Why all the violence? Surely there is enough in the turbulance to satisfy your worst nightmare? In a spin the bigger the airplane the less violently it behaves - to a point and, by the way, centrifugal force builds in a flat spin with both wingtips pulling towards the horizon, which is why it is a spin and not a continuing roll.
If you think about what you wrote there is little difference between what you say and what might be found in severe turbulance - I might submit that you could stall an airliner and enter a spin, in conditions of severe turbulance, without even noticing any change to your discomfort and the real point is that there is little, if anything, that will tell you something else has happened - except, perhaps, systems will start shutting down.... including engines, at the high angles of attack associated with the situation. So it is not impossible that some of this might be passed along via ACARS and much of it... not.
Referring to an accident report I have read, conditions of a large airplane in a flat spin can be violent. The following involves such an airplane roughly in the weight class of the A330 (but with a different planform).
In this accident one crew member of a crew of two survived because he was able to eject, the second crew member did not eject. The violence during the flat spin was the likely cause of the failure to eject.
Quoting the report:
"The airplane started to roll slightly, and when the pilot put in a little aileron to correct the roll. it yawed violently to the right. The pilot pulled the left throttles to idle, and was trying to advance the right-hand throttles to stop the yaw, but the airplane was out of control. The airplane rolled rapidly to the right and during the second rotation, the left wing separated at the manufacturing splice.
The pilot remembers:
"At some time during those violent maneuvers, I encapsulated, which was the first step in the bail out procedure, I expected the co-pilot would have done the same. The airplane settled into a flat spin and the forces became strong and almost constant, pushing us forward and to the side. I was having a hard time trying to keep my feet back against the heel kickers."
The pilot reported that he seemed for a period to be unable to move in the capsule due to loads throwing him forward and to the left. Finally he pulled the right handle of his escape capsule and encapsulated ballistically and was able to complete his ejection. In statement and testimony, the pilot indicates extreme forces were holding him forward and to the left during the period after loss of control of the airplane and until his own ejection was completed. The following three quotes from his statement indicate the severity of these forces:
"For the next few seconds I seemed unable to move in the capsule; the loads being somewhat oscillatory, throwing us forward and to the left. During this period of time I tried to talk, thinking that I had a hot mike; but I could only hear myself grunting under the excitement and extreme forces that seemed to be excerted on us and throwing us forward and to the left. Since it is mandatory for succesful completion of ballistic encapsulation and ejection from the airplane that the seat be moved to the full aft position, the gas pressure must overcome any forward forces. (Manual encapsulation under these conditions would be extremely difficult, if not impossible.)
Post crash capsule analysis (of the co-pilot) indicated that the relief diaphragm which releases the gas overpressure when the seat reaches a full aft position had been ruptured. This could have occurred as the result of gas pressure building to the limit when the system attempted to move the seat back against extreme forward forces. Had the latter occurred, no further opportunity for ballistic encapsulation would have existed. Even though moments of lowered force levels may have allowed successful ejection by one crew member, an unfortunate timing for actuation of the ballistic cycle during this forward force by the other may have resulted in the seat failing to retract precluding further possibility of escape.
It should be noted that the airplane remained in a flat spin, which would impose forward forces on the crew, from shortly after loss of control until ground impact. It is concluded that this was a likely cause for the co-pilot's failure to escape."
End of quote.
It took 76 seconds from the beginning of the event at 25,000 ft until the moment of impact on the ground. These 76 seconds included 16 seconds of level flight.
Because this was a test aircraft it carried an instrumentation package and its associated data recorders and telemetry equipment. Therefore, lots of data was available to the investigators.
http://www.pprune.org/5010930-post2070.html