Boeing 737 Max design error

Well, you should NEVER fly a 737 because you don't know what you are talking about. The weight & balance of the 737 Max IS NOT the issue, and never was. The issue has to do with MCAS (Maneuvering Characteristics Augmentation System):

The MCAS as delivered was deeply flawed and has been fixed; the aircraft is now undergoing flight certification testing and will be back in service shortly.

Actually, tail-heavy makes for an easy stall, and nose-heavy makes for a dive. The crash planes weren't stalling, the AOA sensors just thought they were. So you have it backward.

This photo should put your mind at ease.

500-something people dead and Boeing seems to just shrug it off like they're Microsoft and they're gonna patch a bug in Windows 10 at the next update. "Sorry, our bad." 500 dead people used to be the kind of thing executives tendered their resignations over, and people get fired or go to prison over. Anyone at Boeing going to do any time? Any execs on the gravy train going to take the fall for this one? lol. They have a former exec as SoD, they're untouchable and might as well be considered a branch of government at this point, nothing gonna happen. Keep them checks rolling in, peasants, hey sorry for murdering all those people with our shit software but at least it didn't happen here.

On a sunny day (Sun, 5 May 2019 23:13:13 -0700) it happened Banders wrote in :

Normally software is tested and debugged, crashes happen, bit of a nono to debug it in flights that carry people.

My opinion is that such software should be written by pilots, not by spaced out no flying experience people.

I have bluntly refused to write code for things that I could not use myself.

Boeing and Trump standing there 'selling' it when whe got elected... Does anybody see the link?

Ever write the code for an artificially intelligent sex-robot that replicates the sensation of making love to a barely-legal Asian college student majoring in microbiology? Asking for a friend.

Ah I got it. Trump is a sex-robot salesman from the future accidentally stranded in our time. I knew it.

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

The planes did not stall.

Your grasp of aeronautical engineering appears to rest near nil, as does the credibility of your opinions.

"I looked at photos..."

Yeah, you're a real expert... not!

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

The software was for IF the plane stalled, which it did not. It was a sensor error.

It is because the pilot does not always have a sense of a stall situation, which the craft never get into anyway unless the pilot and copilot are sleeping.

A stalling plane is pilot error, not airplane error.

The biggest issue to me is that there was no release switch to return pilot control.

bitrex wrote in news:c1RzE.535275$cD4.504076 @fx43.iad:

You are so full of shit. You have no clue what they are doing with the families of the victims, etc. And you are obviously also clueless as to what they did to fix it.

You are the worst kind of speculator.

On a sunny day (Mon, 6 May 2019 03:52:33 -0400) it happened bitrex wrote in :

Interesting, yes, this is interesting too:

Should not be a problem, try on monkeys first ;-) Anyways AI is your solution.

Like Trump University, normally somebody would get jailed for running a fake university and handing out fake certificates? A Leader That Is A Fake and does not take things like reality and laws seriously, will cause its minions to behave the same, and cut corners, there is the cause and effect.

hell even CNN sings his praises these days. NY times changed its wallstreet page to a useless piece of shit after he commanded it. And US deficit is still growing.

In a world were machines and AI should now be doing all the work, in the USA more and more people are forced to work!

He sells that as good!

I watched a move last night, 'passengers', recommended.

Warships heading to Iran, making trouble in Venezuela, bullying Germany and the EU, and just now more tariffs on China. Your capacitors will be more expensive, your PCBs too, your 5G will suck without Huawei, Apple will go belly up due to no sales in China, a WW is on the horizon.

I was considering a project to beam up people to some satellite, got some code for that? LOL

MCAS was the software *BODGE* installed to allow marketing to pretend that the 737 Max was just another 737 model despite it having perverse handling characteristics resulting from the physically larger engines and a shifted centre of gravity. MCAS was badly flawed but something was necessary to prevent the plane from stalling if flown like a real 737.

MCAS as implemented would put the plane into a power dive to avoid stalling if the AoA sensor went bad. A well trained aircrew might have been able to counteract this although according to the last crash the procedures do not work if take off is from a high altitude airport.

Heads must roll in the FAA who signed this off on the nod without properly checking that Boeing engineers had done the job right!

--
Regards, 
Martin Brown

It wouldn't worry me unless it came from Microsoft.

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Dunno about that, but I *do* know Obama posted a crudely-forged birth certificate on the WH website, so maybe Trump is simply following a recently-established precedent. :-D

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The effect of the software behaviour, as was, was to trim the aircraft forward for no good reason.

The pilots should have treated it as a runaway trim, and acted accordingly. Then the crashes would not have occurred.

It seems likely that Boeing expected that that would happen in the event that this non-redundant computer system misbehaved.

Yet in both cases the pilots let the aircraft get itself seriously out of trim. So much so, that in the case of the second crash, when the the pilots did eventually disable the electric trim, the aircraft was so far out of trim that the pilots were not strong enough to turn the trim wheels (or they didn't try - it's rather unclear at the moment).

Serious questions need to be asked about the competence of the pilots. Would a properly trained crew have had any difficulties, even in the absence of details about MCAS? I rather think not.

Sylvia.

The MCAS software commanded a dive for a very *good* reason: the AoA was dangerously high. Or so it was being told by a faulty sensor.

They were overridden by the MCAS.

Disabling the MCAS wasn't trivial. Normally manually operating the controls will disable the autopilot and give control back to the pilots. But MCAS wasn't part of the autopilot and was designed to prevent that.

Don't forget that the *purpose* of MCAS was to *pretend* nothing had changed, i.e. pretend that MCAS didn't exist!

It was far more than "trim".

Hiding behind "properly trained" is frequently an inadequate figleaf. That's definitely the case here, since the the whole purpose of MCAS is, *very explicitly*, to *avoid* having to retrain pilots!

For a long time Boeing has trumpeted that they allow their pilots full autonomy, unlike the Airbus fly-by-wire system. MCAS is a complete change in that philosophy.

On a sunny day (Mon, 6 May 2019 19:00:05 +1000) it happened Sylvia Else wrote in :

The system could not be turned off AFAIK.

Have not read all the details, but it seemed they increased speed / engine thrust to prevent a stall. What th3 stupid system should do it check for altitude and a lot more parameters before doing the fatal trim.

Where I live in the old days pilot training to get out of a stall was on a little 'Tiger Moth', little bi-planes:

They used to do that next to our house, above the neighbors land ..... Training, yes, and it did not always go smooth.

No, that is Boeing PR shit. That plane is a disaster, it is unstable by its nature. Pilots were not even informed of that system. Try reading a 'manual' (having severe deficiencies in it) in the 60 seconds or so you have before the crash.

A properly trained crew would have a pair of cutters to cut the wires to the thing before takeoff. :-)

The procedure for a runaway trim involves tripping two switches that disconnect the electric trim. It prevents the MCAS, or anything else, from moving the trim electrically.

In the Ethopian crash, they did trip those switches, and it did prevent the MCAS from doing anything, but they also couldn't, or didn't, rotate the trim wheels manually to get the aircraft back into trim. They then, unaccountably, tripped the switches again, reenabling the electric trim, and in the process letting the MCAS make the situation even worse.

Sylvia.

They were in no danger of stalling, but the increased engine thrust will induce a pitch up, or at least reduce the pitch down, and that may have been their intent.

It was my own conclusion, with no input from Boeing.

The runaway trim procedure is a memory item. They're supposed to be able to action it without reference to the handbook.

Sylvia.

It doesn't stall so easily. The problem only arises at very high levels of angle of attack, that a plane would only experience in extreme, very unusual situations. And then the problem is that if you let go of the controls, instead of heading back toward a lower angle of attack, the plane can nose up more, which would stall it. The plane likely could not have been certified with that problem. That's what MCAS was put in there to counteract. Granted it's not the best design and a totally new plane design would have been better. But then that costs a lot more, both in development and then you have increased costs for the airlines due to training, type ratings, and now you have a mixed fleet that adds to maintenance costs, etc.

Software cannot fix that

That's not true, except at very high angles of attack it behaves just like any other 737.

And apparently you can add some pilots to that list, exactly how many, no one knows. Because when the AOA failed, it presented itself as runaway trim, which all pilots are trained to deal with. The Lion Air flight, they flew around for about 10 mins and couldn't figure out that the plane can't fly with the trim wildly oscillating back and forth and that the procedure is to turn off the trim and set it MANUALLY. The flight the say before, neither pilot there could figure it out, by chance their happened to be another pilot in the jump seat and he had to tell them what to do. The Ethiopian pilots screwed the pooch too.

Personally, I'm a lot more worried about incompetent pilots that don't understand flight basics and that Boeing and the FAA were OK with a very, very bad and obviously flawed MCAS system that relied on just one AOA sensor. If they could do that, who knows what else is lurking.

On Monday, May 6, 2019 at 4:31:20 AM UTC-4, Martin Brown wrote:

The only place the Max behaves differently is at extremely high levels of attack, ones that a plane would only see in testing or very unusual, abnormal flight.

What exactly happened with the Ethiopian crash is unknown. For one thing, the Ethiopians have been slow to release information, we still haven't heard the voice recorder AFAIK, only some conclusions they are trying to put forth from it. One interesting thing was that it was the co-pilot that correctly identified that they had a runaway trim condition and that they should turn off the electric trim. They did. And then he apparently tried to trim it "manually", and indicated that he could not. But, it's not clear what he meant by "manually" and there is no more discussion. Did he mean using the wheels by hand? Or was he confused and using the trim buttons on the wheel and calling that manual? Then they turned the electric trim back on, at which point MCAS shoved the nose back down again. The question here is can it be impossible to turn the trim wheels? If so, then there is another serious problem. In retrospect, the obvious best procedure would be to first use the trim buttons to get the trim back to near neutral and only then turn off the electric trim and trim manually. The Ethiopian pilots had a lot less time to figure out what to do than Lion Air, where they flew around for about 10 minutes. But still, after all the news about LA, the new Boeing directive, you'd think they would have had plenty of time to think about it, consider it, etc. So, maybe they did the right thing and the trim wheel would not move. From the limited transcript that the Ethiopians released, the communication back and forth between the two pilots was poor. For example, had the co-pilot said, I'm going to use the *trim wheel* or I can't move the trim wheel, then we'd know what he was doing. Also, quite shocking that someone turned the electric trim back on, without any discussion or informing the other pilot. And how did MCAS then immediately push the nose down again? Whoever turned it back on should have had their thumb on the trim UP button, so that it would immediately move in the desired direction and that would have overridden MCAS. At least that's how it's supposed to be wired up and working.

You would hope that would happen at both FAA and Boeing, including the CEO. So far, his handling of this has been abysmal. It's shocking that such an obviously flawed MCAS design could ever have been conceived of and built at Boeing or any other aircraft manufacturer, for that matter.