Illusions .
Section 2.4 of the report discusses the possible effect of somatogravic illusions (page 166) - longitudinal acceleration and false pitch perception.
Discussion in the 737 Max thread raises associated issues of sensed pitch rotation with reduced vertical acceleration (g). The report does consider ‘negative g’ perhaps using a wider definition of illusion as a false sensation, and separately considers issues of pitch control and trim which contribute to the pilots sensation of flight path and aircraft feel - control feedback.
Normal flight conditions range 0.8 to 1.3 g, generally in a steady sate between manoeuvres; greater g values can be encountered for short duration, e.g. turbulence. Aircraft motion (sensed acceleration) relates to control movement and stick force, and ‘seat of the pants’ feedback referenced to general experience.
Abnormal, infrequently encountered conditions, may require larger stick inputs which could contribute to the assessment that additional trim is required. Alternatively the aircraft trim changes quickly due to speed increase, large change in thrust (pitching moment), or configuration change, thus requiring more pilot control input and longer duration trim change.
In pushover manoeuvres the pilot could experience reduced g more than generally experiences (often reported as negative g); in this condition pilots can encounter combined reduction in g, and negative pitch rate simultaneously. Also with the need for nose down trim and large stick defection the flying task is beyond normal expectation which could be interpreted a false sensation - like an illusion - even surprise. Large stick inputs in GA configuration at low speed, differ significantly from normal flight experiences - only requiring small stick input at higher speeds.
Thus during a GA the pilot may be reluctant to use large stick defections to avoid unusual g conditions; or with larger control input quickly seek to reduce the higher stick force with longer periods of trim.
In either case the pilot is experiencing less g than normally experienced, simultaneously with the unusual pitch change and control feel in a very short time scale. The combination could contribute to poor understanding of the aircraft flight condition, which with false sensation reduces the ability to correctly interpret the situation and apply corrective control inputs and trim - particularly where the duration of abnormal control change and sensations are longer than normal experience suggests.
Any thoughts on this view ?