uk TRAINING MANUAL

HUMAN FACTORS
THE POTENTIAL FOR
HUMAN ERROR

engineering MODULE 9 SECTION 2

THE POTENTIAL FOR HUMAN ERROR

In our study of human factors we will be mostly concerned with identifying those aspects of
behaviour that can result in people making mistakes or errors which could result in
accidents. Our capacity to perceive what is going on in our working environment by sight,
touch, feel, smell, hearing etc: together with our capacity to remember, process information
and act upon it are all relevant in the context of human error.

Factors which can contribute towards mistakes leading to accidents are incalculable.
However, some of them will fall into one or more of the following:

 Inadequate information - be it visual or verbal can, does and will lead to people
making mistakes. If you think the information you have is inadequate or insufficient
do something about it.

 Lack of understanding - possibly stemming from inadequate information or maybe

lack of training can lead to people making presumptions as to how a particular
process or procedure is carried out. This can and does lead to accidents. If you're
not sure ask.

 Poor design - which can result in the best of intentions turning out wrong.
Remember Murphy? If there's a wrong way to do it that's the way you'll do it! If you
recognise a Murphy do something about it if it's only telling others about it.

 Lapses of attention - can and will allow errors to creep in, especially if it’s a simple
straightforward repetitive task. The lesson here is that the more expert you become
at a particular task the more likely you are to make a mistake because, you think you
can afford to allocate less attention to it. Beware the "expert" both in yourself and in
others.

 Mistaken actions - brought about by the classic situation of doing the wrong thing
under the impression that it's right. A classic example of this is the 'short cut' wherein
the engineer knows what has to be done but chooses his own method of doing it.
Don't take short cuts.

 Misperceptions - meaning the capacity we have to see what we want to see, hear
what we want to hear, feel what we want to feel etc: This factor is particularly
relevant to the work of an aircraft engineer in as much as a great many tasks are of a
repetitive nature. The lesson here is to be vigilant and on guard against it.

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 Vision

Vision can be adversely affected by certain medications or drugs, alcohol excess,

oxygen shortage (hypoxia), injury (eg a blow to the head), etc. It can also be affected
either temporarily or permanently by medical conditions (eg migrain, cataracts,
inflammation, corneal problems or refractive surgery) or by dirty or dehydrated
contact lenses or even very dirty spectacles.

 Noise

Can detrimentally affect human performance in terms of damaging hearing,

interfering with speech communication, and affecting concentration and performance.
It can also be fatiguing. Effects vary between individuals, and noise of a certain type
and level may be good for one individual but bad for another.

Noise can affect motivation, reduce tolerance for frustration and reduce levels of aspiration.

There may be an impact upon the individual's ability to think. It is almost certainly likely to
affect inspection or troubleshooting activities where the strategy used is left to the individual,
being primarily assessment - rather than activity-based, possibly reducing the likelihood of
successfully thinking laterally under such circumstances. How many of us can recall, when
concentrating hard on a task, shouting "Stop that noise; I can't think straight!"?

In order to understand the effect both vision and hearing have in terms of maintenance it is
useful to know a little about the anatomy of them.

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 Vision

The eye is the organ which receives light information from the external world and
passes it to the brain. The visual cortex area of the brain interprets this information,
presenting it as a rational, realistic image.

The basic structure of the eye is similar to a simple camera with an aperture, a lens,
and a light sensitive screen, the Retina.

The Structure of the Human Eye

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The Function and Structure of the Eye

 The Cornea. Light enters the eye through the cornea, a clear window at the front of
the eyeball. The cornea acts as a focusing device and is responsible for between 70
and 80% of the total focusing ability of the eye.

 The Iris. The amount of light entering the eye is controlled by the iris, the coloured
part of the eye, which acts as a diaphragm.

 The Pupil. The amount of light allowed to fall on the retina is governed by the size of
the pupil, the clear centre of the iris. The size of the pupil can change rapidly to cater
for changing light levels.

Note: The amount of light allowed to enter the eye can be adjusted by a factor of
five to one by the pupil.

This 5:1 factor is not sufficient to cope with the different light levels
experienced between full daylight and a dark night and a further mechanism
is required. In reduced light levels a chemical change takes place in the light
sensitive cells on the retina (cones and rods). This dark adaptation does take
time, about 7 minutes for the cones and 30 minutes for the rods. When
complete the chemical change can cope with large changes in luminance
level (of the order of 150,000 : 1 for the cones). After passing through the
pupil the light passes through a clear lens, which can change its shape
(accommodation) to achieve the final focusing onto the retina.

 The Retina. The retina is a light sensitive screen lying at the back of the eyeball. On
this screen are light sensitive cells. The cells are of two types; cones and rods. The
cones can only detect colours, the rods can only detect black and white but are much
more sensitive at low light levels. This means that in poor light we see only in black
or white or varying shades of grey. When light falls on these cells a small electrical
charge is generated which is passed onto the brain by the optic nerve.

 The Optic Nerve. The optic nerve enters the back of the eyeball along with the
small blood cells needed to carry oxygen to the cells of the eye.

 The Fovea. The central part of the retina, the Fovea, is composed only of cone cells
and only at this part of the retina is vision 20/20 or 6/6. The figures are a means of
measuring visual acuity, the ability to discriminate at varying distances. An individual
with 20/20 vision should be able to see at 20 feet that which the so-called normal
person is capable of seeing at this range.
Any resolving power at the fovea drops rapidly as the angular distance from the
fovea increases. At as little as 5° from the fovea the acuity drops to 20/40 that is half
as good as at the fovea. When the angular displacement increases to 20° the visual
acuity will only be one tenth of that at the fovea, that is 20/200.
Anything that needs to be examined in detail is automatically brought to focus on the
fovea. The rest of the retina fulfils the function of attracting our attention to
movement and change.

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 The Blind Spot. The point on the retina where the optic nerve enters the eyeball
has no covering of light detecting cells. Any image falling at this point will not be
detected. This has great significance when considering the detection of objects
which are on a constant bearing from the observer.
If the eye remains looking straight ahead it is possible for example for a closing
aircraft to remain on the blind spot until a very short time before impact. Safe visual
scanning demands frequent eye movement with minimal time spent looking in any
direction.
Visual Defects. Most visual defects are caused by the natural shape of the eyeball.

 Hypermetropia. In long sightedness, (Hypermetropia), a shorter than normal

eyeball along the visual axis results in the image being formed behind the retina and
unless the combined refractive index of the cornea and the lens can combine to
focus the image in the correct plane a blurring of the vision will result when looking at
close objects. A convex lens will overcome this refractive error.

 Myopia. In short-sightedness, (Myopia), the problem is that the eyeball is longer

than normal and the image forms in front of the retina. If accommodation cannot
overcome this then distant objects are out of focus whilst close up vision may be
satisfactory. A concave lens will correct the situation.

 Astigmatism. This condition is usually caused by a misshapen cornea. Objects will

appear irregularly shaped. Modern surgical techniques can reshape the cornea with
a scalpel or more easily with laser beams.

Colour Defective Vision

Affecting about 8% of men and 0.5% of women "colour blindness" is usually associated with
the inability to differentiate between reds and greens. Other more rare types may involve
blues and yellows. There are degrees of colour defective vision, some suffering more than
others and, ageing of individuals will change their colour perception. Care should be taken
not to discriminate personnel from tasks merely because they are "colour blind". Tasks that
require positive colour perception must however be carried out by personnel who have been
tested to an appropriate standard.

Conclusion

Ultimately, what is important is for the individual to recognise when their vision is adversely
affected, either temporarily or permanently, and to carefully consider the possible
consequences should they continue to work if the task requires good vision. AWN47 states:
"Organisations should identify any specific eyesight requirements and put in place suitable
procedures to address these issues". General human factors advice would be to stress the
joint moral responsibility upon both the individual to admit to poor vision and upon the
Organisation to create an environment whereby engineers will not be penalised if they do so.

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Hearing

The ear performs two quite separate functions: firstly it is used to receive vibrations in the
air (sounds), and secondly it acts as a balance organ and acceleration detector.

Structure of the Human Ear

Function and Structure of the Ear

The ear is divided into three sections, the outer, middle, and inner ear:

 The Outer Ear. The outer ear consists of the Pinna, which collects the vibrations of
the air which form sounds and a tube, the Meatus, which leads to the eardrum. The
sound waves will cause the ear drum to vibrate.

 The Middle Ear. The ear drum or Tympanum separates the outer and middle ear.
Connected to the ear drum is a linkage of three small bones the Ossicles, which
transmit the vibrations across the middle ear, which is filled with air, to the inner ear
which is filled with liquid. The last of the bones connects to another membrane in the
inner ear.

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Hearing - contd

 The Inner Ear. The vibrating membrane causes the fluid in the Cochlea to vibrate.
Inside the cochlea there is a fine membrane covered with tiny hair like cells. The
movement of these small cells will be dependent on the volume and pitch of the
original sound. The amount and frequency of displacement is detected by the
auditory nerve which leads directly to the brain where the tiny electrical currents are
decoded into sound patterns.
Note the eustachian tube which allows the pressure in the middle ear to equalise with
the atmospheric pressure.
Hearing Impairment. Hearing difficulties are broadly classified into three categories:
 Conductive deafness. Any damage to the conducting system, the ossicles
or the ear drum, will result in a degradation of hearing. It is possible that
perforations of the ear drum will result in scarring of the tissue thus reducing
its ability to vibrate freely. A blow to the ear may cause damage to the small
bones in the middle ear again limiting the transfer of vibrations. Modern
surgery may help in some circumstances.
 Noise Induced Hearing Loss (NIHL). Loud noises can damage the very
sensitive membrane in the cochlea and the fine structures on this membrane.
The loss of hearing may at first be temporary but continued exposure to loud
noise will result in permanent loss of hearing. The early symptoms are an
inability to hear high pitched notes as these notes are normally detected by
the finer cells which suffer the greatest damage.
The loudness of a noise is measured in Decibels (db). For example a sound
proofed room will have a rating of 9 db, an average office 50 db and a busy
street corner 70 db. An observer standing by a runway whilst a large jet takes
off will experience 100 - 120 db.
To cause permanent damage to hearing a noise level of 90 db or more is
required. The amount of damage is related to the total noise energy so time
of exposure is important. A noise level of 90 db for 8 hours will cause the
same damage as exposure to 103 db for 30 minutes or 116 db for 1 minute.
The noise level on and around a busy airport can be very high and it is
essential that ear defenders are worn by all personnel working in the area of
high noise levels.
For the younger element the noise level in discos can be excessive and
personal stereos can reach above the safety level.
Noise Induced Hearing Loss (NIHL) is not treatable at the moment. Recent
experiments hold out some hope of a cure as researchers have been able to
regrow the fine hair like cells in the cochlea of young rats. The treatment
involves the use of retinoic acid, made from vitamin A. The treatment in
humans is still however a long way off and the only sure way to avoid NIHL is
to protect the ears from loud noises.
 Presbycusis. (Loss through ageing). Hearing deteriorates with advancing
age. Young children can hear high pitched noises outside the range of adults.
The loss of some hearing is natural as one grows older but if combined with
some NIHL there may be a chance of increased impairment.

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Hearing - contd

The Ear and Balance. As well as acting as the organ to detect sounds, the ear is used to
detect angular and linear accelerations. Our primary source of spatial orientation is sight but
the ear provides a secondary system, particularly if vision is restricted.
Within the inner ear are three Semi-circular canals, tubes filled with liquid and arranged in
three planes at 90 degrees to each other. Within these tubes are fine hairs which are bent
as the liquid in the tubes moves in relation to the walls of the tubes. The movements of
these hairs generates a small electric current which is passed to the brain to be detected as
a movement of the head.
The semi-circular canals detect angular movement; linear acceleration is detected by the
Otoliths at the base of each of the canals.
The otoliths, literally 'stones in the ears', are fleshy stalks surmounted by a small stone or
crystal. Acceleration in any plane causes the stalks to bend and this bending is interpreted
by the brain to decide the new position of the head.
The semi-circular canals and the otoliths together make up the Vestibular apparatus which
helps to maintain spatial orientation and control other functions. For example it controls eye
movement to maintain a stable picture of the world on the retina even when the head is
moved.
The Effects of Alcohol. Alcohol has a lower specific gravity than water. Alcohol in the
middle ear may dilute the liquids and cause unfamiliar results for certain movements, leading
to disorientation. Alcohol in the fleshy stalk of the otolith may persist for days after all traces
of alcohol have vanished from the blood. It is not unusual for even small movement of the
head to cause disorientation or motion sickness up to three days after alcohol was last
consumed.
Conclusion

The effects of noise on performance are extremely complex, with no clear guidance
emerging as to what noise levels are likely to adversely affect performance in relation to
aviation safety. As a rule of thumb and in the absence of more detailed guidelines, if noise
levels are kept within the bounds to protect against hearing damage (see Table 1) this
should also avoid situations where noise is likely to have a significantly detrimental affect on
performance in general terms. This may not, however, be sufficient to avoid breaking
someone's concentration.
TABLE 1

Duration per day (hr) Sound Level in dB(A)

8 90
6 92
4 95
3 97
2 100
1.5 102
1 105
0.5 110
<0.25 115
Source: OSHA
Maximum Recommended Noise Exposure for Occupational Noise

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Memory

Memory is the process of retaining, recognising and recalling experience (remembering) and
is particularly associated with how people learn things. It is, essentially, the storage facility
of the human system. We have both short-term and long-term memory.

 Short-term memory Short-term or immediate memory refers to the temporary

storage of information for a few seconds, as in the case of a telephone number. It is
also associated with the amount of information one can take in and retain and is, in
many cases, a limiting factor on individual ability and safety.

Short-term memory and its limitations can be a significant factor in the causes of
accidents at work, and one that is frequently associated with human error or poor
memory skills. Important on-the-spot instructions should, therefore, be repeated
several times to ensure that the recipient fully understands and can recall them.

 Long-term memory Long-term memory is concerned with the ability to store and
subsequently recall information. It is a vast store of information that is organised in
some form of classification. On this basis, any new information is perceived in terms
of these categories and forces into the classification system even when it does not fit
exactly. In this process there is a chance that it may become distorted.

Long-term memory is developed from an early age through the repetition of items
and codifying them to produce a meaning. There is a characteristic drop in memory
over a period of time associated with the ageing process.

Interference with long-term memory can be caused by:

 events of close similarity that tend to confuse.

 the effect of recall on the subsequent memory that can, again, cause
confusion.

RESULTING IN THE INDIVIDUAL FORGETTING.

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Information Processing

Generally, people cannot do more than one thing at a time, the speed and sequence of
response varying from person to person. This factor can be significant in accident
causation.

With well-known and practised tasks, such as operating a machine or driving a vehicle, the
monitoring action of the brain can be reduced, depending on the speed with which a person
can respond to stimuli and not monitor specific movements or actions. Results are achieved
through continuous practice or the speed-accuracy trade-off, whereby the monitoring is
voluntarily removed.

The feedback that people receive is an important feature of monitoring a task. Where an
individual may be highly skilled, it can be a hindrance and actually destroy performance. In
the teaching, for instance, of learner drivers or certain activities, such as golf, the instructor
has to put the monitoring aspect back into the task. This can adversely affect the individual's
level of performance.

In the information processing operation, people ascribe different values to various outcomes
of their decisions. These values may be influenced by extraneous factors, such as any
financial benefits to be derived or the possibility of saving time and effort, which are
subjective and influenced by the personality of the person making the decision and previous
experience of similar situations.

The level of brain arousal can also effect the efficiency and rate of mental processing.
Arousal is defined as an increase in alertness and muscular tension. Levels of arousal vary
significantly. Generally, at low arousal levels, performance is poor. As arousal increases to
an optimum, performance rises accordingly, but then drops as further arousal takes place.
Changes in arousal levels take place during the average working cycle.

Conclusion

Memory is an important feature of human behaviour, particularly where people may be

exposed to hazards. It is directly affected by learning, past experience, feedback from
events of particular significance and an individual's capacity for storing information.

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The Aloha Incident

The Aloha accident, involved 18 feet of the upper cabin structure of a Boeing 737 suddenly
being ripped away, in flight, due to structural failure. The aircraft involved in this accident
had been examined, as required by two engineering inspectors. One inspector had 22 years
experience and the other, the chief inspector, had 33 years experience. Neither found any
cracks in their inspection. Post-accident analysis determined there were over 240 cracks in
the skin of this aircraft at the time of the inspection.

The Aloha accident investigation report stated also that:

"Inspection of the rivets required inspectors to climb on scaffolding and move along the
upper fuselage carrying a bright light with them; in the case of an eddy current inspection,
the inspectors needed a probe, a meter, and a light. At times, the inspector needed ropes
attached to the rafters of the hangar to prevent falling from the airplane when it was
necessary to inspect rivet lines on top of the fuselage. Even if the temperatures were
comfortable and the lighting was good, the task of examining the area around one rivet after
another for signs of minute cracks while standing on a scaffolding or on top of the fuselage is
very tedious. After examining more and more rivets and finding no cracks, it is natural to
begin to expect that cracks will not be found. Further, when the skin is covered with several
layers of paint the task is even more difficult. Indeed, the physical, physiological, and
psychological limitations of this task are clearly apparent."

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Claustrophobia, Physical Access and Fear of Heights

 Claustrophobia. Claustrophobia is defined as "abnormal fear of being in an

enclosed space". This is the extreme case. However, 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. Most people have no difficulty in entering a lift, for instance, but would not
consider going pot-holing under any circumstances! In this text, claustrophobia is
reserved for the extreme case where a person is extremely uncomfortable, often to
the extent of experiencing panic, in circumstances which most people would not
consider a problem.
It is unlikely that someone suffering from claustrophobia would take up aircraft
maintenance engineering as a career, but it may be the case, however, that
susceptibility to claustrophobia is not apparent at the start of employment but comes
about because of an incident when working within a confined space, eg panic if
unable to extricate oneself from a fuel tank. If an engineer feels that they suffer from
this problem, they should make their colleagues and supervisors aware so that if
tasks likely to generate claustrophobia cannot be avoided, at least colleagues may
be able to assist in extricating an engineer from the confined space quickly and
sympathetically.

 Physical Access. Problems associated with physical access are not uncommon in
aircraft maintenance engineering. Maintenance engineers and technicians often
have to access, and work in, very small spaces (eg in fuel tanks), cramped conditions
(such as beneath flight instrument panels, around rudder pedals), elevated locations
(on cherry-pickers or staging), sometimes in uncomfortable climatic or environmental
conditions (heat, cold, wind, rain, noise). This can be aggravated by aspects such as
poor lighting or having to wear breathing apparatus.

 Fear of Heights. Work at high levels can also be a problem, especially when doing
'crown' inspections (top of fuselage or top wing engine). Some engineers may be
quite at ease in situations like these whereas others may be so uncomfortable that
they are far more concerned about the height, and holding on to the access
equipment, than they are about the job in hand.

Conclusion

If a person is working in uncomfortable conditions, he may be inclined to get out of that

situation as soon as possible, possibly resulting in checks not being carried out quite as
diligently as they might be. Although there is no formal evidence of this, there is anecdotal
evidence of situations where this has occurred. Engineers should be aware of this and
guard against it. Managers and supervisors should attempt to make the job as comfortable
and secure as reasonably possible (eg providing knee pad rests, ensuring that staging does
not wobble, providing ventilation in enclosed spaces, etc) and allow for frequent breaks if
practicable.

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Responsibility: Individual and Group

 Individual. Traditionally, in the maintenance engineering environment, responsibility

has been considered in terms of the individual rather than the team (whether the
team working on a specific job, the shift, the site or the Company). This is historical,
and has much to do with the manner in which engineers are licensed and the way in
which work is certified. This has both advantages and disadvantages. The
advantages are that it can be a strong incentive to an engineer to do the work
correctly or to check what others have done, if he knows that he will invariably be the
one held responsible if something goes wrong, probably resulting in punitive measure
or loss of job. However, this applies mainly to Licensed Aircraft Engineers (LAEs),
and may not provide quite the same incentive to those who are not licensed. This
does not mean to say that engineers would not have personal responsibility if they
were not licensed; indeed, it is hoped that all staff working in aircraft maintenance
are well aware of their personal, moral responsibilities to ensure that the work that
they do does not compromise the safety of an aircraft. The disadvantages of the
emphasis upon personal responsibility, especially that of LAEs, is that this may
lessen the concept of team or group responsibility.

AWN No 3 details the certification responsibilities of LAEs, adding that "It should be
noted that where the holder of a license is performing maintenance activies on
aircraft which he or she is not appropriately licensed, ie acting as a non-certifying
engineer, they are still expected to act responsibly and carry out such work in
accordance with the procedures and standards identified in [the paragraphs of
AWN3]".

BAe 146 HYDRAULIC BAY ACCESS DOOR OCC NR: 99/02670

NOT PROPERLY CLOSED
STATUS: CLOSED

FLT PHASE: CLIMB DATE: -- MAY 99

A crew change had been carried out at an European airport, the aircraft having
arrived late, and with only 20 minutes before the departure slot. The aircraft was
handed over with an automatic pressurisation defect which required use of manual
pressurisation control. Problems with catering loading caused the slot to be missed,
with a 40 minutes a delay. During starting checks a 'lower door not closed' caption
remained illuminated. The ground crew were asked to check all lower doors were
closed, and the despatcher on the headset assured the flight crew that this was so.
However, the caption remained on. A request was made for a second check with the
same result. The ground crew were then asked to open and close all lower doors as
failed microswitches on these doors are a known problem. The avionics bay and
forward cargo bay doors were heard to be opened and closed again, but operations
of the hydraulic bay and rear cargo doors cannot be heard from the flight deck. Once
again an assurance was received that all doors were closed, and accepting that the
caption was due to a faulty microswitch, a normal departure was carried out.
However the cabin failed to pressurise, so the aircraft returned. An external check
found that the hydraulic bay door was latched but not closed. A ground
pressurisation test was carried out satisfactorily. An interview with the despatcher on
the head set revealed that he had delegated the check of the doors to another
person and had not checked himself.

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Responsibility: Individual and Group - contd

 Group. Group responsibility, also, has its advantages and disadvantages. The
advantages are that each member of the group ought to feel responsible for the
output of that group, not just their own output as an individual, and ought to work
towards ensuring that the whole 'product' is safe. This may take the form of cross-
checking others' work when not strictly required, politely challenging others if you
think that something is not quite right, etc. The disadvantage of group responsibility
is that it can act against safety, with responsibility being devolved to such an extent
that no-one feels personally responsible for safety, each member of the group
assuming that 'someone else will do it'. There has been a great deal of research
carried out on the phenomenon whereby an individual, on his own, may take action
but, once placed within a group situation, he may not act if none of the other group
members do so. This is referred to as diffusion of responsibility. Two researchers
named Latané and Rodin conducted several experiments whereby they set up a
situation where someone was apparently in distress, and noted who came to help. If
a person was on their own, they were far more likely to help than if they were in a
pair or group. In the group situation, each person felt that it was not solely his
responsibility to act, and assumed that someone else would do so. Whilst these
situations were rather contrived, and dissimilar to the maintenance engineering
context, nevertheless they serve as a good illustration of the dangers of devolved
responsibility among a group, against which engineers should guard.
Responsibility is an important issue, and ought to be addressed not only by licensing,
regulations and procedures, but also by education and training, attempting to
engender a culture of shared, but not diffused, responsibility.

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Management, Supervision and Leadership

Managers and supervisors have a key role to play in ensuring that work is carried out safely.
It is no good instilling the engineers and technicians with 'good safety practice' concepts, if
these are not supported by their supervisors and managers. It is appreciated that line
managers, particularly those working as an integral part of the 'front line' operation, may be
placed in a situation where they may have to compromise between commercial drivers and
'ideal' safety practices, eg if there is a temporary staff shortage, deciding whether that
maintenance tasks can be safely carried out with reduced manpower, or whether an
engineer volunteering to work a "ghoster" to make up the numbers will be able to perform
adequately. The adoption of Safety Management Principles may help by providing
Managers with techniques whereby they can carry out a more objective assessment of risk
(eg of operating a shift with one man short) and make decisions based on this knowledge.
Similarly, engineers must realise that compromises will have to be made from time to time.

In terms of the relationship between managers and engineers, a 'them and us' attitude is not
particularly conducive to improving the safety culture of an organisation. It is important that
managers, supervisors, engineers and technicians all work together, rather than against one
another, to ensure that aircraft maintenance improves airworthiness, as opposed to
converting what was previously a perfectly serviceable aircraft into a potential incident or
accident by injecting a latent failure.

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Culture

The culture of an organisation can be described as 'the way we do things here'. It can refer
to safety culture, professional culture, political culture, business culture, etc, although the
safety culture is obviously the area with which this text is primarily concerned. It is difficult to
pinpoint where the culture of an organisation is driven from. It is not necessarily always
generated or driven from the top, as one might think, but this is the best point from which to
influence the safety culture, Whilst it is possible for cultural differences to exist between
sites or even between shifts, a certain cultural climate tends normally to be associated with
an or with a particular branch of the industry (eg helicopter maintenance, light aircraft
maintenance, line maintenance, etc).

The culture of an organisation can best be judged by what is done rather than by what is
said. Organisations may have grand 'mission statements' concerning safety but this does
not indicate that they have a good safety culture unless the policies preached at the top are
actually put into practice at the lower levels. It may be difficult to determine the safety
culture of an organisation by auditing the procedures and paperwork; a better method is to
find out what the majority of the staff actually believe and do in practice.

A method for measuring attitudes to safety has been developed by the Human Factors in
Reliability Group (HFRG) violations sub-group, utilising a questionnaire approach. The
questionnaire takes the form of statements to which respondents are asked the extent to
which they agree. Examples include:

 It is necessary to bend some rules to achieve a target

 Short cuts are acceptable when they involve little or no risk
 I often come across situations with which I am unfamiliar
 I sometimes fail to understand which rules apply
 I am not given regular break periods when I do repetitive and boring jobs
 There are financial rewards to be gained from breaking the rules

The results are scored as outlined in the methodology and results are given which give an
indication of the safety culture of the organisation, broken down according to safety
commitment, supervision, work conditions, logistic support, etc. In theory, this enables one
organisation to be objectively compared with another.

Whilst safety culture has been discussed from the organisational perspective, the
responsibility of the individual should not be overlooked. Ultimately, safety culture is an
amalgamation of the attitude, beliefs and actions of all the individuals working for the
organisation and each person should take responsibility for their own contribution towards
this culture, ensuring that it is a positive contribution rather than a negative one.

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Motivation and De-motivation

Motivation, is a force coming from within your brain that drives you to act in certain ways. It
is usually considered to be a positive rather than a negative force in that it causes you to
move forward as opposed to remaining stagnant. It manifests itself both in intensity and in
direction. Generally we say a person is motivated if he/she is taking action on some subject.
The action, however, can be either good or bad, and just because someone is positively
motivated, this does not mean to say that they are doing the right thing. Many criminals are
highly motivated, for instance. Motivation to do the right things, in terms of safety, is vital. In
Aviation, you can be motivated to take risks (eg for the satisfaction of getting an aircraft
turned around more quickly) or to make safe decisions (eg to satisfy your own personal
integrity). It is important to associate motivation with the right type of actions, ie point it in
the right direction.

The psychological concept of motivation and what we understand as being motivated, are
subtly different.

Highly motivated people tend to show the following characteristics:

 high performance and results being consistently achieved

 the energy, enthusiasm and determination to succeed
 unstinting co-operation in overcoming problems
 willingness to accept responsibility
 willingness to accommodate change

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Motivation and De-motivation - contd

People who lack motivation, either intrinsically or through a failure of their management to
motivate the staff who work for them, tend to demonstrate the following characteristics:

 apathy and indifference to the job

 a poor record of time keeping and high absenteeism
 an exaggeration of the effects/difficulties encountered in problems, disputes and
grievances
 a lack of co-operation in dealing with problems or difficulties
 unjustified resistance to change

However, care should be taken when associating these characteristics with lack of
motivation, since some could also be signs of stress.

It is important that maintenance engineers are motivated by a desire to ensure safety rather
than necessarily a fear of being punished and losing one's job. The fears associated with
job security in aircraft maintenance engineering are very real in the modern, commercially
competitive world. It is possible that the "can do" culture, which is evident in some areas of
the industry, may be generated by the expectancy that if individuals do not 'deliver', they will
be dismissed or punished and, conversely, those who do 'deliver' (whether strictly by the
book or not, finding ways around lack of time, spares or equipment) are rewarded and
promoted. This is not motivation in the true sense but it has its roots in a complex series of
pressures and drives and is one of the major influences upon human performance and
human error in maintenance engineering.

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Peer Pressure and 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". In the work
context, in particular, this is sometimes referred to as 'peer pressure', which is the actual or
perceived pressure which an individual may feel, to conform to what he believes that his
peers or colleagues expect.

A researcher named Solomon Asch carried out several experiments investigating the nature
of conformity, one of the better known experiments being where he asked people to judge
which of lines A, B & C was the same length as line X.

An experiment to illustrate conformity

X A B C

(B is the same length as X)

He asked this question under different conditions, one where the individual was asked to
make the judgement on his own, without being influenced, and the other where the individual
was asked to judge last, after a series of 'stooges' had all judged that line A was the correct
choice. In the latter condition, about 25% of people yielded to group pressure and agreed
with the incorrect 'group' finding.

Peer pressure may be actual or perceived. It is often not overt, and it can be difficult to find
actual evidence that it exists. An individual engineer may feel that there is pressure to cut
corners in order to get an aircraft out by a certain time, in the belief that this is what his
colleagues would do under similar circumstances. There may be no actual pressure from
management to cut corners, but subtle pressure from peers, eg taking the form of comments
such as "You don't want to bother checking the manual for that. You do it like this …" would
constitute peer pressure.

As already mentioned, peer pressure can be good or bad, depending on the context and on
whether the group view is the correct one. As far as safety is concerned, if the group (or
shift) view is one which believes that safety is very important, then peer pressure will have a
positive effect in influencing others to conform to this attitude. Too often, however, it works in
reverse, with safety standards gradually deteriorating as shift members develop practices
which might appear to them to be more efficient but which erode safety, placing pressure,
albeit possibly unwittingly, upon new engineers joining the organisation, to do likewise.

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Team Working

The importance of teamwork in aircraft maintenance cannot be over-stressed. As aircraft

and their systems become more complex, a greater emphasis on technical specialities(eg
sheet/metal structures, electrical/electronics/avionics, hydraulics, etc) is emerging. An
unfortunate parallel trend is to organise the technical specialists into distinct departments or
'functional silos', which tends to inhibit teamwork. This is true particularly of support services
where technical specialists are often separated out from the aircraft fleets. The larger the
organisation, the more this tends to be the case, and the greater the need for more
formalised team skills to overcome the barriers (eg in communication, or even availability of
staff when needed) between the various specialists and technicians.

Establishments of maintenance teams should be carefully planned; it is not enough simply

to separate people into groups and label them team A or team B. Principles of job design
should be employed when creating work teams. Well-structured teams can result in
improvements in work performance and employee satisfaction; poor team design can lead
to effects in the opposite direction. Without adequate management direction and regular
evaluation of team performance, negative results are likely. Groups left to their own devices
can lack direction, making poor decisions as a consequence. Inter-and intra-group conflicts
can emerge with devastating effects. To maintain team cohesiveness, there may be a need
to redefine goals and objectives as well as a need to periodically exchange or replace team
members for a variety of reasons as suggested above.

Team members should be trained in their roles. This training is important especially for
newly formed groups of people who are accustomed to working as individual engineers and
technicians. The training should include methods of group decision making, development of
interpersonal skills and working with other teams.

It may be worth noting that, in many companies, line engineers tend to work as individuals
whereas base engineers tend to work in teams. This may be of significance when an
engineer who normally works in a hangar, finds himself working on the line, or vice versa.
This was the case in the A320 incident involving double engine oil pressure loss, where the
Base Controller took over a job from the Line Maintenance engineer, along with the line
maintenance paperwork. The line maintenance paperwork is not designed for recording
work with a view to a handover, and this was a factor when the job was handed over from
the Line engineer to the Base Controller. Although there was no suggestion that this incident
was due to differences between team working vs working as an individual, nevertheless it
illustrates some of the differences between the Line and Base maintenance working
practices.

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