Originally Posted by
MurphyWasRight
What I was trying to point out is that the "greybeards" statement was that the first thing they would instinctively do when trim acted up for whatever reason was to hit the cutout switches then use the manual wheel to trim, not first attempt to correct the trim using thumb switches.
The greybeards may have another reason - in the "old" days it was specifically advised
not to use main electric trim to counter a runaway.
Peter Lemme (satcom.guru) has tweeted parts of 727 manuals and found the procedure was to hit cutouts "immediately" with no mention of trimming in opposition (see image attached). He also shows other bits of the manual that were specifically advising against it.
Of course the greybeards also had the rollercoaster technique in their manuals and were possibly in their training too. It is possible that
everything changed at the
same point between classic and NG:
1. "Control airplane pitch attitude manually with control column and main electric trim as needed" added to procedure
2. trim wheel made smaller so manual trim less likely to work if mistrimmed
3. rollercoaster taken out of manuals
EDIT: and quite possibly related: 4. Stab trim actuators combined - classic had AP servo and main trim motor, NG has just single motor driven by AP or main elec trim
Then the MAX removed the separate autopilot-trim cutout too.