Exploratory Study Of Pilot Performance During High Ambient Temperatures/Humidity

Historically, the design and development of aircraft environmental systems have been largely inadequate because of the lack of suitable quantifiable data describing human performance changes under high cabin temperatures. It was the purpose of this study to explore techniques which could provide this quantifiable information and to assess actual pilot performance in a hot environment. A prototype OH-6A helicopter was instrumented as the test vehicle. Four experienced pilots flew precision air patterns, observed and recorded ground targets, and performed normal flight duties of monitoring flight and engine instruments and other tasks during two-hour flight test periods. Four separate clothing configurations were worn by the pilots during the study. During each flight two observers simultaneously measured pilot physiological and psychological performance as well as the crew station environment. The physiological performance was measured by heart rate, skin and rectal temperatures, and perspiration weight loss. Measures of psychological performance were defined as photopanel exposures of the instrument panel during precision flight patterns, response and reaction time measures, ground target identification, and assessments of subjective comments during post-flight debriefings. Both airborne and ground environmental measures by Dry Bulb, Wet Bulb aud Globe Temperature were taken to determine the Wet Bulb Globe Temperature (WBGT) Index of heat stress, which provided a base by which pilot performance changes were compared.