A major part of this thread has been and still is (very appropriately and usefully) along the lines of looking at the bark of one tree using a variety of microscopes. I would like to step back for a moment and try to look at the wood. Bear with me for a moment.
A good deal of the credit for eventually finding AF447 must go to the Russians who pointed out that in nine fatal LOC cases they had looked at of a/c getting into trouble at high altitudes, eight had crashed within 10 miles of the start of the event. The images below from the
Metron report list the cases and show the distribution of distances.
The a/c involved were an A-310, a Tu-154B, two Tu-154Ms, two B737s, an IL-18V, an ATR 72, a MD-82, and if we add AF447, an A-330-200.
One case involved icing, and the Silk Air case may have involved something unusual.
In six cases the LOC started at over 30,000 ft above the crash site, and in eight cases at over 20,000 ft above the crash site, i.e. with plenty of altitude to execute a recovery.
So here we have nine out of ten fatal LOC cases involving a/c manufacturers from different countries, flown by crews from different airlines, regulated by different government authorities, with crews trained under different systems, and using different technologies, some FBW, some not, but all but one of which crashed within ten miles of the start of the incident.
To me as a distant observer there is more than a hint of human factors, or human/machine interface factors, at work here. These data do not
prove anything, but do hint (to me) that these (very, very, rare) accidents do happen whether the technology is FBW or not, i.e. human factors or human/machine factors were likely to be important (or dominant) causal factors in the outcome independent of technology, training, nationality, government regulation, or ………
And now back to the microscopes.