following maintenance work. In such a case, a convicted person could expect to receive the penalty for manslaughter within the State concerned. At this stage, the law generally has a blame mentality and a maintenance engineer should be aware of that. The public normally want somebody to blame when things go wrong. Do not be an easy target.

HUMAN ERROR Avoiding and managing errors The first point is to accept that reducing errors to an absolute minimum is always a goal of any error management process. The second issue is to contain them. Error management (EM) is a very broad term covering a wide variety of measures. These can be classified under two headings: Error reduction: Measures designed to limit the occurrences of errors, and Error containment: Measures designed to limit the adverse consequences of those errors that still occur. Error management has actually been around for a long time as anyone would expect. It just has not been put forward as an acceptable approach. In the past, people have targeted zero error as the safety issue rather than error management per se. This has as much to do with the culture of the industry people are in as it has to do with any particular management or organisational bent towards punishment for errors. In the past, the regulatory authorities have been guilty of leaping out from behind bushes having regarded errors being committed. This tactic has more to do with the mandate of an enforcement agency than it does with a safety regulatory authority. It is fair to say that most authorities have changed their approach to regulation quite markedly over the last 10 or 15 years for the better. Managing errors within the aviation industry has always been part of the mandate and many of the systems currently have in place are set up for specifically that reason. The following list presents the broad error management techniques that are used in aviation maintenance are Personnel Selection, Human Resource Management and etc. These are the big picture systems that help people do their job better. In terms of individual errors, humans need some way of compensating for them also. For this process a measure of human reliability is needed and it can be measured using risk assessment techniques. In a Human Reliability analysis (HRA), the probability that a human operator might misread a display (for example), is included among other mechanical and failure modes that might cause a process plant to move outside its operational envelope. The results of a human reliability analysis for any task can be put into the management equation and provide safeguards to catch all errors. Human variability is a little harder to take into account especially in larger organisations but it is important to recognise that all individuals have different strengths and weaknesses. There really is not such a thing as a stereotypical maintenance engineer. To manage errors it is also important that humans determine what the root cause of any errors.

Hazards in the workplace - Recognising and avoiding hazards Numerous studies and statistical reports show that the workplace can be dangerous. This is especially true for work environments with heavy parts being moved about, with rotating machinery, with toxic or hazardous materials, and with work locations that are above the ground. All those factors are present in aviation maintenance shops. It is well accepted that an aviation maintenance workshop can be a hazardous place. Dangerous means risky, hazardous, or unsafe. In the safety profession, situations, tools, or other elements can be either of the following: Imminently dangerous impending or immediate risk, such as a bare electrical cord Inherently dangerous usually risky, such as poisons or explosives. Human Factors has played a part in reducing workplace injuries but the bulk of its contribution has been targeted at reducing human error. Much of this work is directly applicable to the aviation maintenance workplace. If nothing else, Human Factors has presented evidence that humans will commit errors unintentionally no matter how good they are. This evidence alone has been instrumental in developing systems that can identify and manage those errors. The ultimate fear of any maintenance supervisor, technician, or inspector is that an error, once committed, will remain undiscovered and ultimately lead to an accident. There has been some success to date but there is still no room for complacency. There are both active and latent errors out there waiting to happen. Over the last 50 years, humans have come to understand many of the factors that contribute to human error. When control is combined with good human factors design and testing techniques, the effects of many sources of human error can be controlled.

Hazards in the workplace Dealing with emergencies The aviation industry is well aware of the concept of system safety. Supporting and enhancing the continued safety of the flying public underlies nearly all trainings, regulations, and working procedures in the industry. Most of this emphasis, however, is placed on the airworthiness of equipment and crews. Safety is also relevant to the maintenance workplace. The aviation maintenance system is not safe until all of the system's components are safe, including the maintenance workers. The Human Factors discipline is having an effect on safety in the workplace by addressing the characteristics of human workers and their environment that affect performance. Workplace safety is directly related to workers' ability to perform their jobs without making errors. Thus, human factors methods can be used to reduce errors and increase safety. Research shows that there are three primary groupings of accident producing factors. They are human fallibility, technical and procedural shortcomings, local hazards. In terms of recognising the hazards, one of the easiest measures is to look at the number of genuine complaints that come through an open and non-disciplinary reporting system. This was done with a number of organisations in the United States and the resulting statistics showed that local hazards could be recognised quite easily if they were looked in the right place. The list above shows the types of problems that form part of the complaints list and the areas in which they could be found. The three most important factors for engineers are: 1. Inadequate lighting, particularly underneath an aircraft's fuselage or wings. 2. Noise, especially short-term impact noise, such as from riveting. 3. Ambient temperature resulting from the open floor plan associated with hangars. Workplace safety depends upon a combination of complete, systematic preparation and responsible individual behaviour. Another way of categorising them for Human Factors purposes is as follows: 1. Individual issues 2. Task related issues 3. Tool and equipment issues 4. Facilities and environment issues 5. Materials issues 6. Administration / organisational issues All of these factors have serious implications for workers in the maintenance engineering industry. While some of them might appear to be common sense, it is fair to say that too often they are ignored as potential hazards. In some respects, this has been the major role that Human Factors has had to play within the industry and that is to bring to the attention of those that can make a difference those elements that serve to increase safety and reduce both workplace errors and workplace injuries.

COMMUNICATION WITHIN AND BETWEEN TEAMS There is a difference between upwards, downwards and horizontal communication. The nature and form of the specific communication depends upon the individuals and their jobs in the organisation. Top down communication is the passing of information from individuals higher up in the organisational structure to those lower down. This may occur when management issues a memo to the workforce, or when a team leader or more senior person discusses an issue with a younger, junior worker. People in leadership roles have certain responsibilities when communicating, including creating an environment where communication is not only passed down through the organisation but also back in the other direction. The downward flow is comprised of messages and information sent from top management to subordinates. The flow usually follows the formal lines of authority downward from position to position. The downward flow is the strongest of the three directions. Management has the power to put messages in motion and start them on their downward journey. Unfortunately, messages are sometimes not received, arrive distorted, arrive too late, or are not sent at all. Sideways or horizontal communication is passing information between individuals at a similar level within an organisation. This may occur between groups of individuals or teams that work on different but related tasks. Communication in a lateral or diagonal direction within the charted organization is called horizontal. This is the most frequent flow of communication because individuals at the same level talk to each other constantly about work-related events, management, and personal matters. Work-related communication revolves around formal tasks and goals that are vital to the organization. Personal, informal communication serves the social and emotional needs of people who work closely together for long periods of time. Employees at the bottom of an organization's structure have a greater need for information and a wider gap to fill than those at the top. Horizontal communication flow is the mechanism whereby subordinates evaluate their superiors in areas such as skills, attitudes, values, personality, problem solving, planning, and organizing. Messages transmitted on this level are important to a supervisor because they serve as feedback on how well that individual is managing a unit. However, such information is seldom provided in person. Instead, it is usually transmitted through the grapevine. If top down communication is the passing of information down through the different levels of an organisation it follows that upwards communication is the passing of information in the opposite direction. As mentioned above the ideal situation in an organisation is to create a working environment where the workforce does not feel reluctant to do this. Upward communication flows from subordinates to superiors. Downward communication is usually better than most people recognise. It is frequently more accurate than people at higher levels want it to be. Conversely, upward communication has to be pumped and primed, with a minimum of filters, in order to be effective.

SHIFT CHANGE-OVER Team communication during the shift change-over one of the more critical elements of communication in a maintenance engineering organisation. Effective shift turnover depends on three basic elements are: The outgoing worker's ability to understand and communicate important elements of the job or task being turned over to the incoming worker. The incoming worker's ability to understand and assimilate the information being provided by the outgoing worker. A formalized process for exchanging information between outgoing and incoming workers and a place for such an exchange to take place. An effective shift turnover process is composed of at least four components are Shift turnover meetings, Turnover walkdown, Turnover checklists and Work status markers. To ensure the change-over process is effective it is important to ensure team members are attending and that feedback is sought to ensure information passed has been correctly understood. Attending is letting someone know that attention is being paid to what is said so that he or she will be encouraged to continue. Good attending involves both attention and retention, that is, paying attention to what is being said and remembering it as the conversation continues. The smaller the group the easier attending is. In a one on one situation a person only have to attend to what one other person is saying. In a larger group, attending becomes much more demanding as each group member is entitled to the attention. If a person is the leader of a group, attending will be an important part of involving everyone in the group and hence a step in building a cohesive team. Attending also plays an important role in gaining a better understanding of someone. For teams or team members who have just met for the first time, yet are expected to perform as a unit, attending to each other will be important in helping to understand how another individual works and to build rapport. In seeking feedback, make sure the transmitter knows the receiver is listening. When they make an important point, restate it. What is heard should be restated if there is any doubt in what is said. If a message is received (verbally or non-verbally) but the correct message is not passed, the message should be repeated by the speaker. Communication is a two-way street. It is too often the case that human communicate in on open-loop fashion. That is, people send messages, but they never really know whether they are properly received or, if they are received, the reactions of those to whom the messages were sent. People will address the general subject of feedback in the following section, but broach the topic here to point out that meetings can be a valuable source of feedback. It was indicated earlier that most feedback, especially from workers to managers, tends to travel through the grapevine. Although the grapevine tends to be extremely fast and efficient, it can also seriously distort messages travelling through it. Meetings called for the explicit purpose of giving feedback on a particular topic can provide more accurate and structured information than ad hoc methods. The trick, of course, is to carefully plan and structure the meeting so the feedback is honest, open, and constructive.

WORK LOGGING AND RECORDING Humans, unlike machines, are very flexible and can adapt to changing conditions. Often this flexibility is an advantage but sometimes it is not. The downside of humans flexibility is that human performance is variable, it fluctuates and can produce errors. Forgetting things, or making small mistakes is a normal part of human performance. Because humans do not have perfect memories, they need to have procedures in place to help them remember what has been done and also provide information to other team members about what has or has not already occurred. Procedures such as recording work and logging work times, when applied in a disciplined and standard manner, are intended to support the human workers, by providing a foundation on which to base their performance. This element of the daily job has a variety of aspects to it. In the first instance it can provide the evidence for which they receive their fortnightly or monthly pay cheque which gives it an immediate interest for them as individuals. On a wider basis though, it provides management with the data by which they can manage the job tasks and schedules so as not to create labour wastage within the organisation and to provide confirmation that specific work elements have been attended to. This aspect becomes far more critical following an accident or incident when these records become a formal part of the evidence for the courts relating to what was and was not done. Work logs and records can become a critical safety tool in this respect.

Physical Work Physical work, as the name suggests, requires strength and action by the body. The fact that everyone has differing strength levels and each of them have a different biomechanical capacity to do physical work means that some of them will be prone to injury when asked to do physical work outside of their capability. In some cases there is a just need to learn how to manage the physical work better, whereas in other cases there is a need to know that it cannot be done without incurring risk of injury or error. Posture has quite a substantial effect on the error rates that are committed. There was a time when posture was only directly related to back injury especially when lifting heavy objects but as time has gone on, research has shown that it is an important safety concept in most jobs. It also has a role in improving productivity. Most senior workers in organisations these days can remember times in which they just did the best they could with what they had. Computer stations for example were just any desk space that was available. Poorly configured computer workplaces in offices require workers to adopt body and arm/hand postures that can lead eventually to injury. Commonly, however, workers went about their job without thinking about optimising their performance. Optimising performance is not just a matter of getting a posture right for a job but providing the opportunity for flexibility as well. The following diagram shows an awkward working posture that is quite common in maintenance engineering. There is plenty of evidence from the workplace to support this. For example, data entry staff's performance at a Singapore airline was examined before and after changes in the workplace's features and procedures. The workplace changes included simple changes to the work environment such as improved lighting, the provision of document holders and footrests, and were given extra rest breaks. As a result, the data entry staffs hourly output increased by 25 percent and their error rate fell from 1.5 percent to 0.1 percent. There was also a notable reduction in reported musculo-skeletal aches and pains. For example, neck and shoulder problems were reduced by more than half. Appropriate attention to posture and the provision of resources, which encourage appropriate posture, should be considered an investment by organisations. From a biomechanical perspective, the human body is a series of physical links (bones) connected at certain points (joints) that allow various movements. Muscles and tendons provide the motive force for all movements. The force that can be applied in any given posture is dependent on the strength available from muscles and the mechanical advantage provided by the relative positions of the load, muscle connections, and joints. Obviously there are individual differences in the ability of workers to get some types of physical work done. The point is to be aware of their own limitations for physical work as well as those they might ask to do tasks. The limitations that should be taken into consideration are Strength, Capacities to perform different types of work over time, Age, Gender, Energy and Work environment comfort.

REPETITIVE TASKS Even when tasks can be done satisfactorily and easily, other factors have to be taken into account. Repetitive tasks are also a way of contributing to error and injury. A major problem associated with repetitive tasks is habituation. Habituation refers to a persons decreased response to stimuli that the person sees, hears, feels, smells, or tastes frequently or continuously. Eventually, the person may cease to respond to the stimulus at all. It is also a real de-motivator because repetitive tasks are, by and large, boring. Habituation occurs both physically, when a stimulus becomes physically imperceptible, and psychologically, when the stimulus fades from the working memory and needs to be retrieved in order to be acted. Good examples of habituation include wearing hard hats or ear protectors when required. They always seem a bit strange at first but after a while they become such a habit that it would feel funny going into a work situation that required them without them. A more complex example would be driving a car or operating a lathe. After a while all of the necessary actions were performed without even thinking about them. This is when things can get dangerous. If a job task is particularly hazardous, a person is likely to be very careful the first few (or few hundred) times when it is performed. Eventually, however, the person will habituate to the danger and must constantly be reminded oneself to be careful. In the aviation maintenance environment, habituation allows the adaptation to dangerous or noxious environments and ignores potentially dangerous indicators. Be aware of the issue and look after work colleagues too if who are believed to become complacent.

VISUAL INSPECTION As a particular repetitive task that suffers from quite different problems, the visual inspection needs to be singled out for attention. Problems related to visual inspection are not physical in nature, by and large, but rather reflect the capacity of humans to concentrate on a repetitive task for long periods without error. In fact, the human capacity to do much of this work is at a far lower level than was realised for many years and engineers were asked to perform duties, particularly those of visual inspection, that were in fact impossible to do without error. It is now known that: Within about a half hour of beginning a vigilance task, detection performance drops dramatically and never recovers during the watch. Many other factors such as fatigue cause vigilance performance to decrease more rapidly and to a lower level. Vigilance tasks are common in the maintenance domain. Any type of repetitive inspection work in which the probability of finding a problem is low qualifies as a vigilance task. Although several methods for doing so have been described, it is quite difficult to ease the effects of the loss of sensitivity during a vigil. This just reflects the capability of the human body rather than the stamina or will, or experience, or expertise, of the engineer. There are essentially two ways, or a combination of both, to reduce or eliminate task-related performance decrements are varying the task and taking periodic rest breaks or some combination. By changing a persons task on a regular basis presented much improved performances. The changes in task can be as simple as just asking the person to get a cup of coffee, such that their concentration is broken from the repetitive task that they are involved in. At a more productive level, however, the ideal situation has individuals rotating around different tasks over a set time period. For example, 20 minutes on rivet inspection followed by 20 minutes on sheet metal preparation, followed by 20 minutes on assessment for metal fatigue. Other strategies to sustain performance on repetitive tasks, which have been cited, relate to using other forms of stimulation to help bolster attention and concentration. Favoured music is often cited as having a positive effect on visual inspection tasks. However, it is important that such forms of stimulation do not distract the individual further from the task at hand.

COMPLEX SYSTEMS Complex systems such as those found in the maintenance engineering business need regular evaluation to improve safety and cost effectiveness. There are several reasons for this. In the first instance there is actually a need to improve safety levels in order to maintain public confidence in flight as a transport option. In the second, there is always a need to remain competitive in a very dynamic aviation industry. Two of the evaluations that have become essential tools in the modern industry are regular task analyses and user analyses. Task analyses have been around for a long time now and books have been written about them. The term task analysis is not just one method; it is the name given to a range of methods used to determine important task elements. While the actual steps may vary from one task analysis method to another, the intent of each is to describe just what users have to do and know to complete their job tasks. Ideally, task analysis requires the analyst(s) to interact directly with end users in their job setting. It is very important that task analysis include actual end users and their job setting. The most common source of errors in gathering task information arises from a failure to interact with real end users. It is not good enough to talk with supervisors of end users, with people who know a lot about end users, or with people who used to be end users. For task analysis, there is a need to gather task information from the people who perform the tasks. By observing users in their actual job settings, the analyst(s) can gather environmental, organizational, and other job-related information that might have a drastic effect on system design or evaluation. A user analysis is a bit more recent but as the name suggests, if some way can be found to clone successful users, it is likely to get more successful users in the future. The principle of the method is to effectively design or evaluate the human factors aspects of products or systems. It is a must to understand the people who use them and a user analysis is a category of methods aimed at understanding users. Regardless of the particular method's name, its goal is to identify any user factors that might affect performance on job tasks. User analysis methods typically gather demographic, physical, and experience information. Demographic information includes age, gender, ethnic background, education, income, etc. Physical information includes size, weight, perceptual, disability, and other data that can help determine the distribution of these characteristics in the user population. Experience factors can include any type of work experience that might be of interest. For example, the amount and type of computer usage is a typical experience factor. Experience factors also include skills such as typing, riveting, etc. While there are several general methods used to identify human factors problems and to embed user capabilities and limitations into systems and products, the methods are always used to accomplish one or more of the following tasks are to identify task requirements, identify user characteristics and evaluate jobs, tasks or products. And the reasons to do those things come back to the basic premises of: Safety, both in terms of reduced accident and incident rates and workplace injuries Efficiency, in turnaround times and time on task Effectiveness, in terms of getting the job done right the first time every time and on time and of course Cost savings. And there are plenty to be made through good human factors audits

Noise and Fumes Two separate issues associated with noise and human factors. The first one was covered in some depth in the module for Human Performance and Limitation when the workings of the information processing capability were described. In the module, it was noted that humans have a sensory memory, or sensory register, that picks up a whole range of stimuli in the environment. One of those sensory memories was associated with the auditory, or aural, system. The aural system used the ears and is the basis for hearing. Noise in this context is all of the sensory information that comes in through the ears. From the module, it was known that humans need to attend to specific elements of noise to listen to them, hence the first major issue associate with noise is the discrimination between what is that a person wants to listen to and the rest of the information that comes in through his or her auditory system. In general terms, the unwanted information is called noise. Noise is measured in decibels (dB) and normally rated on a scale called the A scale hence dBA as a standard measure. The A weighted sound pressure level means sound pressure level measured by an instrument with an electrical network having the characteristics specified in the International Electrotechnical Commission (IEC) Publication 651. This method of reducing noise is to provide workers with some type of hearing protection device (HPD). If the noise SPL is 90 dBA or higher in a particular area, OSHA regulations require the use of HPDs. The most common types of HPDs include plugs inserted into the ear canal, caps which seal the ear canal near the outside opening, and muffs which completely enclose the outer ear. Two common complaints regarding HPDs are that they are uncomfortable and that they interfere with speech communication. Fumes are an issue that is commonly ignored until after a disastrous event. Reason for this appears to be the insidious, or sneaky, nature in which fumes affect individuals. It is included here as part of the working environment to raise the awareness of the possible dangers associated with fumes in the workplace. The places that toxic fumes are most likely to be generated, are most likely already signposted as dangerous areas. In most cases, the items that would generate toxic fumes and/or be the catalyst for the generation of toxic fumes are often dangerous or toxic chemicals themselves, in solid or liquid form. In these cases, they are likely to be well signposted through regulation. Examples are battery bays, and acid baths. In each of these cases mandatory signpostings informing workers of the associated dangers with particular reference to their flammability, which is normally brought about by fire regulations, should be posted. These warnings, however, do not often include the dangers associated with any fumes that are generated by such places, but one should assume that such storage places or work places will emit toxic fumes should they catch fire and/or change their status from solids or liquids to gas. Areas of particular concern include are Composites, Degreasers and solvents, De-icing fluids, Fuels and flammables. Possibility of toxic fume generation by a range of ordinary every day products once a fire starts. If a person has any doubt, the person should undertake an emergency egress and worry about whether he was correct or not afterwards. Passengers on an aircraft, workers on the job should also be informed about emergency egress and the proper terminology that are used. In particular, formal egress instructions require a person to look after him or herself in the first instance. Others cannot be helped if all of them are overcome by fumes. Once personal safety is assured, the alarm can be raised and help others where possible without being endangered personally. For fume generation, one of the most important requirements is to be able to supply as much accurate information as possible to the experts so that they can make an informed decision on how to handle the problem. It requires specialist knowledge on antidotes as well as special breathing apparatus to overcome the problem.

ILLUMINATION The sense of sight also gives humans some problems in the workplace. While it is the primary source of sensory information, and some illusions that it suffers from will be discussed, there are also other aspects that can cause humans problems. In general this is to do with illumination. Illumination in the workplace provides humans with the capability to be able to see things clearly or not as the case may be. It is included here as part of the physical environment because it has been cited as a causal factor in so many accidents and incidents. It has also been fairly well scrutinised in terms of research for improving illumination in the workplace and Chapter 5 of the FAA Guide has a particularly good synopsis of the issues associated with lighting in the workplace and is specifically addressed at the problems of maintenance engineers. Illumination is the technical measurement of how much light is falling on an object which necessarily has an impact on how well a person can see it. The concepts of illumination and luminance are associated with the quantity of light falling on or emanating from a surface, respectively. While it is not really important to understand all of the mathematical intricacies associated with these concepts, it is helpful to understand the fundamental difference between them. Illumination is related to the amount of light falling on a surface or an object. The illumination of any point in a facility is dependent on the placement and light output of all light sources that can shine on that point. Luminance is related to the amount of light coming from an object, such as a video display terminal or a wall. Luminance is associated with humans subjective impression of brightness. From the FAA Guide, the source of illuminance is a light of some type. Permanent light sources in facilities are generally fixed to a ceiling or wall. As a person moves away from these light sources, the intensity of illumination decreases. In fact, it decreases predictably as the square of the distance. If the distance between an object and a light source is doubled, the illuminance measured at the object drops to one-fourth its previous level. It suggests that the best source of illuminance is not direct light but rather an even diffuse lighting which requires a number of light sources. It is important to keep light levels fairly even throughout the work areas. The most common recommendation is to keep the ratio of highest to lowest illumination in and around a work area to 3-to-1 or less. In general, even, diffuse, shadow-free, glare-free illumination in all areas of a facility used by people should be provided. The best way to diffuse light and minimize shadows is to use a large number of small light sources rather than a few large fixtures. By itself, however, the placement of fixtures will not eliminate shadows or bright spots.

CLIMATE AND TEMPERATURE Humans have been able to work, to some extent or other, in just about every environment on Earth. This has not always been the case though and much of it has to do with the range of temperatures in which a person can work. The human body has a fairly narrow set of parameters and in many parts of the world humans have had to wait for technology to provide them with the capability to modify the local climate through heating or cooling before any productive work could be done. In the modern world, people tend to rely on air conditioning systems to cool the working environment down for them in the tropics, and heaters to warm things up for others in more temperate parts of the world. Without these climate modifications humans quickly become susceptible to error, both physically and mentally. Differences do not have to be extreme, just outside their normal comfort zone, for them to have a diminished performance. The further the climate and temperature is outside the normal comfort zone, the more debilitating the effects. Establishing a safe and comfortable working environment requires the maintenance of a worker's internal body temperature ("core" temperature) within a certain narrow range. Various environmental and work factors affect body temperature. Both the core temperature and the subjective feeling of comfort are affected by air temperature, radiant heat, humidity, air velocity, type of work and clothing.

MOTION AND VIBRATION Motion and vibration in the aviation industry are commonly considered to be hazards for the pilots. The engineer does however, get involved in a number of tasks that can be subjected to some major motion or vibration input. A simple example would include test flying an aircraft following maintenance work but there are any number of equipment types used by engineers that could cause problems. Distraction is the most common issue associated with motion and vibration and the source of many errors of omission. Habituation can also be bought on by both motion and vibration and there is a particularly fatiguing aspect to prolonged exposure to either which once again leads to error being made unintentionally by engineers. Typically, segmental vibration of a part of the body (especially the hand and arm) is more troublesome than whole-body vibration. Various body parts have resonant frequencies when they vibrate in unison with a source in the range of 4-150 Hz. The range between 50-150 Hz is most troublesome for the hand and is associated with Vibratory-Induced White Finger Syndrome (VWF). Pneumatic tools can produce troublesome vibrations in this range and are implicated in the reduced local blood flow and pain of VWF. It is necessary to reduce these vibrations in amplitude, to change their dominant frequency to one higher or lower, to provide dampening material, and to limit workers' exposure time. The best countermeasure to these possible effects is awareness. If engineers are alerted to the possibility and probability that their work will be negatively affected by such things, they are more likely to be vigilant and call in support to check the work they are doing. Most sets of Standard Operating Procedures (SOPs) will ensure that the procedures do not set engineers up to be caught in these traps and in many countries, the OSH guidelines are equally cautious about the possible debilitating effects of motion and vibration. There is also medication available now to suppress the effects of motion sickness.

WORKING ENVIRONMENT Workplace design and job design are usually treated separately. However, it is difficult to change a workplace without changing the way a job is done. Likewise, even slight changes in a job's structure or content can drastically effect what is an appropriate workplace. In this section the two issues or workplace design and job design where a workplace design centres around the task and the job design centres around the worker and how they might achieve the required work will be considered. The argument will suggest that two key areas for such as the Workplace redesign improves posture, productivity, quality and safety. While the other key area is Job redesign is to increases job satisfaction and reduces process errors which therefore improve safety. Examples of poor workplace design can be found in many maintenance operations. Due to an aircraft's structural design, components may not be easily accessible, resulting in awkward postures, restricted space for movement, decreased safety and performance. In workshops, postural problems can be caused by benches located at inappropriate heights, heavy power tools with ill-designed handles and uncomfortable chairs. Appropriately designed workplaces with well-chosen access stands, benches, chairs, and tools can improve both safety and productivity. Improving lighting that reduces the need for close viewing improves working posture. Applying an ergonomics audit to the broad spectrum of maintenance and inspection jobs can reveal examples of poor and of good design for elimination and emulation, respectively. Aircraft inspection and maintenance are part of a complex activity chain that includes scheduling, planning, and cleaning. For such tightly scheduled activities, safe and efficient outcomes require that team members work together smoothly and intelligently. The consequences of poor job design include errors, delays, and frustrations. When activities are not well-coordinated or when workers are unaware of how tasks are linked together, good teamwork cannot exist. Symptoms of poor job design include disputes over who has authority; physical interference between activities, such as inspection and cleaning; and inability to respond smoothly to unplanned events, such as discovering an unusual structural defect. Most enterprises find that good jobs include some element of multifunctional teams empowered to change jobs and functions in a bottomup manner to make process improvements.

FITNESS AND HEALTH While humans may not always be able to control the occurrence of stressful events or situations in their lives, the ability to cope with stress, or increase stress tolerance can be improved. Keeping oneself fit through good diet and adequate exercise is an excellent way to increase tolerance to stress. When a person is physically fit he or she tends to feel better about him or herself and this in turn means that more positive attitude increases the ability to cope with whatever comes along. Long term stress can affect a persons health, but if he or she is physically fit to start with, the person is less likely to become ill when under stress. Likewise, good social supports and the ability to communicate and share concerns can make what appears to be a highly stressful condition more manageable. Having a balanced lifestyle and getting adequate sleep not only contributes to a persons physical fitness, but also to his or her mental fitness. Finally, the way in which a person tackles stressful situations, or personal coping style, can enhance or degrade an individuals tolerance to stress. Some people try to manage their stress by simply ignoring it, hoping that it will fix itself or go away or maybe by keeping themselves busy doing other things to distract themselves from the situation. A much better approach is to look at the problem or the situation and gain the resources necessary to tackle the problem, whether that is gaining extra skills, acquiring more knowledge or asking for assistance from someone.

DOMESTIC AND WORK RELATED STRESS While there has been a lot of research conducted in the academic domain under controlled circumstances, practical studies in the maintenance engineering workplace have been somewhat limited. It is, however, one of the more significant aspects to any profession and the maintenance engineering fraternity is no exception. In some respects, their susceptibility to stress related issues is more significant than most professions. This is because the work done by maintenance engineers has a public safety application and the working environment requires a significant amount of shift work, which has family and social consequences. In this section, there will be attempts to at least highlight each of these issues for engineers and where practical, provide some guidance and countermeasures for reducing the affects of stress, both in the workplace and at home. The symptoms of stress can be separated into physical and psychological symptoms. Physical symptoms include High blood pressure, increased respiratory rate, Sweating, Gastrointestinal problems, Headaches and Diminished immunity. Psychological symptoms include Depression, Moodiness, Alcohol and drug abuse, increased aggression, Fatigue, Isolation and Poor concentration. However, a person does not necessarily experience all of these at the same time or even to the same degree. There are many different things that can produce such stress responses and some of them will be considered. Stress can be related to the type of work that people do. For example checking whether Airworthiness Directives have been incorporated into the manual is a relatively low stress task, while a high stress task might be using the boroscope to check for stress fractures on the turbine blades. Task related stressors can include type of work, workload and breaks, and duration Physical and environmental factors can also be considered potential stressors. For example, working in a confined space in high temperatures with poor ventilation, may make a persons work much more stressful and reduce his or her ability to perform at ones best. Physical, environmental stressors are Temperature, Cramped spaces, Humidity, Noise, Vibration, Health and Age How an individuals work is organised can be stressful too. Having to work night shifts for a long period of time, having last minute roster changes, or being unsure of how long a job will continue are likely to be stressful because of the impact they have on a persons social and home life. So, organisational stressors include Work scheduling, Work predictability, Job insecurity, Career development and Poor communication. Being unsure of his or her exact role or responsibilities at work is considered to be a psychological stressor. Work relationships can also create stress. Psychological stressors in the workplace include Role ambiguity, Work relationships, Responsibilities, and Loss and grief. In summary, there is a whole range of stressors that can and do affect maintenance engineers and more importantly, affect the performance of engineers.

TIME PRESSURE AND DEADLINES One way some of the stress can be reduced in ones live is to better manage the time that is available. Unfortunately, time is not a resource that can be accumulated. So the problem is not time per se but what one do with it. Therefore, people must manage themselves with respect to the clock. People may not have enough time to accomplish all the tasks they wish to do therefore they must select those tasks that are the most important. When determining ones priorities a person should consider his or her goals. Set goals that reflect ones priorities. With the priorities in place, the person is now in a position to set goals that help to fulfil them. Using ones time to pursue goals that reflect his or her priorities has many benefits, including increased life satisfaction and less stress. Successful time management starts with writing down ones goals, beginning with longer term goals (such as lifetime goals, followed by five-year goals and one-year goals) and moving down to shorter term goals (such as one month and one week goals). Goals should be specific, positive, realistic and measurable. Each goal needs an action plan. Goals can be made to reflect the different roles one play in his or her life (such as husband, father, worker, citizen, etc.) or along different life dimensions (family, work, leisure). The important thing is to find a system that works. Items from the master list that need immediate attention can be placed on a new list, which is the persons daily 'to do' list. At the end of the day make tomorrow's daily list that comprises of immediate tasks, calendar items that have become current and further items from the master list. Remember to be realistic about what can be accomplished, to divide and conquer, and consolidate and control. From the daily to do list, rank the priorities either A, B, or C. As are the most important items. Bs are basic items. Cs are everyday items. Attempt to do 2 to 3 items per day that have been ranked as A and do them first. Make the rest Bs and Cs. Finally remember the most important activities tend not to be urgent and the most urgent are usually not the most important. Urgency often takes over and the most important tasks do not often need to be done today. So, it is crucial that a person plans so that important tasks are kept track of.

WORK OVERLOAD AND UNDERLOAD Performance varies with different levels of workload. To explain the variation in performance in relation to different levels of workload there is a theory proposed by Yerkes and Dodson in 1908. The model is from the section on stress discussed earlier in this topic. Sometimes called the "Inverted U theory" or the "Yerkes-Dodson law". It is believed that the best performance on a task occurs when workload levels are somewhere between two extremes, having insufficient work to keep a person occupied at one end resulting in boredom, and at the other having too much work to manage and becoming distressed. There is an optimal level of workload for any task which lies somewhere between these two extremes. This optimal level of workload changes depending on the type of task and differs between individuals. For example, simple tasks can be completed under far more stressful conditions than complex tasks. These issues obviously need to be considered when allocating work. In terms of priorities, they are not the highest. An individual has to be competent to do the job in the first place but whether the job is stressful or not, how much time there is to do it and what other work priorities the individual has must all be taken into account.

SLEEP AND FATIGUE, SHIFTWORK Everyone has an ideal amount of sleep they require to feel fully rested. For example, some people require 9 hours of sleep per night to feel well rested and function the next day, while others may only need as little as 5 hours sleep per night. What ever an individual need is, when the person gets less sleep than this or remains awake for an extended period of time he or she becomes sleepy. Sleepiness is a physiological signal that the body requires sleep. It is similar to hunger indicating the need for food, or thirst indicating the need for water. However, unlike hunger or thirst, if the person continues to ignore the bodys signal for sleep the person will eventually fall asleep no matter where he or she is or what he or she is doing. With as little as 2 hours sleep loss, a persons performance begins to decline. So if an individual needs 7 hours sleep per night to feel fully rested, but only get 5, then the individual can expect his or her performance to be worse the following day. Age-related changes in sleep may create difficulties for shift workers. A NASA study found that pilots aged 50-60 years lost 3.5 times more sleep per day on international trips, than did pilots aged 20-30 years. The most important aspect of sleep quality, for how an individual feels and function the next day, is sleep continuity. If a persons sleep is broken up by waking up many times, then its quality is reduced, even if the awakenings are very brief and the person does not remember them. Sleep can be disturbed by a wide variety of things, from environmental factors (noise, light, work schedules), to physical sleep disorders. More than 80 different sleep disorders have been identified so far. Under normal circumstances, there are two times in the 24-h day when people can fall asleep easily (around 0300-0500 and 1500-1700 for day workers - siesta time). There are also occasions where it is very hard to fall asleep, even if a person has gone without sleep. Caffeine can be used strategically to help at times when a person is struggling to stay awake. It is a stimulant but will be more effective if he or she does not use it continuously. Try to avoid caffeine when one is already alert, for example at the beginning of a shift or after a nap. Save it for the difficult times, like the early hours of the morning and just after lunch. Caffeine usually takes about 15-45 minutes to have an effect. People differ widely in their sensitivity to caffeine. This depends on such things as body size, previous food intake, and how much it is regularly use. The stimulant effects of caffeine generally last 3-5 hours, but can last up to 10 hours in sensitive people, so it is important to pay attention to how it affects an individual. A person needs to stop taking it far enough in advance of bedtime so that it does not interfere with his or her sleep. Some researchers recommend stopping caffeine as much as 6 hours before bedtime.

ALCHOL, MEDICATION, DRUG ABUSE There is no place for alcohol and drug abuse in the aviation industry. All major organisations, as well as the regulatory authorities, are starting to put significant time and effort into this issue. The aviation industry has unfortunately had alcohol as part and parcel of its early culture. In some organisations this has continued despite all of the evidence that suggests that alcohol and safety do not mix in anyway, shape or form. This section will briefly look at what is meant by fitness for duty in relation to alcohol, medication and drug abuse. Fitness for duty means Readiness to perform which is the capability of effectively and safely performing their duties at work. Tests, which can distinguish between people who are fit for duty and people who are not, include biochemical indicators of the presence of certain substances (e.g. alcohol) and Performance tests Symptoms of alcohol and drug abuse include degraded performance, as evidenced by decreased productivity, unacceptable work, diminished ability to concentrate, increase in failed inspections, sloppy work, increase in judgment errors, signs of increased fatigue and poor reliability. Poor attendance, which starts in the forms of excessive sick leave, increased leave abuse, e.g. before and after weekends, frequent and unexplained disappearances and on-the-job absences, unscheduled vacation, early leaving, extended lunch breaks, and repeated tardiness and frequent complaints of vaguely defined illnesses There are also changes in both attitude and physical appearance such as uncharacteristic anger, unprovoked emotional outbursts and irritability, sudden changes in mood, blaming others for own shortcomings, avoiding colleagues and supervisors and personal hygiene. Finally, there are associated health and safety hazards such as increased health and safety hazards, increased number of on-the-job accidents, careless handling and maintenance of equipment, needless risk-taking, and disregard for others safety. Note that these are all the signs of a person in trouble and who needs help. While people do not condone wilfully disregard of fitness for duty, there is an obligation to help colleagues as soon as possible if any of these symptoms are seen before it is too late. Once a worker has been identified as at risk, the likely follow-up is as follows remove employee from safety-sensitive function, seek medical advice, employee to be tested as soon as possible, if positive, prohibit from safety-sensitive duties, employee assessed to determine needs, e.g. treatment or rehabilitation, if an employee receives treatment or rehab, the employer MAY decide to return the individual to work and employees returned to safetysensitive duties are subject further testing It should also be pointed out that sometimes things do not always go according to plan even when people are trying to do the right thing. Helping a colleague who is in a bit of a rut with alcohol for example might spurn a persons good intentions for any of a number of reasons are confidentiality issues, work culture, potential for being ostracised by work mates and fear of being sacked. Just because it does not work out right the first time does not mean a person have not done the right thing. Some day doing the right thing might just save somebodys life.

MURPHYS LAW There are several versions of the law, however, the most known version is the first one in the list. If anything can go wrong, it will. If there is a possibility of several things going wrong, the one that will cause the most damage will be the one to go wrong. Corollary: If there is a worse time for something to go wrong, it will happen then. If anything just cannot go wrong, it will anyway. If an individual perceives that there are four possible ways in which something can go wrong, and circumvent these, then a fifth way, unprepared for, will promptly develop. Left to themselves, things tend to go from bad to worse. If everything seems to be going well, something obviously had been overlooked. Nature always sides with the hidden flaw.

THE NEED TO TAKE HUMAN FACTORS INTO ACCOUNT Humans and machines have different strengths and weaknesses and recognition of these differences goes a long way to giving the right jobs to people and the right jobs to machines thereby reducing the chance of errors. The point is that the system needs both humans and machines to interact in synergy each utilising the strengths of the other to provide total system safety. The human is an integral part of the system. Public and personal safety relies on competent individuals and systems working together to meet specific safety standards. It is difficult to overestimate the importance of training in this process. In many respects individuals are a product of the training they receive and apart from a few innate abilities and a large number of experiences, what the individuals learn through training reflects their capability and their competence. Liveware (Software) is the interactions between individuals and the organizations policies, procedures, manuals, etc, mostly contain errors of interpretation or understanding. Many of the manuals engineers were expected to use were not user friendly, policies were interpreted differently by different supervisors and rules were often ignored because they conflicted with common sense. Liveware (Hardware) is the interactions between individuals and the machinery or tools that they used also required some major rethinking to reduce the error rate. Controls that required extreme physical strength, displays that were easy to misread and hours of boring monitoring contributed to high error rates in these interactions. User friendly controls and displays and a better understanding of the relative strengths of humans and machines provided a platform for reducing error rates considerably. Alarm systems were also provided to keep operations within the established parameters. For example, it would not be cost effective of an organisation to purchase expensive, highly specialised equipment (a common requirement in aviation), if they did not get their personnel trained appropriately on that machinery. Further, these personnel can risk serious injury to themselves or to airline passengers if they are not competent in operating the machinery. In the same way, all training is primarily aimed at reducing errors of one form or another. This Human Factors course is just another example of the company providing training to individual with the intention of reducing maintenance errors that may have occurred if he or she had not undertaken this training. Time will tell whether it has been successful.

INCIDENTS ATTRIBUTABLE TO HUMAN FACTORS / HUMAN ERROR Air Ontario accident led to maintenance engineering focus groups identifying what has been termed The Dirty Dozen of maintenance engineering. These are all human factors. Lack of communication, this has been a well-established cause of error in the aviation industry and had been included on CRM courses since they first began and it is one of the Dirty Dozen. Lack of communication means not passing on information, either written or oral, and passing on information but not being sure that it has been understood properly. Complacency is a real danger for engineers. Following the Aloha Airlines incident, the FAA issued an Airworthiness Directive (AD) requiring the close visual inspection of 1300 rivets on every single Boeing 737. If ever there was an opportunity for complacency in the inspection business. Lack of knowledge, it is impossible to know all there is to know in the maintenance engineering business. In the absence of specific knowledge, it is a human trait to fill in the gaps with good enough actions or do nothing, hiding behind the expression I didnt know what to do. Distractions in the engineering business are common. Irrespective of whether the distraction is home life or just a friend at work interrupting when work is done, distractions have been cited on many occasions as the reason for checks or steps being missed during an engineering process. Lack of teamwork has mentioned a number of times as a major source of error. Humans are all members of a number of teams and it is important that they play their role in each team to the best of their ability. Fatigue recognised as a source of error but aviation personnel works in a 24 hour industry and the demands are high. Education seems to be the major countermeasure to this problem at the moment. Lack of resources is unlikely to be a problem in most organisation but there will be times when the person might say I wish I had just one more person to help us with this job or where are the spare floodlights when you need them. It is easy to improvise but it is also easy to get caught out improvising. Pressure comes in many and varied forms. Time pressure, for example, will always be part of the aviation industry and particularly for engineers. An aircraft cannot make any money when it is on the ground and the sooner it can be turned around the better. Lack of assertiveness is generally a result of the hierarchy or rank structure in an organisation. There are both formal and informal versions. The formal ones are normally part of the company or profession structure while the informal ones are related to where a person perceives oneself amongst peers and the organisation. Stress is part and parcel of everyday lives. When a person goes to work, and simple things such as an argument with the persons spouse or partner at home in the morning can result in errors at work. Situation awareness is also a big problem in the aviation industry and there is a whole module at the end of this course devoted specifically to situation awareness.Norms are a part of the culture of an organisation and each organisation has sets of norms which are positive and those which are negative. The trick is to enhance the positive and suppress the negative.

VISION Vision might seem to be an unusual human performance to be considering here as it is almost impossible to become an engineer without satisfactory vision but the fact is, that a persons normal vision has many more limitations that affect ones performance than is usually realised. In considering this issue, some advantages of using appropriate visual discrimination methods for design decisions will be identified; good and bad visual clues will also be distinguished and the physiology and anatomy of the eye that leads to these points will also be looked into. HEARING Like the visual system, the auditory system suffers from a range of limitations. We will not go into all of the aspects of this subject for the purpose of this module, but rather, concentrate on the differences between hearing and listening and what has become known in the literature as the active listening process. INFORMATION PROCESSING In this section, the importance of the human senses as people interact with their environment will be described. This human senses include vision and hearing that were discussed in this topic. Other senses used in acquiring, processing and applying information will also be identified and described. A person has five senses. Some people claim a sixth sense and there is no doubt many people have some intuition. The five are: Sight through the visual system using the eyes as the primary sensor. Hearing through the auditory system using the ears Touch and feel through the skin are said to use the integument Taste is sensed via the gustatory system using the tongue as the primary source of sense. Smell is through the noses using the olfactory system. In addition, there are several other senses that are used to acquire information. The vestibular sense allows a person to detect balance, motion, and acceleration. The proprioceptive sense tells the position and location of the limbs, and the kinesthetic sense tells how a person is moving various parts of the body. Disregarding any possible psychic powers, if a person cannot detect something with one or more of his senses, the person usually is not aware of its presence.

ATTENTION AND PERCEPTION The importance of attention in transferring of information from the sensory memory into the short-term memory was mentioned. In this section, there will be attempts to identify factors which improve an individuals attention and the difference between attention getting factors and attention suppressing factors will be distinguished. Attention is the focussing and concentrating of consciousness. It implies withdrawing from something in order to deal effectively with something else. Attention has a limited capacity and if a certain activity requires attention then some of the limited capacity must be allocated to that activity. Thus another activity requiring attention will suffer in quality or be delayed as a result of its simultaneous performance with the first activity, particularly when the primary task is more complex. Humans interact with the environment by acquiring information, processing it, and then taking certain actions. Various senses to gather the information that are needed are used. The five basic senses are vision, audition, touch, olfaction (smell), and gestation (taste) As a result of a vast amount of sensory research, several facts regarding perception are known. First, the minimum levels of stimuli needed for detection by each of the senses are known. These are called "threshold values" for detection. Also known is generally how many different and distinct levels of particular stimulus humans can distinguish. There is a difference between detection and perception. Detection refers to the physical response of the senses, or detectors, in the presence of some event or stimulus. Perception refers to the combination of psychological and physical processes that allow a person to know that he or she has detected something. It is possible, even likely, under certain conditions, that the person will not perceive an event, even one well above the threshold level for detection. This fact cannot be doubted by anyone who has been married and accused of never hearing anything one's spouse says. Certain environmental characteristics affect the ability to perceive certain events. Physical and psychological stress, attention demands, heavy workload, and other conditions common in the aviation maintenance environment can cause a loss of perceptual capabilities.

MEMORY Sensory memory is the first point in the process. The sensory memory is just the reception point for the plethora of information that it receives by each of the five senses. The human senses pick up an extraordinary amount of information at any time but the sensory memory does not hold on to it for very long. Sensory memory can be imagined in the following way. If someone sets off a flashbulb in a persons eyes, the light from it stays in front of his or her eyes for a little while after the flash has stopped and the person has closed his or her eyes. Information is passed from sensory memory into short-term memory bythe process of attention which are just discussed, thereby filtering the stimuli to only those which are of interest at a given time. Long-term memory requires a person to actually make sense of what it is that he or she is trying to remember. In this respect, a person has to analyse it and actually separate it into its components before the person can store it in his or her long term memory. From there, it can actually be retrieved in a whole range of forms, rather that just as a single entity. There are methods of enhancing memory, or at least making things easier to remember, and it can be tested even on past memories. Rehearsal can be very effective in the short term memory, but it also has a place in the long term memory if it is done often enough. People use this technique for phone numbers.

CLAUSTROPHOBIA AND PHYSICAL ACCESS This topic is very important particularly for engineers. People do not always appreciate that some of their colleagues may have a lot more trouble doing the job than they imagine. In this module, individual differences in human perception and performance will be recognized and particular reference to the anxiety that some people associate with small spaces will be made. First, it is important to remember that all people are different and many of them have phobias. Common phobias include a fear of snakes, spiders, sharks etc. A phobia is described as an irrational fear. Some people might contend that a fear of snakes is a rational fear rather than an irrational fear. The distinction is made when that particular fear prevents a person from doing his or her job properly. For example, if a person is not prepared to do a job in the hold of an A340 because he or she is afraid of snakes, then that can be reasonably considered to be a phobia. Having a fear of snakes while a person is walking through the jungle in Malaysia or Australia might be considered wise. The most common phobia, or fear, according to research is a fear of public speaking. This sort of phobia is unlikely to have a big bearing on the role of a maintenance engineer. Agoraphobia, however, and most particularly claustrophobia, are very relevant to engineers. A fear of heights or a fear of small spaces can have a detrimental effect on the work being done by individuals. Their anxiety levels rise considerably and their chances of focussing on the job at hand are almost nonexistent. As work colleagues, there is a need to be aware of this and help colleagues out if they are caught in such a situation. Someone who suffers from claustrophobia will experience a real anxiety attack if put in the situation of being enclosed in a small space. It is a colleagues job to help them out without making them look incompetent (which they are not), or silly (which is not the case either).

INDIVIDUAL AND GROUP RESPONSIBILITY The focus will be on the responsibility as work mates to either help them, or get them the appropriate help, which invariably the company will be able and willing to supply. The first point is to know when something is going on in a work colleagues life that could affect their performance. It is rare that individuals will be able to recognise that their troubles are affecting their work and research has shown that the individuals are often the last to accept that they have a problem. The term troubled employees is used as a generic term to imply one of the workmates who could probably use a bit of a helping hand if it was offered. So how is a person going to recognise him or her? They do not always have the hang-dog expression. There are some behavioural signposts. These are degraded performance, poor attendance, changes in attitude and physical appearance, and increase in health and safety hazards. Employee Assistance Program refers to a broad range of company programs helping employees deal with various problems, including emotional and financial distress and substance dependency. FAA rules have required aviation employers to establish Employee Assistance Programs (EAPs). EAP requirements are limited to drug and alcohol use and treatment for misuse. Generally, EAPs in other industries address a broad array of performance-related issues, including mental, emotional, financial, marital, and even physical problems. While this is not the case in all countries, most responsible companies will have some variations on these FAA requirements. Employee Assistance Programs (EAPs) invariably include some type of counselling. Both individual and group counselling require a trained counsellor to identify and help clients solve problems. Counsellors must undergo specialized training to be effective. Group counselling is not something that can be undertaken by Human Resource facilitators or others conducting group meetings or focus groups.

MOTIVATION AND DEMOTIVATION People need some sort of motivation to do their job. In most cases it consists of pay packet each week but there are a whole range of motivators for doing any task. Most particularly it is worth noting that different people are motivated by different incentives. It is very uncommon to find a motivator that will affect all people the same way. While money is a prime motivator in many respects, once the basic needs are covered there is a real change in peoples attitude towards it. Someone who is saving up for a new computer or a new car might be very motivated to earn a bit of extra cash whereas someone with a new bride or a new child might much rather some extra time off to spend with their family. There are warnings to this. People can be offered incentives to work until they become dangerous and sometimes the motivation to earn extra money or recognition from management might override the recognition that they have become too tired to do their job properly and pose a danger to themselves and others. If recognition for doing something good is a motivator then making sure that everyone knows a mistake was made can be a big de-motivator. If reward is a motivator then punishment is a de-motivator and ridicule has a special place as the opposite of status as a motivator. It can really make sure people do not want to be part of the team.

PEER PRESSURE Peer pressure, as with most social psychology subjects, has both positive and negative aspects. Peer pressure can, for example, have a particularly good effect. For example, friends in a care might warn the driver that he or she is breaking the speed limit and thereby bring down their speed. Not only does this reduce the chances of an accident and/or the damage if an accident does occur, but it might be as simple as saving that driver from a speeding fine. Positive peer pressure can also bring about better performance in the workplace. For example, having a small side competition on who will make the least mistakes in a rivet check might see everybody going through the whole check without making any mistakes. The negative side of peer pressure can be quite disastrous, both socially and in the workplace. Those same people in the speeding car could in fact, urge on the driver to go faster still. At some stage, the drivers reactions will not be quick enough to save the occupants of the car when something unexpected happens, like a truck backing out of a blind side road or a child runs across the road without looking. The work environment has the same problems. If the competition was set to see who could finish their allocated rivets first, then in fact, the likelihood of mistakes would increase exponentially with the speed at which the job was being done.

CULTURE ISSUES In terms of cultural issues, there are a number of different cultures that need to be recognised in this section. They are national culture, professional culture, organisation culture and safety culture. With respect to national culture, a number of norms have to be taken into account. Specifically, they are history, religion, politics and identity. Professional culture in this context refers to the industry wide norms of maintenance engineers. What is it about maintenance engineers that goes with them no matter who they are working for or in fact, where they are working anywhere in the world. All companies will have an organisational culture which a person will fit into and which will influence his or her work practices. It necessarily affects the persons behaviour and it will reflect practices and procedures, both written and unwritten, that have been part of the companies since its inception. An organisation with a good safety culture is one which has managed to successfully institutionalise safety as a fundamental value of the organisation, with personnel at every level in the organisation sharing a commitment to safety. One of the key elements is effective support from the top levels of the organisation for safety. It is necessary for senior management to demonstrate their commitment to safety in practical terms, not just verbally or only as long as safety is a no-cost time. It is all very well for an organisation to commit to putting in place, say, a safety reporting and investigation scheme but if such a scheme is not resourced properly, or if safety recommendations are not acted upon, it will be ineffective. It is also important that such commitment to safety is longterm, and that safety initiatives are not the first times to be cut in terms of financial support when the organisation is looking for cost savings. One of the long term objectives of a Human Factors Error Management Programme is to develop a Reporting Culture an organizational climate in which employees are prepared to report maintenance errors, safety, health or quality non-conformances. All levels of staff are encouraged to report maintenance errors, safety issues, health concerns or near miss, especially those that jeopardize airworthiness or safety. The feedbacks are important, as it will helps an organisation to identify the root cause and take the necessary corrective actions and avoid repeating the same errors or nonconformances. This will improve the workers health and safety, the reliability of the operation and reduce cost.

TEAMWORK Teamwork is always an interesting issue because people normally belong to a whole range of different teams. In this section, factors, good and bad, that affect team performance will be described. How effective teams or team working can reduce maintenance errors will also be described, along with the principles of effective team dynamics within an organisation and how operation of an effective team may be identified. Groupwork and teamwork will not only be important, but unavoidable in twenty-first century life. People normally belong to a number of different teams both socially and in the workplace. Aircraft engineers work in teams of engineers on a particular aircraft on a particular day, work as part of a team in the organisation in a particular section, may even belong to sporting teams of one form or another, and could even team up within social contexts to form clubs. Building effective teams is both difficult and time-consuming. While it is sometimes difficult for a number of people just to get together and call themselves a team, there is a big difference between a high performing team and a low performing team. Team sports provide the best analogy of this. To have a team to work together so closely that they can win championships is probably the best possible example of good teamwork but every successful team will tell that the building process was both difficult and time consuming. It rarely just happens. Conversely, team building can be both rewarding and productive if the process takes place in a supportive organisational framework. In fact, the McDonalds restaurant chain has been recognised as being able to build high performing teams of individuals throughout the world. This is an example of an organisation putting the infrastructure in place to allow teamwork to flourish. The advantage of teams in the workplace is that they can significantly reduce maintenance errors. They reduce errors by motivating individuals to do their individual work better than they would if left to their own devices. This may be because they want to be seen as an equal and effective member of the team or because their performance is enhanced by the support offered by their colleagues. It also reduces the impact of errors because team members tend to cover each others work and pick up on any errors before they become accidents or incidents.

MANAGEMENT, SUPERVISION AND LEADERSHIP Decision-making is a combination of two fundamental factors. These are the attitude of the person or group of people making the decision and the process they use to derive their decision. In simple terms, decision-making is a combination of attitude and headwork. Attitude can be described as "the less deeply internalised components of your personality that are subject to change fairly easily, especially under pressure from several sources at the same time". That changeability is the key factor though many attitudes tend to be enduring and quite resistant to change. Our attitudes towards seniority, duty schedules and pay are examples that tend to be resistant to change. However, not all attitudes are so resistant. Those that are not central to a belief or an essential part of ones basic perception of life and living may be changed more easily. The headwork aspect of judgement is the rational part of the equation. As a definition it can be broken into several parts. Ability to derive and evaluate information about a critical situation and motivation to select and implement an appropriate timely action. There are a few decision-making tools available to managers and supervisors involved in aircraft maintenance engineering. Some of them are decision tree, expert system, hypothesis, failure modes and effect analysis, and fault tree analysis. One type of maintenance job performance aid is called a "decision tree". A decision tree is a printed or computerized chart that directs the maintenance technician along a logical testing and diagnosis path for a particular system or product. After each test or observation, the decision tree branches to another test based on the test results. Another example of a decision tool might be an expert system. Expert systems are diagnostic decision-making aids used in a number of different domains, including medicine, geological exploration, a