We also know, that this was the scene of a monster storm system.
This is the key to the whole incident. While it certainly would be nice to be able to reconstruct what went on in the cockpit and with the aircraft systems including freezing of the pitot tubes, the bottom line is that no aircraft is designed to fly through monster storm systems and clearly this one did. Even if the recorders are never found, we have still learned
again the hard way to: "NEVER FLY THROUGH A THUNDERSTORM!"
