Overview
ISO 2436:1973 specifies standardized methods of test for heat-resisting equipment wires used in aircraft. The procedures are intended to establish compliance with the performance requirements of ISO 2032 and to provide a basis for national test specifications when existing tests are inadequate. Tests are organized by purpose: type tests only, type and production routine tests, and type and production quality tests.
This standard focuses on practical, repeatable test methods including high-temperature ageing, low-temperature bending, voltage and insulation verification, dimensional and conductor resistance checks, and inspection requirements for coatings and solderability.
Key Topics
- Classification of tests: Type tests; Type and production routine tests; Type and production quality tests.
- High-temperature ageing:
- Specimens may be wound on a metal mandrel (diameter = 10 × maximum specified conductor diameter).
- Typical ageing condition: air oven at 275 ± 5 °C for 168 hours, followed by insulation and voltage testing while under mechanical strain.
- Purpose: confirm insulation integrity and electrical withstand when insulation is strained at high temperature.
- Low-temperature bend test:
- Specimens stored at −50 ± 5 °C for 6 hours, then wound on a cooled metal mandrel (mandrel diameter = 10 × maximum specified conductor diameter), one turn per second.
- Inspect for cracking while the specimen remains on the mandrel.
- Voltage and immersion tests:
- After mechanical tests, specimens may be immersed in water at 20 ± 5 °C for 5 minutes with ends protruding 100 mm and subjected to the appropriate voltage for 1 minute (see ISO 2032 / standard table references).
- Other tests and inspections:
- Flammability/self-extinguishing checks as required by national specifications.
- Tensile and elongation tests on conductors per ISO 2032 clause references.
- Coating and braid inspections for silver or other metal coatings; solderability testing as specified by national requirements (IEC Publication 68-2-20 Test T cited as an option).
- Stability (non-retraction) test: a 2 m length stored at 275 ± 5 °C for 1 h; allowable total insulation retraction ≤ 3 mm.
Applications
- Supporting type approval and production quality control of heat-resisting wiring for aircraft equipment and harnesses.
- Defining national test specifications where current tests are inadequate for aviation type-approval.
- Ensuring electrical safety, mechanical durability and thermal performance of wires used in aircraft and space vehicle equipment.
Related Standards
- ISO 2032 - Performance requirements for heat-resisting equipment wires for aircraft (test compliance reference).
- IEC Publication 68-2-20 (Test T) - Solderability (solder globule method) cited as a candidate solderability test.
- ISO technical committee background: developed by ISO/TC 20 (Aircraft and space vehicles).
For implementation, reference the clauses and test conditions within ISO 2436:1973 and the performance criteria of ISO 2032 to ensure consistent type and production testing for heat-resisting aircraft wires.