A/C Certs
 

Please assist this confused Yank with understanding all the certs now required to fly in Europe. Is 8.33 mHZ spacing only required at FL240 & above? If my a/c is not RVSM-certified, but is RNP-5, can I fly above FL410 on the NAT tracks and then at all altitudes intra-Europe? IS the UK flight environment different from the Continent? It's getting more confusing and my head is spinning. Any general overview would be greatly appreciated. Thanks for the assist.