Sim Data
HC, you are correct in surmising that OEM's now typically add specific flight test data flights at the direction of the sim manufacturers design/software group.
Kidding about " Simulitis " aside, it is fair to say that the fidelity ( if that is the word ) of helicopter flight siimulation today is far superior to what it used to be, and is presently being pushed particularly by the OEM's effforts in bringing fly by wire technology into the industry. Still, as efforts in the RAH-66, S-92 Canadian MHP, X2 have shown to date, and now ( I'd expect ) with the 53K, the sim work allows flight test to proceed safely, but one should expect a good deal of flight control software mods based on flight test results.
Getting back to this accident, there are the questions re the reaction to the dual engine stoppage, and then the behavior of the rotor at perhaps very low Nr. Can we place any confidence in a present day flight simulation of this sort of event? I have a mental list of problems that showed up in flight test at SA which did not show up in preparatory Gen Hel simulations: empennage issues, rotor stability issues, that type of thing, and I think that some degree of skepticism remains a healthy attitude to take toward simulation applied to the edges of the flight envelope. Guess I'm saying that readers ought to pay attention to both HC and DB.