:The INTEGRATED SUBSYSTEM combines the functions of the auxiliary power, main-engine starting, emergency power, environmental control, and thermal management. The integrated subsystem is a closed air-cycle system that utilizes a three-wheel turbo-machine to provide power and cooling for the functions above. The primary integrated-subsystem heat sink is the engine fan air, thus avoiding ram air systems, which increase aircraft drag and signature.Lockheed Martin has baselined the integrated subsystem for its next-generation fighter aircraft and has conducted additional studies to validate and refine this concept. Coordinated efforts between Lockheed and our suppliers have provided the data necessary to predict system performance and to size the integrated subsystem suite. When traded against segregated subsystems, the integrated subsystem shows both improved performance potential and a significant weight reduction at the subsystem level. In addition, a substantial reduction in subsystem volume is achieved, this volume may be used for additional fuel volume or a reduction in the overall size of the aircraft.