Overview - ISO 244:1979 (Aircraft - Sealing wire)
ISO 244:1979 specifies requirements for steel sealing wire used in aerospace assemblies. The standard defines material, mechanical and physical properties, surface treatment, dimensional limits and procurement/acceptance requirements for wire intended to indicate equipment use or to prevent inadvertent operation. Typical uses include tamper-evident seals, locking of access panels and preservation of calibrated adjustments.
Key topics and technical requirements
- Material: Steel wire with a specified tensile strength range (230–300 MPa).
- Surface treatment: Core and layer wires shall be zinc coated before wrapping to provide corrosion resistance.
- Breaking strength: The wire shall not have a breaking strength over 36 N, establishing a predictable failure point for inspection and safety.
- Linear density: Specified as approximately 1.3 × 10^-3 kg/m (as given in the document).
- Ductility/bending test: At room temperature the sealing wire must withstand, without breaking or cracking, bending through 180° over a mandrel of the same diameter as the nominal wire diameter.
- Dimensions and form: Nominal diameters, sectional area and wrapping (core + layer) dimensions are defined in the standard (including allowance for left- or right-hand laying of the layer wire).
- Procurement: The standard sets out procurement and acceptance criteria so purchasers and suppliers can ensure consistent compliance with mechanical and surface requirements.
Practical applications and users
ISO 244 is aimed at the aerospace industry where controlled access and tamper evidence are required. Typical users include:
- Aircraft manufacturers and integrators specifying tamper seals on components and panels
- Maintenance, Repair and Overhaul (MRO) organizations applying or inspecting seals
- Quality assurance and procurement teams defining purchase specifications for sealing wire
- Suppliers of aerospace wire, fasteners and security seals who must meet dimensional and mechanical requirements
- Regulatory and certification bodies referencing consistent sealing practices
Practical applications include wiring seals for fuel panels, avionics access covers, control system locking, and securing calibrated or safety-critical adjustments.
Related standards
ISO 244 complements other aerospace standards covering fasteners, coatings, corrosion protection and material testing. When specifying sealing wire in procurement documents, pair ISO 244 requirements with relevant fastener and coating standards used by the organization or regulatory authority.
Keywords: ISO 244:1979, aircraft sealing wire, steel sealing wire, aerospace sealing wire, zinc coated, breaking strength, tensile strength, linear density, wire sealing requirements, aircraft maintenance.
