This SAE Aerospace Information Report (AIR) contains information on the thermal design requirements of airborne avionic systems used in military airborne applications. Methods are explored which are commonly used to provide thermal control of avionic systems. Both air and liquid cooled systems are discussed.This document describes guidelines for the configuration and design of military aircraft subsystems that provide cooling to airborne avionic systems and recommendations for the basic cooling concepts, analytical methods and design practices used for the thermal design of those airborne avionic systems. The efficient design of the interface between the airframe system and the avionic system is considered.