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New It kinda sounds like a PID tuning issue to me.
PID controller.

tl;dr - by studying how a system changes in response to a step function input, you can set up a controller to minimize overshoot and minimize the time necessary to get to a steady state. But if you're too aggressive in setting the PID control parameters, then a very small change in the input can lead to wild oscillations.

Yes, the system should be easy to disable. But imagine you're on a roller coaster and trying to hit certain buttons to disable something... :-(

I know Boeing issued safety bulletin(s) after the Lion Air crash, but it obviously wasn't enough.

:-(

I hope they solve the problem soon.

My $0.02.

Cheers,
Scott.
New Re: But imagine you're on a roller coaster...
They're supposed to have had adequate training for that.

I, too, hope they solve the software/hardware problem soon. Where we part (I think) is in my view that there's entirely too much software flying the aircraft and too little flying done by the pilots. So much so, imo, that when the software malfunctions their first instinct is not to turn off as many automated systems as they can.
bcnu,
Mikem

It's mourning in America again.
New As said before (not just by moi)
This "air-worthiness Certificate" was granted SANS: the usual requirements necessary for a NEW MODEL: under just the rubric, We've covered the 'remedy' of disengagement.. in our Heads-Up Bulletins cha. cha. CHA.

Thus: no pilots have gone through the requisite Simulator experience of just WHAT this porpoising behavior CAN DO--and we see: HAS DONE--well BEFORE! these pilots have to find-out in-extremis; either Pilots don't read the Heads-up very well or it's poorly worded and insufficiently WARNING of just how likely is the phenomenon to occur: cf. TWICE ALREADY.

Boeing saved the airlines $$$ in Crew TRAINING via achieving an end-run about procedures which have normally shown to be adequate nay, EFFECTIVE in preventing just such possibilities in any NEW model...as, I aver: IS this greatly-altered machine. Specifically: changes in dynamic C.G./center of gravity to accommodate the new engine weight AND this nonesuch-BEFORE: anti-stall gadgetry, so obviously nowhere near 'fail-safe' ... even when operating "properly" via engr. calculations. A lying sensor should be immediately verifiable and auto-disconnect ordered by the Boolean (and I ain't even an aurcraft engineer.) At very least next: how about a NEW and large Big Red Light? added to all the others: whenever "nose down" has become SIMPLY-ot-of-control.. by humans.

(Then . in another NEW plane disaster, following its first inspection) as I recently read,
there's the abject-failure of a mechanic to properly lube the screw-driven vertical stabilizer [wrong specified lubricant; only 1 hour spent on task which takes 3 hours per-book] as caused the entire screw/nut assembly to destroy itself ... as they were flying back to LAX, lastly in INVERTED FLIGHT! == it was just *then* that the assembly disintegrated and 0-control was left and it went directly into the ocean, off LA (80% some-odd recovery of the plane for analysis.) All dead, natch.

Can't blame FAA for an incompetent technician, but I do blame FAA for letting this NEW-Model escape its sane/proper Intro via Simulator experience for ALL PILOTS who will have to fly the sucker with a load of PEOPLE aboard. I hope this "special favor by FCC" causes some heads to roll .. not passengers' heads.
New From 11-14-18: "Boeing’s automatic trim for the 737 MAX was not disclosed to the Pilots"
Here.


Boeing’s automatic trim for the 737 MAX was not disclosed to the Pilots
By Bjorn Fehrm

November 14, 2018, © Leeham News.: The automatic trim Boeing introduced on the 737 MAX, called MCAS, was news to us last week. Graver, it was news to the Pilots flying the MAX since 18 months as well.
Boeing and its oversight, the FAA, decided the Airlines and their Pilots had no need to know. The Lion Air accident can prove otherwise.


Emphasis added; if that's not A Smoking Gun (then I never fired that B.A.R.)

Seattle Times 11-12 report

[the Who's the more Stupid? game]
Beginning with admittedly-cynical description of *cough* fly-by-wire-Airbus.
"OK look: $$-wise we just gots to get rid of these primadonna Aviators [Then, Mr. CIEIO--ya gets to buy that Island Escape from the Proles!] See, we needs bus-drivers, then we needs to inculcate just how Magick is our Artifishul-Intelligence stuff ..until they each Believe. Fly'em around in a Cessna, etc.; make sure they Get that: "houses getting bigger==you're heading Down" and like that. aka The Plane IS Smarter Than You Are."

So then, is Boeing any less-Stupid? NOW?? even after all that flack from reporters re Lion Air. The very idea that "Pilots don't EVEN NEED TO KNOW" about this insidious NEW-SYSTEM ... ... surely is a q.e.d on that, No?




Sorry.. now we can All havebutterflies ... emplaning in whatever the brand of Flying Bus wherein nothing-can-go-Rong-go-Rrrrrrrr.
(I haven't flown since pre-911; may have to in some next. What will I do, first-confronting Securitat??)

Carrion, sometimes it's your brain-in-aspic

Ed-PS:
About that design change with elevated heavier engines -vs- redesigning wings and raising landing gear elevation (necessary were the plane to be at least similar in "handling performance by pilot or HAL-9000")

Is it not still possible ..even likely that: their Graphics-designed Re-Do has made this Model now enter the class of 'Unstable Design'? such that we've barely scratched the surface beyond the Obvious shortcomings of its Boeing-testing and experiences to date by actual [Pilots, as you've said: ~~"rarely-if-ever actually Flying" the beast in which they are surrounded /99% just watching displays ...like the video-game Tech ..from their childhood(s)?

What if this sucker IS a c.g.-unto flying manageability $$$-Clusterfuck?? Hmmm? (You saw it here first)
Expand Edited by Ashton March 11, 2019, 07:08:54 PM EDT
New Whom to believe?
Your points are well taken. But, the United pilots said they *were* made aware of the design change and appropriate remedies to MCAS malfunction (or in perfect aerospace-ese, should MCAS begin "to work in a method that is not intended.") Aside from whose version of Boeing's willingness to share this information - and how clearly and strongly - is true, the point remains that they *did* design a method for disabling it. If this had been an Airbus flaw, no such method would exist.

In the cases of both Boeing and Airbus I never believed that these AI systems were intended to do anything other than diminish the apparent skills required of pilots and thereby suppress their wages even further - gotta add value to the shareholders somehow, right? To be sure, the addition of these systems has, largely, contributed to safer commercial flying. But at what cost? There's an old saying concerning the acting as pilot in command that goes, "Flying is hour upon hour of boredom punctuated by moments of sheer terror." Pilot training is largely about what to do in those moments and I fear we've supplanted much of that with our Genius Design™ software and systems, which as you note, never fail, right? Our entire society has been buffaloed into believing in IT and the people who build it, most of whom are "into computers" because they prefer virtual reality to the genuine article and have the kindness, empathy and sense of community that your average slab of granite possesses (see: Gates, Jobs, Zuckerberg, et al.). But, I digress.

The thing is, when these "fantastic software systems" inevitably *do* fail, is there a way to fly the aircraft without them? Or is there not? For me, I'll continue to take a gamble on the former and hope the pilot is old enough to have gone through flight training when it comprised more than just pushing the right buttons in the panel.
bcnu,
Mikem

It's mourning in America again.
New not sure what it takes do disable that particular fly by wire function
but when it is during takeoff which is when this last jet crashed, you dont have much time to react
"Science is the belief in the ignorance of the experts" – Richard Feynman
New If I were captain or first officer on one, I think I'd turn it off during taxi.
bcnu,
Mikem

It's mourning in America again.
New makes sense
"Science is the belief in the ignorance of the experts" – Richard Feynman
New Methinks that in this compact essay..
You have created something which should be read to all pockets of growing yout, but on a much larger Scale:

Er maybe, ~~ "Kiddies, here are some wise words about Vulture Capitalism [in which you dwell] and just how it is that "investors" [and their Corporations: ever in thrall to the moods of the folk, the .01% who OWN well over HALF of the 'Gross-'--and I mean that via several definitions--$$$National Product of these dis-United States. YESS, that small coterie gets More of the national-Pie than: the 160 million folks of-which-You-are a tiny slice.

Go Forth --> and Reform, or die a slavey: like your cohorts and ancestors."

(OK that's just a rough draft) ;^>

Nice work, Mike..
New Bemused LRPD sez: "There should be an opportunity for somebody here". ;^> Love. It.
New Former DOT Inspector General echoes the themes of this thread--on Amanpour:
especially re the IMPLICATIONS (for the Futchah!) of --> "Pilots Don't Need to Know". This was the last part of a thoroughly sound Q&A. Clearly both Got It, without imputing mere-$$$Greed specifically. Except perhaps body-language-wise..

Interview with above; another of Amanpour's often Al Punte programs ... PM then later, nightly (here).
I deem her among the sharpest yet at elucidating in few well-chosen words: A Problem, eschewing all the talking-aoround of the regular MO of so many.
She's that Jewel in the left-eye of some Heathen idol. She's just ... fucking-erudite beyond most mere 'reporters-with-good-diction'.
New B may have pushed the 737 design a step too far
The new motors are much larger than the originals and do not fit under the wing, even with an extra 8" of lift in the front undercarriage. Boeing had to move the things forward and up. That in turn has made a previously stable airframe unstable at high angles of attack because the new engine configuration wants to keep lifting the nose.

Enter MCAS in an attempt to keep the engines from pulling the plane over the stall threshold.

One thing that may not be apparent to all is that the MCAS cutout does not restore things to normal as would shutting down other software controls. The trim change must be undone manually.

(And American Airlines apparently told its crews to turn it off after the Lion Air crash. [There's no off button. Read that as "pull the breaker"])
New No "off button" but there *are* "Cut-Out Switches". And they aren't hidden.

Normal electric trim control on the yoke can stop the MCAS-driven stabilizer movement, however MCAS will activate again within five seconds after the switches are released if the angle of attack is still sensed too high. Pilots can deactivate MCAS and automated control of the stabilizer trim with the cutout switches and hand-crak the trim wheels on each side of the throttle quadrant for manual trim.

More here: https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/

If it turns out that this second CFIT is related to MCAS, what do you want to bet that neither captains nor first officers hit those switches?
bcnu,
Mikem

It's mourning in America again.
New "Pilots complained about the 737 Max in a federal database"
CNN.


Pilot: Flight Manual on 737 MAX "is inadequate and almost criminally insufficient"

Other pilot complaints from the federal database include a report saying it is "unconscionable" that Boeing, the US aviation regulatory agency (the Federal Aviation Administration) and the unnamed airline would have pilots flying without adequate training or sufficient documentation.
The same entry also charges that the flight manual "is inadequate and almost criminally insufficient."



..can't add much to that.

Prediction: the phrase, "PILOTS DON'T NEED TO KNOW _______" (about whatever predicate)
will never again be uttered by anyone in the $$$$Industry, including the bloody-FAA.
Guess also: Perhaps the flight Manual departments everywhere will revise their entire M.O. Perhaps writing-in-RED: such hints as EXACTLY how you COMPLETELY-DISABLE a strongly or weakly SUSPECTED item. And no more "six seconds after you kill after a first porpoise": IT COMES BACK TO LIFE! aka

"For want of a nail the horse-shoe came off; for want of a horse ...WW-III began" to-coin-a-phrase. :-/
Expand Edited by Ashton March 13, 2019, 03:00:59 PM EDT
New From that very article.
Emphasis Mine.
In another complaint, a first officer reported that the aircraft pitched nose down after the autopilot was engaged during departure. The autopilot was then disconnected and flight continued to its destination, according to the database.


Is the system flawed? Obviously. Are there mitigating steps a pilot can perform? Obviously. I'm as disappointed in Boeing as anyone, but the fact remains that it was not exclusively Boeing's fault those aircraft ended up in the ground. I had to look it up and it turns out that for many airlines the autopilot can be turned on as low as 400 ft AGL on take-off. I asked a couple of retired ATP's about that and they both said they hand flew to about 10,000 ft or so before engaging the AP on take-off. I'd bet that isn't common these days.
bcnu,
Mikem

It's mourning in America again.
New from the WaPo today
Pilots were abuzz over publicly available radar data that showed the aircraft had accelerated far beyond what is considered standard practice, for reasons that remain unclear.

“The thing that is most abnormal is the speed,” said John Cox, an aviation safety consultant and former 737 pilot.

“The speed is very high,” said Mr. Cox, a former executive air safety chairman of the Air Line Pilots Association in the United States. “The question is why. The plane accelerates far faster than it should.”
I suppose we can’t rule out “pilot error” when it comes to the crew’s response, but it appears to me that a Boeing product ought not to require the pilots to correct behavior like this a few minutes into the flight.

cordially,
New Somewhat agree.
While I agree "a Boeing product ought not to require the pilots to correct behavior like this", I also hold that it is more important that "any product allow for pilots to correct behavior like this." This is the heart of my rationale for never looking at airlines when booking flights, but only at aircraft and only fly an Airbus product if (1) it is an emergency and (2) there is no other option available.
bcnu,
Mikem

It's mourning in America again.
New Thanks. Misread that first time around.
I found that in the wake of the Lion Air crash, but my brain somehow glued the cutout and the 5 sec reactivation together. Not good for reasoned arguments :-/
New 'Twas my first wonderment also;
IF you've altered ALL the C.G. relationships to such a degree that: you even have to glue-together an MCAS kluge ...
[shades of the "flies like a brick"==completely un-Pilotable IF the many feedback systems are cut off: in most War-planes du jour]

THEN: (the difficulties always of, 'proving a negative') until you do all the white-knuckle aerobatics tests--so highly unlikely re any gigantic Flying Auditorium--
[save for that period of Inverted-flight for n-minutes : in that Crash (not a MAX IIRC) near LAX wherein they indeed kept the sucker almost stably in-the-air until the same uncontrollability sent it augering-in to the ocean, straight down]

THEN: just HOW 'flyable' IS? this NEW-design amidst the vicissitudes of weather, engine-failure on one side [new "virtual-CG physics" re that lopsided-power thing, added to physical CG matters] ..and like that. I mean, when the static-CG MEANS that the plane will always want to fly Nose-^UP^ unless a bloody handful of sensors and software/assumed Perfect ... are always on-line? Acceptable in a Military plane? Yess, one supposes. In an aircraft with hundreds aboard? 'Course then there's Airbus, but I digress.

{Don't ask the dis-U.S. Supreme Court to make This call, eh? :-/ }

Worst case: what IF this glue-on-some bigger/heavier engines wherever we can make them fit has created a Very-expensive Franken-Liner?
(which brings us back to the FACT): that *this* 'NEW Design" was permitted by FAA et alia: to SKIP the mandatory Flight Simulator Time/per every Pilot: and go into production as a mere ".."made a few improvements", cha. cha. cha.
I smell BIG-$$$ payed-out and Boeing public spanking--and a reduced Trust of the entire U.S. plane-certifying process--at least in the minds of the semi-ept ..and maybe even the proles.
Expand Edited by Ashton March 13, 2019, 03:53:17 PM EDT
New It still handles fine in level flight
The nacelles are designed so they do not generate lift at cruising attitude. The problem shows up at higher angles of attack, as at take-off, because then the nacelles do generate lift and the moment acts to push the nose even higher.
     I would be quite nervous about flying in a 737-Max - (Another Scott) - (23)
         It's the anti-stall system. - (mmoffitt) - (20)
             It kinda sounds like a PID tuning issue to me. - (Another Scott) - (19)
                 Re: But imagine you're on a roller coaster... - (mmoffitt) - (18)
                     As said before (not just by moi) - (Ashton) - (17)
                         From 11-14-18: "Boeing’s automatic trim for the 737 MAX was not disclosed to the Pilots" - (Ashton) - (16)
                             Whom to believe? - (mmoffitt) - (15)
                                 not sure what it takes do disable that particular fly by wire function - (boxley) - (2)
                                     If I were captain or first officer on one, I think I'd turn it off during taxi. -NT - (mmoffitt) - (1)
                                         makes sense -NT - (boxley)
                                 Methinks that in this compact essay.. - (Ashton) - (2)
                                     Bemused LRPD sez: "There should be an opportunity for somebody here". ;^> Love. It. -NT - (Ashton) - (1)
                                         Former DOT Inspector General echoes the themes of this thread--on Amanpour: - (Ashton)
                                 B may have pushed the 737 design a step too far - (scoenye) - (8)
                                     No "off button" but there *are* "Cut-Out Switches". And they aren't hidden. - (mmoffitt) - (5)
                                         "Pilots complained about the 737 Max in a federal database" - (Ashton) - (3)
                                             From that very article. - (mmoffitt) - (2)
                                                 from the WaPo today - (rcareaga) - (1)
                                                     Somewhat agree. - (mmoffitt)
                                         Thanks. Misread that first time around. - (scoenye)
                                     'Twas my first wonderment also; - (Ashton) - (1)
                                         It still handles fine in level flight - (scoenye)
         some Boeing background - (rcareaga)
         story on the history of the 737 - (lincoln)

This is only a test.
149 ms