No Lone Zones
Not strictly correct Smuj. The idea of "two man control" was originally meant for nuclear custodians. Then it dumbed down a bit to secure area entry and finally emerged as being "two persons with the same knowledge of the purpose of their mission". So it could mean two GEs BFing an aircraft. But you are quite correct in stating that few could understand the complexities of a flight mission as well as the Navigator. I'm glad that I don't have to bear that burden today. My round, I think.