http://www.atsb.gov.au/media/3532398/ao2008070.pdf
is the final report. Quite a scary read. 30 warnings on the displays with master caution and master warning going on and off. All of it because of a bug where the binary representation of the altitude was interpreted as angle of attack and a design problem in the flight computer which does filtering on the signals but couldn't cope with spikes exactly 1.2 seconds apart.
Result - the vertical acceleration went to -1.5G in 3s and then to 1.7G in the next 2s. That can look something like this
http://www.faa.gov/other_visit/aviation_industry/airline_o...
I don't understand why the flight computers don't perform more aggresive smoothing on the signals from the sensors - AoA just can't go from 4 deg to 50 deg in 1/25s.
I think the biggest problem is simply that it was a software bug that occured infrequently enough. To change a working piece of software that has thousands if not millions of problem free flying hours behind it is not something you do "just because". It requires lots of analysis and testing to make sure that they don't introduce new problems.
I don't understand why the flight computers don't perform more aggresive smoothing on the signals from the sensors - AoA just can't go from 4 deg to 50 deg in 1/25s.