this is a system where the pilot is more or less outside of the control loop it is a computer predominantly driven aircraft. boeing designs the aircraft same fly by wire but the pilot remains within the control room. >> we are both former military pilots f 18 in the navy flew a bunch of airplanes in the navy you were a test pilot as well. can you explain what fly by wire means and how it could contribute to having problems with the. >> they had the push pill and the cables new you have the push pull but it is hooked up to motors and driven by hydraulic systems. now you have the wires and these are being controlled but they have got one step further. in the air bus you have five computers controlling many of the functions that re always took for p granted. in other words this aircraft has for instance a stall system that prevents the pilot as much