The prior comments about the mechanics are correct. The pilot realized too late he was low, slammed on power and tried to nose up, but that moved the tail down just enough to impact the seawall. The tail and vertical stabilizer separated and he lost control. One poster on another thread said
"... The g forces in the rear seats must have been tremendous."
This indicates horrendous spinal column injuries in the rear cabin area. It also appears that the two fatalities were cabin crew in the rearmost seats, against the rear bulkhead.
My first thought...without knowing anything.... was pilot error. Windy conditions and cross-winds on landing in SAN FRAN. Wing dipped and touched tarmac.....sending plane in cart-wheel (based on initial reports)
Sounds like he came in too low and clipped tail.
Out of ignorance, I thought planes had altimeters and auto-landing computers. Are most touch-downs done manually by the pilot?
I think the pilots forgot to reset the computer to the new runway. Based on the tail debris field, it looks like they tried to correct to the new runway on visual approach. The tail debris starts on the right side of the left runway. Means they were landing in between the two runways. There was another plane waiting to take off on the right runway.