Longitudinal Changes in the Body Mass Index of British Army Pilots.

INTRODUCTION: Aircraft are manufactured according to design parameters that must account for the size and physical characteristics of the pilot. While cockpit dimensions, seats, restraints, and related components do not change substantially over the airframe lifecycle, it is conceivable that the occupant may, even if initially well-suited. This investigation focused on longitudinal body mass index (BMI) changes within a cohort of British Army Air Corps pilots.METHODS: The study was a retrospective examination of electronic medical record data to assess longitudinal change within a representative cohort of Army pilots. Voluntary subjects were assigned unique subject numbers matched with individual electronic medical record data. Subject's age, service length, height, weight, and BMI were extracted from routine historical aviation medical exams.RESULTS: Among 106 British Army Air Corps pilots, the mean age was 35.3 yr (SD = 7.4) with average length of service as a pilot of 9.0 yr (SD = 5.2). Within the observed cohort, the mean change in individual weight over time was an increase of 4.6 kg (SD = 7.3). Height remained relatively stable with a mean increase of 0.6 cm (SD = 1.9). Given the increase in weight, BMI was noted to increase longitudinally with a mean of 1.3 kg · m-2 (SD = 2.4).DISCUSSION: British Army pilots experience increases in BMI over time much like the general population. Results of this study serve to inform future policy related to the body composition of aviation applicants, the retention of previously qualified pilots, and the safety concerns of crashworthiness design specifications.Porter WD, Wilde GD, Jeffery NP, Walters PL, Eke AJ, Bushby AJR, Adams MS, Gaydos SJ. Longitudinal changes in the body mass index of British Army pilots. Aerosp Med Hum Perform. 2024; 95(2):118-122.

Spatial Disorientation Scenarios for the AW159 Helicopter Within a Synthetic Training Environment.

BACKGROUND: Spatial disorientation (SD) remains a stubborn and formidable challenge among rotary wing (RW) aircrews, particularly during times of high workload and deceptive visual cues. With tri-Service agreement, British RW Forces employ a layered training approach that now includes simulator-based immersive scenarios.METHODS: Ten bespoke RW SD training scenarios were developed for the AW159 Wildcat helicopter simulator by a multidisciplinary team. Scenarios were embedded within advanced training packages that were not solely focused on SD. A voluntary, anonymous survey instrument was distributed post-SD sortie to assess hazard awareness, training effectiveness, role and mission relevance, and perceived ability to respond to future SD threat. A corresponding assessment from the simulator instructor was used for independent determination if the crew became disoriented during the training.RESULTS: Over a 6-mo training cycle, 69 surveys were completed. Seven-point Likert-scale assessments yielded elevated median scores (6.0, respectively) across all four categories, suggesting favorable aircrew perceptions of training objective success. Elevated scoring of previous SD training received suggests good penetrance among the RW community surveyed. Of all sorties flown, the majority of aircrew (68%) became disoriented at some point during the sortie.DISCUSSION: This report provides limited evidence in support of bespoke SD training scenarios within a synthetic training environment. The merits include flexible ability to address root causes, provision of an interactive and immersive environment, and compatibility with extant tactics and mission configurations. SD simulator-based training can serve as an important component of a layered, multimodal approach.Bushby AJR, Gaydos SJ. Spatial disorientation scenarios for the AW159 helicopter within a synthetic training environment. Aerosp Med Hum Perform. 2023; 94(5):377-383.

Retrospective Analysis of Medical Attrition for Pilot Applicants to the British Army Air Corps.

INTRODUCTION: Management of aeromedical risk is essential for flight safety. Given the many operator stressors for pilots, militaries maintain a vested interest in selecting aircrew applicants who meet rigorous initial medical standards. Very little published literature exists regarding the extent of medical disqualifications or precluding conditions for initial candidates.METHODS: For the British Army, pilot selection is a phased, multistep process that includes Phase I medical screening followed by a comprehensive Phase II medical exam. De-identified summary data were retrospectively reviewed for medical fitness and disqualifying categories for the 5-yr period of 2018-2022, inclusive. For those ultimately deemed unfit for aviation service, etiology was grouped into general categories.RESULTS: Approximately one-third (30.2%) of candidates were disqualified at Phase I initial medical screening with leading categories of attrition due to respiratory etiology, especially a history of asthma or reactive airway disease, followed by ophthalmology. For the Phase II medical exam cohort, 21.0% were medically disqualified with most attrition from anthropometry and ophthalmology. There were no statistical differences in disqualifications for gender or pathway of entry (civilian vs. serving personnel).DISCUSSION: Major categories of medical attrition were similar to that of other nations, yet the published literature in this area is surprisingly tenuous. Given the desire for evidence-based medical selection standards, it is important for regular review of processes and standards such that the risks of known physiological challenges are judiciously weighed with the benefits of a large, diverse pool of selection as well as force structure and recruitment demand.Adams MS, Goldie CE, Gaydos SJ. Retrospective analysis of medical attrition for pilot applicants to the British Army Air Corps. Aerosp Med Hum Perform. 2023; 94(12):939-943.

Obstructive Sleep Apnea Among Army Aircrew.

INTRODUCTION: Obstructive sleep apnea (OSA) is a condition characterized by disrupted sleep and excessive daytime fatigue. Associated cognitive and psychomotor decrements pose a threat to aviators' performance and flight safety. Additionally, the longer term health effects associated with the disease can jeopardize an aviator's career and negatively impact operational outputs. This study reviews OSA prevalence, related comorbid conditions in Army aviators, and analyzes the aeromedical dispositions of affected individuals.METHODS: The U.S. Army Aeromedical Electronic Resource Office (AERO) database was interrogated for all cases of OSA from June 2005 through June 2015 using ICD-9 code 327.23. Prevalence rates for OSA and other comorbid conditions were then calculated using the total number of aviators in the AERO database.RESULTS: A total of 663 unique instances of OSA were found among the aviator population (N = 24,568), giving a point prevalence of 2.69%. Four cases affected women. Mean age of initial presentation was 42.62 yr and mean Body Mass Index was 28.69. The top five most prevalent comorbid conditions were hypertension, lumbago, degeneration of a lumbar or lumbosacral intervertebral disc, PTSD, and testicular hypofunction.DISCUSSION: Prevalence of OSA among aviators is lower than the general population but is not uncommon. A positive diagnosis requires a waiver or can result in suspension if not managed effectively, potentially leading to a reduction in aviator numbers. Aggressive health promotion and robust medical surveillance and aeromedical disposition management by the aeromedical community is essential to reduce OSA numbers, maintain aviator health, and maximize flight safety.Goldie C, Stork B, Bernhardt K, Gaydos SJ, Kelley AM. Obstructive sleep apnea among army aircrew. Aerosp Med Hum Perform. 2022; 93(5):415-420.

Selective Serotonin Reuptake Inhibitor Use Among Army Aviators.

INTRODUCTION: Mental health is an important aspect of Army aviation medicine given that it significantly impacts career longevity, readiness, and healthcare usage. One of the most commonly used classes of medications to treat mental health disorders is the selective serotonin reuptake inhibitor (SSRI). Here we present a descriptive epidemiological review of SSRI use in Army aviators over a 10-yr period.METHODS: An archival dataset retrieved from the U.S. Army Aeromedical Electronic Resource Office covering the years 2005 to 2015 was queried for cases of SSRI use. Frequencies were generated by primary diagnoses and aeromedical disposition for the SSRI subset of data.RESULTS: A total of 114 unique cases of SSRI use were identified (122 total aeromedical outcomes). These cases included 41 waiver recommendations, 59 suspension recommendations, and 22 cases of waiver continuations. The top five most common primary diagnoses were depressive disorder (N 32), anxiety state (N 21), posttraumatic stress disorder (N 16), single major depressive episode (N 13), and adjustment disorder with depressed mood (N 12).DISCUSSION: Understanding of the etiology, pathophysiology, and treatment of mental health disorders particularly within the safety-focused and unforgiving aviation environment has continued to evolve. With the application of evidence-based policy, deliberate aeromedical decision-making, and methodical risk mitigation, SSRI use does have a place within aviation. Aviators suffering in silence with deleterious impact to performance and safety or aircrew seeking services on the outside without knowledge or oversight of certification authorities must remain in the past.Kelley AM, Bernhardt K, McPherson M, Persson JL, Gaydos SJ. Selective serotonin reuptake inhibitor use among Army aviators. Aerosp Med Hum Perform. 2020; 91(11):897900.

Aviation-Modeled Investigation of Significant Obstetric Events.

INTRODUCTION: In this research, the authors attempted to ascertain whether or not the Root Cause Analysis Event Support and Engagement Team (RESET) investigates the use of U.S. Army aviation-based techniques by staff members or organizations in which serious obstetrical events have occurred. Root cause analysis (RCA), originating in the manufacturing and engineering sectors, attempts to elucidate an underlying cause of a problem. Most recently, this process has been applied to the investigation of medical error. RESET was established in order to perform centralized investigation of significant medical error within U.S. Army medical and dental treatment facilities based on request from a hospital commander or general officer. Significant obstetric events are high profile, discussed in multiple safety forums, and an area of close RESET focus. Yet it is unclear if RESET investigates the use of aviation-based techniques by staff and/or organizations involved in serious obstetrical events. Therefore the present survey study was conducted. MATERIALS AND METHODS: A structured, anonymous, voluntary survey was fielded to RESET staff in order to assess whether or not the RESET investigates the use of aviation-based techniques by staff members or organizations in which serious obstetrical events have occurred. RESULTS: Five of six members of this small team completed the survey. Prebriefs, debriefs, and checklist use were consistently investigated. The employment of a sterile cockpit, first-name introductions, annual check ride, and emergency procedure rehearsal were infrequently investigated. CONCLUSION: Obstetric RESET investigations inconsistently ascertain whether or not some of the aviation-based techniques are utilized by staff members or organizations in which serious obstetrical events have occurred. Standardization of investigative procedures and education directed at under-investigated practices may optimize medical investigation using proven tenets of an aviation-based approach.

Medication Adverse Reaction, Risk Stratification (MAR²S) Model.

BACKGROUND: A fundamental responsibility of aerospace medicine is the analysis and mitigation of the human component's risk to the aviation system. Medications are part of this risk mitigation process and are present within a multitude of work environments, including aviation. For example, during fiscal year (FY) 2013-2015, the Army Aeromedical Activity (AAMA) received 8596 medication waiver requests. During this same time period the U.S. Army Medical Department's Patient Administration Systems and Biostatistics Activity reported the organization prescribed over 187,668 prescriptions for opioids, 133,475 prescriptions for SSRIs, 116,649 prescriptions for muscle relaxants, and 71,723 prescriptions for hypnotics to its active duty soldiers in the outpatient setting.METHODS: A conceptual model to mitigate the risk of adverse reactions to medications by severity score was developed based off the methodology published by Prudhomme et al.RESULTS: The mean severity score of the 50 historically safe medications in the Army aviation community is 7346. The standard deviation of the population is 7300. The difference between safe and unsafe drugs determined by subject matter experts (SME) is highly significant when tested with the nonparametric Wilcoxon rank sum test.CONCLUSION: The visual representation of the data from this conceptual model clearly demonstrates room for improvement from current methods. Historically, utilizing SME opinion has created a system with deficiencies related to high variance, inconsistencies, and perceived ambiguity. There is need for a model addressing adverse drug reactions that has concrete strengths of transparency, simplicity, and speed of use.Cronrath CM, Klick MP, Merfeld CM, Gaydos SJ. Medication Adverse Reaction, Risk Stratification (MAR2S) model. Aerosp Med Hum Perform. 2019; 90(10):896-900.

U.S. Army Parachute Mishap Fatalities: 2010-2015.

INTRODUCTION: Despite the large number of U.S. military members who conduct parachuting operations, its inherent safety risks, and the introduction of a new military parachute in 2010, little has been published in the last decade on U.S. military parachute fatalities.METHODS: Parachute fatality investigative records maintained by the U.S. Army Combat Readiness Center were reviewed for U.S. Army fatalities resulting from military parachuting operations from January 1, 2010, through December 31, 2015. De-identified data on cases were collected, including causes, lethal injuries, and demographic, environmental, and missional factors. A descriptive analysis was performed.RESULTS: There were 13 cases which met study inclusion criteria. Most occurred during static-line operations and were jumps from a C-17 aircraft using a T-11 parachute. The two most common assigned accident codes were "improper or abnormal exit" and "unstable or improper body position," which combined accounted for 33% of cases. Also noteworthy at 11% each were "entanglement," "parachute malfunction," and "dragged on the drop zone," and at 6% each were "static line injury," "lost or stolen air," and "drop zone hazard." In 69% of cases blunt force trauma was the cause of death.DISCUSSION: Incident factors included human actions, equipment failure, and the environment. Death from blunt force trauma upon impact with the ground as the most frequent lethal injury was expected for parachute operations. This descriptive study provides awareness to military leaders of circumstances in which fatalities occur. Future investigations should include data on the total number of jumps to provide a more comprehensive analysis of risk.Johnson ES, Gaydos SJ, Pavelites JJ, Kotwal RS, Houk JE. U.S. Army parachute mishap fatalities: 2010-2015. Aerosp Med Hum Perform. 2019; 90(7):637-642.

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.

Transferring Aviation Practices into Clinical Medicine for the Promotion of High Reliability.

BACKGROUND: Aviation is a classic example of a high reliability organization (HRO)-an organization in which catastrophic events are expected to occur without control measures. As health care systems transition toward high reliability, aviation practices are increasingly transferred for clinical implementation. METHODS: A PubMed search using the terms aviation, crew resource management, and patient safety was undertaken. Manuscripts authored by physician pilots and accident investigation regulations were analyzed. Subject matter experts involved in adoption of aviation practices into the medical field were interviewed. RESULTS: A PubMed search yielded 621 results with 22 relevant for inclusion. Improved clinical outcomes were noted in five research trials in which aviation practices were adopted, particularly with regard to checklist usage and crew resource-management training. Effectiveness of interventions was influenced by intensity of application, leadership involvement, and provision of staff training. The usefulness of incorporating mishap investigation techniques has not been established. Whereas aviation accident investigation is highly standardized, the investigation of medical error is characterized by variation. DISCUSSION: The adoption of aviation practices into clinical medicine facilitates an evolution toward high reliability. Evidence for the efficacy of the checklist and crew resource-management training is robust. Transference of aviation accident investigation practices is preliminary. A standardized, independent investigation process could facilitate the development of a safety culture commensurate with that achieved in the aviation industry.Powell-Dunford N, McPherson MK, Pina JS, Gaydos SJ. Transferring aviation practices into clinical medicine for the promotion of high reliability. Aerosp Med Hum Perform. 2017; 88(5):487-491.

Reported Back Pain in Army Aircrew in Relation to Airframe, Gender, Age, and Experience.

INTRODUCTION: Back pain has remained an issue of significance among aircraft crewmembers for decades, occurring in the majority of military helicopter pilots with potential deleterious effects on performance, safety, and operational readiness. This exploratory, correlational survey study was designed to evaluate the presence of patterns and relationships that may require further examination to understand causal factors. METHODS: The study population consisted of U.S. Army aviation crewmembers. Subjects (467) completed an anonymous survey, including questions regarding demographics, airframes, experience, pain history and severity, ergonomics, mitigation strategies, and duty limitations. RESULTS: Overall, 84.6% of participants reported back pain at some time during their flying career, with 77.8% reporting back pain in the last calendar year. Age was found to significantly correlate with earlier time to pain during flight, higher pain rating after flight, and occurrence of grounding. A stepwise linear regression model was used to explore the relationships between age, flight hours, and years of aviation experience, demonstrating age to be the significant variable accounting for the observed variance. Aircrew reported wear of combat-related survival equipment and poor lumbar support to be the most notable contributors. DISCUSSION: Back pain rates were consistent with previous studies. The relationship of age to back pain in this study may highlight unique pathophysiological pathways that should be further investigated within an occupational context to better understand the etiologic role. Enhanced seated lumbar support and combat-related survival equipment remain relatively low-cost/high-yield topics worthy of further investigation for exploiting efficient means to improve health, safety, and operational performance.Kelley AM, MacDonnell J, Grigley D, Campbell J, Gaydos SJ. Reported back pain in army aircrew in relation to airframe, gender, age, and experience. Aerosp Med Hum Perform. 2017; 88(2):96-103.

Comparison of the effects of ketamine and morphine on performance of representative military tasks.

BACKGROUND: When providing care under combat or hostile conditions, it may be necessary for a casualty to remain engaged in military tasks after being wounded. Prehospital care under other remote, austere conditions may be similar, whereby an individual may be forced to continue purposeful actions despite traumatic injury. Given the adverse side-effect profile of intramuscular (i.m.) morphine, alternative analgesics and routes of administration are of interest. Ketamine may be of value in this capacity. OBJECTIVES: To delineate performance decrements in basic soldier tasks comparing the effects of the standard battlefield analgesic (10 mg i.m. morphine) with 25 mg i.m. ketamine. METHODS: Representative military skills and risk propensity were tested in 48 healthy volunteers without pain stimuli in a double-blind, placebo-controlled, crossover design. RESULTS: Overall, participants reported more symptoms associated with ketamine vs. morphine and placebo, chiefly dizziness, poor concentration, and feelings of happiness. Performance decrements on ketamine, when present, manifested as slower performance times rather than procedural errors. CONCLUSIONS: Participants were more symptomatic with ketamine, yet the soldier skills were largely resistant to performance decrements, suggesting that a trained task skill (autonomous phase) remains somewhat resilient to the drugged state at this dosage. The performance decrements with ketamine may represent the subjects' adoption of a cautious posture, as suggested by risk propensity testing whereby the subject is aware of impairment, trading speed for preservation of task accuracy. These results will help to inform the casualty care community regarding appropriate use of ketamine as an alternative or opioid-sparing battlefield analgesic.

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.

Hypoxic hypoxia at moderate altitudes: review of the state of the science.

Unpressurized aircraft routinely operate at altitudes where hypoxia may be of concern. A systematic literature review was conducted regarding hypoxic impairment, including mental functions, sensory deficits, and other pertinent research findings that may affect aviation-related duties at moderate altitude (8000 to 15,000 ft/2438 to 4572 m). The results of this review suggest that cognitive and psychomotor deficits may include learning, reaction time, decision-making, and certain types of memory. However, results are difficult to quantify and reliably reproduce. Inconsistency of results may be related to the subtlety of deficits compared to high altitude, differences among individual compensatory mechanisms, variation in methodology or sensitivity of metrics, presence or absence of exercise, heterogeneous neuronal central nervous system (CNS) response, and interindividual variation. Literature regarding hypoxic visual decrements is more consistent. Rod photoreceptors are more susceptible to hypoxia; visual degradation has been demonstrated at 4000 to 5000 ft (1219 to 1524 m) under scotopic and 10,000 ft (3048 m) under photopic conditions. Augmented night vision goggle resolution demonstrates more resilience to mild hypoxic effects than the unaided eye under starlight conditions. Hypocapnia enhances visual sensitivity and contrast discrimination. Hyperventilation with resulting respiratory alkalosis and cerebral vasoconstriction may confound both cognitive/ psychomotor and visual experimental results. Future research should include augmentation of validated neuropsychological metrics (surrogate investigational end points) with actual flight metrics, investigation of mixed gas formulations, contribution of hypocapnic vasoconstrictive effects on hypoxic performance, and further investigation into cellular- and systems-level approaches for heterogeneous CNS response. Research is also required into the contribution of mild-moderate hypoxia in human factors- and spatial disorientation-related mishaps.

Ten years of spatial disorientation in U.S. Army rotary-wing operations.

INTRODUCTION: Spatial disorientation (SD) has plagued aviation since its inception, contributing to numerous lost lives, destroyed or damaged aircraft, and a reduction in operational mission effectiveness. Military rotary-wing (RW) operations are not immune. The U.S. Army has retired many "legacy aircraft" represented in older studies, developed new training regimens for aircrew, continued to expand its night vision capabilities, and has prosecuted combat operations for some 10 yr utilizing new tactics, techniques, and procedures. For these reasons, it is important and relevant to re-engage the subject of SD among accidents within the Army's RW community. METHODS: The U.S. Army's Combat Readiness/Safety Center database at Fort Rucker, AL, was queried for the previous 10 yr RW mishaps from fiscal year (FY) 2002 through FY 2011 (FY11 current through 01 July). Accidents identified as having SD as a contributing factor were selected. RESULTS: From FY 2002 to FY 2011, there were 100 Class A through C rotary-wing flight mishaps involving SD. This represents 11% of all Class A through C rotary-wing flight accidents for this period. Of the 100 SD-related accidents, 22% involved fatalities, and 39% involved fatalities and/or injuries. The total number of RW SD-related accidents with fatalities represents 31% of the total helicopter accidents with fatalities for the 10-yr period. DISCUSSION: This review of accident data confirms that SD remains a substantial issue for the Army aviation community and reinforces the importance and relevance of SD awareness, research, education, and training in RW operations.

Aquaculture: Environmental, toxicological, and health issues.

Aquaculture is one of the fastest growing food-producing sectors, supplying approximately 40% of the world's fish food. Besides such benefit to the society, the industry does have its problems. There are occupational hazards and safety concerns in the aquaculture industry. Some practices have caused environmental degradation. Public perception to farmed fish is that they are "cleaner" than comparable wild fish. However, some farmed fish have much higher body burden of natural and man-made toxic substances, e.g. antibiotics, pesticides, and persistent organic pollutants, than wild fish. These contaminants in fish can pose health concerns to unsuspecting consumers, in particular pregnant or nursing women. Regulations and international oversight for the aquaculture industry are extremely complex, with several agencies regulating aquaculture practices, including site selection, pollution control, water quality, feed supply, and food safety. Since the toxicological, environmental, and health concerns of aquaculture have not been adequately reviewed recently, we are providing an updated review of the topic. Specifically, concerns and recommendations for improving the aquaculture industry, and for protection of the environment and the consumers will be concisely presented.