PA 18 151 : My mistake on the "valid" speed.
I agree with you, in AF447's case, a return to normal law may have helped, or even have saved the plane.
But I stand still : how can the system decide the speeds are corrects ? It would be a guess. And I think that, in other scenarii, such a guess would be wrong and lead to incorrect actions by the system.
That's why I suggested a comparison between the ADR speeds and other sources. The ADR redudancy is not enough, as 3 (identical) probes can be faulted by an identical phenomenon at ~ the same time : icing, ash cloud...
I suppose that's why ALT2 is latched. The point is, as you said : If the aircraft system doesn't know, let's give control to the crew.
The aircraft system cannot know, cannot be 100% sure (using only the ADRs) that the speeds are back to correct values "just" because the speeds have rised, and/or are consistent again. The crew is better IMO to assume that, based on other sources (pitch, power, feel, visual clues...)
For the record : Agreed with the rest of your posts
