Workload, Sleep, and Alcohol, Drugs and Drug Abuse PDF (CASA Part 66)

Workload, Sleep and Alcohol, Drugs and Drug Abuse (9.4.4-6) Learning Objectives 9.4.4.1 Explain how humans need an optimum level of arousal for task performance and the consequences of too much stimulation or workload (Level 2). 9.4.4.2 Describe the consequences of too little stimulat...

Workload, Sleep and Alcohol, Drugs and Drug Abuse (9.4.4-6) Learning Objectives 9.4.4.1 Explain how humans need an optimum level of arousal for task performance and the consequences of too much stimulation or workload (Level 2). 9.4.4.2 Describe the consequences of too little stimulation or workload (Level 2). 9.4.5.1 Describe stages and cycles of sleep and circadian rhythms (Level 2). 9.4.5.2 Explain how quality of sleep, sleep disorders and informal sleep affect work performance (Level 2). 9.4.5.3 Explain common causes of fatigue, effects of fatigue and ways of managing fatigue (Level 2). 9.4.5.4 Identify advantages and disadvantages of shiftwork (Level 2). 9.4.6.1 Summarise the effects of alcohol consumption on an individual's performance (Level 2). 9.4.6.2 Describe possible effects of prescription and over-the-counter medication on an individual's performance (Level 2). 9.4.6.3 Describe possible effects of various illicit drugs on an individual's performance (Level 2). 9.4.6.4 Describe the effects of tobacco on an individual's performance (Level 2). 2023-01-12 B-09 Human Factors Page 152 of 340 CASA Part 66 - Training Materials Only  Workload: Overload and Underload Introduction The preceding sections on stress and time pressure have both indicated that a certain amount of stimulation is bene cial to an AME, but that too much stimulation can lead to stress or over- commitment in terms of time. It is noteworthy that too little stimulation can also be a problem. Before going on to discuss workload, it is important to consider this optimum level of stimulation or arousal. Arousal Arousal refers to a person’s alertness or readiness to perform work. To achieve an optimum level of task performance, it is necessary to have a certain level of stimulation or arousal. This level varies from person to person. There are people who are overloaded by the obligation to do more than one task at a time; on the other hand, there are people who appear to thrive on stress, and are happy to take on more and more work or challenges. © Aviation Australia To achieve an optimum level of task performance, it is necessary to have a certain level of stimulation or arousal. The optimum arousal leads to the highest level of performance. At low levels of arousal, our attention mechanisms will not be particularly active, and our performance capability will be low (complacency and boredom can result). At the other end of the curve, performance deteriorates when arousal becomes too high. Our best task performance occurs somewhere in the middle. 2023-01-12 B-09 Human Factors Page 153 of 340 CASA Part 66 - Training Materials Only  In the workplace, arousal is mainly in uenced by stimulation due to work tasks. However, surrounding environmental factors such as noise may also in uence the level of arousal. Factors Determining Workload An individual AME can usually identify what work they have to do quite easily. It is more dif cult to assess how that work translates into workload. The degree of stimulation exerted on an individual caused by a task is generally referred to as workload and can be separated into physical workload and mental workload. Humans have limited mental capacity to deal with information. We are also limited physically, in terms of visual acuity, strength, dexterity and so on. Thus, workload re ects the degree to which work demands impose on our mental and physical capacities. Workload is subjective (i.e., experienced differently by different people) and is affected by: The nature of the task, such as the: physical demands it requires (e.g., strength required, etc.) mental demands it requires (e.g., complexity of decisions to be made, etc.). The circumstances under which the task is performed, such as the: standard of performance required (i.e., degree of accuracy) time available to accomplish the task (and thus the speed at which the task must be carried out) requirement to carry out the task at the same time as doing something else perceived control of the task (i.e., is it imposed by others or under your control, etc.) environmental factors existing at the time (e.g., extremes of temperature, etc.). The person and their state, such as: skills (both physical and mental) experience (particularly, familiarity with the task in question) current health and tness levels emotional state (e.g., stress level, mood, etc.). As the workload of aircraft maintenance workers may vary, they may experience periods of overload and underload. This is a feature of some areas of the industry such as line maintenance. 2023-01-12 B-09 Human Factors Page 154 of 340 CASA Part 66 - Training Materials Only  Photo by NOAA on Unsplash Workload is subjective and is affected by the nature of the task. Overload Overload occurs at very high levels of workload. As highlighted previously, performance deteriorates when arousal becomes too high and we are forced to shed tasks and focus on key information. Error rates may also increase. Overload can occur for a wide range of reasons based on the factors highlighted above. It may happen suddenly (e.g., if asked to remember one further piece of information whilst already trying to remember a large amount of data), or gradually. EASA Part-145 states: “The Part-145 approved maintenance organisation must employ suf cient personnel to plan, perform, supervise and inspect the work in accordance with the approval”, and “the Part-145 organisation should have a production man hour plan showing that it has suf cient man hours for the work that is intended to be carried out”. Aviation regulators try to ensure maintenance organisations do not overload maintenance engineers. However, this does not prevent individuals from becoming overloaded. 2023-01-12 B-09 Human Factors Page 155 of 340 CASA Part 66 - Training Materials Only  Coping with Overload Each of the bullet points are examples of strategies which may help to cope with overload: Setting Priorities Whenever you are confronted with work overload it is important to set yourself priorities and to execute your tasks depending on their importance and urgency. Prioritisation helps you to focus on your high-priority tasks that contribute towards your intended output, whereas you can put aside those time intensive tasks that are neither important nor contribute towards the outcome. Controlling Your Emotions Many people panic if they are not used to working with pressure and work overload. It is important to control your emotions whenever you are facing a stressful situation. Stress and fear will only cause you to make careless mistakes, which will increase your workload even further. Delegating Work Some employees consider the delegation of work only as an attempt to avoid responsibility, however at some stage in your career you will have to delegate at least parts of your work as the amount of work you can deal with is limited. Organisation and Planning It can be very helpful to create a to-do-list that helps you get an overview of your current situation. A to-do-list contains all your daily goals and tasks. Elimination of Tasks Work overload does not only consist of highly important tasks, but also less important or even unnecessary tasks that could save you a lot of time, if cancelled. Try to eliminate as many tasks as possible that are not necessary or do not contribute towards the accomplishment of your goals. 2023-01-12 B-09 Human Factors Page 156 of 340 CASA Part 66 - Training Materials Only  Photo by Aaron Huber on Unsplash. Set priorities for yourself and to execute your tasks in order of their importance and urgency. 2023-01-12 B-09 Human Factors Page 157 of 340 CASA Part 66 - Training Materials Only  Underload Underload occurs at low levels of workload (when the engineer becomes under aroused). It can be just as problematic to an engineer as overload, as it too causes a deterioration in performance and an increase in errors, such as missed information. Underload can result from a task an engineer nds boring, very easy, or indeed a lack of tasks. The nature of the aircraft maintenance industry means that available work uctuates, depending on time of day, maintenance schedules, and so forth. Hence, unless stimulating ‘housekeeping’ tasks can be found, underload can be dif cult to avoid at times. Aviation Australia - GL Underload occurs at low levels of workload. 2023-01-12 B-09 Human Factors Page 158 of 340 CASA Part 66 - Training Materials Only  Workload Management Unfortunately, in a commercial environment, it is seldom possible to make large amendments to maintenance schedules, nor eliminate time pressures. The essence of workload management in aircraft maintenance should include: Ensuring that staff have the skills needed to do the tasks they have been asked to do and the pro ciency and experience to do the tasks within the timescales they have been asked to work within. Making sure that staff have the tools and spares they need to do the tasks. Allocating tasks to teams or individual engineers that are accomplishable (without cutting corners) in the time available. Providing human factors training to those responsible for planning so that the performance and limitations of their staff are considered. Encouraging individual engineers, supervisors and managers to recognise when an overload situation is building up. If an overload situation is developing, methods to help relieve it include: Seeking a simpler method of carrying out the work (that is just as effective) Securing further time in order to carry out the work safely Postponing, delaying tasks/deadlines and refusing additional work. Thus, although workload varies in aircraft maintenance, the workload of engineers can be moderated. Much of this moderation can be done by careful forward planning of tasks, manpower, spares, tools and training of staff. 2023-01-12 B-09 Human Factors Page 159 of 340 CASA Part 66 - Training Materials Only  Sleep, Fatigue and Shift Work Sleep Humans must have sleep. Sleep is the only cure for fatigue, but the purpose of sleep is not fully understood. Sleep is a natural state of reduced consciousness involving changes in body and brain physiology which is necessary 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 ve stages: Stage 1 - This is a transitional phase between waking and sleeping. The heart rate slows, 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 the sleeper is now quite unresponsive to external stimuli and so is dif cult 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 dif cult to wake someone up. Rapid Eye Movement or REM Sleep - Even though this stage is characterised by brain activity similar to that of a person who is awake, the person is even more dif cult to awaken than in Stage 4. It is therefore also known as paradoxical sleep. Muscles become totally relaxed and the eyes rapidly dart back and forth under the eyelids. It is thought that dreaming occurs during REM sleep. 2023-01-12 B-09 Human Factors Page 160 of 340 CASA Part 66 - Training Materials Only  Image by Ivan Oboleninov from Pexels Sleep is the only cure for fatigue 2023-01-12 B-09 Human Factors Page 161 of 340 CASA Part 66 - Training Materials Only  Sleep Cycles Stages 2 - 4 are categorised as slow-wave sleep and appear to relate to body restoration, whereas REM sleep seems to aid the strengthening and organisation of memories. Sleep deprivation experiments suggest that a person who is deprived of Stage 2-4 sleep or REM sleep, they will show rebound effects. This means that in subsequent sleep, they will make up the de cit in that particular type of sleep which shows the importance of both types of sleep. The gure below shows that sleep occurs in cycles. The cycle of stage 1 - 4 sleep and REM sleep repeats during the night about every 90 minutes during sleep. Most deep sleep occurs early during sleep and the proportion of REM sleep becomes greater as the night goes on. © Aviation Australia REM sleep repeats during the night about every 90 minutes during sleep 2023-01-12 B-09 Human Factors Page 162 of 340 CASA Part 66 - Training Materials Only  Circadian Rhythms Apart from the alternation between wakefulness and sleep, humans have other internal cycles, such as body temperature and hunger/eating. These are known as circadian rhythms as they are related to the length of the day. Circadian rhythms are physiological and behavioural functions and processes in the body that have a regular cycle of approximately a day (actually about 25 hours for humans). Although, circadian rhythms are controlled by the brain, they are in uenced and synchronised by external (environmental) factors such as light. An example of disrupting circadian rhythms would be taking a ight that crosses time zones. This will interfere with the body’s normal synchronisation with the light and dark (day/night). It breaks the natural link between daylight and the body’s internal clock, causing jet lag, resulting in sleepiness during the day, etc. Eventually however, the circadian rhythm readjusts to the revised environmental cues. A scienti c term for 'jet-lag' is 'circadian dysrhythmia'. The gure below shows the circadian rhythm for body temperature. This pattern is very robust, meaning that even if the normal pattern of wakefulness and sleep is disrupted (by shift work for example), the temperature cycle remains unchanged. It can be seen that if you are awake at 4 to 6 o’clock in the morning, your body temperature is at its lowest. This time is when it is hardest to stay awake. This drop in body temperature appears to be linked to a drop in alertness and performance in humans. The Circadian Rhythm for internal body temperature 2023-01-12 B-09 Human Factors Page 163 of 340 CASA Part 66 - Training Materials Only  Although there are many contributory factors, it is noteworthy that a number of major incidents and accidents involving human error have either occurred or been initiated in the pre-dawn hours, when body temperature and performance capability are both at their lowest. These include the BAC1-11, A320, and B737 incidents summarised previously in this module. The AME’s performance at this ‘low point’ will be improved if they are well rested, healthy and feeling well, motivated and well-practised in the skills being used at that point. Quality of Sleep Most individuals need approximately 8 hours of sleep in a 24-hour period, although this varies between individuals, with some needing more and some needing less. They can usually perform adequately with less sleep this for a few days while building up a temporary sleep ‘de cit’. However, any sleep de cit will need to be compensated eventually, otherwise performance will start to suffer. A good rule of thumb is that one hour of high-quality sleep is good for two hours of activity. Fatigue is best tackled by ensuring adequate rest and good quality sleep are obtained. As fatigue is also in uenced by illness, alcohol, etc., it is very important to get more sleep if feeling a little unwell and drink only in moderation between duties. Taking over-the-counter drugs to help sleep should only be used as a last resort. Image by Pixabay on Pexels Most individuals need approximately 8 hours of sleep in a 24-hour period 2023-01-12 B-09 Human Factors Page 164 of 340 CASA Part 66 - Training Materials Only  When working rotating shifts engineers need to be disciplined with their eating and sleeping times. Moreover, out-of-work activities must be carefully planned. For example, it is obvious that an individual who has been out nightclubbing until the early hours of the morning will not be adequately rested if rostered on an early shift the next day. Shift working patterns encountered by AMEs may include three or four days off after the last night shift. It can be tempting to work additional hours, such as taking voluntary overtime, or another job, on one or more of these days off. This is especially common at the beginning of a career in AMEing when nancial pressures may be higher. Engineers should be aware that their vulnerability to error is likely to be increased if they are tired or fatigued, and they should try to ensure that any extra hours worked are kept within reason. It is always sensible to monitor one’s own performance, especially when working additional hours. A decline in performance can be gradual, and the rst signs of chronic fatigue may be moodiness, headaches or struggling with familiar tasks (such as programming the HDD recorder). Although most engineers adapt to shift working, it becomes harder to work rotating shifts as people get older. Age and Sleep Ageing brings major changes in sleep requirements. New-born babies may sleep for up to 23 hours per day, of which the majority of the sleep is REM. As people get older, they sleep less but become less exible about when the sleep is taken. Shift work becomes more dif cult with age as it is much harder to re-program the body clock. Women tend to sleep longer than men but report more sleep problems. Image by pranav digwal from Pexels Ageing brings major changes in sleep requirements 2023-01-12 B-09 Human Factors Page 165 of 340 CASA Part 66 - Training Materials Only  Informal Sleep Sometimes, sleep happens outside of a normal time and place. It is known that this informal sleep can have a restorative effect. However, microsleeps can be dangerous as they occur unexpectedly. Naps A nap is a short period of sleep taken at any hour. The time of day, the duration of the nap and the sleep credit/de cit of the individual will determine how many sleep stages the person will pass through during the nap. The restorative powers of the nap will vary from one individual to another. Habitual nappers appear to gain more bene t than non-habitual nappers who often perform at a reduced level for some time after awakening. After napping it may take some minutes for the drowsiness to clear. Some nappers take up to 5 minutes for their response time and reactions to be restored to normal. The minimum time for a nap to be restorative appears to be not less than 10 minutes. Image by Gregory Pappas on Unsplash A nap is a short period of sleep taken at any hour 2023-01-12 B-09 Human Factors Page 166 of 340 CASA Part 66 - Training Materials Only  Microsleeps Microsleeps are very short periods of sleep that may be as short as a fraction of a second or as long as 2 - 3 seconds. The individual may be unaware of their occurrence which makes them dangerous when driving or operating machinery. They usually occur when a person is very tired but have no value in reducing fatigue or sleepiness. Image by Erwan Hesry on Unsplash A microsleep is a very short periods of sleep that may be as short as a fraction of a second or as long as 2 - 3 seconds Sleep Disorders Sleep apnoea:- A disorder in which breathing pauses or becomes shallow during sleep. Insomnia:- An inability to get to sleep, or a dif culty staying asleep. 2023-01-12 B-09 Human Factors Page 167 of 340 CASA Part 66 - Training Materials Only  Fatigue Fatigue is a loss of alertness and a feeling of tiredness that can be caused by a lack of sleep, physical activity, a change in work schedule, working longer hours (e.g., overtime or working a second shift) or trying to t too many things into a day. Fatigue re ects the body’s need for rest, replenishment and restoration and refers to the individual’s subjective perception of how tired and sleepy they feel. The US National Transportation Safety Board (NTSB) has found fatigue to be a causal or contributory factor in accidents in every mode of transportation and has issued almost 80 fatigue-related safety recommendations since 1972. The National Aeronautics and Space Administration (NASA) has addressed fatigue in aviation through research and other activities since 1980. Image by Andrea Piacquadio from Pexels Fatigue is a loss of alertness and a feeling of tiredness 2023-01-12 B-09 Human Factors Page 168 of 340 CASA Part 66 - Training Materials Only  Causes of Fatigue Our internal body clock or circadian rhythm clock controls immune function, digestion, performance, alertness, and mood. Blood pressure, heart rate and metabolism vary on roughly a 24-hour cycle. The lowest point occurs around 3 to 5 am each day, making this time period one of the lowest levels of performance activity, although sometimes it can be anywhere from midnight to 6 am. A second period of sleepiness occurs around 3 to 5 pm These low circadian levels are associated with decreased performance and alertness. Desynchronisation of the circadian rhythm (being awake when the body is normally requiring sleep) is a prime cause of fatigue. For AMEs, this is usually because of shift work or working excessive hours, including night work. Other causes of fatigue can be: State of health Alcohol consumption Recent physical activity Delayed sleep Lack of sleep Poor quality sleep Mental stress Physical environment Medication and other drug use. © Aviation Australia Causes of fatigue 2023-01-12 B-09 Human Factors Page 169 of 340 CASA Part 66 - Training Materials Only  Eight hours of sleep is considered the norm for the average person, although it can vary by the individual and range from 6 - 10 hours. Sleep loss can be acute, within a 24-hour period, or cumulative over several days. Recovery from cumulative sleep loss requires more deep sleep and is not an hour- for-hour exchange. How long an individual remains awake is a factor that can affect performance and alertness. Studies have examined the lengths of shifts and their effect on performance. NTSB data has shown an increased risk beyond 12 hours. At 16 hours of work, a national occupation-injury database revealed an accident/injury rate 3 times greater than a 9-hour shift. Seventeen hours or longer of prolonged wakefulness can be similar to changes experienced with alcohol consumption. Fatigue Affects Performance in a Similar Way to Blood Alcohol Content Fatigue affects people in a similar way to alcohol consumption. Research has shown that the effects of fatigue are similar to moderate alcohol consumption. On-the- job performance loss for every hour of wakefulness between 10 and 26 hours is equivalent to a 0.004 % rise in blood alcohol concentration. Eighteen hours of wakefulness are usually considered to be equivalent to a blood alcohol concentration of 0.05 %. A person who has been awake for this length of time will act and perform as if they have consumed one glass of beer. The result is signi cantly delayed response and reaction times, impaired reasoning, reduced vigilance, and impaired hand-eye coordination. 2023-01-12 B-09 Human Factors Page 170 of 340 CASA Part 66 - Training Materials Only  The Effect of Light and other Factors on Fatigue Tied in with the study of circadian rhythms is the effect of light. Research shows that lighting supports more than visual needs; it affects health and well-being. The amount of light needed to in uence health tends to be about 10 times greater than for vision. Studies have shown that a lack of light can cause certain forms of cancer. Further, greater amounts of light can reduce the risk of colon and prostate cancer; prevent myopia; counteract airborne disease transmission; and cure psoriasis, seasonal affective disorder, and sleep disorders. Other factors that in uence fatigue include stress, drugs, certain medications, illness, large temperature variations, noise, boredom, vibration, and dehydration. Image by Miikka Luotio on Unsplash Other factors that in uence fatigue include stress, drugs, certain medications and illness 2023-01-12 B-09 Human Factors Page 171 of 340 CASA Part 66 - Training Materials Only  Potential Effects of Fatigue on Performance Some of the most common effects of fatigue are: Diminished perception (vision, hearing and general awareness) Diminished motor skills, slow reactions and loss of coordination Short-term memory failures Reduced attention and channelled concentration ( xation on certain things) Decreased awareness of surroundings, easy distraction and dif culty concentrating Poor judgement and decision-making Abnormal moods and tendency to withdraw Poor work quality and complacency Lethargy. All of these conditions lead to reduced safety and increased risk due to decreased performance. Awareness of Degraded Performance A maintenance worker must be aware of their performance levels. If there is a problem, examination of lifestyle is important, especially for workers in safety-critical roles. People in these roles have an obligation to work at optimum performance so, if they have a chronic fatigue issue, it should be assessed and dealt with. Temporary fatigue issues are easier to deal with, but of course, can lead to longer-term problems if not addressed properly. There is only one real cure for fatigue, and that is rest. 2023-01-12 B-09 Human Factors Page 172 of 340 CASA Part 66 - Training Materials Only  Personal Management of Fatigue and Performance A challenge is to practice being more aware of the onset of fatigue and do something about it rather than ‘push through’. When feeling tired, people are encouraged to take a break, go for a short walk, drink a glass of water or eat a snack which may give a burst of energy. Talking with co-workers will increase awareness of things in the immediate area. Research has shown that a short nap can also improve alertness and performance. Other solutions concern lifestyle. Try to get adequate rest and good quality sleep, exercise regularly, eat a balanced diet and stay hydrated by drinking at least eight glasses of water a day. A cup of coffee can improve alertness but only for a limited time. Coffee contains caffeine, a stimulant, which temporarily increases level of alertness, but fatigue is a symptom of its withdrawal. Caffeine is also a diuretic, which causes the body to discharge more uid than it is taking in, resulting in dehydration, which can also cause or accelerate fatigue. If your schedule is too hectic to eat a balanced diet, taking vitamin and mineral supplements may help ght fatigue. Use supplements carefully and check with a physician about use and any possible side effects. Working Conditions and Practices to Manage Fatigue Work conditions and practices also need to be considered. A culture that supports safety and conducts human factors training to increase awareness of factors that in uence performance is one that will help prevent fatigue or injuries from occurring. Management should have adequate staff to handle tasks. This includes having the right experience levels as well as the manpower. When designing and planning work schedules, circadian rhythms should also be taken into consideration. Other management practices should include additional inspections, rotating shifts, and longer rest periods following night shifts. If possible, more critical tasks should be allocated for day shifts. Procedures should be documented so that there is a record of what has been done. This will ensure tasks are completed or indicate where someone left off in case someone else has to follow up to complete maintenance procedures. Know your own limits and adjust your behaviour in areas that you have control over, such as hours of sleep, proper diet, and exercise. And, if work affects your energy level, see what steps you can take to make work procedures safer and more productive. 2023-01-12 B-09 Human Factors Page 173 of 340 CASA Part 66 - Training Materials Only  Shift Work Most aircraft movements occur between 6 am and 10 pm to t in with the requirements of passengers. AMEs are required whenever aircraft are on the ground, such as during turnarounds. However, this scheduling means that aircraft are often available for more signi cant maintenance during the night. Thus, aircraft maintenance is clearly a 24-hour business and it is inevitable that, to ful l commercial obligations, AMEs usually work shifts. Some maintenance workers permanently work the same shift, but the majority cycle through different shifts. These typically comprise either an ‘early shift’, a ‘late shift’ and a ‘night shift’, or a ‘day shift’ and a ‘night shift’ depending on the maintenance organisation. Advantages and Disadvantages of Shift Work There are pros and cons to working shifts. Some people welcome the variety of working different times associated with regular shift work patterns. Advantages may include more days off and avoiding peak traf c times when traveling to work. The disadvantages of shift working are mainly associated with: Working ‘unsociable hours’, meaning that time available with friends, family, etc. will be disrupted. Working when human performance is known to be poorer (i.e., between 4 am and 6 am). Problems associated with general desynchronisation and disturbance of the body’s various rhythms (principally sleeping patterns). 2023-01-12 B-09 Human Factors Page 174 of 340 CASA Part 66 - Training Materials Only  Working at Night Shift work arising from the aircraft operating schedules usually requires maintenance workers to work at night, either permanently or as part of a rolling shift pattern. As discussed earlier in this chapter, this introduces the inherent possibility of increased human errors. Working nights can also lead to problems sleeping during the day, due to the interference of daylight and environmental noise. Blackout curtains and use of ear plugs can help, as well as avoidance of caffeine before sleep. Photo by Karl Köhler on Unsplash Working nights can also lead to problems sleeping during the day 2023-01-12 B-09 Human Factors Page 175 of 340 CASA Part 66 - Training Materials Only  Rolling Shift Patterns When a shift worker changes from one shift to another (e.g., ‘day shift’ to ‘night shift’), the body's internal clock is not immediately reset. It continues its old wake-sleep cycle for several days, even though it is no longer possible for the person to sleep when the body thinks it is appropriate. It is only gradually resynchronised, and, by this time, the shift worker may have moved onto the next shift. Generally, it is now accepted that shift rotation should be from earlier to later shifts (i.e., from early shift to afternoon shift to night shift or from day shift to night shift) instead of from later to earlier shifts (night shift to afternoon shift to early shift). Image by JC Gellidon on Unsplash Shift rotation should ideally be from earlier to later shifts 2023-01-12 B-09 Human Factors Page 176 of 340 CASA Part 66 - Training Materials Only  Alcohol, Medication and Drug Abuse Precautions and Responsibilities It should come as no surprise to the AME that their work performance will be affected by alcohol, medication or illicit drugs. Under most legislation, it is an offence for safety critical personnel to carry out their duties while under the in uence of alcohol or drugs. Anyone in an aerodrome testing area, other than a passenger, can be tested by CASA. People can be randomly selected based solely on the fact they are present in an aerodrome testing area. In addition, anyone who is performing (or is available to perform) a 'safety sensitive aviation activity' (as de ned in the regulations) can be tested by CASA, whether or not those activities are conducted in an aerodrome testing area. No one can be forced to undergo CASA testing. However, refusing or failing to give a body sample may constitute a prosecutable offence. Further, anyone failing or refusing to give a body sample must stop performing or being available to perform an applicable SSAA. Failure to do so may result in a criminal charge. © CASA CASA Alcohol Testing (Pilot pre- ight) will also be regularly conducted on Aircraft Maintenance Engineers 2023-01-12 B-09 Human Factors Page 177 of 340 CASA Part 66 - Training Materials Only  Alcohol Alcohol acts as a depressant on the central nervous system, dulling the senses and increasing mental and physical reaction times. It is known that even a small amount of alcohol leads to a decline in an individual’s performance and may cause their judgment (i.e., ability to gauge their own performance) to be hindered. Alcohol is removed from the blood at a xed rate and this cannot be speeded up in any way (e.g., by drinking strong coffee). In fact, sleeping after drinking alcohol can slow down the removal process, as it slows the body’s metabolic systems. UK CAAIP Lea et 15-6 provides the following advice concerning alcohol: ‘Alcohol has similar effects to tranquillisers and sleeping tablets and may remain circulating in the blood for a considerable time, especially if taken with food. It may be borne in mind that a person may not be t to go on duty even 8 hours after drinking large amounts of alcohol. Individuals should therefore anticipate such effects upon their next duty period. Special note should be taken of the fact that combinations of alcohol and sleeping tablets, or anti-histamines, can form a highly dangerous and even lethal combination.’ The effects of alcohol can be made considerably worse if the individual is fatigued, ill or using medication. Even small quantities of alcohol in the blood can impair performance, with the added danger of relieving anxiety and inhibitions, so that the person thinks they are performing well. Alcohol severely affects a person’s judgment and abilities. Working at high altitudes, where there is less oxygen, can worsen the effect. Alcohol is a depressant. It lowers the body’s natural sensitivities, cautions and fears, which means a lot of people exhibit over-con dence when drinking. At the same time, alcohol reduces capabilities. This combination can be deadly in safety-critical tasks, such as driving or operating machinery. Alcohol also represses inhibitions and allows emotions that would otherwise be controlled, to run free. Common characteristics of alcohol consumption are loudness, aggression, anger, passion, violence, showing-off and taking risks. In some personalities, alcohol causes depression and low self-esteem. After heavy drinking, alcohol may still be in the blood 24 hours later. Having coffee, soup or water between drinks only helps if they are taken instead of an alcoholic beverage. Otherwise, it takes the same time for alcohol to be processed by the liver, and for its effects to wear off. Long-term effects of alcohol consumption include damage to kidneys, liver and brain. 2023-01-12 B-09 Human Factors Page 178 of 340 CASA Part 66 - Training Materials Only  Studies suggest that women should drink no more than 14 - 21 standard drinks per week and men should drink no more than 21 - 28 per week; otherwise long-term dependency-related physical and mental problems may occur. A standard drink contains 10 grams of alcohol. Alcohol and Sleep Alcohol has a detrimental effect on both the quality of sleep and daytime attention. Sleep problems are common in alcoholics and in some people who have completely stopped drinking. The effects of alcohol on sleep and attention are complicated to de ne and have considerable variability in individuals. Alcohol and Attention The sedative action of alcohol has variable degrees of effect on attention, reducing it and producing diminished performance. This action is particularly noticeable in subjects who lack sleep or who tend to be lethargic. Alcohol seems to reduce an individual’s ability to wake, even if consumed in moderate amounts, to the point where driving ability is affected, not just in the hours after consumption, but sometimes for days afterwards. DUI Justice Even small quantities of alcohol in the blood can impair performance 2023-01-12 B-09 Human Factors Page 179 of 340 CASA Part 66 - Training Materials Only  Medication Any medication, no matter how common, can have direct effects or side effects that may impair a maintenance worker’s performance in the workplace. Medication can be regarded as any over the counter or prescription drug used for therapeutic purposes. There is a risk that these effects can be ampli ed if an individual has a sensitivity to the medication or one of its ingredients. Hence, an AME should be particularly careful when taking a medicine for the rst time and should ask their doctor whether any prescribed drug will affect their work performance. Medication is usually taken to relieve symptoms of an illness. Even if the drugs taken do not affect the engineer’s performance, they should still ask themselves whether the illness has made them temporarily un t for work. Various publications give advice relevant to the AME on some of the more common medications. This information is summarised below. However, the engineer should seek further clari cation from a pharmacist, doctor or their company occupational health advisor if at all unsure of the impact on work performance. Image by Karolina Grabowska from Pexels Any medication can have direct effects or side effects 2023-01-12 B-09 Human Factors Page 180 of 340 CASA Part 66 - Training Materials Only  Drugs The term ‘drugs’ can include illicit drugs, but also over-the-counter and prescription medicines. The effect of prescription drugs on performance cannot be underestimated. Illegal and Non-prescription Drugs Illicit drugs such as amphetamines, ecstasy, cocaine and heroin all affect the central nervous system and impair mental function. They are known to have signi cant effects +on performance and have no place within the aviation maintenance environment. Possession and use of these drugs are illegal in most countries. Image by Karolina Grabowska from Pexels Illegal drugs 2023-01-12 B-09 Human Factors Page 181 of 340 CASA Part 66 - Training Materials Only  Tobacco Smoking tobacco is detrimental to good health, both in the short term and in the long term. Smoking also signi cantly decreases a person’s capacity to perform by reducing the amount of oxygen carried in the blood. Carbon monoxide, which is present in cigarette smoke, is absorbed into the blood in preference to oxygen. The maximum blood oxygen concentration for a smoker is 90 % of that of a non-smoker. This means that, at sea level, a smoker is already as hypoxic as a non-smoker at an altitude of about 8000 feet. A smoker’s night vision is affected by hypoxia, even at sea level. Any oxygen de ciency reduces the body's ability to produce energy (and it affects brain functions). It is now recognised that cigarette smoking plays a signi cant role in cardiovascular (heart) diseases, cancer and other mental and physical diseases. Prescription Drugs Taking prescription medicine may have adverse side effects that the user must be aware of. Using stolen or fraudulently obtained pharmacy medications without a personal prescription is dangerous. All medications can have side-effects which are largely unknown if the medication has not been speci cally prescribed. Image by Sharon McCutcheon on Unsplash Prescription medicine may have adverse side effects that the user must be aware of 2023-01-12 B-09 Human Factors Page 182 of 340 CASA Part 66 - Training Materials Only  Drug and Alcohol Management Plan (DAMP) CASA have implemented Civil Aviation Safety Regulation (CASR) Part 99 which requires organisations to develop an organisation-speci c drug and alcohol policy, for workers who carry out safety sensitive aviation activities (SSAAs). CASR Part 99 requires organisations to implement the following DAMP programs: A drug and alcohol education program A drug and alcohol testing program A drug and alcohol response program. This DAMP program puts the responsibility on aviation workplaces to inform, monitor and care for their employees with respect to alcohol and other drug use. Image by Kristine Wook on Unsplash Civil Aviation Safety Regulation (CASR) Part 99 requires organisations to develop an organisation-speci c drug and alcohol policy 2023-01-12 B-09 Human Factors Page 183 of 340 CASA Part 66 - Training Materials Only