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A clinical presentation, evaluation and diagnosis of an aviator with stage 0 chronic lymphocytic leukemia discovered while being evaluated for asymptomatic mitral valve prolapse are discussed. The aeromedical disposition of this patient is also presented.
Hygiene problems that arise in connection to sanitation procedures in civil aviation are described; the relevant international regulation and recommendation are explained. The particular problems that arise in connection to prophylaxis to infections, food hygiene, sanitation, refuse disposal and the maintenance lavoratory facilities are emphasized. Relevant rules and recommendations are quoted.
Aviation medical standards world-wide place much emphasis upon the cardiovascular (CV) status of the individual. This is justified, especially in the Western world, because of the high incidence of CV disorders in the population and their likely similar occurrence in the aircrew peer group. These standards do not in general require the demonstration of any objective short fall in performance, but rather guard against a potential threat, that of sudden incapacitation. However, some observers have sought to question whether or not this threat and its potential consequences is as great as it might appear and to quantify the risks. We have now carried out and analysed over 1,300 closely observed simulator exercises, using two protocols, in which sudden and subtle incapacitation has been programmed to occur to the handling pilot at a critical phase of flight. The results have been assembled and extrapolated with the recorded incidence of sudden incapacitation in flight in civil airline operations so the actual degree of risk can be identified. Conclusions can be drawn from this on the relevance of present cardiovascular standards and suggestions for improvement are made.
The use of head space sampling in conjunction with gas chromatography has proved a useful technique for analyzing aviation accident post mortem material for ethanol, carbon monoxide, and volatile contaminants. An account of the experience of the technique to date at the Royal Air Force Institute of Pathology and Tropical Medicine is given, and the problems and advantages associated with the method are discussed.
Safety attitudes were elicited by forced-choice questionnaire responses obtained from 141 general aviation pilots in Ohio. The developed questionnaire was pretested on experienced pilots. Specific attitudes in five major categories significant to flight safety were surveyed: aerodynamics, meteorology, preflight activities, flight operations, and aeromedical factors. All pilots were active members of the Dayton Pilots Club. Two levels of concern were identified through the study: the first relates to those areas that are of extreme importance to safety; the second covers items that constitute a safety hazard when combined with other factors.
The autopsies of 764 pilots involved in fatal general aviation accidents during the years 1975-77 were reviewed to appraise the age specific prevalence of coronary atherosclerosis among the autopsied group. Of the pilots killed in aircraft accidents and autopsied during 1975-77, 51% were found to have some degree of coronary atherosclerosis ranging from minimal to severe. However, only about 5% of the autopsied group were categorized as having severe coronary atherosclerosis. The rate per 1,000 of severe coronary atherosclerosis increased with age from 14.5 for ages less than 30, to 89.9 for ages 50 years and above; the rate nearly tripled from ages 30-39 to 40-49 (22.1 to 63.6). The prevalence of coronary atherosclerosis among this group of autopsied airmen is less than would have been expected based on the results of other recent studies.
Flight activity of all aviators flying naval aircraft and aircraft accident data were analyzed to determine if statistical relationships among lifetime and recent experience variables and accident liability exist. The results demonstrate that accident potential, though not statistically related to flight hours in 30-d periods, is correlated with lifetime flight experience with the higher liability associated with minimal amounts of flight hours and with transitioning into new aircraft.
Approximately 2-3% of all fatal air accidents may be attributed to suicide, and in many other accidents in aviation there are grounds for inferring that self-destructive or suicidal behavior was involved. Narcissistic personality traits are of paramount importance for the choice of this suicide method. Precursors include undetected depressions, alcoholism, and family problems of pilots.
This study examined the time-course of alcohol impairment of general aviation pilot simulator performance. We tested 14 young (mean age 25.8 years) and 14 older (mean age 37.9 years) pilots in a Frasca 141 simulator during alcohol and placebo conditions. In the alcohol condition, pilots drank alcohol and were tested after reaching 0.10% BAL, and then 2, 4, 8, 24, and 48 h after they had stopped drinking. They were tested at the same times in the placebo condition. Alcohol impaired overall performance. Alcohol impairment also depended on the order in which subjects participated in the alcohol and placebo sessions, with larger decrements for the alcohol-placebo order than for the opposite order. To examine the influence of alcohol independent of session order effects, we compared performance in the first alcohol session with performance in the first placebo session. This analysis showed that alcohol significantly reduced mean performance in the alcohol condition at 0.10% BAL and at 2 h. In addition, alcohol increased variability in performance in the alcohol session from 0.10% BAL to 8 h, suggesting that some subjects were more susceptible to alcohol than others. Older pilots tended to perform some radio communication tasks less accurately than younger pilots.
Although the mishap rate in naval aviation has declined substantially over the period from 1950-90, there remains a residual number of mishaps per 100,000 flight hours. Many of these mishaps represent human error. There seems to be an additional risk in certain air-frames and in specific missions. We reviewed mishap trends and causes for all naval aircraft over a 4-year period, 1986-90. These were graphically represented and compared, both statistically and with other methods. The mishap rates contained a significant portion of aircrew error mishaps. Of 308 total Class A mishaps, 179 (58%) were attributed to air-crew error. There were 145 (47%) attributed to supervisory error, another form of human mistakes. Thus, the most common cause factors were directly related to human failure. The effect on training is already being seen with the establishment of air-crew coordination training as one of the top priorities in the Fleet Replacement Squadrons. Studies, both underway and in press, appear to indicate a positive response to this training.
Misjudgment of spatial orientation is reported to be an important factor in a substantial proportion of aviation accidents. The likelihood of such misjudgment is particularly high when there are conflicting interactions between labyrinthine and visual signals. In a manoeuvering aircraft, visual information is often a crucial factor in the pilot's ability to judge the aircraft's altitude and position with respect to external and terrain features. A body of research evidence supports the following conceptual framework. (1) The human visual system processes a limited number of visual dimensions almost independently of each other (for example, colour, luminance, spatial frequency, orientation, changing size, motion in depth, time to contact). (2) Each of these selective sensitivities shows considerable intersubject variability. (3) Intersubject variability is far from perfectly correlated across the set of selective sensitivities. This paper discusses the relevance of this framework for predicting, first the specific situations in which visual judgments are most likely to occur and, second, which individual pilots are most likely to make the visual misjudgments.
Syncope in the aviation environment can be a very difficult problem to assess. Even more difficult is the differential diagnosis between convulsive syncope and epilepsy after the first event. This paper discusses syncope in general and the differential diagnosis between vasovagal syncope and other forms of syncope. About 50% of all syncopal episodes cannot be identified as to etiology. However, a benign outcome for a single syncopal episode, non-cardiac in origin, is the norm. The diagnosis of syncope is discussed, emphasizing that a meticulous history from an observer or the patient, a good physical examination, and an ECG are the cornerstones of diagnosis. Other diagnostic venues are discussed. Convulsive syncope occurs in only about 12% of syncopal episodes, 65% of these being vasovagal in origin. The other 35% are due to a variety of causes. We found no good algorithm to differentiate convulsive syncope from epilepsy. We reviewed the literature to develop a differential diagnostic table, focusing on: age, awake status, position, emotional/physiologic stressors, onset, aura, appearance, injury on falling, seizure characteristics, automatism, length of unconsciousness and subsequent confusion, pulse characteristics, blood pressure, urinary incontinence, seizure duration, recovery time post-event, post-seizure sequelae, amnesia, posture vs. recovery, EEG characteristics, and the value of sophisticated diagnostic procedures.
Optimal visual acuity is a requirement for piloting aircraft in military and civilian settings. While acuity can be corrected with glasses, spectacle wear can limit or even prohibit use of certain devices such as night vision goggles, helmet mounted displays, and/or chemical protective masks. Although current Army policy is directed toward selection of pilots who do not require spectacle correction for acceptable vision, refractive error can become manifest over time, making optical correction necessary. In such cases, contact lenses have been used quite successfully. Another approach is to neglect small amounts of refractive error, provided that vision is at least 20/20 without correction. This report describes visual findings in an aviator who was fitted with a contact lens to correct moderate astigmatism in one eye, while the other eye, with lesser refractive error, was left uncorrected. Advanced methods of testing visual resolution, including high and low contrast visual acuity and small letter contrast sensitivity, were used to compare vision achieved with full spectacle correction to that attained with the habitual, contact lens correction. Although the patient was pleased with his habitual correction, vision was significantly better with full spectacle correction, particularly on the small letter contrast test. Implications of these findings are considered.
Blood alcohol concentrations are reviewed from a series of 250 consecutive fatal accidents, involving 259 pilots, for the years 1962 through 1975. BACs were obtained in 150 of 213 fatally injured pilots whose bodies were recovered. Positive BACs were 18% of total estimations. Impairment by alcohol was probably a factor in about 9% of accidents in which valid BACs were obtained. These percentages are not significantly different from lumped U.S. data. Comparison with fatal accidents in other modes of personal transportation shows alcohol plays a part in the following descending order: cars in single-vehicle accidents, all cars, motorcycles, general aviation aircraft.
Aviation ground personnel are subjected to a wide range of chemical and physical exposures that may lead the occupational physician to see a different spectrum of morbidity in the airport compared to other settings. It is essential to determine the most common medical problems in airport ground personnel in order to identify possible work-related conditions and in order to set the priorities for establishing health promotion programs and training occupational physicians. We compiled the diagnoses in 1000 consecutive visits of ground workers to the airport clinic for return-to-work examinations, and compared them to 7000 workers seen in general occupational clinics. The frequencies of the various categories of disease were similar in both type of clinics, except that low back pain was significantly more common in the ground personnel [251 (20.6%) vs. 1176 (15.2%), p < 0.003]. Over 80% of the diseases occurred in 10 diagnostic categories: cancer, fractures, hypertension, ischemic heart disease, knee pain, low back pain, neck pain, operations for various medical conditions, phonal trauma, and pregnancy. We conclude that, except for low back pain, the spectrum of disease seen in the airport clinic is not significantly different from that seen in general occupational medicine clinics. Focusing on the interaction of a limited number of diseases with the work environment will provide the occupational physician with a comprehensive training program, and the emphasis needed for establishing health promotion programs.
The present study examined U.S. Naval aircraft mishap trends between January 1977 and December 1992 using all Class A, B, and C mishaps. Results of this investigation revealed that mishaps attributable to both human error and mechanical/environmental factors have declined steadily over the past 16 years, although mishaps attributed to human error have declined at a much slower rate. For those mishaps attributed to human error, differences were observed between single- and dual-piloted aircraft when phase-of-flight (takeoff, in-flight, landing) and time-of-day were evaluated. For single-piloted aircraft, in-flight mishaps constituted the highest proportion of mishaps during the day ( > 55%), while landing mishaps constituted the highest proportion of mishaps during the evening and night (43-65%). For dual-piloted aircraft, no consistent variation was evident for phase-of-flight and time-of-day. In-flight (approx. 55%) mishaps constituted the highest proportion of mishaps across all times of day, followed by landing (approx. 35%), and takeoff (approx. 10%) mishaps. These data support focused rather than global investigations of aviation mishaps.
The study centers on refinement of psychological selection of aviation personnel. Evidence is given to the effect that currently the research in this area is bound with the testing-to-job-related-features strategy. An alternative is the job-related-features (JRF)-to-testing strategy. Its implementation is proposed by way of the so-called JRF designer. According to this approach, JRF is narrowed down to a feature underdevelopment of which is the factor of failure in mastering appropriate skills and coming up with the work. Theoretical and applied potentials of this approach are illustrated by several examples.
Careful investigation of restraint harness function can reveal the mechanism of failure and, by rectification, prevent repetition of such failures. The investigation can also lead to alteration in the specification for restraint harnesses, and so eliminate weaknesses in future design. The aviation pathologist can play an important part in the assessment of the efficiency of a restraint system in use. His assessment can sometimes be more revealing than laboratory tests, as the unforeseen event often reveals unknown weaknesses.