Cognitive performance of air personnel following sleep deprivation.

Air forces have developed several methods for reducing fatigue-related accidents. In the Israeli Air Force, the "Dead Tired" workshop was developed with the purpose of presenting aircrew with their objective performance under sleep deprivation conditions. The aim of this study was to examine the cognitive abilities of both aircrew and unmanned aerial vehicle operators, both objectively and subjectively. All Israeli aircrew and unmanned aerial vehicle operators participated in a "Dead Tired" workshop. During the workshop, the participants performed the Psychomotor Vigilance Task, a task that tests their attention abilities, while gathering information on their subjective sleepiness in the form of a Karolinska Sleepiness Scale. Data of 366 participants (25 females), of whom 187 were unmanned aerial vehicle operators and 179 were aircrew, were obtained; and the mean age was 21.8 ± 1.2 years (range 19-26 years). A significant decline in task performance was seen following 20 hr of wakefulness in both unmanned aerial vehicle operators and aircrew (p < 0.001). Unmanned aerial vehicle operators' performance was significantly better throughout the majority of the workshop (p < 0.001). Recovery after the full-night's sleep was seen for unmanned aerial vehicle operators, but not for aircrew (p = 0.008). A high correlation was seen between Psychomotor Vigilance Task performance and Karolinska Sleepiness Scale responses (correlation coefficient = 0.93). Sleep deprivation negatively impacted the performance of both groups of participants. Unmanned aerial vehicle operators were found to be more resilient to the effects of sleep deprivation and were quicker to recover in comparison to aircrew.

Cancer risk among air transportation industry workers in Korea: a national health registry-based study.

BACKGROUND: Flight attendants face various risk factors in their working environments, particularly occupational exposure to cosmic radiation. This study aimed to assess cancer risk among air transportation industry workers, including flight attendants, in Korea by constructing a cohort using national health registry-based data and analyzing cancer incidence risk. METHODS: We used the Korea National Health Insurance Service database from 2002 to 2021 to construct a cohort of 37,011 workers in the air transportation industry. Cancer incidence was defined using the tenth version of the International Classification of Diseases. We calculated the age- and sex-specific standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) by applying the cancer incidence rate of the general population between 2002 and 2019. RESULTS: Approximately 5% of the cohort developed cancer. Overall, the cancer incidence in the cohort was similar to or lower than that of the general population, with the SIRs for all cancers being lower. However, significantly higher SIRs were observed for nasopharyngeal cancer (SIR, 3.21; 95% CI, 1.71-5.48) and non-Hodgkin lymphoma (SIR, 1.57; 95% CI, 1.02-2.32) in male workers and breast and genital cancer (SIR, 1.51; 95% CI, 1.34-1.70) and thyroid cancer (SIR, 1.25; 95% CI, 1.05-1.47) in female workers. CONCLUSIONS: The lower overall cancer incidence among air transportation industry workers observed in this study could indicate the "healthy worker effect"; however, the incidences of certain cancers were higher than those in the general population. Given that these workers are exposed to multiple occupational and lifestyle-related risk factors, including cosmic radiation, further studies are necessary to determine radiation-induced cancer risk while considering potential confounding factors.

Health consequences of exposure to aircraft contaminated air and fume events: a narrative review and medical protocol for the investigation of exposed aircrew and passengers.

Thermally degraded engine oil and hydraulic fluid fumes contaminating aircraft cabin air conditioning systems have been well documented since the 1950s. Whilst organophosphates have been the main subject of interest, oil and hydraulic fumes in the air supply also contain ultrafine particles, numerous volatile organic hydrocarbons and thermally degraded products. We review the literature on the effects of fume events on aircrew health. Inhalation of these potentially toxic fumes is increasingly recognised to cause acute and long-term neurological, respiratory, cardiological and other symptoms. Cumulative exposure to regular small doses of toxic fumes is potentially damaging to health and may be exacerbated by a single higher-level exposure. Assessment is complex because of the limitations of considering the toxicity of individual substances in complex heated mixtures.There is a need for a systematic and consistent approach to diagnosis and treatment of persons who have been exposed to toxic fumes in aircraft cabins. The medical protocol presented in this paper has been written by internationally recognised experts and presents a consensus approach to the recognition, investigation and management of persons suffering from the toxic effects of inhaling thermally degraded engine oil and other fluids contaminating the air conditioning systems in aircraft, and includes actions and investigations for in-flight, immediately post-flight and late subsequent follow up.

A feasibility study for objective evaluation of visual acuity based on pattern-reversal visual evoked potentials and other related visual parameters with machine learning algorithm.

BACKGROUND: To develop machine learning models for objectively evaluating visual acuity (VA) based on pattern-reversal visual evoked potentials (PRVEPs) and other related visual parameters. METHODS: Twenty-four volunteers were recruited and forty-eight eyes were divided into four groups of 1.0, 0.8, 0.6, and 0.4 (decimal vision). The relationship between VA, peak time, or amplitude of P100 recorded at 5.7°, 2.6°, 1°, 34', 15', and 7' check sizes were analyzed using repeated-measures analysis of variance. Correlations between VA and P100, contrast sensitivity (CS), refractive error, wavefront aberrations, and visual field were analyzed by rank correlation. Based on meaningful P100 peak time, P100 amplitude, and other related visual parameters, four machine learning algorithms and an ensemble classification algorithm were used to construct objective assessment models for VA. Receiver operating characteristic (ROC) curves were used to compare the efficacy of different models by repeated sampling comparisons and ten-fold cross-validation. RESULTS: The main effects of P100 peak time and amplitude between different VA and check sizes were statistically significant (all P < 0.05). Except amplitude at 2.6° and 5.7°, VA was negatively correlated with peak time and positively correlated with amplitude. The peak time initially shortened with increasing check size and gradually lengthened after the minimum value was reached at 1°. At the 1° check size, there were statistically significant differences when comparing the peak times between the vision groups with each other (all P < 0.05), and the amplitudes of the vision reduction groups were significantly lower than that of the 1.0 vision group (all P < 0.01). The correlations between peak time, amplitude, and visual acuity were all highest at 1° (rs = - 0.740, 0.438). VA positively correlated with CS and spherical equivalent (all P < 0.001). There was a negative correlation between VA and coma aberrations (P < 0.05). For different binarization classifications of VA, the classifier models with the best assessment efficacy all had the mean area under the ROC curves (AUC) above 0.95 for 500 replicate samples and above 0.84 for ten-fold cross-validation. CONCLUSIONS: Machine learning models established by meaning visual parameters related to visual acuity can assist in the objective evaluation of VA.

Contributions of Stereopsis and Aviation Experience to Simulated Rotary Wing Altitude Estimation.

OBJECTIVE: We examined the contribution of binocular vision and experience to performance on a simulated helicopter flight task. BACKGROUND: Although there is a long history of research on the role of binocular vision and stereopsis in aviation, there is no consensus on its operational relevance. This work addresses this using a naturalistic task in a virtual environment. METHOD: Four high-resolution stereoscopic terrain types were viewed monocularly and binocularly. In separate experiments, we evaluated performance of undergraduate students and military aircrew on a simulated low hover altitude judgment task. Observers were asked to judge the distance between a virtual helicopter skid and the ground plane. RESULTS: Our results show that for both groups, altitude judgments are more accurate in the binocular viewing condition than in the monocular condition. However, in the monocular condition, aircrew were more accurate than undergraduate observers in estimating height of the skid above the ground. CONCLUSION: At simulated altitudes of 5 ft (1.5 m) or less, binocular vision provides a significant advantage for estimation of the depth separation between the landing skid and the ground, regardless of relevant operational experience. However, when binocular cues are unavailable aircrew outperform undergraduate observers, a result that likely reflects the impact of training on the ability to interpret monocular depth cues.

Psychophysiological response in night and instrument helicopter flights.

Instrument and night flights are sources of mishaps: they produce stressful contexts to aircrews in which operability can be affected. This study aimed to analyse the effect of night and instrument flights in cortical arousal, autonomic modulation, muscle strength, and stress perception. 23 people were analysed (8 helicopter pilots, 4 helicopter mechanics - Spanish Air Forces - and 11 controls) before and after instrument and night flight exposition. Lactate and perceived exertion rose after flights. Anxiety was higher in instrument than in night flights. Pilots had a higher sense of anxiety before a flight compared to mechanics, although mechanics experienced a higher raise of heart rate during flight, with lower heart rate variability. Breath capacity was affected in pilots. Cortical arousal was more affected in unexperienced than in experienced aircrew during flights. These data suggest differences in their previous training. Practitioner summary: Night and instrument helicopter flights produced a different psychophysiological response of aircrew. These results could help to design specific training for aircrew that usually face instrument and night manoeuvres. Specific training based on high-intensity interval training integrated with reverse periodisation could improve their preparation. Abbreviations: BMI: body mass index; BOS: blood oxygen saturation; BT: body temperature; CA: cognitive anxiety; CFFT: critical flicker fusion threshold; ES: effect size; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; HF: high frequency; HR: heart rate; HRV: heart rate variability; HIS: isometric handgrip strength; LF: low frequency; NVG: night vision googles; PEF: peak expiratory flow; pNN50: proportion of differences between R-R intervals higher than 50 ms; RMSSD: square root of the mean of the sum of the squared differences between adjacent normal R-R intervals; RPE: rated of perceived exertion; SA: somatic anxiety; SC: self confidence; STAI: state trait anxiety inventory.

Psychophysiological response of different aircrew in normobaric hypoxia training.

Hypoxia remains the most important hazard in high altitude flights, but there is still a need for deeper analysis of the effect of hypoxia exposition in the psychophysiological and cognitive functions. The aim of this study was to study the effect of hypoxia training in cortical arousal, autonomic modulation, muscle strength and cognitive function. We analysed 23 male aircrew personnel of the Spanish Army and Air Force (10 Helicopter Pilots, 7 Transport Aircrew, 3 Transport Pilots and 3 F-18 Fighter Pilots) before, during and after a normobaric hypoxia exposition. Hypoxia produced an increase in perceived stress and effort, a higher Heart Rate and a decreased function of breath muscles. Working memory and pattern recognition were impaired after hypoxia exposition. Significant differences were found in cognitive tests performance among aircrew groups, suggesting differences on their previous training. These results can improve specific training for better preparation of pilots and aircrews for hypoxic threats. Practitioner summary: Distinct aircrew preparation produces a different hypoxia exposition effect on psychophysiological response and cognitive functions. Hypoxia produced an increase in Heart Rate, a decreased function of breath muscles, being more negatively affected in Transport Pilots. Cognition abilities were impaired after hypoxia exposition, independently of the aircrew group.

Incidence of cancer among licenced commercial pilots flying North Atlantic routes.

BACKGROUND: To evaluate cancer incidence among licenced commercial pilots in association with cosmic radiation. METHODS: Cohort study where ionizing radiation dose of cosmic radiation was estimated from airline data and software program and cancer incidence was obtained by record linkage with nation-wide cancer registry. All licenced commercial male airline pilots were followed from 1955 to 2015, ever or never employed at airline with international routes. Standardized incidence ratios were calculated and relative risk by Poisson regression, to examine exposure-response relation. RESULTS: Eighty three cancers were registered compared with 92 expected; standardized incidence ratios were 0.90 (95% CI 0.71 to 1.11) for all cancers, 3.31 (95% CI 1.33 to 6.81) for malignant melanoma, and 2.49 (95% CI 1.69 to 3.54), for basal cell carcinoma of skin. The risk for all cancers, malignant melanoma, prostate cancer, basal cell carcinoma of skin, and basal cell carcinoma of trunk increased with an increase in number of employment years, cumulative air hours, total cumulative radiation dose, and cumulative radiation dose sustained up to age of 40 years. The relative risk for the highest exposure categories of cumulative radiation dose were 2.42 (95% CI 1.50 to 3.92) for all cancers, 2.57 (95% CI 1.18 to 5.56) for prostate cancer, 9.88 (95% CI 1.57 to 190.78) for malignant melanoma, 3.61 (95% CI 1.64 to 8.48) for all basal cell carcinoma, and 6.65 (95% CI 1.61 to 44.64) for basal cell carcinoma of trunk. CONCLUSIONS: This study was underpowered to study brain cancer and leukaemia risk. Basal cell carcinoma of skin is radiation-related cancer, and may be attributed to cosmic radiation. Further studies are needed to clarify the risk of cancers in association with cosmic radiation, other workplace exposure, host factors, and leisure sun-exposure, as clothes, and glass in cockpit windows shield pilots from the most potent ultraviolet-radiation.

[Study on the health effect of the occupational stress in aircrew].

Objective: To explore the relationship between occupational stress and physiological and biochemical indexes, to research the health effect of the occupational stress in aircrew. Methods: 450 aircrews were conducted with the OSI-R questionnaire survey, examine the level of blood pressure, blood routine, ALT and UA. Results: The concentration of HB was positively related with task conflict and entertainment and leisure (ß=0.262 and 0.106, both P<0.05) , while heavy task, task discomfort and psychological stress reactions were negatively related with HB (ß=-0.163, -0.102, and -0.137, all P<0.05) ; task conflict and self-care were positively related with RBC (ß=0.221 and 0.159, both P<0.01) , heavy task, psychological stress reactions and social support were negatively related with RBC (ß=-0.157, -0.119, and -0.113, all P<0.05) ; task ambiguity and self-care had a positive relationship with ALT (ß=0.144 and 0.159, both P<0.01) while heavy task, psychological stress reactions and social support had a negative relationship with ALT (ß=-0.176, -0.096, and -0.102, all P<0.05) ; self-care was positively related with SBP (ß=0.170, P<0.01) , task discomfort, interpersonal stress reactions and social support were negatively related with SBP (ß=-0.093, -0.103, and -0.111, all P<0.05) ; while self-care was positively related with DBP (ß=0.139, P<0.01) , social support was negatively related with DBP (ß=-0.114, P<0.05) . Conclusion: Occupational stress of the aircrew is significantly related with blood pressure, RBC, ALT and UA, occupational stress can make effects on the health of aircrew.

Evaluating a prototype device designed to alleviate night vision goggle induced neck strain among military personnel.

The purpose of this study was verify the design of a novel Helmet System Support Device (HSSD) that can be used by military aircrew to help intervene on and reduce the high prevalence of neck trouble. Twelve healthy participants repeated simulated helicopter aircrew tasks on 3 separate days. On each day they wore a different helmet configuration, where measures of performance, perceived demand/preference and muscular demand were recorded. The results showed that vigilance tasks were performed over 10% faster with the HSSD configuration compared to wearing the normal helmet configuration. Participants were able to maintain static (endurance) postures for 28% longer, and use of the HSSD helped to prevent neck muscle fatigue in the most demanding task. The results of this design verification study indicate that the HSSD may be a realistic, feasible near-term solution to intervene on the high prevalence of neck trouble among rotary-wing aircrew. Practitioner Summary: This paper verifies the effectiveness of the Helmet System Support Device (HSSD) as an on-body personal protective device to help control exposures associated with aircrew neck trouble. The HSSD reduced perceived demand, reduced cumulative muscle activity in select muscles and provided improved fatigue resistance, meeting its desired design objectives.

High blood pressure and aeronautical fitness: experience at the aeromedical expertise center of Rabat.

High blood pressure is a major cardiovascular risk factor closely linked to serious cardiovascular events. A real public health problem affecting more than one in three adults. Aircrew does not escape this pathology, despite very strict medical selection and rigorous and regular medical monitoring by the aircrew doctor during revision visits. We conducted a retrospective study at the medical expertise center for aircrew in Rabat which made it possible to collect 34 hypertensive civilian aircrew for 10 years, from January 2012 to December 2022. The median age at the time of the study was 56.5. The aeronautical specialties practiced by our aircrew population were dominated by class 1. The prevalence of hypertension in Moroccan civilian aircrew: out of 2000 monitored annually at the Aeromedical Expertise Center for 10 years, 34 cases were collected, i.e.: 1.7%. The average age of discovery was 49 years and in 23 cases the diagnosis was established by systematic screening during periodic fitness visits. More than 24 aircrews had no family history of hypertension. On the therapeutic level, lifestyle and dietary measures were systematically prescribed in all our aircrew, 18 patients were put on monotherapy, 11 on dual therapy, and 2 on triple therapy. Compared to fitness decisions, they were variable according to the grade of hypertension, the control of complications, and the aeronautical function. The discovery of hypertension in aircrew can jeopardize aviation safety with the risk of subtle or sudden incapacity in flight through neurological or cardiovascular complications, which could impact the fitness decision. However, advances in medicine and the management of hypertension made in recent years have prompted the medical and aeronautical authorities to revise the standards of aptitude.

Simulator sickness among helicopter pilots: Incidence, threshold and severity using the SSQ.

BACKGROUND: Flight simulators have an essential role in aircrew training. Occasionally, symptoms of motion sickness, defined as simulator sickness, develop during training sessions. The reported incidence of simulator sickness ranged widely in different studies. OBJECTIVE: The aims of this study were to calculate the incidence of and to define a threshold value for simulator sickness among rotary-wing pilots using the validated Simulator Sickness Questionnaire (SSQ). METHODS: CH-53 and UH-60 helicopter pilots, who trained in helicopter simulators in the Israeli Air Force, were asked to fulfill SSQ. A score of 20 in the SSQ was defined as the threshold for simulator sickness. Simulator sickness incidence and average SSQ were calculated. Correlations between age and simulator training hours to SSQ scores were analyzed. RESULTS: A total of 207 rotary-wing aircrew participated in the study. Simulator sickness was experienced by 51.7% of trainees. The average SSQ score was 32.7. A significant negative correlation was found between age and SSQ score. CONCLUSIONS: Simulator sickness was experienced by more than half of helicopter pilots. A score of 20 in the SSQ was found to be suitable as the threshold for this condition.

Subjective Dry Eye Symptoms and Objective Ocular Surface Signs in a Civil Air Crew Population: A Cross-Sectional Study.

Background Aviation professionals are often exposed to conditions such as low cabin air pressure, reduced humidity, and prolonged artificial lighting, which may predispose them to dry eye disease (DED). We therefore designed a cross-sectional study with three primary objectives. Our first aim was to determine the prevalence of subjective dry eye symptoms among civil flight personnel. To achieve this, we administered the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. Second, we performed ocular examinations to assess objective DED indicators, such as the Schirmer's-1 (SCH-1) test and tear film break-up time (TBUT). We then correlated the results of these objective tests with the subjective symptoms reported by the participants. Last, we aimed to identify the independent risk factors for positive SCH-1 and TBUT results among aircrew personnel who did not report subjective dry eye symptoms. Methods The study sample consisted of 189 aircrew personnel (94 men and 95 women; mean age: 35.8 ± 10.4 years). They completed the SPEED questionnaire, a tool for assessing ocular surface symptoms. Participants' symptoms were classified as normal (SPEED scores 0-6), moderate (SPEED scores 7-15), or severe (SPEED scores 16-28). The objective assessment included the SCH-1 test for tear production and the TBUT test for tear film quality. Results A significant majority of participants (n = 165; 87.3%) did not report any subjective symptoms of DED. However, 12.2% (n = 23) and 0.5% (n = 1) of the study subjects experienced moderate and severe symptoms, respectively. The SCH-1 test and TBUT test were positive in 25.4% (n = 48) and 24.9% (n = 47) of the participants, respectively. Interestingly, among the aircrew personnel who did not report any subjective dry eye symptoms (SPEED scores 0-6), 18.8% (n = 31) and 17.6% (n = 29) showed abnormal results on the SCH-1 test and TBUT, respectively. Age was identified as the only independent predictor of a positive TBUT (odds ratio = 1.05, 95% confidence interval (CI) = 1.01-1.08, p = 0.01), with a borderline significant association with a positive SCH-1 test (odds ratio = 1.03, 95% CI = 0.99-1.07, p = 0.06). Conclusions The disparity between subjective symptoms and objective tests emphasizes the significance of incorporating objective measures for screening and diagnosing DED in civil flight personnel. If independently confirmed by future research, our findings could potentially lead to the routine implementation of surveillance protocols that incorporate objective DED indicators. Moreover, as age emerged as an independent predictor of positive results on objective tests, it is crucial to consider age-specific screening strategies.

Civil aircraft accident investigation.

This talk reviews some historic aircraft accidents and some more recent. It reflects on the division of accident causes, considering mechanical failures and aircrew failures, and on aircrew training. Investigation results may lead to improved aircraft design, and to appropriate crew training.

Aircrew Health: A Systematic Review of Physical Agents as Occupational Risk Factors.

The primary objective of this systematic review was to analyze the main physical agents representing risk factors for commercial aircrew, together with their consequences. The secondary objective was to identify the countries in which studies on the topic were conducted, as well as the quality of the publications available. Thirty-five articles, published between 1996 and 2020, were selected for the review, having met all inclusion criteria. The majority of studies were conducted in the United States, Germany, and Finland and had moderate or low methodological quality of evidence. The main risk factors for aircrew identified in publications were exposure to abnormal air pressure, cosmic radiation, noise, and vibrations. Hypobaric pressure was explored in response to demands for studies on this agent, a factor which may lead to otic and ear barotraumas, as well as acceleration of atherosclerosis of the carotid artery. However, there is a dearth of research exploring this phenomenon.

Management of atrial fibrillation in German military aircrew.

INTRODUCTION: Arrhythmias are one of the most common causes of loss of flying privileges for both military and civilian pilots in the Western World, and atrial fibrillation (AF) is one of the most common arrhythmias worldwide. Aircrew, and particularly pilots, are subject to a unique and exacting working environment, especially in high-performance military aircraft. This manuscript analyzes AF cases in German military aircrew from both a clinical and occupational perspective to point out specific characteristics in this comparatively young, highly selected, and closely monitored group, and to discuss AF management with the aim of a return to flying duties. METHODS: The digital information systems of the German Air Force Centre of Aerospace Medicine (GAFCAM) were searched for aircrew (pilot and non-pilot aircrew from German Air Force, Army, and Navy) with the diagnosis of AF. Evaluation results for underlying disease, AF characteristics, important clinical findings, and occupational decisions were analyzed in the light of current clinical guidelines and aeromedical regulations. RESULTS: In a 34-year period, between March 1989 and January 2023, 42 aircrew with at least one episode of AF were registered, all of them were male. The median age at initial diagnosis was 47 years (min 22 years, max 62 years). The median follow-up period was 5.35 years. 19 of them (45%) were pilots. The breakdown of events and occurrence was found to be: single (23), paroxysmal (16), persistent (2), permanent (1). In 27 aircrew (64%) AF terminated spontaneously. Long-term recurrence prevention was variable with catheter ablations in 8 cases. 36/42 aircrew were returned to flight status with restrictions, while 6/42 were permanently disqualified from flying. CONCLUSION: Management of AF in military aircrew requires a comprehensive approach regarding the flight environment as well as clinical guidance. Aeromedical disposition should be case-by-case based on aeromedical regulations, individual clinical findings, and specific occupational requirements in this challenging field of work.

Fatigue among Air crews on (Ultra)-Long-Range flights - A comparison of subjective fatigue with objective concentration ability.

Introduction: Long duty times are common in the aviation industry, especially with the introduction of ultra long range flights (ULR). This article aims to compare the subjective fatigue assessment and concentration ability of flight crews with objective concentration and alertness tests during (U)LR-flights. Method: The study examined different (U)LR-flights. Before, during and after the flights subjective fatigue and concentration ability of the flight crew was examined with visual analog scale and objective attention and concentration ability with the FAIR-2 test respectively the 3-min Psychomotor Vigilance Test. For statistical analysis we used a repeated ANOVA with a post-hoc-analysis and a Wilcoxon signed-rank test for connected samples. Results: In total 28 crew members were examined. Subjective concentration ability declined and fatigue increased significantly over the course of flights. However, no significant changes were observed in the objective concentration tests performed before and after the flights. Conclusions: The study found that fatigue significantly increased with flight time, particularly during night hours at the window of circadian low of the crews. However, objective concentration performance showed no significant deterioration over time. The study's results were consistent with previous research, except for the finding that objective concentration was still stable. The study also compared the findings to another profession and found similar results regarding the performance of complex tasks after long working hours while experiencing fatigue. Pratical applications: This study helps to understand the effects of ultra long-range flight on fatigue and concentration of the air crew and can help to improve safety issues on such flights.

Unraveling Abusive Supervision Climate in Aircrew Workplaces: The Roles of Temporary Organizational Features, Trust, and Gender Dynamics.

This study aims to advance the theoretical understanding of the contextual antecedents underlying abusive supervision. It provides a fresh perspective on how subordinates' perceptions of an abusive supervision climate are shaped in temporary work environments. By developing a robust model, this research examines the relationships between temporary organizational characteristics (i.e., temporariness and membership flexibility), trust in ad-hoc supervisors, and perceived abusive supervision climates. We tested the hypothesized model using data from 340 aircrew engaged in temporary and constantly shifting supervisor-subordinate relationships. The results revealed that: (a) temporariness has a direct negative relationship with trust in ad-hoc supervisors, whereas membership flexibility positively affects this trust; (b) the link between temporariness/membership flexibility and a perceived abusive supervision climate is mediated by trust in ad-hoc supervisors. Furthermore, this study highlights gender interactions in a transactional context, indicating that: (c) females perceive a stronger negative association between trust and abusive supervision climates compared to males; and (d) the relationship between temporariness/membership flexibility and trust in ad-hoc supervisors is significant for women and men, respectively. In conclusion, this study underscores the importance of considering the unique organizational characteristics of temporary work settings when examining abusive supervision. It also emphasizes the role of gender in shaping subordinates' perceptions of a workplace victimization climate, particularly in situations where leader-member exchanges are ephemeral and contractual.

Prevalence of sleep disorders in a large French cohort of aircrew members and risk of in-flight sleepiness.

BACKGROUND: /objectives: Sleep disorders are a critical issue for flight safety. Previous studies have shown a high prevalence of sleep disorders and excessive sleepiness in the general population and some aircrews. The objectives of this study are to measure the prevalence of excessive daytime sleepiness and sleep disorders in aircrews, and to determine the risk factors of falling asleep during a flight. METHODS: this is a monocentric study based on questionnaires, including all professional civilian and military aircrews examined in an aeromedical center between January and May 2021. The questionnaire, created for this study, included information about socio-demographic characteristics, aeronautical experience, lifestyle, sleep habits, an Epworth sleepiness scale, and screening tests for chronic insomnia, sleep apnea syndrome and restless legs syndrome. RESULTS: 749 aircrew members were included (86.2% male, 58.9% civilian, 74.1% pilot, mean age 43.4 ± 9.6 years), 45.9% of the population had at least one sleep disorder (chronic insomnia 39.5%, sleep apnea syndrome 10.5%, restless legs syndrome 4.1%), 15.5% had an excessive daytime sleepiness, and 24.6% reported in-flight sleep while on duty. Chronic insomnia, screen use before bedtime, use of sleeping pills, inadequate recovery time after a flight, female gender and civilian status were found as risk factors of in-flight sleep in the multivariate analysis. CONCLUSION: this study emphasizes the need to improve the screening and prevention of sleep disorders in this particular population.

Burden of Proof: The Debate Surrounding Aerotoxic Syndrome.

Since the 1980s, some commercial airline pilots and flight crews in the United States, United Kingdom and Australia began to report an illness they believed was caused by exposure to contaminated cabin air. Despite a body of scientific research and health activism calling for this condition, termed Aerotoxic Syndrome (AS), to be classified an occupational illness, it has not been accepted as a clinical entity because its causation remains contested. This article contends that debates over the recognition of AS have been shaped by the politics of science and what can be considered evidence of a causal link; the burden of proof lay with survivors and their allies rather than with airlines and manufacturers. The history of AS shows the challenges of reacting to health risks in a global industry that provides an important form of transportation, and enjoys considerable political and economic influence. It also reveals that at the heart of commercial jet air travel remains an unresolved public health issue, and those who claim to be suffering from AS expected prompt recognition, reform and assistance in light of scientific research and personal testimony, as well as a range of chemical, medical, legal and air safety reports.