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M G Braithwaite

Publications and source records attributed to M G Braithwaite.

11 recordsLinked to original sources
PubMed1998

An evaluation of the British Army spatial disorientation sortie in U.S. Army aviation.

BACKGROUND: Following didactic instruction, most aircrew are able to experience some of the disorienting illusions and limitations of the orientation senses in a variety of ground-based devices. In order to reinforce instruction in spatial disorientation (SD) within the environment in which they operate, British Army Air Corps helicopter pilots also receive an airborne demonstration of the limitations of their orientation senses prior to rotary-wing instrument flight training. The objective of this assessment was to determine whether the SD demonstration sortie would be an effective adjunct in training aircrew in SD in the U.S. Army. METHODS: There were 45 aviators and training personnel who experienced the sortie and gave their opinion in questionnaires. RESULTS: The following conclusions were made: the maneuvers performed in the SD demonstration sortie, and the sortie overall, were extremely effective at demonstrating the limitations of the orientation senses; the SD sortie attracted a significantly higher rating in its effectiveness to train aviators in SD than all the currently available methods; the introduction of the sortie into the initial flight training syllabus would be a distinct enhancement to the SD training of aviators and associated personnel; and the introduction of the sortie into refresher training in field units would also be an advantage. CONCLUSION: Other services are encouraged to consider this enhancement to the SD training of aviators.

Aerospace Medicine↗
PubMed1998

Flight simulator evaluation of a novel flight instrument display to minimize the risks of spatial disorientation.

BACKGROUND: Spatial disorientation (SD) in flight remains a major source of attrition. Many SD accidents would occur regardless of the instrument display in use, since the aircrew are simply not looking at the instruments. However, there are a number of accidents which might be amenable to improved instrument displays. In an attempt to improve maintenance and reattainment of correct orientation with a reduced cognitive workload, a novel instrument display has been developed. This paper describes an assessment of the display in a UH-60 helicopter flight simulator. HYPOTHESIS: This study tested the hypothesis that during instrument flight and recovery from unusual attitudes, the novel display permits a more accurate maintenance and reestablishment of flight parameters than the standard flight instruments. METHODS: There were 16 male aviators who flew a simulated instrument flight profile and recovery from unusual attitudes using both the standard flight instruments and the novel display. The two display formats were tested both with and without a secondary task. RESULTS: When compared with the standard instruments, both control of flight parameters and recovery from unusual attitudes were significantly improved when using the novel display. Analysis of the secondary task scores showed that cognitive workload was reduced when using the novel display compared with the standard instruments. CONCLUSIONS: Results from all aspects of the assessment indicated benefits of the new display. Future testing should be carried out during real flight, and the display should be further developed to be used in a head-up or helmet-mounted device.

Adult↗
PubMed1998

Spatial disorientation in U.S. Army rotary-wing operations.

This paper describes two surveys concerning spatial disorientation (SD) in U.S. Army rotary-wing operations that sought to assess the hazard and to identify recommendations to control it. One survey was of accident records, and the other was of aircrew experiences. Both surveys highlighted the magnitude of the problem. The accident survey showed that 30% of class A to C accidents involved SD as a significant factor, while the aircrew survey showed that 78% of aircrews have been disoriented (8% to the extent that flight safety was threatened). Both surveys showed a significant increase in SD associated with combat operations. Several differences between the two surveys were noted: 90% of the reviewed accidents were thought to involve type I (unrecognized) SD compared with only 43% of the reported incidents; both pilots in a particular aircraft were considered to have been disoriented in at least 59% of accidents compared with 23% of incidents; sudden loss of visual cues ("brownout," "whiteout," or inadvertent entry to instrument meteorological conditions) accounted for 25% of SD accidents compared with 13% of incidents; and 62% of the accidents occurred at night compared with only 36% of incidents. Neither survey showed any association between SD and fatigue or other human factors. The results of both surveys suggested that crew coordination, alerting devices (e.g., audio warnings on the radar altimeter), flight information displays, and autopilot functions would be good targets for improvement.

Accidents, Aviation↗
PubMed1998

The hazard of spatial disorientation during helicopter flight using night vision devices.

INTRODUCTION: Night Vision Devices (NVDs) provide an enormous advantage to the operational effectiveness of military helicopter flying by permitting flight throughout the night. However, compared with daytime flight, many of the depth perception and orientational cues are severely degraded. These degraded cues predispose aviators to spatial disorientation (SD), which is a serious drawback of these devices. METHODS: As part of an overall analysis of Army helicopter accidents to assess the impact of SD on military flying, we scrutinized the class A-C mishap reports involving night-aided flight from 1987 to 1995. The accidents were classified according to the role of SD by three independent assessors, with the SD group further analyzed to determine associated factors and possible countermeasures. RESULTS: Almost 43% of all SD-related accidents in this series occurred during flight using NVDs, whereas only 13% of non-SD accidents involved NVDs. An examination of the SD accident rates per 100,000 flying hours revealed a significant difference between the rate for day flying and the rate for flight using NVDs (mean rate for daytime flight = 1.66, mean rate for NVD flight = 9.00, p < 0.001). The most important factors associated with these accidents were related to equipment limitations, distraction from the task, and training or procedural inadequacies. CONCLUSIONS: SD remains an important source of attrition of Army aircraft. The more than fivefold increase in risk associated with NVD flight is of serious concern. The associated factors and suggested countermeasures should be urgently addressed.

Accidents, Aviation↗
PubMed1998

The optokinetic cervico reflex during simulated helicopter flight.

INTRODUCTION: The optokinetic cervico reflex (OKCR) is a recently hypothesized, visually driven reflex that serves to stabilize the image of the external horizon on the retina during roll maneuvers in high-performance aircraft. Although reported anecdotally, head tilt during helicopter flight has not been studied formally. Such research is required to determine the full impact and significance that it may have on the flying performance of a rotary-wing aviator. OBJECTIVE: The aim of this study was to investigate the relationship between horizon position and the perception of orientation and, thus, to generate vital information to assess whether OKCR plays an important role in spatial disorientation. HYPOTHESIS: Pilots of rotary-wing aircraft will exhibit the OKCR. METHODS: A UH-60 flight simulator study, with 20 volunteer pilots participating, was performed to examine the effects of this reflex during day flight and during flight with night vision goggles (NVGs). RESULTS: The results confirm that the OKCR occurs during simulated helicopter flight, both with and without NVGs. As with previous studies, head roll increased during flight under visual meteorological conditions in relation to an increasing aircraft roll angle up to a maximum sustainable level and then remained constant. Head roll did not occur during flight under instrument meteorological conditions. CONCLUSION: The presence of the OKCR will impact rotary-wing operations. Various aspects are discussed, and recommendations are made for future research.

Adult↗
PubMed1997

The British Army Air Corps in-flight spatial disorientation demonstration sortie.

Following didactic instruction, most aircrew are able to experience some of the disorientating illusions and limitations of the orientational senses in a variety of ground-based devices. In order to reinforce instruction in spatial disorientation (SD) within the environment in which they operate, British Army Air Corps helicopter pilots also receive an airborne demonstration of the limitations of their orientation senses. Since 1982, a specific SD sortie has been programmed towards the end of the basic rotary-wing phase of flight training approximately 6 weeks after the aeromedical training module, and before students commence rotary-wing instrument flight training. Refresher sorties are flown every 4 years. The conduct of the SD sortie is described in detail. Analysis of helicopter accidents demonstrates that this training is operationally effective by contributing towards the reduction of SD-related mishaps. It is cost-effective and the addition of this type of in-flight demonstration to the aeromedical training syllabus is regarded as being of great value to British Army helicopter aircrew. Similar instruction could be readily adopted by other services.

Accidents, Aviation↗
PubMed1990

Simulator sickness in an army simulator.

Simulator sickness describes a symptom reported by aircrew during or after flight simulator training. Some features are common to motion sickness but others, which are unusual during real flight, are believed to result specifically from the simulator environment. This paper describes the results of a questionnaire study examining the incidence and factors influencing simulator sickness in any army training system. Case histories are described and conclusions drawn with respect to health and safety, training and the effect on flight operations. One hundred and fifteen aircrew were registered in the questionnaire study. Data were collected from a history questionnaire, a post-sortie report and a delayed report form. Sixty-nine per cent of aircrew gave a history of symptoms in the simulator and 59.9 per cent experienced at least one symptom during the study period although few symptoms were rated as being other than slight. Only 3.6 per cent of subjects reported symptoms of disequilibrium. Comparative analysis of the results was performed after scoring symptoms to produce a sickness rating. This showed: association between simulator-induced sickness and greater flying experience; adaptation to the simulator environment; a history of sea sickness may predict susceptibility to simulator sickness; and no association of crew role and simulator sickness. Although some authorities believe simulator sickness to be a potential flight safety hazard there was little evidence from this study. Guidelines for the prevention of the problem are presented now that many factors have been identified. A general policy to 'ground' aircrew for a period following simulator training is not necessary, but severe cases should be assessed individually.

Adult↗
PubMed1983

Prophylaxis of hepatitis A with immune globulin.

Hepatitis has been outstanding as a military disease. Although it was not recognized as a commonplace illness in civilian populations until 35 years ago, hepatitis has been a problem in all major wars during the last two centuries. Much of the knowledge of this disease has been obtained by investigation of outbreaks in military populations. The military importance of hepatitis during World War II led to studies of this disorder which defined it as a distinct clinical entity and delineated both the epidemiology and its mode of transmission.

Adult↗