A proposed Walk-Around Sleeping Bag for inclusion in the F-111 and survival kits for other aircraft was evaluated in a cold chamber with temperatures below -40° F. Rectal temperature drops of 1° C were experienced with a mean heat debt of 57 kcal/m2 during six-hour exposures with human subjects. It was shown that insulation was insufficient and that larger men could not don this garment. Recommendations were made to drop consideration of this garment in favor of standard Air Force down-filled arctic survival equipment.