This document has been declasred "CANCELLED" as of April 2011 and has been superseded by ARP 1270. By this action, this document will remain listed in the Numerical Section of the Aerospace Standards index noting that it is superseded by ARP 1270.This specification covers the general requirements for cabin air safety valves for use in pressurized cabins of aircraft to prevent excess positive and negative pressures in the cabin and to provide a means of cabin pressure release in case of emergency.