Nope. There is a clear temporary loss of input in many of the manual, but none of the automatic commands. The latter show only "ragged" flanks.
https://cimg5.ibsrv.net/gimg/pprune....6952148c88.jpg
Lionair Upper: manual trim middle: automatic trim

On the ET FDR PF asks PNF to help him with the manual electric trim. So he may have had difficulties actuating his thumb switch.

I do not agree with your analysis. We will know in the end if that is identified as a contributing factor. I predict it will not be.

There is an excellent article in Flight International this week: "Questions persist after Ethiopian loss".

If there are questions about pilot training, I feel that they should be directed not so much at type-rating and airline training, but rather at the first 200 hours of a pilot's training. There have been too many crashes where the very, very basics of flying an aeroplane seems to have been forgotten.

Quote from the 'Effect of Controls' lesson at the very beginning of flying training: "At high airspeeds, typically with a low nose attitude, the controls are harder to move, very effective and require only small movements to bring about a change of flight path. They feel firm." The last paragraph of that Flight article is very very pertinent.

Am a 737 pilot.

Reason I was given was to provide redundancy in case of a rare instance of switch (or actually relay) welding. That phenomenon occurs when a relay remains in a set position for so long that it basically welds the contacts closed. I'm not an electrical engineer, so I don't know how to evaluate this statement, but it is not unlike the rationale for the split thumb switches on the yoke.

I suspect another unspoken reason was to maintain the look and feel of the 737NG switches. As long as there were two switches that were always used together, then Boeing could take the position that no additional training was required.

That could be one explanation of the seemingly tentative trim inputs especially by Lion Air FO, although the (possible) ergonomic factors discussed above are intriguing.

As has been pointed out many times in the two main threads discussing the 737 MAX crashes, the LT610 PF counteracted uncommanded (MCAS) nose-down trim on 21 separate occasions, yet for whatever reason did not believe he was experiencing a stab trim runaway, and failed to activate the CUTOUT switches.

There are two big questions:

• why did he fail to recognize the stab trim runaway and activate the CUTOUT ?
• why did he hand control of the trim to the FO with such a critical malfunction occurring ?

Good questions, but as I said much much earlier, I think we can turn this one on its head and ask "what enabled the supernumerary Captain on the prior flight to recognise, at least in part, that CUTOUT was the solution?". I believe that, even then, electric trim was re-engaged albeit briefly.

So, even with 3 heads in the cockpit, one of whom was free from immediate control issues, it did not appear to that crew the Trim Runaway NNC was the obvious choice.

Thankyou for the heads-up. When looking for that I also saw this previous article from Flight Global:

I disagree. It appears it occurred to someone (the jump seat pilot) pretty quickly that it was a runaway. They got pitch under control and hit the cutouts. My guess is they re-enabled stab trim in a troubleshooting / curiosity activity (lets see if its still doing it?) because clearly they did not need the electric trim to fly the plane.

The jump seat pilot was in a better position to see the trim wheels spinning, watching the videos of runaway trim it is blindingly obvious from jumpseat view, likely much less so for pilots where it would be in peripheral vision, and has been pointed out hearing it over the stick shaker is questionable.

As to why it was not handled exactly per Trim Runaway NNC once recognised (re-enabling trim) one factor is that it did not match the at the time checklist perfectly since the 'runaway' was not continuous.

AA To Have Pilots Do Sim Training on MAX: WSJ
 

By
Andy Pasztor

Updated April 15, 2019 5:33 p.m. ET American Airlines Group Inc., AAL +0.06% after saying for months that its pilots didn’t need additional ground-simulator experience on Boeing Co. BA +0.26% 737 MAX jets, now plans to include such instruction in training sessions for the aircraft, according to industry officials.

The decision, these officials said, means as soon as late summer, American 737 MAX pilots will start encountering some simulator scenarios tied to problems with an automated flight-control system, called MCAS, that has been implicated in two fatal nose-dives of the plane in less than five months.

The enhanced training also will deal with similar emergency situations in which pilots need to intercede to manually correct movement of flight-control surfaces on the jet’s tail.

American’s choice highlights growing differences between carriers—and in American’s case, with federal air-safety regulators—regarding the best way to ensure flight crews will be able to safely operate 737 MAX jets once they resume service.

At this point, the Federal Aviation Administration isn’t planning to mandate simulator training targeting potential MCAS misfires. American’s voluntary effort to go beyond minimum federal requirements hasn’t been reported before.

Southwest Airlines Co. and United Continental Holdings Inc., the other U.S. carriers with MAX aircraft, don’t intend to adopt similar training changes, the officials said. Some overseas carriers, however, have signaled they may opt for enhanced simulator training.

In the immediate wake of a Lion Air jet crash in Indonesia in October, American said it continued “to believe the Boeing 737 MAX aircraft is safe and that our pilots are well-trained and well-equipped to operate it.”


https://www.wsj.com/articles/america...&mod=djemITP_h
https://m.wsj.net/video/20190404/040...ia_960x540.jpg
Investigators Blame Boeing Flight-Control System in Ethiopian Crash
An initial probe into the crash of the Ethiopian Airlines Boeing 737 MAX 8 found that the pilots followed emergency procedures. Investigators went on to recommend that the MAX fleet stay grounded until authorities validate changes that Boeing has made to the aircraft. WSJ’s Robert Wall explains. Photos: Getty ImagesAmerican’s pilots were critical of Boeing for not providing enough information initially about the MCAS system, but determined that they had learned enough about how MCAS worked to continue flying the plane without additional simulator training. But on Sunday, a spokesman for American Airlines said the carrier is “looking at the potential for additional training opportunities” in coordination with the FAA and representatives of the pilot union.

A Southwest spokeswoman said the airline’s current training covers operating in conditions present during “an MCAS misfire.” She added, “We briefed our pilots on MCAS post-Lion Air and emphasized the training for operating in unreliable airspeed conditions.”

On Monday, United said, “Our training is consistently refreshed and updated, and we will make any updates to our training necessary should the FAA decide more is required as part of their ongoing investigation.”

Within weeks of the Lion Air crash, American already was working behind the scenes on possible training changes. Without any prodding from the FAA, the carrier’s safety and training experts began considering possible additional simulator training, according to internal FAA documents reviewed by The Wall Street Journal.

According to one email at the time from a senior FAA inspector, the carrier was developing new simulator scenarios for the MCAS system malfunctions and potential consequences. The email added that FAA and American officials determined “it would be better to wait for further guidance” from the plane maker and agency certification experts before proceeding to develop full-blown simulator scenarios.

The carrier, according to one industry official familiar with the details, didn’t follow through with the proposal at the time because managers decided there was too much uncertainty about the cause of the Lion Air crash. But now, after a second fatal 737 MAX crash—in Ethiopia in March—in which MCAS was implicated, American is working in earnest to implement extra simulator training for MCAS-related events, this official said.

Possibly they were trying to understand the (changed) function of the cutout switches:

"I thought the right switch killed auto but allowed manual electric trim"

tries various combinations of switch positions, ending with both up..

"There it goes again"

"That's strange, I have the conversion notes in my carry on, let me go get them"

This

Except I **believe** that s/he had already gotten the documentation out. It is interesting that the (altered) function of the cutout switches appears to have required clarification on this forum.

Not sure it has been confirmed either way on when the library run occurred relative to cutout.

"What did you say? I can't hear you over that stick shaker racket...."

I'm not quite sure why this myth that the previous Lion Air crew quickly realized they had a stabilizer runaway and used the cutout switches is still going strong.

It's obvious from the FDR traces that is not the case, and that they actually fought MCAS for about 5 minutes before using the stab trim cutout switches. For the Ethiopian flight, 4 minutes after they experienced the first MCAS activation they were already hitting the ground.

And the Ethiopian crew used the cutout switches about 40 seconds after MCAS first activated. So about 7 times faster than the Lion Air crew. It still didn't save them. In fact it may have made things worse for them, because it appears that they could not use either the manual electric trim or the trim wheels after using the cutout switches.

I was trying to understand why the Ethiopian pilots have retracted the flaps, which allowed MCAS to activate. Looking at their FDR traces it seems to have happened when they were getting close to 250 knots. The VFE on the 737-800 is 250 KIAS at flaps 1, 2 and 5, and it's probably similar on the MAX. So it's not surprising they retracted them. About 20 seconds later, when the flaps completed retraction, they were over 250 knots. I wonder what would have happened if they didn't retract them and they got close to 340 knots. Would they fully retract automatically at some point to prevent damage to them?

Amazing.
We have been reliably informed that nobody was told about MCAS - but a pilot before any crashes not only had knowledge of procedure (cut out Stab Trim) which saved the aircraft; but also had documentation of the effect on MCAS in his carryon?

Ian, I don't believe that this is a claim that MCAS was in the documentation, the suggestion is that a) the difference in CUTOUT switches was and b) that it took another head in the cockpit to suggest trying the CUTOUT as if there was runaway trim. As the previous poster indicates, it took them a while to get there and they subsequently reported STS running in REVERSE (and not MCAS)

The documentation would have described the changed functionality of the trim cutout switches, which appears to have been glossed over in at least some conversion slideware.
No need to know about MCAS (why) to use the cutout switches to kill uncommanded trim (what).

Also they had autopilot engaged. On LionAir accident flight MCAS problems appeared to start with flaps up, on ET it was with autopilot disengage.

By the time of the ET flight it was known that autopilot was a protection against MCAS, from one of the ASRS reports:

Unfortunately the autopilot didn't stay engaged - not sure why.

It also appears to have pitched, and trimmed, them down when apparently set to climb, this I do not understand. I cannot find any autopilot-engage preconditions other than "no stick force", but if the autopilot actually cares about AOA why on earth would it engage at 74deg - if that is true there is no way you are flying. On the other hand if it didn't care about AOA what on earth was it doing with the pitch when set to climb? One of several WTFs on this one.

Autopilot pitching down unexpectedly was also a feature of some of the MAX ASRS reports, including the one I quoted - issues may or may not be related.