The simulator time that one pilot 'missed' ?

The Lion Air flight also had thousands more feet of altitude to play with in order to manually trim the jet.

"hey, the plane ALMOST crashed but didn't because a check pilot happened to be in the cockpit," ...certainly isn't my standard for flight safety. I don't want even a HINT of this sequence of events to be possible when I'm on board a MAX.

Despite some of the statements here, it isn't just disengaging the trim --

From a Youtube video I watched last week of a simulated trim runaway, the electric trim moves the stabilizer a *lot* faster than the manual trim wheels. Despite some of the statements here, it isn't just disengaging the electric trim -- once that's done it can take a ton of spinning to get it back to level, all while the plane requires a lot of elevator force to keep flying level. If the pilots followed the training and checklists, were spinning and spinning the trim back but it didn't seem to be helping, they could felt that re-engaging the electric trim was their last resort. Perhaps even relying in Boeing's statement that MCAS should disengage if pilot-electric-trim commands are given.

Clearly a lot is not yet understood about the actual interaction between MCAS and pilot inputs, how it presents itself to the pilots, and the human factors around reactions and procedures. It's clearly not as simple as "those 3rd world pilots didn't follow runaway trim procedures like *I* would have"

The lift from the nacelles, and other factors, result in a lighter pitch-feel in high angles-of-attack and steep turns. It does not result in negative static stability, which is what you describe. This has been reported incorrectly frequently over the past weeks. The best way to describe it is how the steering wheel "feel" in your car can get "lighter" when driving over a slick surface. The MCAS trim input introduces a nose-down bias so as to eliminate the "too-light" feel.

MCAS does not operate when flaps are extended because you don't have the lighter pitch-feel with flaps. MCAS also doesn't operate when the autopilot is engaged because the autopilot doesn't care what the pitch "feels" like.

This discussion is being filled with speculation and conclusions based on incomplete data. I'm not going to attempt to address that. I will continue to answer any technical or procedural questions that are asked.

It is not my suggestion, I am just quoting the suggestion of Jack Webb who allegedly was Piper’s chief engineering test pilot during most of the Piper Cheyenne development process. Cheyenne allegedly had "SAS." a “stability-augmentation system” that would push the nose down if it got too high when its big engines were placed forward in an old airframe originally designed for piston engines. “Webb believes that, based on his experience with the Cheyenne, these fixes won’t eliminate the plane’s [737 MAX] predilection for roller-coastering. …….."

If you believe that Piper’s alleged chief engineering test pilot is incorrect in his assessment of the 737 MAX having a "predilection for roller-coastering, " then explain with a scientific assessment or quote from an expert's opinion or quote from reference to an expert why he is likely to be wrong. The 737 MAX having a "predilection for roller-coastering" is Mr. Webb's alleged conclusion based on actual experiences with airplanes and engine placement. I put that statement out there to be discussed & analyzed, then challenged or supported by posters in this forum. Mr. Webb’s statement may on its face sound logical to me, and if it is dismissed, it should be done so with reference to credible & admissible professional opinion and other evidence. On its face, Jack Webb appears to be an expert with actual experience on impact of placement of large engines on an aircraft. He is one source of alleged evidence, and on the surface appears reasonably credible.

Again, I am welcoming discussion based on scientific evidence / analysis, -- refuting or supporting Mr. Webb's professional opinion.

Too-light feel is a side effect if I understand it right, not the root of the problem. I'd rather believe MIT professor of aeronautics; how would you explain his " This reinforces itself and results in a pitch-up tendency which if not corrected can result in a stall. This is called an unstable or divergent condition"

Having difficulty understanding the nature of the MCAS "reset" phenomena being discussed in the aviation press
It resets to its original trim position or advances after the pilot resists by pulling the yoke?
Is the trim a series of stops or continuous?
Continues to the max 2.5 degrees?

Something doesn't make sense between the report linked by [MENTION=88376]rdchen[/MENTION] and the assumptions made by those who assert the MAX has an inherently faulty design. The issue cited by those who claim the MAX is inherently faulty or unstable is increased lift from the engine placement but the reason the flight crew presumably turned the electrics (including MCAS) back on was that they couldn't get the aircraft to climb. Those are polar opposite conditions -- which means something else was responsible for the situation. If anything the MAX design should have helped them with the lack of lift when they turned off the electrics.

As for Mr. Webb's assertion of predilection for roller-coastering or porpoising, the downward portion of that behavior would happen after stall -- they have to get the upward climb to get to that stall condition in the first place. He may be quite correct in the plane design overall but be completely irrelevant to this particular situation.

As [MENTION=10236]LarryJ[/MENTION] said, this discussion is filled with speculation based on incomplete data; we need more information.

The MCAS can't be reset. The pilot's response to runaway trim is to turn off the electric trim and use the manual trim wheel to get the airplane properly trimmed.

All fine, but if you extend this particular line of thought, then you're strongly implying that there was nothing wrong with DC-10s operating without hydraulic fluid because one set of pilots in one situation (UA232) was able to get the plane down without total loss of life. <shrugs>