Machinbird;
It boggles my mind how some participants in this forum continue to seize on loss of the VS as the likely cause of the AF447 accident.
I would not want to criticize theories if they are developing and/or promising, but if someone believes something strongly, in this context there is the requirement for substantiation.
Determining that the VS was attached at impact takes the examination of this accident in one direction, and assuming the VS was lost at altitude takes it in another. That is why it has been a constant source of discussion between contributors.
If the problems with the VS-loss theory were addressed such that the evidence of the recovered wreckage and the photographs were accounted for, I don't think anyone would resist the notion.
However, a number of contributors have provided sufficient opportunity to demonstrate the validity of the theory against specific objections, and have found no response.
The idea isn't to shut down a path of thought but to test a line of thought against serious objections. That is the way investigations are done. The theory must make sense. If the evidence does not support a line of thinking, the thinking must change or it becomes irrelevant to the investigation.
I think using what we have and our imagination to consider how an aircraft cruising at M0.82, ended up in a high-velocity vertical fall, is the most important question to consider.
I believe that examining everything after 0135, (INTOL) is important. I think the fact that the crew did not respond to DAKAR's request for their TASIL estimate is significant.
I'm sure others here will have been in similar situations, but in the initial contact from VHF to HF, there is a routine process. For a few moments, waypoint passage is a busy time, recording passage on the flight plan, checking the track and distance for the next leg, confirming ETA for the next waypoint, observing/recording fuel, preparing (tuning) the HF for transmission, making contact with the HF, (dealing with the CPDLC log-on issue in this case), providing position and estimates again on HF and doing the SELCAL check and responding that the SELCAL checks, (or repeating the check if it doesn't work first time) are all routine procedures.
But after the initial contact, the crew didn't respond to three requests for a TASIL (the FIR Boundary) estimate from DAKAR, (and then DAKAR gave up!). I am wondering if the process was interrupted by something and if so, what?
I think things began to develop before the loss of airspeed, and were compounded by the loss of airspeed in a situation they were already wrestling with, (was the radar on and were they using it to best effectiveness?). These are the questions that I believe will help us understand what happened around 0210.
Clearly to those who have stuck with and read the thread, none of this is original. But it is an attempt to provide focus on what occurred at FL350 after INTOL.
PJ2