I had told JT that I didn't want to participate in this thread, but I must admit that the debate has been to a much higher standard than I feared it might be.
At last I see what Confiture has been getting at, although I am not convinced that the difference matters much.
So far as 'phugoid damping' is concerned, the discussion has centred on the response in the last three or four seconds. The phugoid period at 118 kts is around 27 seconds - there is no way that phugoid motion is going to affect the issue.
The point made about timing deduced from the DFDR record is well made; since any one of the parameters can be up to a second adrift relative to another and the whole debate relates to a period of four or five seconds it is, IMHO, almost pointless to attempt to deduce much from that data.
In any case, the data available does not give enough detail to assess the motion, and in particular the effect of elevator lift on the motion. It has been said that the AI laws attempt to drive the aircraft so as to maximise performance. The usual way of improving pitch response would be to overdrive the elevator to improve the pitch acceleration and then to back it off to avoid overswing.
But when you apply a load of 'up' elevator the first thing that happens is that the aircraft starts to accelerate downwards because of the negative lift. It is only after the pitch/AoA has built up enough to overcome this negative lift that the aircraft starts to accelerate upwards. The net result is that there is a slight delay after application of elevator before the CG gets above the original height. The delay isn't much - from memory it would be around 0.5 to 1 second on something like an A320, which is unimportant in normal operations but if you are only one second away from disaster it is very important. And of course the back end will lag the CG in terms of height development!
At the very end of the BEA report there is a graph of an AI flight test to repeat the Habsheim event (done at a safe height of course). That graph, with pretty much the same stick input as the actual event, shows that once alpha-prot was triggered the AOA followed the stick position over the first five seconds at the end of which time the AOA was about 16 deg. It then took another 10 seconds
with the stick held fully back until the AOA got to 17.5 deg. This is entirely consistent with the AI report mentioned by Chris Scott which says:
The maximum achievable angle of attack is frequently called "Alpha Max". To maintain the AOA near this value the crew must maintain full nose up input to the sidestick which requires the pilot to sustain a high nose-up force.
It also explains why the aircraft did not develop 17.5 deg AOA during the accident sequence - it was simply not given enough time to do so before contact with the trees.
That is one reason why I am not convinced that failure to achieve 17.5 deg AoA is important - the important thing IMO was the timing. The other reason is also related to timing; increasing AoA is not going to give an increase in flight path angle unless accompanied by enough thrust. Increasing AoA to 17.5 deg would indeed produce more lift but it would also increase the drag significantly and unless thrust were increased the aircraft would either decelerate further towards stall or sink. But if he had increased thrust earlier there would not have been a problem .......