Aviat Space Envir Md
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Aviat Space Envir Md · Nov 1996
The effect of a headset leakage on speech intelligibility in helicopter noise.
Speech intelligibility tests in recorded helicopter noise were performed on 10 subjects with normal hearing, using a Peltor aviation headset. The subjects acted as their own controls, a pair of sunglasses being the only variable factor. ⋯ Our findings show that even small leakages due to fitting of the headset or helmet should be avoided, particularly in noisy aircraft with communication-demanding mission profiles.
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Aviat Space Envir Md · Nov 1996
Instrument flying performance after G-induced loss of consciousness.
While both the USAF and the USN have characterized the immediate sequelae of G-induced loss of consciousness (G-LOC) as resulting in approximately 24 s of incapacitation, very little is known about the effect of a G-LOC immediately after this incapacitation period. This study is an attempt to determine the effect of G-LOC on instrument flying performance immediately after G-LOC. ⋯ Whether or not a pilot's flying performance is affected after G-LOC may be related to the severity of the G-LOC. Some pilots may experience seizure activity relating to the G-LOC with a resulting sustained performance decrement that appears to resolve by 45 min. It is possible that some of the other G-LOC pilots in the study might have had measurable performance decrements if we had been able to have them fly the task while they were still in the gondola (i.e., immediately after the G-LOC).
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Aviat Space Envir Md · Oct 1996
Performance of color-dependent air traffic control tasks as a function of color vision deficiency.
This experiment was conducted to validate the requirement for normal color vision in Air Traffic Control Specialist (ATCS) personnel who work at en route center, terminal, and Flight Service Station (FSS) facilities. ⋯ We conclude that these findings provide support for the requirement of normal color vision in the initial medical screening of ATCS personnel.
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Situation Awareness (SA) is a crucial factor in effective decision-making, especially in the dynamic flight environment. Consequently, an understanding of the types of SA errors that occur in this environment is beneficial. ⋯ These results give an indication of the types and frequency of SA errors that occur in aviation, with failure to monitor or observe available information forming the largest single category. Many other causal factors are also indicated, however, including vigilance, automation problems, and poor mental models.
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Aviat Space Envir Md · May 1996
Clinical Trial Controlled Clinical TrialHypercapnia lowers the shivering threshold and increases core cooling rate in humans.
Hypercapnia, which may be encountered during diving operations or by patients under general anesthesia with spontaneous respiration, alters the basic thermoregulatory responses of animals and humans. In cold-exposed animals, 3-10% inspired CO2 impairs thermal homeostasis by attenuating shivering and promoting heat loss through peripheral vasodilation. Experimental results with humans are equivocal. ⋯ Therefore, hypercapnia enhances the core cooling rate during mild cold stress. This may be attributed in part to a delay in shivering onset, as well as increased respiratory heat loss during hypercapnic hyperventilation.