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At least 145 records · Page 8Linked to original sources
PubMed1994

Pilot-related factors in aircraft crashes: a review of epidemiologic studies.

The epidemiologic studies of pilot-related factors in aircraft crashes are reviewed with regard to: 1) study design and methods; 2) major findings; and 3) data and methodological issues. In the last 60 years, numerous studies have been conducted to examine the relationships of pilot characteristics to the risk of aircraft crashes. Much attention has been paid to pilots' medical condition, age, flight experience, and alcohol use. Most studies were based on crash analysis, using case reports and case series. Few studies have applied a formal, rigorous epidemiologic design. Planned case-control and cohort studies are extremely rare. In some cases, the deficiencies in study design and data analysis have resulted in controversial findings. More epidemiologic studies using state-of-the-art methodology are needed to identify various risk factors of aircraft crashes, to better understand the interrelationships among pilot, aircraft, and environment, and to develop and assess safety policies and other intervention programs.

Accidents, Aviation↗
PubMed1977

Characteristics in the atmosphere of long-range transport aircraft cabins.

In the long run, the fatigue in aircrews performing frequent, long-range flights is linked to factors connected to the aircraft, such as noise, temperature, cabin pressure, atmosphere quality, and flight characteristics. These are the factors inherent to the aircraft which we have investigated during six long-range flights without time zone changes in DC-8 and DC-10 aircraft of the U.T.A. Cie. The results show that none of the pollutants researched reach doses considered hazardous by FAR 25 or by French legislation. This fact is due to the effective ventilation in the cabins. In flight, thermal comfort is limited by a too-low hygrometry RH = 12%. Even in a modern aircraft, the noise level remains high, but acoustical energy is spread over the less detrimental frequencies.

Air Pollutants↗
PubMed1991

Raptor responses to low-level jet aircraft and sonic booms.

We estimated effects of low-level military jet aircraft and mid- to high-altitude sonic booms (actual and simulated) on nesting peregrine falcons (Falco peregrinus) and seven other raptors by observing their responses to test stimuli, determining nesting success for the test year, and evaluating site reoccupancy rates for the year following the tests. Frequent and nearby jet aircraft passes: (1) sometimes noticeably alarmed birds, (2) occasionally caused birds to fly from perches or eyries, (3) most often evoked only minimal responses, and (4) were never associated with reproductive failure. Similarly, responses to real and simulated mid- to high-altitude sonic booms were often minimal and never appeared productivity limiting. Eighteen (95%) of 19 nest sites subjected to low-level jet flights and/or simulated sonic booms in 1980 fledged young during that year. Eighteen (95%) of 19 sites disturbed in 1980 were reoccupied by pairs or lone birds of the same species in 1981. We subjected four pairs of prairie falcons (Falco mexicanus) to low-level aircraft at ad libitum levels during the courtship and incubation phases when adults were most likely to abandon: all four eyries fledged young. From heart rate (HR) data taken via a telemetering egg at another prairie falcon eyrie, we determined that stimulus-induced HR alterations were comparable to rate changes for birds settling to incubate following flight. While encouraging, our findings cannot be taken as conclusive evidence that jet flights and/or sonic booms will have no long-term negative effects for other raptor species or for other areas. In addition, we did not experiment with totally naive wild adults, rotary-winged aircraft, or low-level sonic booms.

Journal Article↗
PubMed1996

Fractional effective dose model for post-crash aircraft survivability.

The development of a survival model for post-crash aircraft cabin fires is described in this paper. Its development is based on an extensive review of the literature on the toxicity of combustion gases and on thermal hazards. This model is to be used as a predictive tool to gauge human survivability in full scale aircraft cabin fire tests. The extensive literature search was conducted for carbon monoxide (CO), carbon dioxide (CO2), hydrogen cyanide (HCN), low oxygen, hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen bromide (HBr), nitrogen dioxide (NO2), sulfur dioxide (SO2), acrolein (CH2CHCHO), and heat exposures. Those studies by various investigators of exposures to single and mixed gases on humans, primates, rats, and mice at different physical activity levels were compared. Regression equations were derived from those studies to give the best fit to the gas exposure concentration and duration data. The equation judged to best model the human escaping from an aircraft cabin was selected for each gas. This survival model uses incapacitation data to obtain a fractional effective dose (FED) for incapacitation (FED(I)) and lethality data, inclusive of post exposure deaths, to obtain a FED for lethality (FED(L)). The exposure time required for either FED(I) or FED(L) to reach unity, using a projected set of gas concentrations, represents the exposure time available to escape from the specified fire environment or to survive post exposure, respectively. The effect of CO2 in increasing the uptake of other gases was factored into the concentration term in the FED equation for all gases with the exception of CO2 and oxygen. Higher respiratory minute volumes due to CO2 exposure were found to be an important factor in predicting the time available to escape. This FED-based model can be applied to the evaluation of the toxicity of smoke in computer modeling of aircraft fire situations.

Accidents, Aviation↗
PubMed2001

Factors associated with pilot fatality in work-related aircraft crashes, Alaska, 1990-1999.

Work-related aircraft crashes are the leading cause of occupational fatality in Alaska, with civilian pilots having the highest fatality rate (410/100,000/year). To identify factors affecting survivability, the authors examined work-related aircraft crashes that occurred in Alaska in the 1990s (1990-1999), comparing crashes with pilot fatalities to crashes in which the pilot survived. Using data from National Transportation Safety Board reports, the authors carried out logistic regression analysis with the following variables: age, flight experience, use of a shoulder restraint, weather conditions (visual flight vs. instrument flight), light conditions (daylight vs. darkness), type of aircraft (airplane vs. helicopter), postcrash fire, crash location (airport vs. elsewhere), and state of residence. In the main-effects model, significant associations were found between fatality and postcrash fire (adjusted odds ratio (AOR) = 6.43, 95% confidence interval (CI): 2.38, 17.37), poor weather (AOR = 4.11, 95% CI: 2.15, 7.87), and non-Alaska resident status (AOR = 2.10, 95% CI: 1.05, 4.20). Protective effects were seen for shoulder restraint use (AOR = 0.40, 95% CI: 0.21, 0.77) and daylight versus darkness (AOR = 0.50, 95% CI: 0.25, 0.99). The finding that state of residence was associated with survivability offers new information on pilot survivability in work-related aircraft crashes in Alaska. These results may be useful in targeting safety interventions for pilots who fly occupationally in Alaska or in similar environments.

Accidents, Aviation↗
PubMed2005

Aircraft-protection radar for use with atmospheric lidars.

A modified X-band radar system designed to detect aircraft during atmospheric lidar operations is described and characterized. The capability of the radar to identify aircraft approaching from a variety of directions was tested, and first detections were found to occur between the -10 and -3 dB perimeters of the gain horn's antenna pattern. A model based on the radar equation projects the performance of the radar for different sizes of aircraft and at different altitude levels. Risk analysis indicates that the probability of accidently illuminating an aircraft with the laser beam during joint lidar-radar operations is low.

Journal Article↗
PubMed1999

Aircraft control forces and EMG activity: comparison of novice and experienced pilots during simulated take-off and landing.

BACKGROUND: Flying an aircraft requires a considerable degree of coordination, particularly during activities such as takeoff and landing. No studies have examined the magnitude and phasing of muscle activity required to fly an aircraft. The aim of this study was to examine the muscle activation patterns and control forces of novice and experienced pilots during simulated flight. METHODS: Twelve experienced and nine novice pilots were tested on an Aermacchi flight simulator while performing a randomized set of take-off and landing maneuvers. Four different runaway trim settings were used to increase the difficulty of the landings (elevator-up, elevator-down, aileron-left, and aileron-right). Variables recorded included aircraft attitude, pilot applied forces, and electromyographic (EMG) activity. Discriminant function analysis was used to distinguish between novice and experienced pilots. RESULTS: Across all landings, wrist flexors and wrist extensors were the predominant muscles used, with EMG activity consistently around 20-30% maximum voluntary contraction (MVC). In respect to differences in EMG activity between novice and experienced pilots, novices had significantly more activity in wrist extensors during all landings. In contrast, experienced pilots had consistently more vastus lateralis activity for all landings than did novice pilots. Over all landings and take-off, 89.5% of pilots were correctly classified as novice or experienced. When the maneuvers were analyzed individually, normal, elevator-down, and aileron-left landings were the most accurate maneuvers for pilot prediction. EMG and force variables were more important than aircraft attitude in discriminating between novice and experienced pilots (83%, 79%, and 65%, respectively). CONCLUSION: The consistency of the finding that EMG activity and control forces are accurate discriminators of pilot experience is indicative of underlying differences in neuromuscular control strategies between novice and experienced pilots.

Adult↗
PubMed2000

Medication use in a group of aircraft mechanics.

BACKGROUND: Aeromedical studies of human factors have focused on the pilot and pilot error rather than on aircraft maintenance workers and maintenance error. This is a report of a survey on medication use in a group of U.S. Air Force aircraft mechanics. METHODS: A questionnaire was used to retrospectively examine aircraft mechanic medication use, side effects experienced, and return to work. RESULTS: Of those surveyed, 67% (26/39) returned to work while taking medication that could potentially impair job performance. CONCLUSION: For flying safety reasons, occupational medicine education for aircraft mechanics and their supervisors should address on-the-job use of prescribed medication and self-medication.

Accidents, Aviation↗
PubMed2002

Electromagnetic interference in pacemakers in single-engine fixed-wing aircraft: a European perspective.

BACKGROUND: The aim of this study is to evaluate the possible interference by avionics with cardiac pacemakers of aircrew or passengers/patients in single-engine fixed-wing aircraft. Pacemakers which are implanted in patients are in part electromagnetic sensors and can be subject to interference from various external electromagnetic sources. Although modern (chip-based) pacemakers are effectively shielded from electromagnetic interference (EMI), the magnitude of electromagnetic radiation in cockpits of general aviation aircraft is higher and of a different nature than experienced in daily life. An increasing number of pacemaker-bearing individuals are being transported by air. However, the possible EMI with modern types of pacemakers during flight has not been investigated until now. METHOD: In order to evaluate the effect of EMI on five modern types of pacemakers in the cockpit environment of a single-engine fixed-wing aircraft, we have subjected the pacemakers, each implanted into an artificial thorax, to a series of test flights. Each pacemaker was equipped with data logging capabilities which were used for detection of possible EMI. After each flight, the pacemakers were examined by means of the dedicated programmers. In addition, two single lead ventricular pacemakers (VVI) were analyzed by means of beat-to-beat Holter recordings during two separate flights. This enabled an exact analysis of pacemaker function and of possible EMI. RESULTS: No effect of EMI could be detected in any of the pacemakers by interrogating their internal counters after the test flights. In addition, no signs of EMI could be detected on the Holter recordings of the VVI pacemakers. CONCLUSION: We conclude that modern pacemakers are unaffected by EMI in the cockpit environment of single-engine fixed-wing aircraft.

Aerospace Medicine↗
PubMed2002

Light aircraft crash--a case analysis of injuries.

BACKGROUND: As air travel increases and the number of commercial and non-commercial flights rises, so does the number of aircraft accidents. The improved safety standards of the aviation industry result in a growing number of survivors of aircraft crashes, but there are no management guidelines for the treatment of these survivors. OBJECTIVES: To present our experience in treating five survivors of a light aircraft crash that occurred in August 1995 near Jerusalem. RESULTS: All five survivors sustained vertebral column injuries, which was the only injury in most of the survivors. We discuss the mechanism of injury. CONCLUSIONS: Investigation of injuries' pattern in survivors of aircraft crash is important for establishing management protocols in trauma centers.

Accidents, Aviation↗
PubMed2002

Complaints and Annoyance caused by Aircraft Operations: Temporal Patterns and Individual Bias.

The impact of aircraft movements on annoyance in the local community surrounding a major international airport was assessed for (a) patterns of complaints for the year, month, day-of-the-week and time-of-day and (b) the frequency of complaining by individuals. Complaint data from Manchester Airport since 1991 and detailed analysis for 1998 were compared with associated information on noise monitoring and aircraft movements to investigate underlying biological and sociological patterns. The annual number of complaints peaked in 1996 when the 'Manchester Airport Second Runway Public Inquiry' was a major local issue and had a high profile in the local media. Since 1996 the number of flights has increased while the number of complaints has steadily fallen; from 50 to13 complaints per 1,000 movements from 1996 to 1999. Detailed inspection of the 1998 data revealed a total of 2072 noise complaints from 594 individuals but, while the majority of individuals complained once or twice, three individuals accounted for 41% of complaints. This introduced some bias into the results but there was; (a) a steady increase in complaints (per 1,000 movements) over the week from a low on Monday to a high on Saturday/Sunday; (b) a marked hourly variation over the 24 hours in both flight frequency (movements per hour) and complaints. However, the hourly patterns in flight frequency and complaints were clearly distinct. Calculations of the complaints per aircraft movement (a reflection of sensitivity) for each hour of the day showed a striking 24h pattern with twice as many complaints between 23.00 and 07.00 as the rest of the day (07.00-23.00). Late evening and night-time, particularly during the early hours of sleep, was the time of greatest sensitivity to aircraft, with or without the serial complainers. These results could be used to inform airport operations to minimize community disturbance.

Journal Article↗
PubMed1999

Assessment of the effectiveness of aircraft noise regulation.

A fundamental goal of aircraft noise regulation is control of the prevalence of noise-induced annoyance in airport communities. A common regulatory strategy is to identify values of long-term, time-weighted average aircraft noise exposure that may not be exceeded in the vicinity of airports without certain consequences. Noise exposure per se is neither the sole cause nor a perfect predictor of the annoyance of aircraft noise, however. Regulatory limitation of noise levels to certain values of favored noise metrics may therefore provide the appearance, rather than the substance, of a solution to problems of community reaction to aircraft noise. Response bias, as identified by Green and Fidell (1991), is a factor that exerts about as much influence on the observed prevalence of annoyance in communities as cumulative noise exposure. The importance of formal consideration of response bias in assessments of the adequacy of regulatory enforcement levels is addressed.

Journal Article↗
PubMed1978

Visual detection of commencement of aircraft takeoff runs.

Among other things, airport control towers should be sited so that controllers can readily detect whether an aircraft cleared for takeoff has commenced its takeoff run. The detection of movement is not well enough understood to enable confident prediction that a particular site for a tower will enable commencement of takeoff run to be easily observed. A field study was undertaken to establish detection times for commencement of takeoff run by groups of trained and trainee air traffic controllers and untrained observers. It was found that the mean response of observers occurs when the aircraft is displaced about 5' of arc, a value essentially independent of observer experience, observation distance, aircraft velocity, and the clarity with which the aircraft can be seen. Binoculars reduce the mean response time and response variability, although not as much as might be expected. Domains within which control towers can be located to enable detection of takeoff runs within 2 s and 4 s are defined.

Aerospace Medicine↗
PubMed1981

Recognition of the aircraft navigation light color code.

Navigation lights are a set of color-coded signals intended to indicate the presence, orientation, and relative direction of aircraft at night, and thereby reduce the possibility of midair collisions. It is known that some people with defective color vision have difficulty with quite simple codes. Accordingly, the International Civil Aviation Organization (ICAO) has recommended -- and most countries apply -- that applicants for pilot's licences demonstrate the ability to recognise colored light signals. Pilots who fail to meet this requirement are restricted from flying at night. But is the navigation light signal system effective? This paper concludes that the navigation light system at night can serve as a crude screening method to categorize intruder aircraft into "potential threat" and "no threat" categories. An experiment is described which shows that observers with normal color vision can determine intruder aircraft orientation and relative direction from the navigation light code with a moderately high degree of reliability. The reliability of judgement is, however, decreased by the higher-intensity presence lights also displayed by aircraft.

Accidents, Aviation↗
PubMed1996

Aircraft fires, smoke toxicity, and survival.

In-flight fires in modern aircraft are rare, but post-crash fires do occur. Cabin occupants frequently survive initial forces of such crashes but are incapacitated from smoke inhalation. According to an international study, there were 95 fire-related civil passenger aircraft accidents worldwide over a 26-yr period, claiming approximately 2400 lives. Between 1985 and 1991, about 16% (32 accidents) of all U.S. transport aircraft accidents involved fire and 22% (140 fatalities) of the deaths in these accidents resulted from fire/smoke toxicity. Our laboratory analyses of postmortem blood samples (1967-93) indicate that 360 individuals in 134 fatal fire-related civil aircraft (air carrier and general aviation) accidents had carboxyhemoglobin saturation levels (> or = 20%), with or without blood cyanide, high enough to impair performance. Combustion toxicology is now moving from a descriptive to a mechanistic phase. Methods for gas analyses have been developed and combustion/animal-exposure assemblies have been constructed. Material/fire-retardant toxicity and interactions between smoke gases are being studied. Relationships between gas exposure concentrations, blood levels, and incapacitation onset are being established in animal models. Continuing basic research in smoke toxicity will be necessary to understand its complexities, and thus enhance aviation safety and fire survival chances.

Accidents, Aviation↗
PubMed1996

U.S. naval aviation mishaps, 1977-92: differences between single- and dual-piloted aircraft.

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.

Accidents, Aviation↗
PubMed1977

Joint Committee on Aviation Pathology: XV. Medical investigation of fatalities from aircraft-accident burns.

Burn deaths of medicolegal importance are of two main types: those in which the circumstances suggest that the fire was used to commit or conceal a homicide or suicide, and those that involve the public interest or safety, such as an aircraft accident fire. The great majority of fire deaths are accidental, but it would be foolish for anyone, particularly an aircraft accident investigator, to assume anything about a death associated with an aircraft fire. This paper will discuss the medical investigation of fatalities from aircraft-accident burns.

Accidents, Aviation↗
PubMed1998

A modified crash brace position for aircraft passengers.

BACKGROUND: In 1989, a Boeing 737-400 aircraft crashed at Kegworth, near Nottingham, England. The survivors suffered a large number of pelvic and lower limb injuries, and approximately one-third of the passengers died. Subsequent research has suggested that the "brace-for-impact" position that passengers are advised to adopt prior to a crash landing might be modified in order to reduce the incidence of such injuries. The aim of this research was to evaluate biomechanically such a modified crash brace position. HYPOTHESIS: A modified brace position would help to prevent injuries to some passengers in the event of an impact aircraft accident. METHODS: Impact testing on forward-facing seats was performed at the Royal Air Force Institute of Aviation Medicine, Farnborough, England. Aircraft seats, mounted on a sled, were propelled down a track to impact at -16 Gx. A test dummy was used as the experimental model. Four dummy positions were investigated: a) upper torso braced forward and lower legs inclined slightly rearward of the vertical; b) upper torso braced forward and lower legs inclined forward; c) upper torso upright and lower legs inclined slightly rearward of the vertical; and d) upper torso upright and lower legs inclined forward. The impact pulses used were based on Federal Aviation Administration guidelines. Transducers located in the head, spine, and lower limbs of the dummy recorded the forces to which each body segment was exposed during the impact. These forces were compared for each brace position. RESULTS: Impact testing revealed that the risk of a head injury as defined by the head injury criterion was greater in the upright position than in the braced forward position. The risk of injury to the lower limbs was dependent in part on the flailing behavior of the limbs. Flailing did not occur when the dummy was placed in a braced, legs-back position. CONCLUSIONS: A modified brace position would involve passengers sitting with the upper torso inclined forward so that the passenger's head rested against the structure in front, if possible. The legs would be positioned with the feet resting on the floor in a position slightly behind the knee. The position differs from those previously recommended in that the feet are positioned behind the knee. This study suggests that such a position would reduce the potential for head and lower limb injury in some passengers, given that only a single seat type and single size of occupant have been evaluated. Standardization to such a position would improve passenger understanding and compliance. Such a recommendation should not obscure the fact that an occupant seated in a forward-facing aircraft seat, restrained only by a lap belt, is exposed to considerable forces during an impact accident. Such forces are capable of producing injuries in the femur, pelvis, and lumbar spine.

Accidents, Aviation↗