This International Standard specifies performance and quality requirements for the qualification and manufacture of standard 24° cone fittings and manufacture of 24° cone fittings to ensure reliable performance or equivalent inch-dimensioned fitting ends to ensure reliable performance in aircraft hydraulic systems. This International Standard specifies baseline criteria for the design and manufacture of system fittings that are qualification-tested on engines. This International Standard covers fittings of the temperature types and pressure classes specified in ISO 6771.