Overview
ISO 9738:2000 - "Aerospace - Turnbarrels, for aircraft control wire rope - Dimensions and loads" - defines the characteristics, dimensions and loading data for turnbarrels used with aircraft control wire rope. The standard applies to turnbarrels manufactured in corrosion‑resistant steel, copper‑zinc alloy, aluminium alloy or low alloy steel, and specifies configuration, marking and surface‑treatment options to ensure interchangeability and airworthiness in aerospace applications.
Key topics and requirements
- Scope: Applicable to turnbarrels for aircraft control wire rope made from four material codes (A–D).
- Configuration and dimensions: Geometry, thread details and dimensional limits are specified graphically (Figure 1) and numerically (Table 1). The standard also provides mass and nominal breaking‑load references for relevant wire‑rope sizes.
- Materials: Four material codes:
- Code A: corrosion‑resistant steel
- Code B: copper‑zinc alloy
- Code C: aluminium alloy
- Code D: low alloy steel
- Surface treatments (codes and options):
- Passivation (P) or peening (G) for corrosion‑resistant steel
- No treatment (N) or peening (G) for copper‑zinc alloy
- Anodic oxidation (A) for aluminium alloy
- Cadmium plating for low alloy steel
- Annex A provides correspondence to national/industry equivalents (EN, SAE, MIL, QQ‑P).
- Designation and marking: Each turnbarrel must carry a standardized identity block and marking position per Figure 1; marking method is at the manufacturer’s option.
- Normative references: Relies on related aerospace standards (e.g., ISO 10955 technical specification for end fittings and turnbarrels, ISO 2020‑1 for wire rope dimensions and loads, ISO 9761 for locking clips).
- Technical specification: Manufacturing and quality requirements reference ISO 10955.
Applications and users
ISO 9738 is used by:
- Aerospace designers and systems engineers specifying control‑cable hardware for flight control systems.
- Component manufacturers and suppliers producing turnbarrels and end fittings to ensure dimensional interchangeability and correct load rating.
- Quality assurance and procurement teams verifying material, surface treatment and marking conformity.
- Maintenance, repair and overhaul (MRO) organizations selecting replacement parts compatible with aircraft control wire rope.
Practical uses include selecting the correct turnbarrel material and surface finish for corrosion resistance, matching dimensional/thread specifications from Table 1, and ensuring traceable marking and conformity to aerospace interchangeability requirements.
Related standards (examples)
- ISO 10955 - End fittings and turnbarrels: technical specification
- ISO 2020‑1 - Preformed flexible steel wire rope: dimensions and loads
- ISO 9761 - Locking clips for turnbuckles
- National/industry equivalents in Annex A (EN, SAE, MIL, QQ‑P)
Keywords: ISO 9738:2000, turnbarrels, aircraft control wire rope, aerospace standard, dimensions and loads, corrosion‑resistant steel, aluminium alloy, copper‑zinc alloy, surface treatment, cadmium plating, passivation.