This document has been declared "Stabilized" and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability or technical requirements. New technology may exist.This report provides information on the design and use of aircraft oxygen systems. It explains the physiological oxygen requirements of the human body in both a normal environment and in an hypoxic environment.It includes an overview of the continuous flow, demand and pressure demand, and liquid oxygen systems. A basic understanding of how each system operates is then specifically addressed in its own titled section.The charts, tables and schematics provide a specific example of a theoretical oxygen system design and the calculations shown how that system would meet the regulations established by the FAR's. A comprehensive overview of the theoretical oxygen requirements of the human body at altitude is also provided.A detailed list of specifications and standards applicable to aircraft oxygen systems is included.