Thanks Jim for posting the Aeroassurance summary. It clarifies some of the points I made in my initial posts. Namely that they did indeed have some HUET training (as already mentioned and discussed by others), and also that what I called a "probably deliberate" inflation of the safety vest inside the cockpit may well have been an inadvertent inflation.
Regarding the CH-148, the Aeroassurance report seems to indicate that the autopilot and prevailing control laws misguidedly flew the aircraft into the drink?