Human Factor

  Maintenance of aircraft involves working with a variety of fluids and  chemical substances.         Lubricants                                                                hydraulic fluids,       paints,        cleaning compounds         solder.          aircraft fuel and exhaust.  AME is   exposed to a number of these substances  in the workplace. Each substance  gives off some form of vapour or fumes  which can be inhaled by .  Some fumes have their odour,  whereas others have no smell to indicate their presence.  Some substances will be  benign most of the time, but may, in certain circumstances, produce fumes (e.g.  overheated grease or oils, smoulde...

Potential Hazards in Aircraft Maintenance  very bright lights (e.g. from welding); very loud sounds (sudden or continuous);  confined or enclosed areas; working at significant heights; noxious substances (liquids, fumes, etc.); excessive temperature (i.e. too cold or too hot);  moving equipment, moving vehicles and vibration. Health and safety policy Carry out assessments of work including inspections to determine H&Safety risks; Provide safe working practices and procedures for plant, machinery, work equipment, materials and substances; Inform employees and other persons including temporary workers of any risk; Provide suitable training and/or instruction to meet any Health and Safety risks; Develop and introduce practices and procedures to reduce risks to Health and Safety including the provision of special protective devices and personal protective equipment; Provide for the welfare of employees; Discuss with and consult employee rep...

 Where procedures allow some leeway, AMT often develop  their own strategies or preferred way of carrying out a task. Often, a ‘good’ rule or  principle is one that has been used successfully in the past.  These good rules become   ‘rules of thumb’ that an engineer might adopt for day-to-day use.  Problems occur   when the rule or principle is wrongly applied. For example, aircraft pipe couplings are   normally right-hand threads but applying thi  s ‘normally good rule’ to an oxygen pipe   (having a different thread) could result in damage to the pipe. Also, there can be   dangers in applying rules based on previous experience if, for example, the design philosophy differs, as in the case of Airbus and Boeing. This may have been a factor in an A320 locked spoiler incident, where subtle differences between the operation of the spoilers on the A320 and those of the B767 (with which the engineers were more familiar) meant that act...

S lips, lapses and mistakes ;  Slips  can be thought of as actions not carried out as intended or planned, e.g. ‘transposing digits when copying out numbers, or misordering steps in a procedure. Lapses  are missed actions and omissions, i.e. when somebody has failed to do something  due to lapses of memory and/or attention or because they have forgotten something, e.g.  forgetting to replace an engine cowling.    Mistakes  are a specific type of error brought about by a faulty plan/intention, i.e. somebody  did something believing it to be correct when it was, in fact, wrong, e.g. an error of  judgement such as mis-selection of bolts when fitting an aircraft windscreen.          Violations  sometimes appear to be human errors, but they differ from slips, lapses  and mistakes because they are deliberate ‘illegal’ actions,

 O ne team passes on tasks to another team . I nformation conveyed include: tasks that have been completed; tasks in progress, their status, any problems encountered, etc.;  tasks to be carried out; general company and technical information. Communication between teams  involves passing on written reports of tasks from  one shift supervisor to another -  backed up by spoken details Written reports (job cards, procedures, work orders, logs,  etc.)  Warning flags / placards provide a record of work completed and work yet to  be completed -  provide tractability.  Information communicated at shift handover ensures good continuity. It is important that handovers are not rushed, so as to minimize omissions. Communication Problems - lack of communication -  engineer who forgets to pass on pertinent information to a colleague,      or when a  written message is mislaid. Poor communication . -  ...

  Noise Induced Hearing Loss (NIHL)  -  Hearing loss can result from exposure to even relatively short duration noise. The degree of impairment is influenced mainly by the intensity of the noise. Such damage is known as Noise Induced Hearing Loss (NIHL).   Hearing loss can be temporary - lasting from a few seconds to a few days - or permanent.     Temporary hearing loss may be caused by relatively short exposure to very loud sound, as the hair-like cells on the basilar membrane take time to ‘recover’. With additional exposure, the amount or recovery gradually decreases and hearing loss becomes permanent. Thus, regular exposure to high levels of noise over a long period may permanently damage the hairlike cells in the cochlea, leading to irreversible hearing impairment. Three levels of noise at which an employer must act:      a) 85 decibels (if normal speech cannot be heard clearly at 2 metres), employer must;      ...

Model are used to understand human factor  as a framework around which human factor issues can be structured. SHEL(L),PEAR, Dirty Dozen  S - Software H - Hardware L - Liveware E - Environment                                         Liveware  is at the center of the model, is   the most critical and flexible component in the working  Environment and subject to considerable variations in performance and suffer many limitations.                           Physical size and shape.  In the design of workplace and equipment, body measurements and movements is considerd , which may vary according to factors such as age, ethnicity and gender. Human Factors inputs is provided  in the design process, and data for these inputs are available from anthropometry, biomechanics and k...

Maslow’s Hierarchy of Needs attempts to describe human motivation,   considered that humans are driven by two different sets of motivational forces:        1. those that ensure survival by satisfying basic physical and psychological needs;        2.  those that help us to realise our full potential in life known as self-actualisation needs (fulfilling ambitions,                etc.). Maslow's hierarchy of  needs  is often portrayed in the shape of a pyramid with the largest, most fundamental needs at the bottom and the need for self-actualization and transcendence at the top. Crux of the theory is that individuals’ most basic needs must be met before they become motivated to achieve higher level needs. Physiological needs   is a concept that was derived to explain and cultivate the foundation for motivation.              ...

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...

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...

          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 ...

Peer pressure is the actual or perceived pressure which an individual may feel, to conform t o what he believes that his peers or colleagues expect.  Peer pressure thus falls within the area of conformity.  Conformity is the tendency to  allow one’s opinions , attitudes , actions and even perceptions to be affected by  prevailing opinions, attitudes, actions and perceptions. Culture  of    an organisation -    ‘the way we do things here ’.  It is a group or company norm. ICAO HF Digest 10 - a safety culture is “a set of beliefs, norms, attitudes, roles  and social and technical practices concerned with minimising exposure of employees,  managers, customers and members of the general public to conditions considered  dangerous or hazardous” Social Culture -  The influence of social culture (one’s background or heritage) can be  important in determining how an individual integrates into an organisa...

Anatomy of the Human  eye   1.  Cornea  2.  Iris and Pupil 3.   Lens  4.  Retina Cornea  -  is a clear ‘window’ at the very front of the eye .  Cornea  acts as a fixed  focusing device.    Focusing is achieved by the shape of the cornea bending the  incoming light rays.            Responsible for 70%-80% of the total    focusing ability (refraction) of the eye. Iris and Pupil  Iris ( coloured part of the eye ) controls the amount of light that is allowed to  enter the eye.       It does this by varying the size of the pupil ( the dark area in the centre  of the iris ).               The size of the pupil can be changed very rapidly to cater for changing light  levels.    The amount of light can be adjusted by a factor of 5:1. After passing through the pupil, the lig...