Dunbar, let me correct you; they were conducting a TEST of the system, it is called Low Speed CONF FULL.
The TEST is to reduce the speed(1 KT/sec), wait for ALFA FLOOR to activate, cancel it; note when AUTO TRIM stops and then stabilize the aircraft at V ALFA MAX for a speed reading, prior to this TEST they must calculate(normally done by the Flight Test Engineer) the minimum speed at which to STOP THE TEST and never go below it.
The crew was not trained to do this TEST and very important, they did not have a Flight Test Engineer on board, a key part of any Flight TEST.
G