A process used by commercial aircraft developers to determine whether an existing certification remains applicable after incorporating some particular change in the design. This process lies close to the core of how the developer stays in business.
The basis of the process is found in 14 CFR 21.93.a : “A ‘minor change’ is one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the product. All other changes are ’major changes’…”1.
Footnotes- The CFR goes on to list some exceptions to this last assertion.[↩]