Thanks mm43, takata discussed the reasons for latching the alt law but I am looking for the confirmation of notion that has made circles around this thread lately: namely that latching of ALT2B disables the autopilot until ground reset. What logically follows is that since other crews normally used autopilot while remaining in ALT mode after regaining the normal airspeed display, they never got as far as ALT2B and AF447 was pretty unique. However, pretty old FCOM I have shows ADR disagreement doesn't result in AP being lost, so I'm looking for further reference.
Maybe a bit semantic
Maybe semantic but it looks to me like a scope issue.
Originally Posted by DP Davies
If a stick pusher is used to meet the stall requirements it must provide two qualities: clear and unmistakable identification of the stall, by a sharp positive forward movement of a control column, and an adequate nose down pitch by the aircraft.
(...)
It is obvious that those constructors forced to use stick pusher, installations did so because they either found that their natural stall was quite unacceptable, or were not prepared to investigate the aeroplane's qualities beyond Max. Cl by other than a small margin, or decided that some part of their structure could not take the hammering in the violent buffet before the nose drop.
It follows form all these considerations, therefore, that that the stick pusher must always prevent the natural stall being reached in service.