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PubMed1990

Aircraft noise and social factors in psychiatric hospital admission rates: a re-examination of some data.

Jenkins et al. (1981) published data on rates of admission to three psychiatric hospitals for 12 large samples of people living near London's Heathrow Airport. The percentages of people who were classified as being affluent, living alone, males having moved within last five years, unemployed, and immigrants, as well as the levels of aircraft noise to which they were exposed, were given for each of the samples. Multiple-correlation analyses revealed the following: (1) movement of males in the previous five years was not generally associated with hospital admission rates; (2) immigrant status, living alone, and affluence were negatively, and generally statistically significantly, associated with admission rates; and (3) unemployment and level of exposure to aircraft noise were positively, and generally statistically significantly, associated with admission rates. Unlike the conclusion reached by Jenkins et al., it is concluded from the present analysis of their data that there are statistically significant associations between psychiatric hospital admission rates and level of exposure to aircraft noise. This difference in findings appears to be due to a more comprehensive assessment of the interrelations of all the tested socioeconomic and aircraft noise variables by the multiple-correlation procedure used in the present analysis, in comparison with the graphic modelling assessment applied by Jenkins et al. to a limited portion of the socioeconomic data. Together, the five socioeconomic and aircraft noise variables correlate at about 0.98 with hospitalization rates for most population groups.

Adult↗
PubMedDate not supplied

Aircraft noise annoyance and average versus maximum noise levels.

A questionnaire study was performed in seven areas located around the airports of Landvetter and Save, Gothenburg, in an attempt to elucidate the extent of annoyance in populations exposed to aircraft noise. Noise exposure was estimated as the energy equivalent level (Aircraft Noise Level--FBN) or as the number of aircraft with levels that exceeded 70 dBA, combined with the maximum noise level. The results were compared with data obtained from the earlier Scandinavian Aircraft Noise Investigation. The results supported the conclusion that the annoyance reaction is better related to the number of aircraft and the maximum noise level than to energy equivalent levels for noise exposure.

Adolescent↗
PubMedDate not supplied

An experimental study of pilots' control characteristics for flight of an STOL aircraft in backside of drag curve at approach and landing.

In general, most vehicles can be modelled by a multi-variable system which has interactive variables. It can be clearly shown that there is an interactive response in an aircraft's velocity and altitude obtained by stick control and/or throttle control. In particular, if the flight conditions fall to backside of drag curve in the flight of an STOL aircraft at approach and landing then the ratio of drag variation to velocity change has a negative value (delta D/delta u less than 0) and the system of motion presents a non-minimum phase. Therefore, the interaction between velocity and altitude response becomes so complicated that it affects to pilot's control actions and it may be difficult to control the STOL aircraft at approach and landing. In this paper, experimental results of a pilot's ability to control the STOL aircraft are presented for a multi-variable manual control system using a fixed ground base simulator and the pilot's control ability is discussed for the flight of an STOL aircraft at backside of drag curve at approach and landing.

Acceleration↗
PubMed1998

Indoor air quality: recommendations relevant to aircraft passenger cabins.

To evaluate the human component of aircraft cabin air quality the effects of respiration of a resting adult on air quality in an enclosed space are estimated using standard equations. Results are illustrated for different air volumes per person, with zero air exchange, and with various air change rates. Calculated ventilation rates required to achieve a specified air quality for a wide range of conditions based on theory agree to within 2% of the requirements determined using a standard empirical formula. These calculations quantitatively confirm that the air changes per hour per person necessary for ventilation of an enclosed space vary inversely with the volume of the enclosed space. However, they also establish that the ventilation required to achieve a target carbon dioxide concentration in the air of an enclosed space with a resting adult remains the same regardless of the volume of the enclosed space. Concentration equilibria resulting from the interaction of the respiration of a resting adult with various ventilation conditions are compared with the rated air exchange rates of samples of current passenger aircraft, both with and without air recirculation capability. Aircraft cabin carbon dioxide concentrations calculated from the published ventilation ratings are found to be intermediate to these sets of results obtained by actual measurement. These findings are used to arrive at recommendations for aircraft builders and operators to help improve aircraft cabin air quality at minimum cost. Passenger responses are suggested to help improve their comfort and decrease their exposure to disease transmission, particularly on long flights.

Adult↗
PubMed2000

Overview of aircraft radiation exposure and recent ER-2 measurements.

The intensity of the different particles making up atmospheric cosmic radiation, their energy distribution, and their potential biological effect on aircraft occupants vary with altitude, geomagnetic latitude, and time in the sun's magnetic activity cycle. Dose rates from cosmic radiation at commercial aviation altitudes are such that crews working on present-day jet aircraft are an occupationally exposed group with a relatively high average effective dose. Crews of future high speed commercial aircraft flying at higher altitudes would be even more exposed. Present calculations of such exposures are uncertain because knowledge of important components of the radiation field comes primarily from theoretical predictions. To help reduce these uncertainties for high-altitude flight, the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) started the Atmospheric Ionizing Radiation (AIR) project. The measurement part of the AIR project is an international collaboration of 12 laboratories placing 14 instruments on multiple flights of a NASA ER-2 aircraft. This paper describes the basic features of cosmic radiation in the atmosphere as they relate to exposure of aircraft occupants and then describes the AIR ER-2 measurements and presents some preliminary results from a series of flights in June 1997.

Aircraft↗
PubMed2001

Ecological risk assessment framework for low-altitude aircraft overflights: II. Estimating effects on wildlife.

An ecological risk assessment framework for aircraft overflights has been developed, with special emphasis on military applications. This article presents the analysis of effects and risk characterization phases; the problem formulation and exposure analysis phases are presented in a companion article. The framework addresses the effects of sound, visual stressors, and collision on the abundance and production of wildlife populations. Profiles of effects, including thresholds, are highlighted for two groups of endpoint species: ungulates (hoofed mammals) and pinnipeds (seals, sea lions, walruses). Several factors complicate the analysis of effects for aircraft overflights. Studies of the effects of aircraft overflights previously have not been associated with a quantitative assessment framework; therefore no consistent relations between exposure and population-level response have been developed. Information on behavioral effects of overflights by military aircraft (or component stressors) on most wildlife species is sparse. Moreover, models that relate behavioral changes to abundance or reproduction, and those that relate behavioral or hearing effects thresholds from one population to another are generally not available. The aggregation of sound frequencies, durations, and the view of the aircraft into the single exposure metric of slant distance is not always the best predictor of effects, but effects associated with more specific exposure metrics (e.g., narrow sound spectra) may not be easily determined or added. The weight of evidence and uncertainty analyses of the risk characterization for overflights are also discussed in this article.

Aircraft↗
PubMed1999

Indoor air quality investigation on commercial aircraft.

Sixteen flights had been investigated for indoor air quality (IAQ) on Cathay Pacific aircraft from June 1996 to August 1997. In general, the air quality on Cathay Pacific aircraft was within relevant air quality standards because the average age of aircraft was less than 2 years. Carbon dioxide (CO2) levels on all flights measured were below the Federal Aviation Administration (FAA) standard (30,000 ppm). The CO2 level was substantially higher during boarding and de-boarding than cruise due to low fresh air supply. Humidity on the aircraft was low, especially for long-haul flights. Minimum humidity during cruise was below the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) minimum humidity standard (20%). The average temperature was within a comfortable temperature range of 23 +/- 2 degrees C. The vertical temperature profile on aircraft was uniform and below the International Standard Organization (ISO) standard. Carbon monoxide levels were below the FAA standard (50 ppm). Trace amount of ozone detected ranged from undetectable to 90 ppb, which was below the FAA standard. Particulate level was low for most non-smoking flights, but peaks were observed during boarding and de-boarding. The average particulate level in smoking flights (138 micrograms/m3) was higher than non-smoking flights (7.6 micrograms/m3). The impact on IAQ by switching from low-mode to high-mode ventilation showed a reduction in CO2 levels, temperature, and relative humidity.

Air Pollution, Indoor↗
PubMed2005

Annoyance with aircraft noise in local recreational areas and the recreationists' noise situation at home.

Few socioacoustic studies have examined the effect of noise on outdoor recreationists. Most studies concentrate on one setting of the everyday life of a noise-exposed population, which mainly has been the residential setting. This article relates annoyance with aircraft noise in outdoor recreational areas to the recreationists' noise situation at home. In conjunction with the relocation of the main airport of Norway in 1998, field studies were conducted before and after the change in one area near the old airport (1930 survey respondents), and one area near the new airport (1001 survey respondents). Multivariate linear regression analyses of the relationship between annoyance and aircraft noise exposure (LAeq for the aircraft events) in the recreational areas were conducted, controlled for noise annoyance at home, or aircraft noise exposure at home, the situation (before/ after the change), context- and demographic variables. People more highly annoyed at home tended to be more annoyed than others while in the recreational areas. A significant effect of aircraft noise exposure at home on annoyance in the recreational setting was not found. More research is warranted regarding the relationship between noise exposure at home and outdoor recreational demands.

Aircraft↗
PubMed1996

Effects of aircraft overflights on wilderness recreationists.

On-site and telephone opinion surveys were conducted to assess outdoor recreationists' annoyance with aircraft overflights of wilderness areas. Although current technology for measuring noise exposure does not yet permit accurate and cost-effective estimates of dosage-response relationships in outdoor recreational settings, it was nonetheless possible to construct a rough relationship between estimated aircraft noise exposure and annoyance from the data of the on-site study. In the second survey, telephone interviews were administered to another sample of outdoor recreationists within 2 weeks of their return from visits to 12 wilderness areas. The prevalence of aircraft noise-induced annoyance (in any degree) among respondents in all wilderness areas ranged from 5% to 32%. The prevalence of a consequential degree of aircraft noise-induced annoyance among respondents was less than 5% in all wilderness areas combined. Noise-induced annoyance proved to be a more direct measure of the effects of aircraft overflights on recreationists than more global measures such as visit satisfaction or intent to revisit.

Acoustics↗
PubMed1970

Interenvironmental transfer of microorganisms on the exterior surfaces of jet aircraft.

The likelihood of microorganisms being transferred to new environments by jet aircraft was investigated. Initial random sampling of the aircraft surface revealed the presence of microorganisms in varying numbers on different aerodynamic surfaces. Bacteria of the genus Bacillus were the most common isolates, comprising approximately one-third of the total organisms found. The most frequently isolated fungi were Cladosporium, Alternaria, Penicillium, and several yeasts. Sampling of surfaces before and immediately after a flight demonstrated that microorganisms were collected during flight in areas protected from the airstream and lost in those areas directly exposed to it. These experiments also showed that the majority of the organisms contaminating the aircraft were acquired from the air at ground level. The placement of microorganisms on the aircraft surface before a flight and determination of their survival after flight indicated that the test organisms were most likely to be transported in the areas protected from the airstream. The organisms showing the best chance of being transferred seem to be the sporeforming bacteria, arthrospore-forming fungi, and some yeasts. All phases of this work showed that microorganisms could be carried by jet aircraft to environments they could not reach by natural means of dispersal.

Air Microbiology↗
PubMed2000

[A field study of health effects of aircraft noise in adults around Komatsu Air Base (1998)].

OBJECTIVE: To ascertain the effects of aircraft noise on complaints about life disturbances and on psychological and physical symptoms in adults around Komatsu air base. METHODS: From April to June 1998, a questionnaire was answered by 203 persons (from 89.8% of families) in 2 areas without aircraft noise, and by 412 persons (from 89.0% of families) in 5 areas with a weighted equivalent continuous perceived noise level (WECPNL) of 75 or more. The questionnaire covered age, gender, work location, noise exposure time, past experience with noisy work and ear disease, complaints about noisiness and life disturbances, and psychological and physical symptoms. Multivariate linear models by JMP (SAS institute Inc.) were applied to analyze the relationships between the above factors including noise level and complaints or symptoms. RESULTS: Subjects in the areas with noise had more complaints about noisiness than 5 years before, although replies were less in areas without noise. Subjects in areas with a WECPNL of 75 or more had more complaints and symptoms than those in areas without noise. Moreover, subjects experiencing higher noise levels gave higher responses for most of complaints and symptoms. The JMP linear models showed that aircraft noise was positively related to complaints and symptoms after taking the effects of age, gender and past experience with noisy work and ear disease into consideration. Higher noise levels and longer exposure times were related more strongly to most complaints and symptoms. CONCLUSION: This study shows that aircraft noise with a WECPNL of 75 or more is related to various complaints and psychological and physical symptoms in adults around Komatsu air base, after considering the effects of age, gender and past experience with noisy work and ear disease. It also shows that higher noise levels and longer exposure times are related more strongly to many complaints and symptoms. The results also suggest that responses to aircraft noise have become more severe than in the past.

Adult↗
PubMed2000

Aircraft control forces and EMG activity in a UH-1H Iroquois helicopter during emergency maneuvers.

BACKGROUND: Some air forces are concerned with the adequacy of existing pilot selection standards in respect to pilot strength. Some studies have provided evidence that a large number of pilots may not be able to match the control force levels specified in both military and civilian aircraft design standards. However, both sets of design standards have been based on the subjective comments of test pilots and may not, therefore, be applicable for the majority of pilots. The aim of this study was to quantify aircraft control forces during emergency maneuvers in an Iroquois helicopter and compare these forces with design standards. The examination of muscle activation patterns of pilots during maneuvers, when normalized, can provide additional information on the relative activation levels that pilots are using to produce the aircraft control forces. METHODS: Six pilots were tested in a UH-1 H Iroquois helicopter. The maneuvers were three engine-out landings and a hydraulics-off landing. The variables recorded were pilot applied forces and EMG activity. Multivariate analysis of variance was used to test for differences between maneuvers. RESULTS: The greatest cyclic and upward collective control forces were observed during constant attitude and variable flare engine-out landings. The greatest downward collective forces were observed during hydraulics-off landing. Greater levels of muscle activation were consistently observed during hydraulics-off landing than during the engine-out landings. Control forces consistently exceeded military design standards for cyclic and collective controls, however muscle activity levels were sub-maximal for all maneuvers. CONCLUSION: Comparisons between existing aircraft control-force design standards and pilot strength may overestimate the number of pilots who are able to produce sufficient force to fly the aircraft. Despite the high control forces observed, all pilots tested were able to successfully maneuver the helicopter without requiring a maximal muscular effort.

Adult↗
PubMed2000

Why aircraft disinsection?

A serious problem is posed by the inadvertent transport of live mosquitoes aboard aircraft arriving from tropical countries where vector-borne diseases are endemic. Surveys at international airports have found many instances of live insects, particularly mosquitoes, aboard aircraft arriving from countries where malaria and arboviruses are endemic. In some instances mosquito species have been established in countries in which they have not previously been reported. A serious consequence of the transport of infected mosquitoes aboard aircraft has been the numerous cases of "airport malaria" reported from Europe, North America and elsewhere. There is an important on-going need for the disinsection of aircraft coming from airports in tropical disease endemic areas into nonendemic areas. The methods and materials available for use in aircraft disinsection and the WHO recommendations for their use are described.

Aircraft↗
PubMed1975

Association of aircraft noise stress to periodontal disease in aircrew members.

A review of the literature reveals a multitude of effects that noise may contribute to periodontal disease, including cardiovascular disease, angiospasm of peripheral vessels, hypertension, and an increase in inflammatory cells with concurrent inhibition of healing. Three groups of 25 men were selected from the Pennsylvania Air National Guard for study. Group 1 consisted of F-102 jet fighter pilots; Group 2, pilots and crew of a four-engine, propeller-driven C-121 aircraft; and Group 3, enlisted men not exposed to aircraft noise, as a control. The degree of alveolar, intraceptal bone loss for each subject was measured from full-mouth radiographs of all groups. The greatest amount of bone loss occurred in crew members of propeller-driven aircraft. Jet pilots had considerably less bone loss while the average number of millimeters of bone lost per tooth revealed a difference between the three groups to the 0.01 significance level (F=24.7). The data suggests there is a degree of alveolar bone loss over a period of years associated with exposure to propeller aircraft noise and vibration, and negligible loss for jet aircraft noise.

Aerospace Medicine↗
PubMedDate not supplied

Nocturnal aircraft noise effects.

Noise protection associated with the construction and extension of airports in the Federal Republic of Germany has been regulated by the law for protection against aircraft noise since 1971. This legislation is due for revision because of different aspects. One aspect is the growth of air traffic which has led many airports to the limits of their capacity and in search of new ways of adaptation to the increasing demand for flight services. Another aspect is the increasing concern of the population about noise effects which has to be addressed by better protection against the effects of aircraft noise. The framework conditions of policy in terms of society as a whole, its health and economic environment need to be put into effect by political action. Science can contribute to this goal by performing noise effects research and by providing recommendations to the political body. However, it remains controversial, what measures are necessary or adequate to assure effective protection of the population against aircraft noise. This is particularly true for the protection of rest and sleep at night. The problem of finding a common basis for adequate recommendations is associated with (1) the low number of primary studies, which also exhibited highly variable results and assessments, (2) the handling of acoustic or psycho-acoustic dimensions for quantifying psychological or physiological reactions, and (3) the conception of how far preventive measures have to go to prove effective. With this in mind, the DLR Institute for Aerospace Medicine is conducting a large-scale, multi-stage study for investigating the acute effects of nocturnal aircraft noise on human sleep. This enterprise is implemented in the framework of the HGF/DLR project "Quiet Air Traffic" for developing sustainable assessment criteria for human-specific effects of aircraft noise at night.

Aerospace Medicine↗
PubMed1992

Loss of cabin pressurization in U.S. Naval aircraft: 1969-90.

During the 22-year period from 1 January 1969 to 31 December 1990, there were 205 reported cases of loss of cabin pressure in US Naval aircraft; 21 were crew-initiated and 184 were deemed accidental. The ambient altitudes varied from 10,000 ft (3048 m) to 40,000 ft. (12192 m). The most common reason for crew-initiated decompression was to clear smoke and fumes from the cockpit/cabin (95%). The most common cause for accidental loss of cabin pressure was mechanical (73.37%), with aircraft structural damage accounting for the remaining 26.63%. Serious physiological problems included 1 pneumothorax, 11 cases of Type I decompression sickness, 23 cases of mild to moderate hypoxia with no loss of consciousness, 18 cases of hypoxia with loss of consciousness, and 3 lost aircraft with 4 fatalities due to incapacitation by hypoxia. In addition, 12 ejections were attributed to loss of cockpit pressure. Nine of the ejections were deliberate and three were accidental, caused by wind blast activation of the face curtain. Three aviators lost their lives following ejection and seven aircraft were lost. While the incidence of loss of cabin pressure in Naval aircraft appears low, it none-the-less presents a definite risk to the aircrew. Lectures on the loss of cabin/cockpit pressurization should continue during indoctrination and refresher physiology training.

Accidents, Aviation↗
PubMed2005

Desensitization to strong vestibular stimuli improves tolerance to simulated aircraft motion.

INTRODUCTION: The extent to which tolerance acquired in one motion environment can be transferred to another has not been fully elucidated. This study compares three provocative motion stimuli and whether tolerance acquired from cross-coupled motion and torso rotation can be transferred to simulated aircraft motion. METHOD: There were 18 healthy subjects (9 men and 9 women), 18-44 yr of age, who were divided into 3 groups. Each group was exposed to the following desensitization procedure in a pseudo-random repeated measures design. In condition D1, subjects were exposed to 4 consecutive days of cross-coupling and on the 5th d they were exposed to simulated aircraft motion. In D2, subjects were exposed to 4 consecutive days of torso rotation and on the 5th day they were exposed to the simulated aircraft motion as in D1. In D3, subjects were exposed to 5 consecutive days of simulated aircraft motion. Based on Graybiel's diagnostic criteria, severity of motion sickness on the 1st and 5th day in D1, D2, and D3 were compared. RESULTS: Cross-coupled motion was the most provocative stimulus followed by torso rotation and simulated aircraft motion. Within each motion stimulus, there was evidence of desensitization (p < 0.001) within 4 d. There were no significant differences in the severity of motion sickness observed on the 5th day regardless of the desensitization stimuli. CONCLUSION: Our results suggest that desensitization to one provocative motion could be transferred to a less severe motion stimulus. This result could be used in the refinement of desensitization programs for aircrew.

Adaptation, Physiological↗
PubMed2006

Aircraft disinsection.

Aircraft disinsection has been an international practice since the 1920s, the purpose of which is to protect public health, the environment, agriculture, and livestock by the eradication of disease vectors. Although most nations of the world have discontinued this practice, about 20 continue with this requirement. Aircraft disinsection is sanctioned by international law with the World Health Organization (WHO) publishing general procedural guidelines in the International Health Regulations (IHR). There are currently four acceptable procedures: blocks away, top of descent, on arrival, and residual. A 2% pyrethrum solution, a naturally occurring substance found in the chrysanthemum flower, or several synthetic pyrethroids, are the recommended agents because they are extremely effective insecticides which pose minimal health risks. Although the use of insecticides for aircraft disinsection is controversial, national policies compelling this requirement must be respected. This paper will explore the background of aircraft disinsection, the procedures, the types of agents, and the toxicity. If aircraft disinsection is regulatory policy, it should be done in accordance with WHO procedures. Residual application is probably the most efficacious method. The use of air curtains or plastic strips should be explored as an alternative to the use of chemicals.

Aerospace Medicine↗