This document has been declared "Stabilized" and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability or technical requirements. New technology may exist.This document outlines proposed test methods for the qualification of O-ring packings intended for use in aircraft hydraulic systems utilizing MIL-H-5606 fluid at rated service pressures up to 3000 psi and temperatures ranging from -65 to 275 F. It will also serve as the basis for the future preparation of a complete packing specification after basic elastomer types have been established by capability of performance.