OK no mechanical malfunction, however, computer systems do not always leave a trail. I worked with systems for over 40 years and most catistrphic system failures did not leave correct records it took a few times for the error to show itself in a way that it could be corrected.

I still think that something happened that was not normal, controls not responding to inputs, etc. that did not show up in the event recorder. Perhaps FRA should look at 2 man crews and a national standard control setup.