Overview - ISO 7169:2014 (24° cone separable tube fittings, inch/metric)
ISO 7169:2014 is an aerospace procurement specification for separable tube fittings with 24° cone ends used in aircraft fluid and hydraulic systems. It defines baseline performance, qualification and manufacture requirements for fittings intended to operate at high pressures (up to 3 000 psi / ~20 684 kPa and classification options up to 21 000 kPa / ~3 046 psi) and a range of temperature/pressure classes (per ISO 6771). The standard ensures that procured inch- or metric-dimensioned fittings match the quality and performance of parts used in original qualification testing - particularly for critical flight-control and engine-related hydraulic systems.
Key technical topics and requirements
- Scope & classification: Covers 24° cone separable tube fittings; defines Type A and Type B pressure systems (Type B applies when unspecified).
- Qualification: Manufacturer and product approval via independent (outside agency) procedures; fittings must pass the specified qualification tests.
- Materials: Acceptable materials (aluminium, carbon steel, corrosion-resistant steel, titanium) and equivalents; material selection tied to system pressure and temperature classes.
- Mechanical & pressure testing: Proof pressure, burst pressure and flexure (bending) tests are specified for different material and pressure classes. Impulse and fatigue-related testing are referenced.
- Design & manufacture:
- Thread standards: ISO 3161 (inch) and ISO 5855-3 (metric).
- Thread quality: rolled/cut/ground (except titanium) threads, surface finish requirement (Ra ≤ 3.2 µm) and limits on laps/seams.
- Fluid passages: drilling alignment and minimum free passage diameter requirements.
- Surface protection & identification, marking, workmanship and preparation for delivery (cleaning, packaging) are specified.
- Quality assurance: Inspection lot definitions, sampling (ISO 2859-1), record-keeping and conformance inspection/testing requirements.
Practical applications and users
- Ensures interchangeability, reliability and safety of hydraulic fittings used in:
- Aircraft primary/secondary flight controls
- Engine hydraulic systems and actuators
- High-performance aerospace fluid systems requiring proven qualification
- Typical users:
- Aerospace OEMs and tiered suppliers
- Fitting manufacturers and subcontractors
- Procurement/specification engineers and quality assurance inspectors
- Certification bodies and maintenance organizations
Related standards (normative references)
ISO 7169:2014 is essential for anyone specifying, procuring or manufacturing 24° cone aerospace tube fittings to ensure documented qualification, consistent manufacture and safe operation in critical hydraulic systems.
Open preview (PDF)Aerospace — Separable tube fittings for fluid systems, for 24 degree cones, for pressures up to 3 000 psi or 21 000 kPa — Procurement specification, inch/metric