Equivalent and Alternative Fasteners
General distinction between equivalent and alternative aircraft fasteners.
Key reference points
- Equivalent and alternative do not mean the same thing.
- Compatibility and joint function matter alongside strength.
- Use only approved substitution or interchangeability data.
Organised training notes
1Equivalent fastener
A controlled standard or approved substitution table identifies the fastener as directly interchangeable with the specified item.
2Alternative fastener
An alternative may provide suitable strength but must also satisfy joint geometry, fatigue, weight, corrosion, temperature and installation requirements.
3Check sealing and magnetism
Pressure or fuel sealing and nonmagnetic requirements can prevent an apparently similar fastener from being used.
4Check material compatibility
Fastener and structure materials, coatings and electrical potential matter, especially with graphite composite structure.
5Keep the approved layout
A substitution does not authorise changes to spacing, edge margin, diameter, grip, thread position or access provisions unless the data specifically allows them.
This summary is not approved repair or maintenance data. Do not inspect, classify, select material, alter structure or perform a repair from this page alone. Use the current applicable SRM, AMM, engineering order, drawing and company procedures.