Regulations and Application of Aeroengine Airworthiness Exemption

Exemption is a way for aeroengines to obtain airworthiness type certification, which can exempt aviation products from obligation to comply with a certain regulation directly on the premise of proving equivalent level of safety. The regulation requirements for exemption home and abroad were introduced in this paper. The exemption cases of aeroengines recorded in the FAA exemption system in recent decades were analyzed. Through an in-depth analysis of documents approved by the authorities, five main types of applications for exemption were summarized as inherited, optimized, deviated, unverifiable and restricted. The frequency and difficulty of all kinds of exemption types are analyzed. Finally, an in-depth discussion on the application of exemption was made, including the application object of various exemption methods, the relationship among them and the priority of application. This study is the first time in China to conduct a full-process and multi-level analysis of airworthiness exemption methods, which fills the gap in domestic aeroengine airworthiness exemption research and provides a reference for domestic self-developed aeroengines to apply for airworthiness exemption.