Why are you dismissing the data the report contains indicating that the flight crew was unable to trim manually, that the column forces were incredibly high, and that the captain repeatedly indicated he could not maintain elevator trim without the co-pilot's aid, then?
Your responses have been incredibly selective about which parts of the report you take as gospel and which you handwave away as "speculation".
From where I'm sitting it appears you've started out by picking a contrarian conclusion you like ("the plane was safe once STAB CUTOUT was set cutout, and the crew could have maintained altitude indefinitely at that point, but fatally fucked up by re-engaging electronic trim to try to trim the stabilizer"), and to maintain that a priori conclusion you've consistently ignored the data and parts of the transcript that indicate that was very likely impossible.
The report does not actually indicate which "manually" the pilots meant, with the switches or with the trim wheel. When the question came up they went and turned the electric trim system back on and appeared to test it (only trimmed 0.2 units). Honestly if I had just turned the thing back on I would have trimmed it all the way to where I want it.
>The report does not actually indicate which "manually" the pilots meant, with the switches or with the trim wheel.
This isn't consistent with any coherent reading of the transcript:
> At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied that the trim was not working and asked if he could try it manually.
They've already hit the stab cutout at this point. Now maybe they're think this is like the older 737s and the cutout cut the autopilot and not the full electrical, BUT if you think the question he was asking was whether or not he could try the thumb switch, what exactly would he have been trying prior to that that "wasn't working"?
There is no other trim to try before the thumb switches such that you'd refer to the thumb switches as "trying it manually" when $OTHER_THING was not working. In the transcript, given what's being said, it's clearly the wheel crank that's meant. It doesn't even make sense otherwise.
>Why are you dismissing the data the report contains indicating that the flight crew was unable to trim manually, that the column forces were incredibly high
> At 05:40:44, the Captain called out three times “Pull-up” and the First-Officer acknowledged.
> At 05:41:30, the Captain requested the First-Officer to pitch up with him and the First-Officer acknowledged.
> At 05:43:04, the Captain asked the First Officer to pitch up together and said that pitch is not enough.
Take a look at the chart of control column position deflections. They're jolting around like crazy at +10 to +15 aft starting immediately at the first big MCAS trim event through to the end of the recording. That's because the stabilizer mis-trim is exerting considerable force on the elevator. The captain wasn't calling for aid on the column for shits and giggles.
Data for "Column forces were incredibly high" would be the force on the column that the pilots experienced. Column position deflection isn't that. Column position deflection data is data that the column position was changing rapidly. Concluding that column position was changing rapidly due to "incredibly high" forces as opposed to say unpredictable forces is speculation.
So your take is that the column shows near constant movements of multiple degrees back and forth practically on a second to second basis, in the grip of someone trying to hold it steady at +10 aft, and who asked several times for help keeping it back enough to keep the nose up, but that that is not in and of itself indication that the force was "high"
You're shifting the goal posts. Obviously the force was "high" because the trim was out of position. That's different from "incredibly high" and can mean anything from "they gotta pull a little harder than normal" to "they have to pull as hard as they possibly can".
Control column position is not a delta. On a 737 that position directly correlates to the position of the elevator in degrees. Elevator position, stabilizer position, and airspeed as they were we can infer a force; corroborated by their own words, it's reasonable that this situation is described in the "mistrim nose down" sketch about 1/3 of the way down here:
05:41:46, 05:41:54 manual trim not working, that is absolutely a trim wheel hand crank attempt; fairly clear (to me) but not stated is that both pilots were not simultaneously cranking on the trim wheel, there's plenty of anecdotal evidence that this exact configuration puts to much upward force on the jackscrew that it is difficult to impossible to turn.
05:43:04, PIC asks SIC to pitch up together says pitch is not enough
As for the noisiness of the control column position data, it could be partly the stick shaker, it could be light turbulence, the accel vert row at the bottom shows it's a bumpy flight, and pitch and roll attitude is also variable but less so than vertical accelerate. And accel vert gets noticably more perturbed as airspeed increases. I think it's light to moderate turbulence, but I'm not certain. A search for PIREPs and weather reports at the time could corroborate it.
