As I mentioned in the first post, I got a sanity check from a guy who reviews crash reports and helps with things like requests for re-examination. I don't see any value in that, because I'm not questioning the cause of the crash, only the description of the impact. I think the breakup sequence is telling, mostly as a detective story and also as archeology - uncovering a historical record that was unsuspected.
I'm getting a feel for the crash investigators, and the more I consider it the more indignant I get over the ALPA writer. Here's what I think happened:
The ALPA writer had access to CAB documents, but it was grudging access. The ALPA and CAB did not always cooperate, and in at least one case the ALPA was more or less accused of sequestering a crew so the CAB could not get toxicology results, etc.
The CAB in one document described prop hits across the railroad embankment. In another document the CAB described how the spacing between prop hits across the ground let them calculate ground speed. I'm positive those two documents described the same sequence of prop hits, but one of them explicitly mentioned the railroad embankment, and the other mentioned only the "ground". So the ALPA writer assumed those were two different sequences, but they were simply one sequence mentioned in two documents.
So with good intentions, the ALPA writer concocted a scenario that had two sets of prop hits, and obviously that had to be engine four and then engine three. And he came up with a sequence that seemed to fit that, but without doing the geometry he was wildly off base. The result of following the ALPA scenario is that the plane had to go from a 90-degree right bank to a 150-degree bank where the number three prop hit, and then reverse and go back around to a belly landing, all in 1.4 seconds. The timing comes from 380 feet between first wingtip impact and nose impact at 160 knots. The guy didn't have a clue.
What kills me about this is that all he had to do was ask. A simple conversation with the CAB guys would have cleared it up. The ALPA writer clearly never went to the crash site, never understood the physics. And because of the prickly relationship or his personal attitude he couldn't ask the question.
This is all conjecture, you understand, but this is what I see behind the scenes.