BOAC :
1) Do we have ANY evidence to rule out some sort of mechanical disruptive event or fire around the cockpit/electronics bays?
No trace of fire in the debris , so far... and we're arguing about inflight break up or ocean surface impact. We don't know enough.
On this subject, there is the Crew Rest Container : two of its parts have been found on separate occasions ; one with the labelling, the other with that arrow pointing FWD. I personally have tried to find out whether they were part of the same debris trail or on very far apart locations. Guess we will eventually be told.
Another mystery is the left #1 spoiler, found by a tanker. Was it surrounded by other debris or was it all by itself away from everything else ?
2) Is it established that we have no ACARS message recording LOSS of cabin pressure AND is it confirmed that the ACARS message we have refers to excessive cabin DESCENT rate?
Yes, apparently. There is an advisory linked to a "cabin vertical speed", related to the ECAM presentation... It indicates a cabin vertcal speed in excess of 1800 ft/min up or down, translated on the ECAM screen as a very small green-pulsing bar.
A depressurisation would have been indicated by an "EXCESS CABIN ALT" warning, telling of a cabin above 9500 ft....That warning is not part of the received ACARS messages.
3) There have been several (I think unanswered) requests here for positions of the groups of bodies found. Do we have any, and has anyone back-plotted the position of the second recovery vis a vis ocean currents to see where they would have been in relation to the first, and likewise for the first to the POSSIBLE crash site?
I, for one, would be interested in that kind of info... See above.
4) All the ACARS messages COULD have related to software interpretations of events. Amongst them, is there any hard evidence of ACTUAL failures?
In this case it's at a very low level of interpretation. The messages are akin to two kinds of reporting :
1/-Hi ! I'm system X. I've diagnosed that I'm too sick to keep on working. Something is wrong with me and I've informed the crew through a warning or an advisory message on their ECAM.
2/-Hello ! This is X and Y. We've determined that Z is going nuts and we don't trust him anymore and we've put him in a straight jacket. We'd like the crew to look into the matter...
We seem to have here a convergence of related failures, detected by the computers which need air data inputs to function properly. In all fairness, that's about the extent of our knowledge.
On the other hand, we've already seen similar events, with very similar messages, in similar orders pointing a finger at the ADRs total pressure channels...