One-Dimensional Human Thermoregulatory Model of Fighter Pilots in Cockpit Environments

Abstract: During flight missions, fighter pilots are in general exposed to vast amounts of stress including mild hypoxia, vibrations, high accelerations, and thermal discomfort. It is interesting to predict potential risks with a certain mission or flight case due to these stresses to increase safety for fighter pilots. The most predominant risk is typically thermal discomfort which can lead to serious health concerns. Extensive exposure to high or low temperature in combination with a demanding work situation weakens the physical and mental state of the pilot and can eventually lead to life-threatening conditions. One method to estimate the physical and mental state of a person is to measure the body core temperature. The body core temperature cannot be measured continuously during flight and needs to be estimated by using for instance a human thermoregulatory model. In this study, a model of the human thermoregulatory system and the cockpit environment is developed. Current thermoregulatory models are not customized for fighter pilots but a model developed by Fiala et al. in 2001, which has previously shown good performance in both cold and warm environments as well as for various activation levels for the studied person, is used as a theoretical foundation. Clothing layers are implemented in the model corresponding to clothes used by pilots in the Swedish air force flying the fighter aircraft Gripen E in warm outside conditions. Cooling garments and air conditioning systems as well as avionics, canopy, and cockpit air are included in the model to get a realistic description of the cockpit environment. Input to the model is a flight case containing data with altitude and velocity of the fighter during a mission. human heat transfer; body temperature regulation; physiological model;cooling garment; cockpit modeling