The article describes a concept for assessing labor intensity (LI) developed by the authors. This concept is based on the results produced by comprehensive assessment of the current working conditions, by analyzing the psychophysiological state of civil aviation (CI) pilots in flight, as well as by assessing a contribution made by flight loads and signs of fatigue to an increase in a risk of aviation accidents (AA). It has been established that, according to sanitary and hygienic profiles, LI levels at all workplaces of civil aviation pilots correspond to harmful working conditions, which are aggravated by exposure to four other harmful factors (noise, microclimate, vibration, and working posture) in 48 % of cases. The research results have shown that the risks of fatigue increase significantly after 5 hours of flight. This fatigue manifests itself in the growing number of gaze fixations by 11 %; an increase in an average latency period of a complex visual-motor reaction, by 12 %; the growing number of significant errors for flight safety, by 50 %. All these processes occur in the absence of physiological recovery of the cardiovascular system, p < 0.05. Pilots who are in a state of fatigue and stress due to violated work and rest regimes tend to have more AA. This accounts for at least 8.4 % of cases from all others causes. It is proposed to introduce the 3rd degree of harmfulness for strenuous work, as well as new LI indicators for sensory, informational and intellectual loads, such as an increase in a time required to fix the gaze on a device (in %), the frequency of image / value change on a screen (times/min), the volume of information flows per unit of time (bps), and the number of multifunctional devices (more than 10 bits per second). It has been established that the assessment of LI should be supplemented with specific indicators of the flight load and work regimes. These indicators include the number of takeoffs and landings, the number of crossed time zones, the number of stress factors during a flight, and the number of night flight shifts per week. They are directly related to developing fatigue among pilots and an increased risk of AA occurrence.

The analysis of the current and cancelled documents concerning the regulation of working conditions in civil aviation (CA) is carried out. There have been established significant factors of working environment and workload, their relationship with indicators of the health status of flight personnel, the development of fatigue and the risks of aviation accidents (AA) has been proved. The design of the study included a multifactorial analysis of the impact of working conditions on the functional state, occupational morbidity and accident rate of CA pilots with the establishment of a list of mandatory factors for rationing and control of the production environment and the labour process. The analysis of sanitary and hygienic characteristics of working conditions, health data was carried out based on the results of retrospective studies of the clinic of the Federal State Budgetary Scientific Institution “Izmerov Research Institute of Occupational Health”, publications indexed in the databases Scopus, Web of Science, RSCI and official statistical collections. Own experimental studies were conducted among one hundred twenty pilots of the case-control type, including the analysis of 10324 standard operating procedures for aircraft management, 59670 studies within the framework of psychophysiological testing, as well as the analysis of 83 AA. The necessity of adjusting the regulatory framework with the expansion of indicators for the normalization of working conditions in terms of the intensity of the labour process is proved. New criteria are proposed to be used for assessing information, intellectual, emotional loads, expanding the boundaries of sensory loads with the allocation of class 3.3 - according factors working load. Proposals have been developed to make additions to SP 2.5.3650-20 for flight crew members and air traffic controllers concerning requirements for all missed and obligatory factors of working conditions; a list of production factors obligatory for control during a special assessment of working conditions at the workplaces of aircraft crew members; new methodological documents relating to the assessment of indicators of the intensity of the labour process, the assessment of the personal risk of fatigue in pilots, conducting psychophysiological studies using a video oculograph, the procedure for conducting special assessment of working conditions, a general assessment of professional risks intended for the implementation of regulatory requirements.

Introduction. The researchers carried out the analysis of work and rest modes (WRM) according to the survey data of 667 pilots and the results of investigations of 83 aviation accidents (AA) that occurred in the Russian Federation with heavy aircraft (HA) weighing more than 5,700 kg for the period 2010-2021. We also considered the data of official statistics for the period from 2005 to September 2021. The obtained results indicate the facts of non-compliance with the work and rest modes (WRM), which may be one of the causes of aviation accidents (AA). In this regard, it is relevant to optimize the work and rest modes in order to improve flight safety in civil aviation and organize their stricter control. The study aims to assess the impact of the actual compliance with the WRM of the crew members of the Civil Aviation Aircraft (CAA) on the occurrence of aviation accidents and to develop proposals for their optimization and control. Materials and methods. The authors studied a compliance of work and rest modes based on the results of 667 online questionnaires developed on the basis of recommendations of the International Civil Aviation Organization (ICAO) on the introduction of a risk management system in airlines related to pilot fatigue, and data from 83 aviation accidents (AA) for the period from 2010 to 2020, presented in the reports of the Interstate Aviation Committee (IAC) on the results of the investigation the causes of their occurrence. When assessing the relevance of the topic, we considered the data of official statistics. Results. The data of the study indicate that in 18% of cases, one of the main causes of AA was non-compliance with WRM. Among the causes of aviation accidents, the following are important: exceeding the norms of flight time for a month (detected in 10% of cases) and for a year (up to 30%); insufficient preflight rest (46.5% of aircraft commanders and 7.4% of co-pilots); lack of full-fledged vacation for a year (32% of cases). In many cases the Researchers revealed several facts of different violations of work and res modes simultaneously. Data of online questionnaire survey confirm the high prevalence of severe fatigue among pilots: 44% rarely have time to rest between flights, 86% go on a night flight shift without having a full day's sleep. We determined the interrelations between the frequency of fatigue of pilots associated with various types of violations of WRM and the risk of air crashes: the prevalence of fatigue and the frequency of disasters increased with a decrease in the duration of pre-flight rest, an increase in vacation arrears and other factors from 1.2 to 2.1 times. Conclusion. The results of the study confirm the high significance of WRM disorders in the occurrence of aviation accidents (AA). The researchers compiled a comprehensive program to reduce accidents in air transport associated with violations of WRM and the development of fatigue among crew members. We have provided proposals to amend the current Regulations on WRM. Ethics. Authors carried out the study in accordance with the International Code of Medical Ethics (1949) and the provisions of the Helsinki Declaration adopted by the World Medical Association (1964). When conducting an online questionnaire survey, before the start of the study, we have introduced all participants with the methodology of its conduct, associated risks and signed an informed voluntary consent.