Originally Posted by
43Inches
Things will fall off just sitting on the ground due to corrosion and other factors over time. However an in-service aircraft of this age will have no doubt been subject to regular inspections and NDT of the critical parts of the airframe for cracking, corrosion and anything else that will lead to break up. Previous accidents involving the type would have generated ADs for the parts most susceptible to these failures, so a failure in straight and level flight at cruise speed even in moderate turbulence is very unlikely if the aircraft was properly maintained. And once again, the ADSB data points to a gradual slow down to close to stall speed, under control, in straight and level flight, very unusual if it was a wing falling off. Excursion from cruise flight only seems to occur once minimum speed is reached and the aircraft then departs into a left spiral. This is shown in a trend in the data, not single points, so it's doubtful the ADSB plots are all in error, as all the plots prior seem relatively accurate and the departure coincides with the loss of contact with the aircraft.
I also don't really believe an experienced pilot would not note an engine failure and let it get to stall, in a training exercise even less likely. I assume multiple bells and whistles would be sounding at various times, being a turbine powerplant. There was also at least one other aviation professional on board in the case of the engineer, who would have had some clue of what was going on had an engine stopped.
You will note I wasn't commenting on the specifics of this accident, but responding to a claim that an airframe couldn't fail in "smooth air".
FWIW, I have seen far too much inaccuracy in publicly available data to feel comfortable reaching any conclusions. If I had a dollar for every piece of bad data I've seen over my years in flight safety, I would no longer need to be working. As for how an in-service aircraft might have been maintained and inspected, that too is for the investigators to determine. I hope you are correct and that no surprises are found in the airframe. I work for an operator of a different variant of this aircraft and while I know we put a ton of time into keeping our aircraft in excellent condition, this one has surely gained our attention.