Best as I can piece together from the report, the successful 11-second (approx) electric ANU trim from 0.4 to 2.3 units took place at 325-330 kts (05:40:28 to 39). Capt control column aft displacement during this time varied from 12 to 5 degrees.
The two “blips” of electric trim (suggested by some as failure of electric trim) from 2.1 to 2.3 units took place at 360-365 kts (05:43:11). Capt control column aft displacement during this time varied from 9 to 6 degrees.
Airspeeds deduced from the narrative based on the F/O’s airspeed (the presumed correct one). VMO for is aircraft is 340 kts. Control column inputs based on the FDR chart.
A question then becomes, is the difference between 325-330 kts and 360-365 kts enough to overwhelm the electric stab trim with these kind of control column displacements?
Obviously the second case is outside of design parameters, and therefore may not even be able to be tested in a simulator (unless the simulator is certified to 365 kts).
On another note: some have suggested that the “blips” would be due to severe G-forces resulting from each blip. I don’t buy it. G-forces are mapped in the FDR plot (vertical acceleration), and they are insignificant - certainly much less than the pilot-induced G-forces of the previous couple of minutes. And let’s get serious for a moment - is a bit of trim-G going to bother you if you’ve had two pilots pulling on the column for dear life for the past few minutes?
I’ve never hand-flown a B737 at 365 kts before, but I have hand-flown one at 320 kts plenty of times - and trimming is not an G-force inducing event at that speed.