the pilot can give a command and the computer on the airplane will say, hey, boss you really don't want to do that it will refuse to do it. they could have done it in the germanwings crash. they could have programmed the plane so the plane knows where it is it knows there's no air field nearby it will refuse to go below a certain altitude. we don't operate a lot that way but we could. >> that raises its own questions. then you're using software you have hackable issues all kinds of things. when you look at the pictures as an expert at the derailment the first passenger car decimated, the other six also derailed three of them end up on their side. it almost looks like tonka toys in terms of how it happened. obviously this is all the physics of exactly how this occurred. when you see this crash and you see which ones went on the side which were flung from the tracks what does it tell you about the force and the derailment itself? >> it tells you that this train is a lot tougher than the spanish train. american trains are heavier and tougher. and in a similar accident you'd rather be on an american train.