Without getting into proprietary data, you would want to consult the current Advisory Circulars for how and why certain things are certified the way they are. ACs actually supercede the FARs in many cases, because they are more detailed, restrictive, and complete. I used to write cert test plans for Part 91/123 bizjets and often had to consult Part 121 ACs. The latter serve as a starting point for manufacturer- specific cert planning. You can search them for free on the FAA website, see
here.