Likely because there are inspection requirements identified for the SFP issuance. By the way, that AD has been superseded by 2023-05-16. As for SFPs...
Basic design of each of the systems identified in 14CFR 43 appendix A could be interpreted to mean the Type Certificated design (the design submitted...
The problem we have with STCs that would otherwise be a minor alteration has to do with parts production. Part 21 specifies that any part known to be...