Continue of Aircraft Maintenance Engineering Human Factors for JAR 66
Violation in Aircraft Maintenance
It is a unfortunate fact of life that violations occur in aviation maintenance. Most stem from a genuine desire to do a good job. Seldom are they acts of vandalism or sabotage. However, they represent a significant threat to safety as systems are designed assuming people will follow the procedures. There are four types of violations:
-Routine violations;
-Situational violations;
-Optimising violations;
-Exceptional violations.
Routine violations are things which have become 'the normal way of doing something' within the person's work group ( e.g. a maintenance team ). They can become routine for a number of reasons: engineers may believe that procedures may be over prescriptive and violate them to simplify a task ( cutting corners ), to save time and effort.
Situational violations occur due to the particular factors that exist at the time, such as time pressure, high workload, unworkable procedures, inadequate tooling, poor working conditions, there occur often when, in order to get the job done, engineers consider that a procedure cannot be followed.
Optimising violations involve breaking the rules for ' kicks'. These are often quite unrelated to the actual task. The person just uses the opportunity to satisfy a personal need.
Exceptional violations are typified by particular tasks or operating circumstances that make violations inevitable, no matter how well intentioned the engineer might be.
Avoiding and Managing Errors
Safety Management System ( SMS )
Error management includes measure to :
-minimise the error liability of the individual or the team;
-reduce the error vulnerability of particular tasks or task elements;
-discover, assess and then eliminate error-producing ( and violation- producing ) factors within the workplace;
-diagnose organisational factors that create error-producing factors within the individual, the team, the task or the workplace;
-enhance error detection;
-increase the error tolerance of the workplace or system;
-make latent conditions more visible to those who operate and manage the system;
-improve the organisation's intrinsic resistance to human fallibility.
It would be very difficult to list all means by which errors might be prevented or minimised in aircraft maintenance. In effect, the whole of this document discusses mechanisms for this, from ensuring that individuals are fit and alert, to making sure that the hanger is adequate.
One of the thing likely to be most effective in preventing error is to make sure that engineers follow procedures. This can be effected by ensuring that the procedures are correct and usable, that the means of presentation of the information is user friendly and appropriate to the task and context, that engineers are encouraged to follow procedures and not to cut corners.
What is sleep?
Sleep is 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.
Sleep can be resisted for a short time, but various parts of the brain ensure that sooner or later, sleep occurs. When it does, it is characterised by five stages of sleep :
-Stage 1 : This is a transitional phase between waking and sleeping. The heart rate slow and muscles relax. It is easy to wake someone up.
-Stage 2 : This is a deeper level of sleep, but it is still fairly easy to wake someone.
-Stage 3 : Sleep is even deeper and sleeper is now quite unresponsive to external stimuli and so is difficult to wake. Heart rate, blood pressure and body temperature continue to drop.
-Stage 4 : This is the deepest stage of sleep and it is very difficult to wake someone up.
- Rapid Eye Movement : Even though this stage is characterised by brain activity similar to a person who is awake, the person is even more difficult to awake than stage 4. It is therefore also known as paradoxical sleep. Muscles become totally relaxed and eyes rapidly dart back and forth under the eyelids. It is thought that dreaming occurs during REM sleep.
Medication
Any medication, no matter how common, can possibly have direct effects or side effects that may impair an engineer's performance in the workplace.
Medication can be regraded as any over-the-counter or prescribed drug used for therapeutic purposes.
There is a risk that these effects can be amplified if an individual has a particular sensitivity to the medication or one of its ingredients. Hence, an aircraft maintenance engineer should be particularly careful when taking a medicine for the first time, and should ask his doctor whether any prescribed drug will affect his work performance. It is also wise with any medication to take the first dose at least 24 hours before any duty to ensure that it does not have any adverse effects.
Medication is usually taken to relieve symptoms of an illness. Even if the drugs taken do not affect the engineer's performance, he should still ask himself whether the illness has made him temporarily unfit for work.
Various publications, and especially AWN47 give advice relevant to aircraft maintenance engineer on some of the more common medications. This information is summarised below, however the engineer must use this with caution and should seek further clarification from a pharmacist, doctor or their company occupational health advisor if at all unsure of the impact on work performance.
-Analgesic are used for pain relief and to counter the symptoms of colds and flu. In the UK, paracetamol, aspirin and ibuprofen are the most common, and are generally considered safe if used as directed. They can be taken alone but are often used as ingredient of a 'cold relief ' medicine. It is always worth bearing in mind that the pain or discomfort that you are attempting to treat with an analgesic ( e.g. headache, sore throat, etc. ) may be the symptom of some underlying illness that needs proper medical attention.
- Antibiotics ( such as Penicillin and the various 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 from the effects of these substances themselves, the side-effects of the infection will almost always render an individual unfit for work.
-Anti-histamines are used widely in ' cold cures ' and in the treatment of allergies (e.g. hayfever). Most of this group of medicines tend to make the user feel drowsy, meaning that the use of medicines containing anti- histamines is likely to be unacceptable when working as an aircraft maintenance engineer.
-Cough Suppressants are generally safe in normal use, but if an over-the-counter product contains anti-histamine, decongestant, etc., the engineer should exercise caution about its use when working.
-Decongestants ( i.e. treatments for nasal congestion) may contain chemicals such as pseudo-ephedrine hydrochloride ( e.g. 'Sudafed' ) and phenylphrine. Side-effects reported, are anxiety, tremor, rapid pulse and headache. AWN47 forbids the use of medications containing this ingredient to aircraft engineers when working as the effects compromise skilled performance.
-'Pep' pills are used to maintain wakefulness. They often contain caffeine, dexedrine or benzedrine. Their use is often habit forming. Over-dosage may cause headaches, dizziness and mental disturbances, AWN47 states that ' the use of 'pep' pills whilst working cannot be permitted. If coffee is insufficient, you are not fit for work.'
-Sleeping tablets ( often anti-histamine based ) tend to slow reaction times and generally dull and senses. The duration of effect is variable from person to person. Individuals should obtain expect medical advice before taking them.
Melatonin ( a natural hormone ) deserves a special mention. Although not available without a prescription in the UK, it is classes as a food supplement in the USA ( and is readily avaible in health food shop ). it has been claimed to be effective as a sleep aid, and to help promote the resynchronisation of disturbed circadian rhythms. Its effectiveness and safety are still yet to be proven and current best advice is to avoid this product.
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