Core Viewpoint - The successful commercial operation of the C919 large passenger aircraft marks a significant milestone for China's aviation industry, showcasing the collaborative efforts of over 200 domestic companies and numerous educational institutions in the development of this aircraft, which has achieved over 50% localization in its key materials [1][4]. Group 1: Domestic Supplier Distribution - The C919 aircraft employs a "main manufacturer-supplier" production model similar to that of Boeing and Airbus, with the overall design completed by COMAC and various components designed and produced in collaboration with other enterprises [1]. - A total of over 200 companies from 22 provinces in China are involved in the development of the C919, with Shanghai serving as the assembly center and a complete industrial chain layout radiating to regions such as the Yangtze River Delta, Southwest, and Northeast [3]. Group 2: Key Material Supply - The material supply chain for the C919 consists of three key material systems: titanium alloy, aluminum-lithium alloy, and composite materials, with domestic suppliers achieving significant technological breakthroughs [4]. - Titanium alloy, supplied by BaoTi Group, constitutes 9.3% of the C919's structure, with over 130 tons of various specifications produced [4]. - Southwest Aluminum Group provides over 600 aluminum alloy components, utilizing third-generation aluminum-lithium alloy, which improves yield strength by 40% and reduces component density by 3% [4]. - Composite materials account for 11.5% of the C919, with applications in critical structural components [4]. Group 3: Role of Private Enterprises - Private enterprises play a crucial role in the C919 supply chain, with Xizi United Holdings being the only private company among the primary structural suppliers [6]. - Zhejiang Xizi Shibori Aviation Industry Co., Ltd. is responsible for the complex design and manufacturing of the aircraft doors, while Zhejiang Huaron Aviation Equipment Co., Ltd. provides essential tooling for composite materials [7]. - Zhejiang Meidun Protection Technology Co., Ltd. supplies engine insulation materials that significantly reduce high temperatures, showcasing the diversity and innovation within the supply chain [7]. Group 4: Material Innovation Breakthroughs - The C919 has achieved several major breakthroughs in material applications, including the use of third-generation aluminum-lithium alloy for the front fuselage, which required extensive testing and new manufacturing facilities [8]. - Advanced third-generation carbon fiber composite materials are utilized in critical structural areas, marking a first in domestic civil aircraft development [8]. - Chongqing Zaiseng Technology Co., Ltd. has developed "aircraft cotton," a unique product designed for weight reduction and space-saving, filling a domestic gap in the market [8]. Group 5: Supply Chain Security and Challenges - Despite significant achievements, the C919 supply chain faces challenges, particularly in international airworthiness certification, which is essential for global market access [9]. - Key material technologies still require breakthroughs, especially in specialized materials and onboard systems [10]. - As the C919 enters mass production, there is a pressing need to enhance production capacity to meet delivery requirements, with plans for significant capacity increases by 2025 [10].