这是14份相关文件中的第一份。14个文件集是在入门级编写的，适用于任何想了解飞机氧气系统基本知识的人，特别是最近被分配到飞机氧气系统的工程师。

This is the first document of a set of fourteen related documents. The fourteen-document set is written at an introductory level, suitable for anyone who would like to understand the basics of oxygen systems in aircraft, and specifically for the engineer who has just recently been assigned to aircraft oxygen systems.