Human Factor

Complex system means having a wide variety of inputs. There may be a single output, or many distributed outputs from the system. . The system typically performs complex modifications on these inputs, or the inputs may trigger complex responses. There may be a single output, or many distributed outputs from the system. All large modern aircraft can be described as complex systems.  Within these aircraft,  there are a myriad of separate systems, many of which themselves may be  considered complex, e.g. flying controls, landing gear, air conditioning, flight  management computers.  Maintaintenance of   complex systems ,  the engineer will need to have  carried out some form of system-specific training which would have furnished him  with an understanding of how it works (and how it can fail) and what it is made up of  (and how components can fail).  It is important that the engineer understands enough  about the o...

Visual inspection can be described as the process of using the eye,  alone or in conjunction  with various aids to examine and evaluate the condition of systems   or components of an  aircraft. Visual inspection is one of the primary methods to   ensure the aircraft remains in an airworthy condition.  AME  may use magnifiers and   borescopes to enhance their  visual capabilities.  AME may accompany his   visual inspection by examining  the element using his other senses  (touch, hearing, smell, etc.).  He may also    manipulate the element being inspected  to make further judgements about its  condition. For instance, he might feel a   surface      for unevenness, or push against it to  look for any unanticipated movement. Visual inspection is often the principal method used to identify degradation or  defect  in systems or components of ...

Repetitive tasks   - tasks that are   performed several times during a shift,  or a number of times during a short time period,  e.g. in the course of a week.  Repetitive tasks can be tedious and reduce arousal (i.e. be boring).  Most of the human  factors research associated with repetitive tasks has been carried out in  manufacturing environments where workers carry out the same action many times a  minute. This does not generally apply to maintenance engineering. Main danger with repetitive tasks is that engineers may become so practiced at  such tasks that they may cease to consult the maintenance manual, or to use job  cards. Thus, if something about a task is changed, the engineer may not be aware of  the change.  Complacency  - an engineer may skip steps or  fail to give due attention to steps in a procedure, especially if it is to check something  which is rarely found to be wrong, damag...

Physical Work   - Aircraft maintenance is a relatively active occupation.   Regardless of the  job being done, most tasks tend to have elements of fine motor control, requiring precision, as well as activities requiring strength and gross manipulation. Biomechanical perspective,  human body is a series of physical links  (bones) connected at certain points (joints) that allow various movements.  Muscles   provide the motive force for all movements , both fine and gross. 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. Ease of maintainability -It is important that maintenance tasks on aircraft are within the physical limitations of aircraft maintenance engineers. Physical work over a period of time will  result in fatigue. This is normally not a problem if there is...

                Task -  a piece of work to be done .  Task implies work imposed by a person in authority or an employer or by circumstance. charged with a variety of tasks duty implies an obligation to perform or responsibility for performance.    Planning  -    is the function of management  that involves setting objectives and determining a course of action for achieving those objectives.   Planning  requires that  managers  be aware of environmental conditions facing their organization and forecast future conditions.   Planning  is the  process  of thinking about the activities required to achieve a desired goal. It is the first and foremost activity to achieve desired results. It involves the creation and maintenance of a  plan , such as psychological aspects that require conceptual skills.         Before commencing a task, an enginee...

Humans can work within quite a wide range of temperatures and climatic conditions ,  Temperature  is a property of the universe whereas  climate  is primarily a feature of the atmosphere of a planet or a region on a planet's surface.  Temperature  causes  climate  whereas  climate  is the result of  temperature . Climate   is the average weather in a given area over a longer period of time Performance is adversely affected at extremes Tempperatures and climatic condition. Too cold and/or wet or too hot and/or humid , performance diminishes.  AME routinely work both within the hangar and outside.  Exposure to the widest  range of temperature and climate is likely to be encountered outdoors.  Engineer may have to work in direct summer sun, strong winds, heavy rain, high  humidity, or in the depths of winter.  Although hangars must exclude inclement  weather, they can be cold and draughty,...

             AME is work in a variety of different   environments, from ‘line’ to ‘base’, in all types of weather and climatic conditions, day and night. AME encounters the impact of noise , fumes , illumination , climate and temperature , motion and vibration , as well as the  requirement  to work in confined spaces and issues associated with the general working environment. CAR 145.A.25 (c) The working environment including aircraft hangars, component workshops and office accommodation is appropriate for the task carried out and in particular special requirements observed. Unless otherwise dictated by the particular task environment, the working environment must be such that the effectiveness of personnel is not impaired: 1. Temperatures must be maintained such that personnel can carry out required tasks without undue discomfort. 2. Dust and any other airborne contamination are kept to a minimum and not be permitted to r...

Illumination  -  lighting both within the general working environment and also in  the locality of the engineer and the task he is carrying out.  Amount  of light striking a surface.  To work safely and efficiently, proper lighting conditions is required.  Cones in the retina of the eye  require good light to resolve fine detail. Colour vision requires adequate  light to stimulate the cones.  Inappropriate or insufficient lighting can lead to mistakes  in work tasks or can increase the time required to do the work.    Illuminatio n  availableability is important where the engineer needs it (i.e. both  in the hangar and one the line). Supplemental task lighting must be adequate in  terms of its brightness for the task at hand , which is best judged by the engineer.  When using task lighting , it should be placed close to the work being done,  but should  not be in the engineer’s line of s...

Noise  - any unwanted sound, especially if it is loud, unpleasant and  annoying. Noise in  the workplace can have both  short-term and long-term negative effects :                  it can be annoying,                  can interfere with  verbal communication and mask warnings,                 and it can damage workers’ hearing  (either temporarily or permanently).   Ear is sensitive to sounds  between 20 HZ to 20 KHz.  Intensity of sound is  measured  in decibels (dB),   Exposure in excess of 115 dB without ear  protection even for a short duration is not recommended.  This equates to standing  within a few hundred metres of a moving jet aircraft. General background noise can be ‘filtered out’ by the brain through focused  attention.   Hearing protection   ...

Memory can be considered to be the storage and retention of information, experiences and knowledge, as well as the ability to retrieve this information.   Memory  processes      1. registration                                              2. storage                                              3 .  retrieval  Ultra short-term memory  - Physical stimuli are received via the sensory receptors (eyes, ears, etc.) and stored  for a very brief period of time in sensory stores (sensory memory). Visual information  is stored for up to half a second in iconic memory and sounds are stored for slightly  longer (up to 2 seconds) in echoic memory.  Short term memory receives a proportion of the infor...

Motor Programmes -  If a task is performed often enough, it may eventually become automatic and the  required skills and actions are stored in long term memory. These are known as  motor programmes and are ingrained routines that have been established through practice.  Use of a motor programme reduces the load on the central decision  maker. example - driving a car: at first, each individual action  such as gear changing is demanding, but eventually the separate actions are  combined into a motor programme and can be performed with little or no awareness. Motor programmes allow  - to carry out simultaneous activities, such as  having a conversation whilst driving. Situation Awareness -  the process of attention, perception and  judgement should result in awareness of the current situation               Situation awareness is the synthesis of an accurate and up-to-date 'mental model' ...

Attention  - Having detected information, our mental resources are concentrated on specific elements - this is attention.  Attention can be thought of as the concentration of mental effort on sensory or mental events. Selective attention occurs when a person is monitoring several sources of input, with greater attention being given to one or more sources which appear more important. A person can be consciously attending to one source whilst still sampling other sources in the background.   the ‘ cocktail party  effect’   Distraction is the negative side of selective attention. Divided attention is common in most work situations, where people are required to  do more than one thing at the same time. Usually, one task suffers at the expense of the other, more so if they are similar in nature.    Focused attention is merely the skill of focussing one’s attention upon a single source and avoiding distraction. Sustained attention re...

            Information processing is receiving information through the senses, analyzing it, and making it meaningful.             Information Processing Model   -  captures the main elements of the process, from receipt of information via the senses, to outputs such as decision-making and actions.  Information processing theory is mainly developed for the process of our  memory .                                IPM is used to analyze memory  while receiving some information.                                             IPM   captures the main elements of the process, from receipt of information via the senses, to outputs such as decision-making and actions. Sensory Receptors and Sensory Stores Physical...

Physical Access and Claustrophobia   Claustrophobia can be defined as abnormal fear of being in an enclosed space.      There are many circumstances where people may experience various levels of physical or psychological discomfort when in an enclosed or small space, which is generally considered to be quite normal. When this discomfort becomes extreme, it is known as claustrophobia . Fear of Heights - Working at significant heights can also be a problem for some AMT , especially when doing ‘crown’ inspections (top of fuselage, etc.).if an engineer finds working high up brings on phobic symptoms (such as severe  anxiety and panic), they should avoid such situations for safety’s sake

During on job, AME shall not  be under the influence of drink  or a drug to such an extent as to impair his capacity to exercise such  privileges.” Alcohol acts as a depressant on the central nervous system, dulling the senses and increasing mental and physical reaction times.  Medication - Any medication can possibly have direct effects or side  effects that may impair performance in the workplace.   Medication can be regarded as any over-the-counter or prescribed drug  used for    therapeutic  purposes. Analgesics are used for pain relief and to counter the symptoms of colds and ‘flu.  Paracetamol, aspirin and ibuprofen are the most common, and are generally considered safe if used as directed.  Antibiotics ( Penicillin, mycins and cyclines) may have short  term or delayed effects which affect work performance.  Their use indicates that a  fairly severe infection may well be present and apart...

Sleep is a natural state of reduced consciousness involving changes in body and brain  physiology which is necessary to man to restore and replenish the body and brain. Five stages of sleep: Stage 1 : Transitional phase between waking and sleeping. Heart rate slows and muscles relax. It is easy to wake someone up. Stage 2 :  deeper level of sleep, but it is still fairly easy to wake someone. Stage 3 : Sleep is even deeper and the sleeper is now quite unresponsive to external stimuli and so is difficult to wake. Heart rate, blood pressure and body temp continue to drop. Stage 4 :  deepest stage of sleep and it is very difficult to wake someone up. REM Sleep :  the person is even more difficult to awaken than stage 4. Brain is active. It is also known as paradoxical sleep. Muscles become totally relaxed and the eyes rapidly dart back and forth under the eyelids.  dreaming occurs during REM sleep. Stages 1 to 4 are  known as N on-REM Sleep . NREM...

          Stress  -  any force, that when applied to a system, causes some  significant modification of its form, where forces can be physical, psychological or due to s ocial pressures.            Causes of stress  :   Physical : such as heat, cold, noise, vibration, presence of something damaging to health (e.g. carbon monoxide); psychological factor:  such as emotional upset (e.g. due to bereavements, domestic problems, etc.), worries about real or imagined problems (e.g. due to financial problems, ill health, etc.); Reactive : such as events occurring in everyday life (e.g. working under time pressure, encountering unexpected situations, etc.). Acute stress - intense but of short    duration. Cronic stress - frequent recurrence or of long duration.   Possible signs of stress Physiological symptoms - such as sweating, dryness of the mouth, etc.;   Health effects ...

AME job is physically demanding.  AME work in widely varying physical environments,  including cramped spaces, extremes of temperature, etc. Two aspects to fitness and health:  the disposition of the engineer prior to taking on employment and  the day-to-day well being of the engineer once employed.          Pre-employment Disposition ; Medical check up before employment ensure that applicant is fit for particular job.   Airworthiness authority requie medical certificate CA Form 19-06 before issuing AME licence.         Day-to-Day Fitness and Health - Fitness and health can have a significant affect upon job performance (both physical  and cognitive). Day-to-day fitness and health can be reduced through illness (physical  or mental) or injury. Many conditions can impact on the health and fitness of an engineer -  • Minor physical illness (such as colds, ‘flu, etc.); • More major physic...