The Definition of Fatigue in Aviation
Before analyzing and researching fatigue in aviation, one should be acknowledged with the general definition of fatigue. ICAO (2015) defines fatigue as a “physiological state of reduced mental or physical performance capability resulting from sleep loss, extended wakefulness, circadian phase, and/or workload (mental and/or physical activity) that can impair a person’s alertness and ability perform safety-related operational duties” (p. xiii). Thus, although the aviation industry provides one of the safest ways to travel, pilots’ and crew members’ fatigue can cause accidents and incidents (ICAO, 2015). Moreover, the most threatening feature of crew members’ fatigue is that it is inevitable because of the all-day operations and brain activity. Therefore, there should be introduced and established some approaches to address and manage this psychological state. ICAO (2015) provides an overview of the various approaches to fatigue management in the aviation industry, emphasizing the role of such fatigue grounds as the need for adequate sleep, daily rhythms, workloads.
Some scholars emphasize not only the lack of sleep as a contributing factor to fatigue and its possible consequences but also timing and quality of sleep itself. For instance, in the literature review collected by Bendak and Rashid (2020), it is claimed that the “amount, timing, and quality of sleep each day (sleep/wake schedule)” is crucial in preventing fatigue (p. 2). Moreover, such a variable as operations made in multiple time zones is also considered while defining fatigue in pilots and crew members (Bendak and Rashid, 2020). Lee and Kim (2018) also concluded that aviation workers’ night schedules often fail to provide an adequate time for sleep, making the crew members feeling more tired during night shifts. Consequently, pilots and others may experience mental or physical decline or the rest of the defects, which define fatigue (Lee & Kim, 2018). It cannot be claimed that the listed above crucial factors of such a psychological state oppose the definition suggested by ICAO (2019). On the contrary, such research as Lee and Kim (2018) only complements the model definition of fatigue in aviation.
Previous Studies about Fatigue in Aviation
Different studies about fatigue in aviation have already been conducted, and a summary can be made concerning the suggested methods to manage the discussed psychological state. To begin with, AlcĂ©u (2015) analyzed planned pilots’ flights and their psychological state during work. The study revealed the high-risk areas during the early morning flights, late evening, and days with more than four sectors. In such risk areas, the predictions regarding safety were not followed, and the pilots’ estimation of the fatigue level was higher than it should be. Thus, based on the schedule analysis, this study suggests a new approach to managing workload in fatigue and reconsidering the safety settings’ management:
- control should be maintained in the groups that have a higher duty and block hours on specific periods and throughout the year as to maintain them in an acceptable level of safety and capable of dealing with the risks on the daily basis. (Alcéu, 2015, p. 63)
Moreover, Alcéu (2015) recommends that future researchers should conduct a 365-days study to see the correlations in the increase of fatigue level and winters or summers, meaning the most extreme times in a year.
Previous studies on the damaging consequences of fatigue in the work of pilots also provided an understanding that this psychological state can lead to severe accidents, mostly in activities demanding the concentration of attention. Impairment of critical skills and functions is one of the main consequences of cases when pilots cannot concentrate their attention, have poor memory, slow response, and mood changes (Hobbs et al., 2018; Stokes & Kite, 2017). According to Hobbs et al. (2018), “The National Transportation Safety Board (NTSB) has estimated that fatigue is a contributing factor in approximately 20% of major transport accidents” (p. 14). Moreover, the agency included the decrease of fatigue-related accidents in all transport modalities to the list of the first ten safety priorities (Hobbs et al., 2018). This research conducted surveys of Bar Pilots, which are marines, and analyzed their dispatch records for one year. It is an important notion that marine pilots have similar high-risk navigating jobs to airline pilots, and therefore the fatigue itself may have a similar impact. Thus, the study made by Hobbs et al. (2018) emphasizes the necessity of accepting basic safety management measures. Such measures include minimizing the night shifts and providing the personnel with at least 36 consecutive hours to rest in a 14-days working period. Summing all above, there are various studies about fatigue in aviation and other related industries, so it is crucial to review the measures converted into a variable by different scholars.
The Ways to Measure Fatigue in Airline Pilots
In their literature review and meta-analysis, Jerman and Meško (2018) discussed the various instruments that measure fatigue among pilots. Several scales were used: FAI test (a fatigue assessment instrument), a standing-position balance test, CFF test (critical flicker fusion frequency test), subjective rating of sleepiness and fatigue, and many others (Jerman & Meško, 2018). The most crucial notion here is that all the instruments mentioned above are in terms of what they measure and focus on various sides of the psychological state under analysis. However, if some airline companies want to implement the safety management policies recommended in the paragraphs above, they can choose those discussed by Jerman and Meško (2018). Moreover, their literature analysis provides an overview of the tendencies followed by scholars in this research field. Regarding tendencies, even though Jerman and Mesko (2018) conducted a deep analysis of the existing literature, they did not provide readers with recommendations or outline advantages of the discussed instruments to measure pilots’ fatigue.
The work about fatigue measurement through the questionnaire should be discussed in this section. Bourgeois-Bougrine et al. (2003) conducted a study that measured fatigue among 739 pilots from short and long-haul flights using a questionnaire. The results of these self-reported manifestations analysis revealed that night flights and jet lag were the most critical factors that generated this psychological state (Bourgeois-Bougrine et al., 2003). Long periods of awakening and poor quality of sleep, which is a factor that was emphasized by various scholars (Bendak & Rashid, 2020), also increase the level of pilots’ fatigue (Bourgeois-Bougrine et al., 2003). Therefore, the measurement of fatigue through questionnaires can be considered an option because it allows drawing conclusions that other academic community representatives confirm.
Fatigue in the COVID-19 Pandemic
The COVID-19 pandemic caused some restrictions on populations worldwide, which led to an increase in overall anxiety. The most common measures that were introduced to cope with infection were avoiding public areas, hand hygiene, wearing masks, and social distancing. MacIntyre et al. (2021) conducted a cross-sectional survey of preventive behaviors in adults (people more than 18 years old) in five cities in Australia, the UK, and the USA. According to MacIntyre et al. (2021), “pandemic fatigue was more common in younger people” (p. 199). Although aircraft crew contain younger and older members, a study should be conducted researching how pandemic restrictions influenced the growth of fatigue in pilots’ behaviors and the general population.
Moreover, Morgul et al. (2021) questioned 4700 people to define factors influencing the psychological fatigue of a person in Istanbul, Turkey. Only 35.9% were declared to be psychologically normal (Morgul et al., 2021); “age, educational level, occupational status, place of residence and number of family members” impact the mental fatigue of a person (Morgul et al., 2021, p. 128). The critical role here is playing the knowledge about the COVID-19: what consequences it has, how many infected people are there in the city/state, what are the symptoms, and etc.
The way people are coping with their life in crises affects their psychological conditions. Morgul et al. (2021) argued that:
- normal participants generally showed more positive attitudes than the fatigued in believing that COVID-19 will finally be controlled, satisfaction with preventive measures taken by the authorities, reporting suspected cases with symptoms, and trusting that Turkey can overcome the COVID-19 pandemic (p. 128).
In other words, beliefs affect the mental fatigue of a person. In addition to that, Teng et al. (2020) claimed that being overwhelmed with news regarding the pandemic and other significant infections or crises may lead to increased fear, anxiety, and fatigue. This overwhelming feeling can be referred to as messaging fatigue, which means being tired because of permanent exposure to similarly themed information (Koh et al., 2020). In their research, Kim and So (2018) show that the reaction to this information overload can negatively affect message fatigue. Moreover, psychological fatigue can be tied to information so that a person starts to fear missing something out (Dhir et al., 2018). Thus, pilots and crew members, who are also taking the risk of getting infected on the job and always overloaded with the COVID-19 news, may have negative beliefs regarding the pandemic, resulting in the psychological state of fatigue.
Activities Causing Fatigue and How to Reduce Fatigue with the Boeing Alertness Model
Bunting (2016) examined relationships between the fatigue level in pilots and crew members with solutions such as napping, spontaneous episodes for sleep, and reports for duties. As Bunting (2016) concluded, napping for a short period, usually less than 30 minutes, could help reduce the levels of psychological fatigue. Other scholars, Sivasankari and Karthika (2014), suggested the usage of the iPhone application Crew Alert. According to Sivasankari and Karthika (2014), “the application is intended for use by pilots as a tool for assessment, logging, and reporting of fatigue, to increase safety in the air” (p. 269). In other words, in addition to a short nap, crew members have been advised to manage fatigue by tracking their sleep patterns and work shifts. However, there are other ways to reduce psychological fatigue, such as the Boeing Alertness Model (BAM).
According to AlcĂ©u (2015), modern alertness models for aircrews, such as the Boeing Alertness Model (BAM), have increased previous models’ complexity and outcome reliability by adding extra variables, generating a more precise prediction of psychological fatigue, and therefore, producing better risk management. The BAM also has one of the highest numbers of applications because of the accurate predictions and wide range of taken parameters (AlcĂ©u, 2015). The predictive biomathematical fatigue the Boing Alertness Model (BAM) used as an output the Karolinska Sleepiness Scale (KSS) and the Samn-Perelli 7-point fatigue scale (SPF) (Jahanpour et al., 2020). The former is a 9-points scale (Shahid et al., 2012), and the latter is a 7-point scale, both starting from 1, which means “fully alert, wide awake” to 7 or 9, meaning “completely exhausted, unable to function effectively” (Samn, & Perelli, 1982). One can claim that the BAM measurement scale should be deliberately accurate to be applied in aviation because of deviation in terms of defined thresholds from other existing scales.
The mental fatigue decrease with the help of the Boeing Alertness Model. By conducting schedule analysis with the BAM, AlcĂ©u (2015) concluded that it is risky to have early morning and late evening flights. Hellerström et al. (2010) presented a methodology (based on the BAM analysis) to improve the efficiency of the prescriptive rules to enhance alertness while maintaining or improving pilots’ and crew members’ productivity. Therefore, one can claim that with the help of the Boeing Alertness Model, scholars can draw some recommendations regarding the safest time of flights and rules that will help detect specific mental conditions.
Summing all written above, a new study should be launched researching the impact of the crises on the level of fatigue. It is obvious from the literature review that pandemic restrictions, such as appeared because of the COVID-19, influence a lot on the growth of fatigue in pilots’ behaviors as well as the general population. Moreover, using the BAM measurement scale is one of the most reliable ways to research this topic.
References
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