On the recent two crashes of Boeings 737 Max

[Rockin Robbins]

Originally Posted by Dowly

Can you point where, during the time the pilots had control of the plane, did they exceed 500 kts?

Dowly, when we're talking about airspeed, you can see (airspeed is the bottom red/blue line, one for each airspeed sensor) the last half of the flight was over Vmo for any altitude. Maximum operating airspeed for under 10,000 feet is 250 knots and the plane was over 300 for that entire time, gaining a 500 knot speed by time of impact, according to the graph from the Preliminary Accident Report. The differences in the speeds supplied by the two sensors reflects the badly out of trim state of the aircraft. Here's a better view of that graph: https://ibb.co/DwpPG45

And a transcript from a simulator session is basically irrelevant to the actual Ethiopian Airlines flight. 340 knots is already 90 knots over maximum flying speed for that altitude, OF COURSE trims are very difficult or even impossible to adjust. The plane was not designed to fly in extreme overspeed conditions. Mentour Pilot proved that, didn't he. Now reflect an additional 160 knots airspeed over the speed where Mentour Pilot couldn't adjust trim and reflect on the consequences of letting the plane get that far outside its rated flight envelope.

However, Mentour Pilot has withdrawn the video of his own volition because "it's wrong." No simulator session can say anything about the facts of what happened on that flight. The final accident report has not been issued and he acknowledged that publishing a "best guess" simulator run with conditions different from the actual flight was wrong and would result in people responding inappropriately to a video that was wrong to produce to begin with. "You subscribe to my channel because you want the facts." The deleted video was pure speculation based on a simulator set up with parameters not reflected in the facts of the case. Mentour Pilot made the right choice for the right reason. Your laborious typing of the transcript from that purely speculative video accomplished nothing at all toward evidence that the pilots don't bear the vast majority of the responsibility for the crash.

Like Mentour Pilot said in his deleted video, "don't try this at home, folks." It's really way beyond any reasonable flying of the aircraft, and not because of MCAS either. Rule #1: fly the plane. Rule #2: see rule #1. These pilots didn't fly the plane. In fact they turned control over, against Flight Manual instructions, to a known malfunctioning electric trim system. Had they followed procedures, they might have saved the flight.

[Rockin Robbins]

Originally Posted by Buddahaid

One might make a similar argument that if you back over a kid on a tricycle in your car, and didn't buy the back up camera with a proximity sensor, that it's the auto manufacturers fault for not making the equipment standard in the first place.

And that perfectly illustrates why safety features don't appear. Manufacturers can't offer them as options because, having the most money in the transaction, if the driver gets it and doesn't turn it on, that's the manufacturer's fault. If the customer doesn't buy the option, then that's the manufacturer's fault. If the driver has a fully functioning backup camera and backs over the tricycle anyway, that's also the manufacturer's fault. It keeps safety equipment from being deployed because of the misuse of the legal system as a lottery with much better odds.

These manufacturers are not our enemy. They make possible the things we enjoy in life. Vendettas to put them out of business are much more dangerous than the real or imagined faults they pretend to remedy.

[Dowly]

Originally Posted by Rockin Robbins

Dowly, when we're talking about airspeed, it's not a great idea to show the altitude plot.

It shows the speed graph, look harder. You can also click it to get a bigger picture. MAGIC!

And a transcript from a simulator session is basically irrelevant to the actual Ethiopian Airlines flight. 340 knots is already 90 knots over maximum flying speed for that altitude, OF COURSE trims are very difficult or even impossible to adjust. The plane was not designed to fly in extreme overspeed conditions. Mentour Pilot proved that, didn't he. Now reflect an additional 160 knots airspeed over the speed where Mentour Pilot couldn't adjust trim and reflect on the consequences of letting the plane get that far outside its rated flight envelope.

The VMO of a 737MAX is 340kts, I think? Sorry, that's over 10,000ft. Is that ASL?


EDIT: I can upload and link you the video, Rockin Robbins if you wish.


EDIT2:

[Catfish]

^ @RR im still with you.
They follow the instructions in this vid, however when the AP is switched off due to wrong IAS the MCAS gets active (within 5 seconds ok), so the pilot tries to hold the plane against the MCAS downtrim which gets worse, then realising there is a runaway trim fail he also switches off auto throttle.

So in the above sim video he put auto throttle to manual at 1:27, but he did not throttle back much or so it seems?
So you say this is why they are unable to trim the plane manually because of the forces on the elevator wuth the plane getting too fast, ok.

So what is the reason they did not throttle back more in the above video?
I mean is there any reasonable explanation when three different experienced pilots in videos do not throttle back in this situation, like the ethiopian pilot did (not)?

edit what i do not understand is why he at first lets the copilot trim the plane forward instead of backward, the latter woulod be bringing them out of the situation?

[Dowly]

Originally Posted by Catfish

I mean is there any reasonable explanation when three different experienced pilots in videos do not throttle back in this situation, like the ethiopian pilot did (not)?

You have a AND (=Aircraft Nose Down) trim, reducing power would make it worse which in turn would make the pilot in charge to have to pull back on the yoke even more. The video also does not show all the other crap the Ethiopian pilots had to deal with. Crap like yoke shaker (stall), over speed warning etc. Contradictory warnings.


Also, to address what RR said elsewhere about MCAS not being a band aid; it absolutely is. The MAX wouldn't have gotten certification without MCAS.


EDIT:

edit what i do not understand is why he at first lets the copilot trim the plane forward instead of backward, the latter woulod be bringing them out of the situation?

@2:09 They start to simulate MCAS pulling the nose down. Mentour Pilot is a 737NG pilot, so the simulator is probably also a 737NG one.
EDIT2: To further elaborate; the first downward trim is a run away stabilisator, the manual trim is to simulate the MCAS behaviour.
Unfortunately I've not the full video.

[Rockin Robbins]

Originally Posted by Dowly

You have a AND (=Aircraft Nose Down) trim, reducing power would make it worse which in turn would make the pilot in charge to have to pull back on the yoke even more. The video also does not show all the other crap the Ethiopian pilots had to deal with. Crap like yoke shaker (stall), over speed warning etc. Contradictory warnings.

With nose trimmed down the plane accelerates from gravity. The proper thing to do is reduce throttle to keep speeds from destroying the airframe.

Originally Posted by Dowly

Also, to address what RR said elsewhere about MCAS not being a band aid; it absolutely is. The MAX wouldn't have gotten certification without MCAS.

Absolutely false. In fact, Mentour Pilot says that pilots have flown the 737 MAX with MCAS turned completely off and had difficulty distinguishing the difference. It seems that MCAS, meant to make subtle differences in handling to produce a duplicate of the feel of other 737s was overpowered, but it's a catch 22 situation. Remove the pilot and the automation crashes the plane. Remove the automation and the pilot crashes the plane. In both situations, zealots with rabies pursue Boeing with sharp instruments aiming to dismember them. Perhaps we need to simply outlaw all forms of air transport.

Originally Posted by Dowly

EDIT:@2:09 They start to simulate MCAS pulling the nose down. Mentour Pilot is a 737NG pilot, so the simulator is probably also a 737NG one.
EDIT2: To further elaborate; the first downward trim is a run away stabilisator, the manual trim is to simulate the MCAS behaviour.
Unfortunately I've not the full video.

You mean the video that Mentour Pilot pulled because it was wrong, morally and factually? Yes, that one. As Mentour Pilot said explicitly, the video was in error. it was wrong, it was baseless speculation in the face of facts in contradiction.

But far from the situation of a "crippled plane" that "couldn't fly without MCAS" it appears our real situation is quite different: an MCAS system meant to intruduce subtle changes to the feel of the aircraft, perfectly able to fly safely without it, but MCAS being far more powerful then it needs to be. What kind of scenario is it when MCAS gives full down elevator trim to achieve a similar feel to other 737s. That makesanosensa at all. MCAS should shake the stick to alert the pilots and that's about it. Maybe two units of down trim maximum, with an electric trim button contradicting the MCAS adjustment turning MCAS completely off for the rest of the flight.

Remember: the only facts we have are in the preliminary accident report. You Tube videos, simulator runs, anything not directly dependent on that preliminary accident report are speculation only and have no force of reality.

I predict that MCAS will have its fangs pulled, pilots all over the world will be called upon to evaluate the flying characteristics of the 737 Max and this plane will have a long, respected and safe rest of production for many years.

[Rockstar]

[Dowly]

Originally Posted by Rockin Robbins

With nose trimmed down the plane accelerates from gravity. The proper thing to do is reduce throttle to keep speeds from destroying the airframe.

You do realise that AND trim doesn't mean the plane is pointing down? Check the preliminary report, the aircraft was flying slightly nose up or at level for most of the flight until MCAS pointed it down.

Absolutely false.

The Maneuvering Characteristics Augmentation System (MCAS) flight control law was designed and certified for the 737 MAX to enhance the pitch stability of the airplane – so that it feels and flies like other 737s.

From: https://www.boeing.com/commercial/73...e-updates.page
Due to the way the engines are placed and being bigger makes the MAX nose up at speed, which is why the MCAS system was put in place to counter that. In other words, it's a band aid.


As for Mentour Pilot's video; since his Q&A videos seem to have been removed from his channel I can't verify, but from what I remember he removed the video because it was indeed speculation, but I don't recall him calling it factually wrong. It does show what pilots, who know what is going on, can do to try recover from the situation. In that they failed, because the manual trim was so hard to use even at <340kts speed.


He also mentioned in the now removed Q&A video that he made the video to show what the situation must have been in the cockpit because he didn't like how people (like you) put the blame on the pilots.

[Rockin Robbins]

Originally Posted by Dowly

Check the preliminary report, the aircraft was flying slightly nose up or at level for most of the flight until MCAS pointed it down.

The nose was level or slightly up during takeoff (no MCAS) and after they threw the electric trim cutout switches to "cutout," when MCAS was not operative, It tried to send down trim signals to the trim motor, but the trim cutout switch prevented it from trimming the plane down. As a matter of fact, for more than half the flight there were no trim changes at all! You can see that for half the flight, MCAS was off, all trims were input by the pilot. Then for unknown reasons, the pilot decided that a known malfunctioning MCAS could fly the plane better than he could. He turned the cutout switches back to on and allowed MCAS to crash the plane. That's pilot error

Originally Posted by Dowly

From: https://www.boeing.com/commercial/73...e-updates.page
Due to the way the engines are placed and being bigger makes the MAX nose up at speed, which is why the MCAS system was put in place to counter that. In other words, it's a band aid.

As both Mentour Pilot and blancolirio have said, pilots who flew the 737 MAX with MCAS turned off were barely conscious that there was any difference to the feel of the aircraft. Flying the plane without MCAS was not only possible, it was easy and straightforward, done without difficulty by 737 pilots. That's the real tragedy here, that a system to introduce very subtle "feel" differences in how a plane flies could have the power to crash a plane when the pilot makes an error. Whether pilot error is the ultimate cause or not, the PROXIMATE cause was MCAS diving the plane 8.000 feet into the ground.

If MCAS automatically turned off for the remainder of the flight when the pilot input 2 units or more of electric trim in the opposite direction as MCAS trim, the plane wouldn't have crashed.

If the amount of down trim MCAS could dial into the stab was limited to under four units, the control console could easily overpower MCAS and the plane wouldn't have crashed.

But let's be fair here. If the plane were really in a stalled condition and the pilot could overpower MCAS to pitch the plane even further up, the headline would be "Boeing Automatic Systems Unable to Save 150 Deaths." And the nay-sayers would be crowing that the automatic system could have saved the plane, but wasn't powerful enough to do so. In the safety biz, you are always wrong.

Originally Posted by Dowly

As for Mentour Pilot's video; since his Q&A videos seem to have been removed from his channel I can't verify, but from what I remember he removed the video because it was indeed speculation, but I don't recall him calling it factually wrong. It does show what pilots, who know what is going on, can do to try recover from the situation. In that they failed, because the manual trim was so hard to use even at <340kts speed. He also mentioned in the now removed Q&A video that he made the video to show what the situation must have been in the cockpit because he didn't like how people (like you) put the blame on the pilots.

Note that 340 knots is 90 knots higher than the "speed limit" below 10,000 feet of 250 knots.

He said "I was wrong. I was speculating, not giving the hard facts that you expect from me." I'm not blaming the pilots. I'm saying that pilot error was the cause of the crash. They would be the first to expect us to find the truth and let everyone know how to avoid making their mistake. It is clear, according to the only source of facts we have, the Preliminary Accident Report, that the pilots, through wrong decisions in conflict with the Aircraft Flight Manual regarding elevator trim overrun situations, caused this plane to crash. They were helped by the ability of a system meant to introduce subtle "feel" that imitated the "feel" of other 737 series planes, having the power to input full down elevator that the pilots would be unable to overpower.

The problem is that the general public treats this stuff like a football game. Pick a side and cheer for them, it's "us" against "them." And "them" need to be punished or executed. Real air accident investigation works entirely differently. Realizing that punishing erroneous decisions results in people clamming up and not saying the words that save future lives, air transportation safety agencies are not an adversarial procedure, but a search for the truth and a search for actions that will prevent future similar accidents.

As long as humans live on the face of this planet, human error will occur, sometimes costing the lives of hundreds or thousands of people. Often those making the error pay with their lives and can't be punished later anyway. But when they don't, unless they committed crimes, punishment only forces them not to talk about what went wrong. Air traffic investigation is solely (in theory and mostly in practice) about preventing recurrence of tragedy.

[Skybird]

Boeing employees raise further accusations over shoddy production standards at Boeing, this time the Dreamliner.

https://www.nytimes.com/2019/04/20/b...th=login-email

[Jimbuna]

Originally Posted by Skybird

Boeing employees raise further accusations over shoddy production standards at Boeing, this time the Dreamliner.

https://www.nytimes.com/2019/04/20/b...th=login-email

Flew to and from Mexico last October in a Dreamliner (only a month old as far as I was aware) and I recall on the homeward flight the steward passing out paper towels to a couple a few seats ahead off us because the ceiling was dripping water (and this was in first calass).

You couldn't pay me the Earth's weight in gold to fly in anything French.

I also happily drive where I need to go. If I can't drive there, I have no business there. But some people don't have that luxury. In short, I don't trust anything with wings, no matter who built it.

What would really help these companies is going 100% automated. It would atleast shut the Union idiots up.

[Catfish]

^ Well, the french literally invented flying. I mean the Wright brothers were first (or maybe Karl Jatho even earlier), but their design had no real chance in the long run.

[Skybird]

Boeing slides deeper into it.

https://www.dayandnightnews.org/faa-...t-year-source/

https://www.japantimes.co.jp/news/20...m-woes-source/

The inspectors learned that Boeing had opted to make the malfunction signal optional and an extra that would cost more money.
This came after Southwest asked Boeing to reactivate the signal after the Lion Air crash, which killed all 189 people on board.
Boeing had deactivated the signal on all 737 Max delivered to Southwest without telling the carrier.
Neither the airline nor its pilots were aware of these changes when they started flying the planes in 2017, a spokeswoman for Southwest told AFP.

What the hell was Boeing thinking.

Called “disagree lights” in Boeing parlance, these lights turn on when faulty information is sent from so-called angle of attack sensors to the MCAS. Those sensors monitor whether the wings have enough lift to keep the plane flying.
In the case of the Lion Air crash, investigators think one of the angle of attack sensors may have failed and sent incorrect data to the MCAS, causing its nose to go down as pilots fought to bring it back up.
The MCAS overrides the pilots manual efforts to point the plane up or down.
With the angle of attack sensor not working properly, the thing to do would have been to turn off the MCAS. But the Lion Air cockpit crew did not know this.

What the hell was Boeing thinking. Heads must roll for this. Decision-makers must go behind bars. A a super-hefty financial penalty is on order. Additional to the damage compensations for the victims' families. And additionally to the compensations for the carriers whose fleets of 737 max are grounded.


What the hell were they thinking...???

A good news in all the bad news for the families of the pilots. The cheap get-out-of-dodge-theory of "pilot error" is almost ridiculous by now.

[Buddahaid]

Not really, but you've already decided.