Originally Posted by
togsdragracing
Before it went wacko the telemetry clearly showed the engine gimballing out of limits and then a very rapid drop in altitude so I'm guessing that the thing tumbled and then underwent an unscheduled disassembly.
I concur - the yellow dot in the blue circle depicting the thrust vector did a merry little dance indicating some instability. Any full scale thrust deflection also likely to put severe aero forces on the launch possibly beyond design limits.
From a few posts back where Ariane V is mentioned, that is what happened on the first launch I believe. Same guidance computer as Ariane IV but with greater acceleration the spacecraft exceeded the expected acceleration limits (reduced testing was the ultimate cause for not finding this prior to launch), computer assumes an "anomaly" so restarts. Part of the restart procedure is exercise full nozzle deflection, which didn't turn out too well at the speed it was going so launch control destroyed the vehicle. I am sure someone will correct me if this isn't what happened precisely.