This SAE Aerospace Recommended Practice (ARP) establishes the factors which should be considered in the design and installation of a hydraulic system that is fitted to a commercial transport aircraft. The purpose of this document is to provide in one document, information and guidelines to the designers of commercial aircraft hydraulic systems and components and to the engineering staff of airlines, including: a. reliability and maintainability requirements; b. Federal Aviation Regulations (FAR)/Joint Airworthiness Requirements (JAR) airworthiness regulations that are applicable to hydraulic systems; and c. design and installation practices.