It would seem that the Boeing simulation, the whole basis for the 158kts impact speed and for the "final flare" which W & D claimed showed that the aircraft was under control 4 secs before crashing is at best a red herring, at worst it brings the motives of those who produced it, offered it as evidence and used it to arrive at the "finding" into question. From the HoL Report:
Detailed examination by the AAIB of the flight control system disclosed that the DASH extensions found did not correspond to a high speed level flight condition whereas the LCTA extensions did, and it appeared possible that the settings could reflect a dynamic aircraft manoeuvre at the point of impact. Boeing were therefore asked to undertake a study to assess the consistency of the settings and to define the possible manoeuvre. The simulation was a mathematical exercise which, as Mr Cable stated, was "looking really for fairly gross manoeuvres over a pretty short period of time" (Q 957). It was not intended to produce an accurate reconstruction of events but rather to demonstrate what could have happened within certain parameters (Q 982)....
123. The Boeing simulation considered a wide range of possible starting conditions, i.e. conditions pertaining immediately prior to a final manoeuvre. Having rejected possible conditions at an airspeed of 135 knots, they concluded that an airspeed of 150 knots (groundspeed 174 knots) with a ROC of 1000 feet per minute provided "a ready match" with the criteria and was therefore the most likely (AAIB statement para 8)....
The groundspeed of 158 knots at impact derived from the Boeing simulation exceeded by 11 knots that of 147 found in the cockpit ground speed indicator (AAIB statement para 6). Moreover, the postulated ROC of 1000 feet per minute at 150 knots airspeed is unattainable. Squadron Leader Burke doubted whether it was achievable with ZD 576's load (Q 920). Witness A explained that while flying he had tried to see whether Boeing's chosen ROC was obtainable at 150 knots and had found that it was impossible in similar conditions (QQ 813-23). He had achieved no more than 400 feet per minute at 150 knots.
There is much more of the same at
House of Lords - Chinook ZD 576 - Report
but I would be getting my collar felt for adverse effects on PPRuNe Bandwidth. The HoL Report demolishes W & D's, the RAF's and the MOD's case. Trouble is of course they just don't admit it. Someone somewhere has to bring them to account. This was a scandal 15 years ago and remains so today. This aircraft was unairworthy and most probably crashed for that very reason. Time that was faced up to.