HUMAN FATIGUE FACT SHEET

Human Fatigue as a Threat to

HUMAN FATIGUE FACT SHEET

Introduction It can be stated that human fatigue – and especially pilot fatigue (i.e. airline, cargo, corporate and charter pilot fatigue) – is a real problem since the beginning of air travel1. Stressors for fatigue are for instance the long workdays, lengthy flights, time zone crossings and night flights. These factors are a threat to pilot performance and flight safety. This fact sheet explores different facets of human fatigue in the aviation industry within the context of human factors and safety; it discusses the impact, causes and countermeasures for fatigue. The information presented in this fact sheet is primarily based on a bachelor thesis on the effect of human fatigue on speech production2.

20 to 30% of transport accidents involve human fatigue Example 1: 6 July 2013 The National Transportation Safety Board (NTSB) estimates that fatigue contributes to twenty to thirty percent of all accidents considering all A relatively recent accident in which fatigue was implicated is Asiana Air- transportation types3. Therefore fatigue is a serious threat to aviation safe- lines flight 214 with a Boeing 777-200ER that crashed during landing at San ty (Example 1). A scientific study concluded that 20 to 25 hours of sus- Francisco International Airport5. Three of the 291 passengers were fatally tained wakefulness resulted in performance decrements that are equiva- injured; 40 passengers received serious injuries. The Boeing was destroyed lent to those of a blood alcohol concentration (BAC) of 0.10%4. This indi- by a post-crash fire and impact forces. The NTSB evaluated a number of cates that being fatigued is just as dangerous as being drunk. criteria regarding fatigue, including recent sleep and its quality, circadian factors as well as time awake and concluded that at the time of the acci- dent all three pilots were experiencing some fatigue (e.g. a disruption of the circadian rhythm and having fragmented and/or less sleep than nor- mal). This likely degraded the performance at the time of the accident.

What is human fatigue? Fatigue is a human phenomenon that is easily recognizable in the observa- tion of others, but difficult to define6. It can be a physical or a psychological (mental) type. Physical fatigue occurs when the muscles become fatigued and they are not capable to maintain optimum physical performance (e.g. performing intense physical exercises). Psychological fatigue is a decrease in cognitive performance; it lessens the ability to perform a task in a safe and effective manner. Fatigue can be a temporary condition due to a lack of sleep, but it can also result in chronic psychological and physical disability. Fatigue is often confused with tiredness or sleepiness. While there is a rela- tion between fatigue and sleepiness, they are not identical. Sleepiness is HUMAN FATIGUE FACT SHEET defined as having the feeling to close the eyes and go to sleep. This is not Memory necessarily the case when a person is fatigued. The memory of a fatigued person is diminished. This can result in a poor memory while executing a task. Someone who is fatigued is more likely to According to the International Civil Aviation Organization (ICAO) fatigue is forget routine procedures. “a physiological state of reduced mental or physical performance capability resulting from sleep loss or extended wakefulness, circadian phase, or Mood workload (mental and/or physical activity) that can impair a crew member’s The mood of a fatigued person can be described as withdrawn. This can alertness and ability to safely operate an aircraft or perform safety related result in an attitude in which a person is more irritable, more easily frus- 7 duties.” (ICAO, 2013) . trated by minor difficulties and is more likely to perform shortcut tasks instead of heavy ones. Communication can also be affected, because What is the impact of human fatigue? someone who is fatigued is less likely to interact with others.

An obvious threat of fatigue is that an individual loses the fight to stay 8 Reaction time awake while performing a certain task . This is extremely dangerous when for instance a person is operating equipment or driving a vehicle. A person Reaction time is also affected when a person is fatigued. It takes more time who is experiencing fatigue may also experience a microsleep: a short (2 to to notice problems and it takes more effort to control equipment or vehi- 30 seconds) period of time in which the person enters the first stage of cles smoothly. Reaction time can also be related to the attention level, be- sleep. During this microsleep the person may continue to perform a relative cause a slower reaction time can be the result of inattention or poor con- simple task before regaining consciousness, could possibly have the eyes centration while performing a certain task. still open and is typically unaware of the situation. Beside the possibility of microsleeps, fatigue has an effect on (1) attention level, (2) memory, (3) mood and (4) reaction time9.

Attention level

The attention level of a fatigued person is significantly reduced. This can result in leaving out different steps while performing a task or focusing on just one part of it. A lower attention level can also lead to tunnel vision in which a person is less likely to notice unexpected situations. The perfor- mance level of the person can be influenced negatively, because he or she is not aware of a certain situation. Concentration may also be affected, because it requires more effort for the person to stay concentrated under normal circumstances. HUMAN FATIGUE FACT SHEET What are the causes for human fatigue? Adults need seven to nine hours of sleep per night13. However, the need for sleep can be different for every individual. When a person obtains less Fatigue can be stated as “a non-pathologic state resulting in a decreased sleep than needed to function properly a sleep debt will be created14. The ability to maintain function or workload due to mental or physical stress." 10 less sleep a person obtains per night, the more the sleep debt will build up. It can be induced by or a disruption of the circadian Even if a person reduces his or her sleep by one hour for a few consecutive rhythm. nights (e.g. sleeping for seven hours per night instead of eight) mental effi-

ciency will decrease (Example 2). Sleep deprivation

Sleep is – as well as for instance food and water – one of the basic needs for survival11. When an individual experiences sleep loss it results in sleepi- Example 2: 12 February 2009 ness. This can be defined as a signal in the brain that indicates that sleep is needed. Sleep loss means that a person has obtained less sleep (i.e. the An accident in which sleep loss was implicated is Colgan Air, Inc., flight 3407 15 person is sleep deprived) than needed for maximal waking alertness and with a Bombardier DHC-8-400 . The aircraft crashed during the approach performance. Sleep loss over several consecutive days results in a sleep phase while it was heading to Buffalo-Niagara International Airport, Buffa- debt. A study concluded that even relatively moderate sleep deprivation lo, New York. Two pilots, two flight attendants and 45 passengers aboard seriously impairs waking neurobehavioral functions in healthy adults12. It were killed and one person on the ground was killed. The aircraft was total- also impairs physical health and the functioning of individuals (Figure 1). ly destroyed by a post-crash fire and impact forces.

According to the captain’s wife, he would normally sleep between eight and ten hours. However, in the days before the accident he had significant- ly earlier awakening times as well as being away from home often. This would have produced some sleep loss. In the 24 hours before the accident

the first officer slept her normal needs, but the quality of the sleep may have been diminished due to the manner in which it was obtained (aboard the aircraft and in the crew room). Furthermore at the time of the accident she was already awake for at least 15 hours.

The NTSB concluded in the accident report that the captain experienced some chronic sleep loss and both pilots obtained poor-quality sleep in the 24 hours before the accident.

Sleep debt can be the result of work commitments (e.g. shift work), family

situations (e.g. young children) but can also be affected by medical condi-

Figure 1 – Effects of sleep deprivation. tions, the use of alcohol or the intake of other drugs.

HUMAN FATIGUE FACT SHEET Disruption of the circadian rhythm Crossing time zones also influences the circadian body clock. The human The human body is constantly experiencing biochemical, physiological and body has to adapt itself to a new time zone when these are crossed, which behavioural rhythms16. The brain is programmed to sleep during the night will take some time. The rate of adaption depends on many factors. For by a biological body clock, which is known as the circadian rhythm (Figure instance the number of time zones that are crossed and the direction of 2). The circadian rhythm is affected by light exposure. This enables the travel affect the rate of adaption. body clock to keep pace with the day/night cycle. When people have to sleep out of step with this circadian day/night cycle, problems may occur. Example 3: 14 January 2011

When Air Canada, flight ACA878 from Toronto, Ontario, to Zurich, Switzer- land was halfway across the Atlantic, the aircraft (a Boeing 767) experi- enced a 46-second pitch excursion during the hours of darkness17. The air- craft deviated 400 feet above and below the assigned altitude of 35,000 feet. Fourteen passengers and two flight attendants were injured from contacting armrests and cabin fixtures.

The Transportation Safety Board of Canada (TSB) concluded that one of the contributing factors to the incident was the circadian phase of the pilots. Due to the time of the incident (in the middle of the night) the pilots were experiencing a circadian low (i.e. periods of high fatigue and poor perfor- mance).

There is a correlation between the circadian body clock and sleep18. The circadian body clock determines when hormones related to sleep and at- tention (e.g. melatonin and cortisol) are released. Circadian disruption may result in difficulty to fall asleep or stay alert. ‘Jet lag’ is a well know example

Figure 2 – Biological body clock. of the effect of circadian disruption.

Circadian rhythm and the aviation industry Some of the people working in the aviation industry have to deal with shift What are countermeasures against human fatigue? work or time zone crossings (Example 3). In case of shift work a person has A problem with fatigue is that it cannot be reduced by typical prevention to be awake when he or she would normally be asleep considering the cir- measures such as training19. However, there are still a few lifestyle recom- cadian body clock cycle. Due to shift work it is more difficult to get ade- mendations that should be taken into account to minimize the risk of be- quate sleep and the chance of sleep deprivation increases. coming fatigued20. HUMAN FATIGUE FACT SHEET Lifestyle recommendations: don’t do this… Minimizing fatigue issues with the FRMS . Consume alcohol or caffeine in the three to four hours before going to ICAO, the International Air Transport Association (IATA) and the Interna- bed. tional Federation of Airline Pilots’ Associations (IFALPA) developed a guide . Exercise in the two to three hours before going to bed. Although exer- for the implementation of a Fatigue Risk Management System (FRMS)21. cising leads to a healthier lifestyle it should not be done very close to This publication adds a new safety dimension to fatigue related issues in bedtime. the aviation industry and should for instance increase pilot safety. . Eat a heavy meal before going to bed. . Take work-related aspects to bed. . Take sleeping pills.

Lifestyle recommendations: do this! . Get a sleeping pattern of eight hours of sleep per night. . Take naps during the day if possible. . Try to get a bedtime routine to fall asleep quicker. . Create (or select when traveling) a comfortable sleeping environment (i.e. free from any noise and light, good temperature, comfortable mat- tress, etcetera). . If falling asleep is difficult within the first 30 minutes, get out of bed and try an activity that induces sleep (e.g. reading, listening to relaxing music, etcetera).

How to cope with circadian rhytm disruption while on duty? Flying across time zones leads to a disruption of the circadian rhythm. The following countermeasures may help to cope with it:

. Make sure to sleep well at home before the flight. . Try to get the same amount of sleep per 24 hours as normally. . Try to get some sleep when feeling sleepy. It is better to take a nap

whenever possible instead of not sleeping at all. . Avoid adaption to a local circadian rhythm in case of short layovers. It is According to ICAO an FRMS is defined as “a data-driven means of continu- better to maintain the circadian rhythm from the place of origin. ously monitoring and managing fatigue-related safety risks, based upon . Use caffeine in a strategic way throughout the flight. scientific principles and knowledge as well as operational experience that . Have a conversation with others, stretch your legs and take regular aims to ensure relevant personnel are performing at adequate levels of 22 breaks while on duty. alertness.” (ICAO, 2013) . HUMAN FATIGUE FACT SHEET The FRMS guide presents the common approach of operators, regulators and pilots to the complex human factor fatigue. It is based on scientific principles of fatigue and provides a possible alternative to the traditional and strict flight rules and duty times. The guide includes a methodology and framework to implement an effective fatigue risk management system. The implementation principle is based on four different phases, which consist of (1) planning, (2) implementing reactive FRM processes, (3) implementing proactive and predictive FRM processes and (4) implementing FRMS safety assurance processes.

How to go further? Although FRMS tries to minimize fatigue and countermeasures can be very helpful against this phenomenon, fatigue still remains a problem. Since it poses a threat to aviation safety it should be taken seriously, which is why the aviation industry is still searching for ways to decrease the risks that are associated with human fatigue.

Scientific research at the Amsterdam University of Applied Sciences (AUAS) is aimed at better understanding fatigue and the effects of fatigue on the performance of aviation professionals, effective ways for the management of fatigue and developing ways to measure fatigue in a fast, easy and non- invasive manner.

HUMAN FATIGUE FACT SHEET Glossary . International Air Transport Association (IATA): A trade association of the world’s airlines. . Above mean sea level (AMSL): The elevation or altitude of an object . International Civil Aviation Organization (ICAO): A specialized agency of that is relative to the average sea level datum. the United Nations, which works with global aviation organizations and . Amsterdam University of Applied Sciences (AUAS): Higher professional the Convention’s 191 Member States to develop international Stand- education institute in the Netherlands, which offers educational and re- ards and Recommended Practices (SARPs). search programmes. Dutch name: Hogeschool van Amsterdam (HvA). . International Federation of Airline Pilots’ Associations (IFALPA): Non- . Blood alcohol concentration (BAC): The amount of alcohol in the blood- political and non-profit organization that represents over 100,000 pilots stream or on someone’s breath. It can be measured by breath, blood or and engineers around the world. It promotes the highest level of avia- urine tests. tion safety. . Crewmember*: A person assigned by an operator to duty on an aircraft . Jet lag: Desynchronization between the day/night cycle and the circadi- during a flight duty period. an body clock, which is experienced as a sudden shift in the day/night . Circadian rhythm: The brain is programmed to sleep during the night by cycle. Symptoms include degraded cognitive and physical performance, a biological body clock. It is affected by the light exposure, which means mood changes, digestion problems and wanting to sleep and eat at that the sensitivity to light enables the body clock to keep pace with the times that are out of step. It is resolved when sufficient time is spent in day/night cycle. the new time zone. . Duty*: Any task that flight or cabin crew members are required by the . Microsleep: A short period of time in which a person enters the first operator to perform, including, for example, flight duty, administrative stage of sleep, which takes approximately between two and thirty sec- work, training, positioning and standby when it is likely to induce fa- onds. tigue. . Nap: A short period of sleep, typically described as less than a half of . Evening wake maintenance zone: A period of several hours in the circa- full night-time sleep duration. dian rhythm, which is just before usual bedtime, in which it is difficult . National Transportation Safety Board (NTSB): An independent U.S. gov- to fall asleep. ernment investigative agency that is responsible for civil transportation . Fatigue*: A physiological state of reduced mental or physical perfor- accident investigation. mance capability resulting from sleep loss or extended wakefulness, . Non-invasive: Not puncturing the skin or penetrating body tissue. circadian phase, or workload (mental and/or physical activity) that can . Shift work: A work pattern in which a person has to be awake when he impair a crew member’s alertness and ability to safely operate an air- or she would normally be asleep considering the circadian body clock craft or perform safety-related duties. cycle. . Fatigue Risk Management System (FRMS)*: A data-driven means of . Sleep: A natural and periodic state of rest for the mind and body in continuously monitoring and managing fatigue-related safety risks, which there is a decrease in physical activity and responsiveness. The based upon scientific principles and knowledge as well as operational brain experiences a cycle with brain-wave activity that consists of inter- experience that aims to ensure relevant personnel are performing at vals of dreaming. adequate levels of alertness. . Sleep debt: Obtaining less sleep than needed for maximal waking alert- . Internal alarm clock: A time in the circadian rhythm in which there is a ness and performance over several consecutive days. strong drive to wake up; it is very difficult to fall asleep or stay asleep. HUMAN FATIGUE FACT SHEET . Sleep need: The amount of sleep that is needed to maintain maximal 6 alertness and performance. Maddox, M. (2008). FAA Human Factors Guide for Aviation Maintenance . Sleep quality: The sleep capacity to reinstate waking function. and Inspection. Chapter 3: Fatigue and fitness for Duty. HumanCentric, Inc. . Transportation Safety Board of Canada (TSB): An independent Canadian government investigative agency that is responsible for civil transporta- 7 tion accident investigation. International Civil Aviation Organization (ICAO). (2013). Operation of Air- craft. International Commercial Air Transport — Part I – Annex 6. * Represents an ICAO definition. 8 References Civil Aviation Safety Authority (CASA). (2013). Safety behaviours Human 1 Factors – Resource guide for engineers. Australian Government. Canberra: Houston, S. (n.d.). The Pilot Fatigue Problem. Retrieved 7 July 2015 from: Civil Aviation Safety Authority Australia. http://aviation.about.com/od/Regulations/a/The-Pilot-Fatigue- Problem.htm 9 Graeber, R. (1988). Aircrew fatigue and circadian rhythmicity. In Human 2 Factors in Aviation. San Diego: Academic Press. Stuut, R. (2015). Effect of fatigue on speech. Amsterdam University of Ap- plied Sciences: School of Technology. Amsterdam. 10 Strauss, S. (n.d.). Fatigue and flight operations. Aviation Medicine. Re- 3 trieved 7 July 2015 from: European Cockpit Association (ECA). (2015). Fatigue in Accidents. Retrieved http://www.pilotfriend.com/aeromed/medical/fatigue1.htm 30 June 2015 from: https://www.eurocockpit.be/pages/fatigue-in-accidents 11 4 Strauss, S. (n.d.). Sleep and sleep loss. Aviation Medicine. Retrieved 8 July Lamond, N., Dawson, D. (2002). Quantifying the performance impairment 2015 from: http://www.pilotfriend.com/aeromed/medical/fatigue1.htm associated with fatigue. Volume 8, Issue 4, pages 255–262. Journal of Sleep Research. 12 Dongen, van, H., Maislin, G., Mullington, J., & Dinges, D. (2003). The Cumu- 5 lative Cost of Additional Wakefulness: Dose-Response Effects on Neurobe- National Transportation Safety Board (NTSB). (2014). Descent Below Visual havioral Functions and Sleep Physiology From Chronic Sleep Restriction and Glide-path and Impact With Seawall, Asiana Airlines Flight 214, Boeing 777- Total Sleep Deprivation. Pennsylvania: University of Pennsylvania School of 200ER, HL7742, San Francisco, California, July 6, 2013. Aircraft Accident Medicine. Report NTSB/AAR-14/01. Washington, DC.

HUMAN FATIGUE FACT SHEET 13 19 National Sleep Foundation (NSF). (2015). How Much Sleep Do We Really Greenwich Maritime Institute. (2006). Fatigue: IMO guidance. Mitigation Need? Retrieved 8 July 2015 from: and management. Seaways. United Kingdom. http://sleepfoundation.org/how-sleep-works/how-much-sleep-do-we- really-need 20 Brown, J.R., Antuñano, M.J. (n.d.). Circadian Rhythm Disruption and Flying. 14 Federal Aviation Administration (FAA). Civil Aerospace Medical Institute. Civil Aviation Safety Authority (CASA). (2013). Fatigue – The rules are chang- Oklahoma City. Publication No. AM-400-09/3. ing. Australian Government. Canberra, Australia: CASA. 21 15 International Air Transport Association (IATA), International Civil Aviation National Transportation Safety Board (NTSB). (2010). Loss of Control on Organization (ICAO) and International Federation of Air Line Pilots' Associa- Approach, Colgan Air, Inc., Operating as Continental Connection Flight tions (IFALPA). (2011). Fatigue Risk Management System (FRMS) - Imple- 3407, Bombardier DHC-8-400, N200WQ, Clarence Center, New York, Febru- mentation guide for operators. (First ed.). ary 12, 2009. NTSB/AAR-10/01. Washington, DC. 22 16 International Civil Aviation Organization (ICAO). (2013). Operation of Air- International Air Transport Association (IATA), International Civil Aviation craft. International Commercial Air Transport. Part I – Annex 6. Organization (ICAO) and International Federation of Air Line Pilots' Associa- tions (IFALPA). (2011). Fatigue Risk Management System (FRMS) - Imple- Image references (top to bottom, left to right) mentation guide for operators. Chapter 2: Science for FRMS. (First ed.). 1 17 Pilot Career News. Retrieved 15 July 2015 from: Transportation Safety Board of Canada (TSB). (2012). Pitch Excursion, Air http://www.pilotcareernews.com/wp-content/uploads/2012/05/March- Canada, Boeing 767–333, C–GHLQ, North Atlantic Ocean, 14 January 2011. 1.jpg Report A11F0012. 2 18 Papermasters. Retrieved 14 July 2015 from: International Air Transport Association (IATA), International Civil Aviation https://www.papermasters.com/images/pilot-fatigue.jpg Organization (ICAO) and International Federation of Air Line Pilots' Associa- tions (IFALPA). (2011). Fatigue Risk Management System (FRMS) - Imple- 3 mentation guide for operators. Chapter 2.3: Introduction to Circadian Wordcloud: http://www.wordle.net Rhythms. (First ed.). Words are from: Civil Aviation Safety Authority (CASA). (2013). Fatigue – The rules are changing. Australian Government. Canberra, Australia: CASA. HUMAN FATIGUE FACT SHEET 19,20 4 een Fatigue Risk Management System (FRMS) ontwikkeld . Het FRMS Medical News Today. Retrieved 14 July 2015 from: geeft een aanpak om vermoeidheidsrisico’s te verminderen in aanvulling op http://www.medicalnewstoday.com/articles/247320.php werk- en rusttijdenregelingen en is van toepassing voor zowel exploitanten, regelgevende agentschappen en piloten. Het berust op wetenschappelijke 5 informatie en beschrijft een implementatieplan als het gaat om Gladstone Institutes. Retrieved 14 July 2015 from: risicobeheer voor vermoeidheid. http://gladstoneinstitutes.org/node/11312 Ondanks al deze inspanningen blijft vermoeidheid een probleem in de 6 luchtvaartsector. De luchtvaartindustrie is daarom voortdurend bezig om The Cagle Posts. Retrieved 17 July 2015 from: manieren te bedenken om het vermoeidheidsrisico te verkleinen. http://www.cagle.com/tag/bill/page/205/ Wetenschappelijk onderzoek bij de Hogeschool van Amsterdam (HvA) richt 7 zich op het verkrijgen van beter inzicht in vermoeidheid, het effect hiervan Maintenance & Ramp Safety Society. Retrieved 14 July 2015 from: op luchtvaartgebied, effectieve managementmethoden tegen http://www.marss.org/posters/D6.html vermoeidheid en methoden waarmee vermoeidheid op een snelle, gemakkelijke en een non-invasieve manier gemeten kan worden. Dutch summary This is a Luchtvaartfeiten.nl / AviationFacts.eu publication. Vermoeidheid is een groot probleem als het gaat om luchtvaartveiligheid.

Volgens de National Transportation Safety Board (NTSB), een agentschap van de Amerikaanse overheid dat onderzoek doet naar transport Author: Rutger Stuut, B.Eng. (Hons) ongevallen, speelt vermoeidheid een rol in twintig tot dertig procent van Editorial staff: R.J. de Boer PhD MSc, G. Boosten MSc & G.J.S. Vlaming MSc alle ongevallen in de transportsector3. Vermoeidheid onder piloten, luchtverkeersleiders en vliegtuigonderhoudsmonteurs vormt een ernstige Copying texts is allowed. Please cite: bedreiging voor de luchtvaartveiligheid. ‘Luchtvaartfeiten.nl (2015), Human Fatigue Fact Sheet, www.luchtvaartfeiten.nl’ Vermoeidheid kan het functioneren ernstig belemmeren. Het heeft zowel effect op (1) oplettendheid, (2) geheugen, (3) stemming en (4) reactietijd9. Een vermindering hiervan kan negatieve gevolgen hebben zodra iemand Luchtvaartfeiten.nl is an initiative by the Aviation Academy at the Amster- een verantwoordelijke functie uitoefent en bijvoorbeeld een voertuig moet dam University of Applied Sciences (AUAS). Students and teachers share besturen of een machine moet bedienen. Het kan ontstaan doordat iemand knowledge with politicians and the general public to ensure discussions are lijdt aan een slaaptekort of doordat er een verstoring plaatsvindt in het based on facts. 10,15 biologisch (circadiaan) ritme . Een probleem is dat het niet voorkomen kan worden door bijvoorbeeld training19. Echter zijn er wel diverse September 2015 tegenmaatregelen te bedenken en is er specifiek voor de luchtvaartsector