The Aerospace Standard (AS) presents a system of graphic symbols intended primarily for usage in hydraulic an dpneumatic system schematic diagrams for all types of aircraft. It is also considered suitable for marine vehicles and other applications and for ancillary documents where schematics are required. Individual graphic symbols shown herein are also considered suitable for use in conjunction with other types of symbols. This AS is intended to promote industry wide acceptance and understanding of uniform standards and employs, where possible, symbols which are internationally recognized.