This document has been declared "CANCELLED" as of December 2008 and has been superseded by ARP 1590. By this action, this document will remain listed in the Numerical Section of the Aerospace Standards Index noting that it is superseded by ARP 1590.This standard presents a recommended part numbering scheme for fluid system component parts which may require complex standard numbers. Standardizing on certain numbering systems provides for numbering simplicity, ease of interchangeability and supersession (when required) and standardization and limitation of usable codes within a fifteen-character limitation.