To define optimum standards of design, construction and performance for Diluter Demand, Automatic Pressure Breathing, Oxygen Regulators. AS 861, 'Minimum General Standards for Oxygen Systems,' is applicable as supplemented by this specification. This document supersedes in part AS 463, 12-15-56, which is cancelled. This specification covers two types of Diluter Demand, Automatic Pressure Breathing, Oxygen Regulators for use in civil type aircraft. The intent is that the regulators be of two configurations, operable at inlet pressures of 40 to 90 psig and 50 to 150 psig.