This part will cover the following topics: general principles of aircraft maintenance for all civil aviation products including drones, the associated regulatory constraints, the economical, operational and safety aspects, business models and environmental challenges. Introduction to the main maintenance stakeholders, how they operate and which are their business relations. Maintenance cost and the aircraft end of life main aspects and related business models. The organization and the tools implemented by aircraft and systems manufacturers to support their products, the services business models and the future development related to the predictive maintenance. Fundamental principles of logistics management of spare parts in Civil and Military aviation. Aircraft operators’ organization and tasks for the technical management of the aircraft and its continuing airworthiness. MRO organization, infrastructure, tools, material, personnel and environmental aspects and how they can be optimized to reduce cost. The safety and Human Factors aspects relate to aircraft maintenance.