I'm interested in why these rudder reversals took place, and what caused this pilot to think this was a valid way of controlling the aeroplane in a violent wake encounter. I think most pilots would 'let it ride' the immediate drama knowing it would only last a few seconds, and then take gentle corrective action afterwards to restore normal flight. I cannot imagine what he was doing thinking you can make large rudder inputs, then reverse them an instant later, then reverse again. It seems to be using a sledgehammer control input, because a wide bodied Airbus doesn't encounter such variable external influences at that rate- not at that rate where it can be identified what is happening and what corrective action should be taken. It is a flying technique that doesn't belong on anything bigger than a Pitts- it is most certainly no way to handle a large aeroplane.
The whole accident comes down to either
-a fatal fin defect causing it to come off in flight, or
-a fatal flying technique by the pilot.
If it is going to be suggested the first is the case, it is inevitable that the pilot inputs should be examined, and this pilot technique is what causes so much disquiet. Pleading ignorance that such a technique may be disastrous is no excuse when the vast majority of pilots are apparently aware of the problems rapid rudder reversals can cause. How on earth can any pilot believe such a technique is viable, unless he believes he must forcibly bully the aeroplane to do exactly as he wishes? Water in the fin or not, there has been shown to be no fatal design flaw in Airbus fins, so it was operated outside design parameters. The flight recorder showed why the fin failed under overcontrol. So why did the pilot fly like this?