Note, Evalu8ter (correctly) didn't mention Boeing!
KK. Not everyone uses the same aircraft 'certification' system. The UK MoD has a 'limitations-based' one. Read across is seldom straight forward. For example, our Home Office dictates some quite important specifications and requirements, which a typical US standard would not (and do not) meet. (And if they claimed to, GCHQ and most of our designers would want to know how, as it's very difficult!). The anonymous and very lowly pleb in MoD who signs the concessions and production permits has a thankless job.