Physiological Impact of Wearing Aircrew Chemical Defense Protective Ensembles While Flying the UH-1H in Hot Weather.

摘要

Six recent graduates of initial entry rotary wing training flew a UH-1H for up to 4 hours while wearing each of three clothing ensembles. Each aviator wore the standard flight suit, the US chemical defense (CD) ensemble, and the United Kingdom CD ensemble in hot weather (mean WBGT 29 C). Skin temperatures (chest, thigh, upper arm and calf), rectal temperature, heart rate, and preflight and postflight body weights were recorded. Three of six aviators terminated flight for medical reasons (heart rates > 140 bpm or nausea) while wearing the US ensemble. Well acclimatized aviators in this study who did not preflight and drank water every hour were able to fly for at least 2 hours (one fuel load) before the most susceptible subjects had to terminate flight due to heat stress. heart rate was the most susceptible subjects had to terminate flight due to heat stress. Heat rate was the most sensitive indicator of this stress. In this study, these susceptible subjects tended to be older and heavier. Although no measures of cardiopulmonary fitness (e.g., V sub 02 max) were made, it may be that these susceptible subjects were somewhat less fit. The US ensemble was somewhat more stressful than the UK or standard ensembles. Subjectively all subjects preferred the AR5 respirator to the M24 mask, were divided on overgarment vs undergarment, and most disliked the US overboots. As a caveat it should be stated that fitness alone is not likely to be sufficient to overcome the heat stress induced by these ensembles as flight times are extended. Some sort of cooling will probably be needed. (Author)