On Friday, I posted a speculation about the causes of the Flt 3407 crash in Buffalo on Thursday evening. I appended an update on Saturday, indicating that the NTSB had reported that the plane's cockpit voice recorder indicated that the pilots were aware they had had a significant icing encounter, though no other particulars were forthcoming.
In that update, I also mentioned that a pilot friend had observed that flying a "coupled approach" (one that uses the autopilot) was not uncommon among commercial pilots, and that if that was the case here, it might mask the effects of icing by re-trimming the airplane automatically, until the effects were quite severe. When an autopilot can no longer deal with the conditions in which it finds itself, it typically sounds an alarm and then shuts off (the pilot's joke is that the machine is effectively saying "OK, hotshot, you got us into this mess, you get us out.").
Since that update, two additional facts have been revealed by the NTSB, both important. First, the crash site investigators have said that contrary to initial reports, all four corners of the aircraft are still recognizable, the nose and both wingtips in addition to the tail. That means that while the concentration of wreckage means the plane hit the ground on a very steep trajectory, it likely didn't crash in a steep nose-down attitude. That doesn't completely rule out the "elevator stall" theory I was espousing, but it does make it much less likely.
The second revelation, that the plane was on autopilot when it crashed, certainly lends credence to my friend's observation about the dangers of such a practice in icing conditions, and indeed, it appears that the airline has a policy of requiring that pilots hand-fly the airplane in potential icing situations. It starts to look more like the plane got a load of ice in a freakishly short period of time, and the wings stalled, possibly at the same time as the elevator. Data recorder analysis will indicate the exact sequence of events, but it's likely that the plane either was too tail heavy (with ice) or too close to the ground to recover, and pancaked into the ground.
Obviously, this too is speculation, and more may well be found wrong, but my pilot's instincts to speculate as an exercise are overwhelming my lack of training as a journalist, which at least should be telling me not to. At least I'm apparently in a lot of journalistic company, but that doesn't really make it right...