Pilots are already supposed to be trained in runaway trim procedure. That's a reasonable evaluation to make, and the FAA agreed with it.

One of the crews followed it, the other two didn't. Crews aren't always trained properly, that isn't on Boeing.

Note that each of the three crews used the column trim switches to restore normal trim, why two did not think to then use the cutoff switches is something for the NTSB to determine.

If you watch "Air Disasters" on the Smithsonian Channel, many many crashes have an inadequate pilot training component, and/or pilots who did not do what they were trained to do.

That's not true. The EA crew DID follow the proceedure and DID uss the cutout switches. See the report: https://flightsafety.org/wp-content/uploads/2019/04/Prelimin...

Timeline: "At 05:40:35, the First-Officer called out “stab trim cut-out” two times. Captain agreed and FirstOfficer confirmed stab trim cut-out."

Initial Findings: "The crew performed runaway stabilizer checklist and put the stab trim cutout switch to cutout position and confirmed that the manual trim operation was not working."

What happened was by the time they did, they were trimmed nose down really far and it took all their effort on the controls to keep the nose up. The aerodynamic forces prevented them from being able to manually trim. They eventually turned the trim back on because they had to use the electric manual control to try to get the nose up because it was physically impossible for them to do so manually. They adjusted the trim in the ANU direction electrically, but then "an AND automatic trim command occurred and the stabilizer moved in the AND direction from 2.3 to 1.0 unit in approximately 5 seconds" which caused them to lose control completely.

To the best of my understanding, this is an accurate summation of events.

With the MAX it isn't possible to have electric trim without MCAS, so if MCAS is malfunctioning pilots have to trim manually. The problem with the EA flight is that it occurred shortly after takeoff, so they lacked altitude (unlike the LA flight). A complicating factor was that they were flying east out of Addis Ababa (i.e uphill).

(from wikipedia): Two minutes into the flight, the plane's MCAS system activated, pitching the plane into a dive toward the ground. The pilots struggled to control it and managed to prevent the nose from diving further, but the plane continued to lose altitude. The MCAS then activated again, dropping the nose even further down. The pilots then flipped a pair of switches to disable the electrical trim tab system, which also disabled the MCAS software. However, in shutting off the electrical trim system, they also shut off their ability to trim the stabilizer into a neutral position with the electrical switch located on their yokes. The only other possible way to move the stabilizer would be by cranking the wheel by hand, but because the stabilizer was located opposite to the elevator, strong aerodynamic forces were pushing on it. As the pilots had inadvertently left the engines on full takeoff power, which caused the plane to accelerate at high speed, there was further pressure on the stabilizer. The pilots' attempts to manually crank the stabilizer back into position failed. Three minutes into the flight, with the aircraft continuing to lose altitude and accelerating beyond its safety limits, the captain instructed the first officer to request permission from air traffic control to return to the airport. Permission was granted, and the air traffic controllers diverted other approaching flights. Following instructions from air traffic control, they turned the aircraft to the east, and it rolled to the right. The right wing came to point down as the turn steepened. At 8:43, having struggled to keep the plane's nose from diving further by manually pulling the yoke, the captain asked the first officer to help him, and turned the electrical trim tab system back on in the hope that it would allow him to put the stabilizer back into neutral trim. However, in turning the trim system back on, he also reactivated the MCAS system, which pushed the nose further down. The captain and first officer attempted to raise the nose by manually pulling their yokes, but the aircraft continued to plunge toward the ground.[8][9]

The electric trim column thumb switches override the MCAS. Turning the cutoff switches back on, activating the thumb switches to bring it to normal trim, then turning the cutoff switches back off would have recovered it.

Read the Airworthiness Directive sent to all MAX crews after the first crash:

https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA...

which deals specifically with that:

"Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT."

Funny, that reads to me “you are screwed. Manually jackscrewed”

In Indonesia this was not even in the manual, and the pilots were never even told MCAS existed.

That’s beside the point. In the story they discuss how airplanes are not intended to require this level of superhuman ability to stay airborne.

You are avoiding that this was a combination of an engineering flaw (reading from a single AOA sensor guiding MCAS, when in reality it should have been redundant) and a regulatory flaw (the role of MCAS was increased despite it being initially regulated as a much milder intervention).

> In Indonesia this was not even in the manual, and the pilots were never even told MCAS existed.

It wasn't necessary to know MCAS existed - the procedure for runaway trim is in the manual and is the correct response to MCAS failure as MCAS failure exhibits itself as runaway trim.

> superhuman ability to stay airborne.

Turning off the stab trim with the cutoff switches is part of the memory procedure to deal with runaway trim, and no superhuman abilities are required. Just remembering to do it.

> You are avoiding

Not at all. I just take issue with the claim that pilots had no role in the accidents, and take issue with the bad design of the MCAS software being a cost saving measure.

Note that the fix is redesigning the MCAS software.

Did you read in the article where Captain Sullenberger said he couldn’t do it in time in a simulator, even expecting it? Have you seen the YouTube videos? It’s a disaster.

> Did you read in the article where Captain Sullenberger said he couldn’t do it in time in a simulator

I did read the article, and that isn't what he said. Furthermore, Captain Sullenberger is an Airbus pilot and hasn't flown 737s in a long time and is not rated on the 737NG.

I don't know what runaway trim procedures are on Airbus airplanes.

It is also possible he is being a guy who knows exactly what he is talking about and has the qualifications and experience to back it up.

If an aircraft starts pitching down, and it wasn't commanded by the pilot, and resetting the trim (temporarily) fixes the problem, the issue is almost certainly with the trim. If it is MCAS and a malfunctioning sensor or a failing motor that occasionally kicks on and drives the trim to its limits, the pilot response should be the same. This is what I hear Walter saying, and it makes sense. MCAS just makes it more probable to manifest.

The thing is the checklist says in a runaway stabilizer scenario, it will trim continously, but MCAS does not apply trim continously. Therefore it does not exhibit itself as a "normal" trim runaway. Checklist: https://i.imgur.com/K7El4K4.jpg

Hence, they might not have thought it was a trim runaway.

Not every emergency manifests as a textbook case. It isn't too farfetched to imagine an intermittent short running the trim motor on an intermittent basis rather than continuously. I'd still shut off the trim motor as a possible remedy, but I'm not an airliner pilot, just a guy who flys for $100 hamburgers.

I'd really like to see the NTSB report on this when it is released. I've read some of them, they're far more detailed and contain a lot of pertinent facts that were omitted from the usual clickbait sensationalist journalism.

If you did, I certainly don't see it in your arguments.

I think you should read his comment again, and evaluate tenses.

Not being rated on the 737NG is significant if someone were to claim to be an expert in that same airplane.

"It wasn't necessary to know MCAS existed...". If I ever read something as dangerous as that I don't when. First, MCAS had only one sensor input foregoing redundancy. Second, everything I know about airworthiness, which is by no means complete, says otherwise.

Sorry, but this is a naive understanding of aviation safety. Have a look at "the Swiss cheese model" as a starting point to gain insight.

Of course many accidents have a "pilot error" component, the central issue is what made the pilots do the wrong thing. This needs to be analyzed on a systemic level, i.e. was the training good enough, did the pilots receive adequate information, did the aircraft system provide the pilots understandable feedback, etc.

For the pilots to do the right thing, they first need to identify the problem. That can be very difficult when a lot of visual and auditory alarms -- sometimes contradicting each other -- goes off at the same time. The aircraft manufacturer has to account for the human factors.

Boeing failed miserably in this regard: 1) MCAS didn't work as intended, 2) they deliberately left out essential info about the system from flight manuals. In addition the FAA failed in their oversight of Boeing.

The deaths are on them, not the pilots.

> Sorry, but this is a naive understanding of aviation safety.

Very few aviation crashes are the result of a single failure. Usually, they are a combination of failures, all of which were required to produce the crash.

These crashes are no different:

1. the design shortcomings of MCAS

2. the refurbished AOA sensor on the LA airplane was not calibrated properly

3. LA put the plane back in service despite the failed AOA sensor

4. The crew of the LA flight were not informed of the failed AOA sensor

5. The flight crews did not follow the memory runaway trim procedure

All of these had to happen. A typical NTSB crash report dispassionately identifies all the contributing factors to an accident and issues corrective action recommendations for each of them.

I was curious about point 3; was lion air responsible for detecting the failed AOA sensor or someone else?

I can't exactly say but a quick read comes up with some relevant points:

"According to the reports presented to the Indonesian parliament, a Florida-based aerospace company performed the repair of the faulty AOA sensor."

https://airlinerwatch.com/broken-aoa-sensor-in-lion-air-737-... [from april 2019]

So possibly it's not LA's fault, however

"On Nov. 5, CNN published an update on the crash investigation from Capt. Nurcahyo Utomo of Indonesia's National Transportation Safety Committee (KNKT) noting that the FDR review also concluded that the aircraft's airspeed indicator had been malfunctioning on four consecutive flights prior to the crash. Utomo also indicated the pilots should have recognized the malfunction when it occurred on flight JT610."

https://www.aviationtoday.com/2018/11/07/faa-issues-boeing-7... [from nov 2018]

There's no excuse for LA putting the airplane back in service after the first crew had to cut off the stab trim, or even bothering to inform the next crew of the issue.

That was my point (edit: and Nurcahyo Utomo's point). I was backing you up on this.

I know, I was just concurring. Thanks for lending a hand here :-)

@WalterBright: “These crashes are no different” ..

“1. the design shortcomings of MCAS”

“5. The flight crews did not follow the memory runaway trim procedure”

How would the pilots have switched off MCAS if they didn't know it was there?

They throw the switch that turns off automatic trim. That the automatic trim system is going nuts due to some new system (MCAS) they don't know about as opposed to it going nuts for one of the reasons it might do so on earlier planes doesn't matter.

Sully Sullenberger's opinions is that the MCAS failure is not a "normal" trim runaway failure:

> These emergencies did not present as a classic runaway stabilizer problem, but initially as ambiguous unreliable airspeed and altitude situations, masking MCAS.

http://www.sullysullenberger.com/my-letter-to-the-editor-of-...

He bases that opinion on having flown the scenario in a professional full motion simulator (explained in the rest of his letter).

What's your response to that?

I replied to this in another message here.

Sully isn’t type rated in the airplane in question. An Airbus that he normally flies is much different than a 737NG.

>One of the crews followed it, the other two didn't. Crews aren't always trained properly, that isn't on Boeing.

Note that the penultimate flight of Lion Air had an extra airman deadheading in the cockpit. That is a CRM luxury most normal crews would not have.

Also, the stab trim runaway procedure is a "memory" item, meaning the pilots are supposed to memorize it rather than digging out a checklist and referring to it.

Since each crew did restore normal trim more than once, they did have more time than just seconds.