SIMS
Comparing SIMS to real world is a complicated matter, Hazelnut.
In a SIM, the tilt of the cabin is used to give an ILLUSION of acceleration, which then is confirmed by the instruments: the attitude indicator tells you that you are straight and level, and the airspeed indicator that you are gaining speed: sensation and information all agree.
Apparently all the information is congruent, but actually you are stationary on the ground, sitting in a box with no real outside vision.
If you would sit in the SIM with your eyes closed, your motion sensing system would tell you the truth, that you are tilted backwards. Your cognizant system however, overrides your feeling, because all instruments tell you that you are level. Your feeling then "corrects" itself, it must be an acceleration that it senses (but in the SIM the instruments are lying to you, compared to the real world)
In the cases of somatogravic illusion in actual flight situations, when they lead to an accident, the feeling system overrode the cognizant system. No matter how correctly the instruments displayed that the aircraft was level (or at a normal pitch attitude) and accelerating, the feel system told the pilot that he was pitching up abnormally, to which he instinctively reacted by a push on the control (yoke or stick).
Instead of resetting their feel system to the reality shown on the instruments (which tell the truth, in real aircraft), the accident pilots try to reset the world to their illusions.
The human feel system is relatively coarse: accelerations go unnoticed, when under the detection threshold. Ask any fast jet pilot about close formation flying in IMC: if the leader rolls in roughly (noticable) but rolls out very smoothly (not noticeable), then you will feel as if still in a bank, when actually level again. Do that twice in a row and the wingie will feel as if almost flying upside down. A quick glance at your attitude indicator would instantly reset your internal gimbals (even though you were supposed to never take your eyes of your flightlead, such a quick check inside your own cockpit was what you really needed to do).
In a SIM, the motion system may quit if you maneuver heavily (unusual attitude recovery, or trying to replicate AF447). Just disregard your feeling system and fly the instruments, that is what instrument flying is about.
Of course, in AF447, some instruments did not tell the truth (airspeed), but as said many times before, pitch and power were shown correctly and were ample info to keep airplane safely in the air, be it with slightly less than the usual accuracy of a knot and a foot that us perfectionist always strive for.