Ageing

Conceptual enhancements:

Enhanced requirements, regulations and standards may result in an ageing of certificates.

Technological enhancements:

Technical advances / technological obsolescence have to be met.

Enhanced test procedures or evaluation methodologies require a re-evaluation of some (old) analysis results.

Physical ageing:

Ageing of systems, structures and components (SSC) due to physical, chemical and biological effects,  resulting in degradation, corrosion, wear, etc.