Cooling for Aircrews

Advanced aircrew clothing for fighter aircraft integrates items required for protection from rife, hypoxia, acceleration and perhaps chemical weapons. However, such multifunction clothing tends to store body heat (1,4), and there is n growing consensus that some form of personal cooling is required for hot-climate flight operations to prevent discomfort and hyperthermia that might otherwise affect crew performance (3). The goal here is not simply extension of tolerance time for work in an excessively hot environment, but assurance of continuing optimal human pect"ormance. Crewmembers are required to perform multiple complex tasks in a setting where a minor error can have a critical impact on mission accomplishment or even lead to loss of an aircraft. Both airand liquid-cooled garments have been shown to improve human tolerance for work under hot conditions, and new fighter aircraft use both. The F-22 is equipped to supply cool air to a vest worn next to the pilot's skin, while the Eurofighter 2000 uses a thermoelectric heat sink (capacity 150W) to provide cool liquid to a tubing-lined undershirt. Crews of older aircraft such as the F-I5 and F-I6 can also benefit from the advanced clothing designs. The United States Air Force has recently funded development of a prototype system named APECS, which uSes a small radiator bolted to the existing air conditioning outlet to cool liquid for circulation through an undergarment. We report here on results from preliminary tests ofF-22 air and APECS liquid systems under hotweather flying conditions as simulated in a thermal chamber at Brooks Air Force Base (AFB).