Interesting stuff rudderrudderrat!
My knowledge of the B777 is very patchy, so that's one for the memory banks. Having said that, I should have made clear that I was referring to a specific conversation I was involved in (many moons ago!) where one of the guys asserted that Boeing never implemented FBW at all, and that the 777 used higher-tech versions of the electromechanical connections in the 75 and 76.
It appears that Boeing opted for defence-in-depth at the electro-mechanical level, whereas Airbus opted to do it at the software level (2 separate and distinct "clean room" implementations per computer etc.). In layman's terms, Boeing opted to have a mode that bypasses the computers entirely in the case of a triple failure, whereas Airbus opted to make it harder for the computers to fail in the same way. Both completely valid ways of solving the problem - and it's a testament to both builders that neither scenario has been put to the test.
Last edited by DozyWannabe; 9th Aug 2012 at 20:43.