Physiological Fitness of U.S. Army Aviators Compared to the U.S. General Population.

INTRODUCTION: U.S. Army aviators are required to maintain a level of physiological fitness as part of their qualifying process, which suggests that they are generally physically healthy. However, it has not been statistically proven that they are more "physiologically fit" than the general population.METHODS: This retrospective study compares physiological measurements of U.S. Army aviators from the Aeromedical Electronic Resource Office database to the U.S. general population using the Center for Disease Control's National Health and Nutrition Examination Survey data. To enable an accurate comparison of physiological metrics between U.S. Army aviators and the U.S. general population, aviators were categorized into the same age groups and biological genders used for segmentation of the national population data.RESULTS: On average, pulse rate was 4.85 bpm lower in male aviators and 6.84 bpm lower in female aviators. Fasting glucose levels were, on average, 10.6 mg · dL-1 lower in aviators compared to the general population. Key metrics like pulse rate and fasting glucose were lower in aviators, indicating cardiovascular and metabolic advantages. However, parameters like cholesterol showed less consistent differences.DISCUSSION: While aviation physical demands and administrative policies selecting for elite physiological metrics produce improvements on some dimensions, a nuanced view accounting for the multitude of factors influencing an aviator's physiological fitness is still warranted. Implementing targeted health monitoring and maintenance programs based on assessments conducted more frequently than the current annual flight physical may optimize aviator safety and performance over the course of a career.D'Alessandro M, Mackie R, Wolf S, McGhee JS, Curry I. Physiological fitness of U.S. Army aviators compared to the U.S. general population. Aerosp Med Hum Perform. 2024; 95(4):175-186.

Medical Suspension in Female Army Rotary-Wing Aviators.

INTRODUCTION: Female aviators with health conditions may face a variety of occupational impacts. Outcomes may include a waiver for continued flight or a permanent suspension, in which flight is no longer possible. The objective of this study is to determine the prevalence of medical diagnosis among female U.S. Army aviators over a ten year period and identify associations of clinical diagnoses leading to waiver or permanent suspension. MATERIALS AND METHODS: This study was a secondary data analysis; data were retrieved on 1,282 female, rated aviator patients from an Army Aviation epidemiological database. The archival dataset was composed of a total of 6,856 cases between June 2005 and June 2015. Age ranged from 19 to 58 years. The data were examined in terms of raw ICD-9 diagnostic codes, grouped system diagnoses (diagnosis categories), and occupational consequence. Spearman's rho correlations were used to determine associations between diagnosis, waiver and permanent suspension. RESULTS: The leading diagnoses were pregnancy, normal delivery, and allergic rhinitis. The systems approach yielded pregnancy, orthopedic disorders, and spinal disorders as the leading diagnosis categories. Leading waivered conditions included spinal, psychiatric, and neurological disorders. In terms of permanent suspension, the leading cause was depression, followed by migraine and post-traumatic stress disorders. In almost all diagnostic groupings, the Spearman's rho correlation coefficients between age and diagnosis were positively related. However, age was not associated with negative occupational outcome (permanent suspension), generally. CONCLUSIONS: A variety of conditions negatively impact the health and occupational status of female aviators, with disparate occupational impacts. Prevalent conditions differed from those reported previously for all aviators in a predominantly male population. The absence of cardiovascular disease is a significant change from 20-30 years ago. Among all medical diagnoses, a minority are responsible for a greater occupational burden.

Rest and Activity Patterns of Army Aviators in Routine and Operational Training Environments.

INTRODUCTION: Fatigue continues to be a leading cause of military aviation mishaps. Several factors, including reversed shift missions, can negatively affect sleep patterns and increase the risk of fatigue due to sleep restriction. Currently, there is a lack of objective data regarding the current rest and activity patterns of military aviators across multiple operational conditions. The purpose of this descriptive study was to document the rest and activity patterns of U.S. Army aviators in operational training and garrison (routine) environments using wrist-worn actigraphy devices.METHODS: Actigraphy data were collected from U.S. Army aviators in training (N = 20) and garrison (N = 77) environments for a period of 1 wk.RESULTS: Results from this study indicate that 90% of subjects in the training environment, even after accounting for small sleep bouts during the day, averaged less than the recommended 8 h of sleep daily across the recording week. Approximately half of subjects in garrison averaged less than 8 h of sleep daily after accounting for smaller sleep bouts. Sleep efficiency was relatively high and similar in both groups (∼84%). Subjects in the training group averaged significantly more time awake and less time sleeping than those in the routine garrison group. Moreover, subjects in training were exposed to more light during sleep than those in garrison.DISCUSSION: Training environments that are representative of deployed conditions restrict aviator restorative sleep. These results highlight the importance of continued research on aviator sleep and fatigue mitigation in operational environments.Bernhardt KA, Kelley AM, Feltman KA, Curry IP. Rest and activity patterns of Army aviators in routine and operational training environments. Aerosp Med Hum Perform. 2019; 90(1):48-52.

Army Aviators' Perceptions of Advanced Cockpit Aircraft.

BACKGROUND: Perceptions of features of automation, such as its safety and effects on basic flying skills, can shape how someone uses automation and accepts newly developed technology. The purpose of the present study was to evaluate current U.S. Army rotary-wing aviators' perspectives of cockpit automation in terms of safety features and effects on the retention of basic flying skills. In doing so, future lines of research can utilize this information to develop programs for the transitioning and training of advanced aircraft into the Army.METHODS: An anonymous, 125-item questionnaire was completed by 214 U.S. Army aviators. A subset of five items related to perceptions of automation were examined based on experience level and are reported here. The majority of subjects were male aviators with a mean age of 33 yr.RESULTS: Results suggest a difference in perceptions of some of the safety features, with 8 and 12% more of the experienced pilots reporting safety concerns on two items. A 13% difference in the perceptions of effects of automation on skills retention items were found based on experience level. More experienced aviators' responses identified possible distrust of several automation features.DISCUSSION: The findings of this survey identified perspectives of automation which differed based on experience level. Specifically, more experienced individuals indicated some distrust of automation features and a possible overconfidence in basic flying skills. This can be used to further develop research aimed at the transition of advanced technology to aviators.Feltman KA, Kelley AM, Curry IP. Army aviators' perceptions of advanced cockpit aircraft. Aerosp Med Hum Perform. 2018; 89(12):1080-1084.

Clinical Diagnoses Leading to Suspension in Army Aircrew: An Epidemiological Study.

INTRODUCTION: There have been few large-scale epidemiological examinations of military aircrew populations reported in recent literature. This study examined 10 yr of medical records contained in the U.S. Army Aeromedical Electronic Resource Office (AERO) in an effort to identify the most prevalent conditions affecting Army aviator career longevity. METHODS: This study was a retrospective epidemiological review; data were retrieved on 24,568 rated aircrew patients from the AERO database, of whom 5.2% were women. The dataset was composed of a total of 181,471 cases between June 2005 and June 2015. Age ranged from 17 to 73 yr. The data were examined in terms of raw ICD-9 diagnostic codes, derived systems-based categories, and occupational consequences. RESULTS: The top 10 diagnoses, causes for waiver, and permanent suspension of aircrew were determined both in terms of the ICD-9 codes and the system groupings. Leading waiver causes included hypertension (11.5%), hearing loss (9.7%), spinal disorder (14.4%), and obstructive sleep apnea (5.2%). Leading permanent suspension causes were psychiatric disorders (28.2%), particularly PTSD, being the leading cause, with spinal pathology (16.1%) second. In almost all diagnostic groupings the Spearman's rho correlation coefficients between age and diagnosis presence were positively related, although often with no association with negative occupational outcome. DISCUSSION: This study revealed the leading medical causes of waiver and suspension from flying duties, producing evidence to inform leadership understanding of disease prevalence and its subsequent impact on flying status. This is of prime importance to help direct policy and implement strategies for health protection.Curry IP, Kelley AM, Gaydos SJ. Clinical diagnoses leading to suspension in Army aircrew: an epidemiological study. Aerosp Med Hum Perform. 2018; 89(7):587-592.

A Survey of Fatigue in Army Aviators.

INTRODUCTION: Fatigue plays a critical role in mission success due to its effect on a number of performance variables. The purpose of this study was to gauge the extent to which U.S. Army aviators experience subjective fatigue on a regular basis presently as well as their perceptions of their own sleep quality, quantity, and daytime sleepiness. This information is valuable for prioritizing future research lines with respect to injury prevention and fatigue management as well as updating policy. METHODS: An anonymous, 125-item questionnaire was completed by 214 U.S. Army aviators. A subset of those items (15 questions related to fatigue) are reported in this study. Subjects were primarily male and the mean age was 33 yr. RESULTS: Results suggest that the majority of subjects sleep less than the recommended 8 h per night and nearly half of them report sleeping less than their own preferred amount of sleep. Approximately 40% of the sample indicated that they believed fatigue to be a widespread problem in the U.S. Army aviation community. DISCUSSION: Overall, the findings identified factors contributing to fatigue and performance degradation currently experienced by those sampled in this study. Specifically, inconsistent shiftwork, less than optimal levels of rest, and poor sleep quality in the field were identified. Compared to past research, the extent to which fatigue is perceived to be a widespread problem is significantly lower than reported 15 yr prior.Kelley AM, Feltman KA, Curry IP. A survey of fatigue in army aviators. Aerosp Med Hum Perform. 2018; 89(5):464-468.

British army air corps accidents, 1991-2010: a review of contrasting decades.

INTRODUCTION: Accident investigation and review are important not only to attribute failure modes, but also mitigate risk, improve safety, and enhance capability. It was hypothesized that an interesting perspective on British Army Air Corps (AAC) rotary-wing (RW) accidents may be garnered by contrasting data from the previous two decades with a general operational (OP) shift from European theaters of conflict to operations in Southwest Asia. METHODS: AAC mishaps for the period from January 1991 through December 2010 were reviewed within an air safety management system. Accidents, defined by category 4 or 5 aircraft damage or death or major injury of personnel, were selected. Analysis was conducted jointly by a minimum of two specialists in aviation medicine. RESULTS: There were 37 accidents that occurred in 6 differing airframes at an average rate of 2.5 per 100,000 flying hours. From 1991-2000, 25 accidents (9 OP) occurred with a rate of 2.8 per 100,000 flying hours. From 2001-2010, 12 accidents (5 OP) occurred with a rate of 2.1 per 100,000 flying hours. Aircrew human factors (HF) errors represented 84% of attributable causation for both decades. Spatial disorientation (SD) represented a higher proportion of HF-related accidents for OP flying. DISCUSSION: Despite the perception of a more difficult OP theater for the latter decade, the overall rate and the proportion of OP accidents did not differ appreciably. Rather than theater-specific threats or challenges, it has been the longstanding and prominent player of HF error and specifically SD in OP flying that has remained entrenched in the causal chain.

Fatigue assessment: subjective peer-to-peer fatigue scoring.

INTRODUCTION: Fatigue is a complex entity with contributing factors that may include insufficient sleep, circadian dysrhythmia, high workload, extended duty periods, clinical sleep pathology, psychosocial aspects, environmental factors, and many others. It can contribute to significant performance deficits and crucial safety lapses. Despite maximal implementation of accepted techniques and best practices for mitigation strategies, the deployed military rotary-wing (RW) environment must still contend with substantial fatigue-related issues among aircrew. METHODS: We introduce a novel subjective peer-to-peer fatigue rating system recently demonstrated in a deployed military RW environment. Each pilot provides an anonymous weekly fatigue rating for every other pilot in the unit exclusive of self. Median and variance of the peer ratings for each pilot are recorded by the safety officer and tracked over time. RESULTS: The program allows for a multidimensional external perspective on a pilot's fatigue state, relative function, and degree of coping. Scoring is predicated upon the recognition of a significant deviation from a peer's baseline that may include social and interpersonal interactions or the observation of deficits in duty performance. DISCUSSION: The research basis for scientific validity and reliability regarding current peer fatigue scoring systems is exiguous. This novel approach may be of merit, particularly among military aircrew in a deployed-type setting with sustained high workload, operational stress, and limited time for supernumerary tasks. An anonymous subjective peer-to-peer fatigue scoring system is worthy of further scientific investigation, particularly warranting studies of reliability and validity.

Airsickness prevention in helicopter passengers.

INTRODUCTION: Despite many existing treatments, airsickness is an issue of concern for soldiers being transported by helicopter. This experiment examined the efficacy of four airsickness treatments and their effects on performance. This study replicated the transport of soldiers in the cabin of an UH-60 Black Hawk helicopter performing many of the flight maneuvers potentially experienced in a night troop transport during turbulent conditions. METHODS: A double-blinded, placebo-controlled design was used to compare the effectiveness of four airsickness countermeasures to their placebo controls. There were 64 male, non-aviator subjects (ages 18-34 yr) who were recruited for the study. Of these, 16 subjects were randomly assigned to each of 4 groups: (1) promethazine (25 mg) + caffeine (200 mg); (2) meclizine (25 mg); (3) Scopolamine patch (1.5 mg); and 4) acustimulation wristband. Each individual participated twice, once with the treatment and once with placebo. RESULTS: The findings indicated that only the combination of promethazine + caffeine showed a statistically significant reduction in nausea and motion sickness severity, and an improvement in reaction time when compared with its placebo control. DISCUSSION: Data from this study indicated that of the countermeasures tested, promethazine + caffeine was the most effective at reducing airsickness while producing the fewest side effects when compared with its placebo. In addition, this study demonstrated that over-the-counter caffeine can serve as an effective stimulant counterpart to promethazine. This may be a more appealing option than employing scheduled sympathomimetic drugs in a combat environment.

An analysis of routine blood testing of British army pilots.

BACKGROUND AND OBJECTIVE: The purpose of the study was to ascertain what had been discovered in the 15 yr that the British Army has been conducting a program of routine blood testing on its pilot population. These results were to be analyzed with respect to the causes of medical retirement, change of flight status on medical grounds, accidents, incidents, and sudden incapacitation in flight. METHODS: Data were collected from the records of 408 aircrew and comprised 1213 records of test batteries. Each battery consisted of: complete blood count, erythrocyte sedimentation rate, urea and electrolytes, liver function tests, fasting glucose, thyroid function tests, and fasting lipids. Altogether 8,491 tests were considered. They were analyzed for degree of abnormality, subsequent action, resultant diagnoses, and therapeutic interventions. RESULTS: The positive predictive values for the tests ranged between 2% and 33%. The overall percentages of tests that resulted in a diagnosis were between 0.08% and 3.5%, and therapeutic intervention between 0.08% and 3.4%. CONCLUSIONS: No evidence to support the continuation of routine blood testing was found other than in the case of lipid estimation. Although this had the highest diagnostic yield, abnormal results were dealt with in an inconsistent manner. Further, the testing was shown to have no predictive value in any of the adverse pilot outcomes mentioned above. Recommendations to alter future practice have been made and accepted in full by the Aviation Medicine hierarchies of all three UK Services.