737 Max

No, the system designers, who are presumably aeronautical engineers and similar came up with the algorithms for the system. The software, written by software engineers, did what it was supposed to do.

No, that is the specs for the software, the algorithm for how it makes it's decisions, presumably at the hands of aeronautical engineers and similar. If the software had a bug, where it freezes or takes some action that is not part of the specs, part of the design, that would be a software flaw.

That has nothing to do with bad programming, it's a bad system design.

Reply to
trader4
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Software engineers are not the ones that decide the decision algorithms. They are not the experts in stalls, how to detect stalls, what to do about stalls. They just write code and by all indications so far, the code did exactly what the Boeing aircraft designers and the FAA expected it to do. If you have evidence otherwise, now would be a good time to find it.

Are you as sure about that as you were about:

The AOA display is not an option, it's standard

MCAS has been on other 737s for decades

The AOA is not a vane, it's done by an inertial guidance system

Reply to
trader4

I think that's mostly an oversimplification. Pilots certainly could fly the plane just fine in almost all circumstances, probably even in the rare circumstance where it started to stall at high speeds. They obviously are doing that with the hundreds out there, MCAS only comes into plane if the plane gets put into an unusual, high angle of attack. Commercial pilots aren't doing that. It's just that it's more likely to enter a stall at high angles of attack, angles that would not be seen unless something exceptionally wrong was already going on. It's more like in extreme testing, you can push existing 737s to point X, but the MAx would stall a little earlier than that. To keep it the same, they put in MCAS so that the MAx could not get to point X. Which isn't any different than more modern designs that are fly-by-wire, where no matter what the pilots do at the controls, the planes will not exceed programmed limits.

Reply to
trader4

Yes, and ended up getting the MAX to point Y.

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 Thanks, 
    - Win
Reply to
Winfield Hill

Yes, and the technical term for that is "angle of attack".

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  When I tried casting out nines I made a hash of it.
Reply to
Jasen Betts

+1

There are some people involved in this design error and signed it off who should never be permitted to work on safety critical systems again.

If MCAS had been properly designed or the review process suitably thorough then the problem of crazy behaviour with a single bad input would never have arisen in the first place. I find it hard to believe that in an aerospace company nobody noticed this glaring vulnerability. FAA is also culpable - they appear to have just rubber stamped it as OK.

Professional engineers are supposed to protect the general public from the avaricious "ship it and be damned" senior management who are only interested in claiming their bonuses and pumping up the share price.

Although the evidence appears to show that it takes three experienced pilots on the flight deck to manage the MCAS critical failure situation successfully when normally planes only fly with two qualified pilots.

The previous flight struggled with the controls for about a dozen cycles before the other Max qualified pilot advised them how to sort it out. He had time to think it through without having to wrestle with the stick and cancel spurious stall warning alarms.

Lion Air ground maintenance crews have questions to answer too (but then they never did have a good reputation).

We will have to wait for the report to be issued to see. It looks like there were ways to get out of the problem iff the pilots realised what was going on. The original 737 Max 8 flight manual did its very best to obfuscate MCAS with just one entry in the "Glossary of terms" section.

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A decision which some industry players are saying was made to avoid having to train existing 737 pilots about what MCAS is and what it does. If MCAS had been more reliable then it would not have mattered so much.

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Martin Brown
Reply to
Martin Brown

+1

And some who might wind up with criminal charges, depending on how the discussions went and on what basis the decisions were made. Key to that will be if voices argued that it was a bad design and/or that the disagree light and display at least needed to be standard, but they were overruled with the motive of profit from selling options in mind. Also, FAA was not updated when the design changed from only applying X correction down to applying 3X. Was that just an oversight or deliberate?

+1

Very shocking for Boeing. The only similar thing I can think of was about

20 years ago, when there were several 737 crashes where they just suddenly had hard rudder movement. This went on for a few years from the first crash to the last. Boeing suspected the hydraulic control for the rudder, kept looking at it, but couldn't find anything wrong. Mind you, this is just a hydraulic valve actuator widget, kind of like the power steering in a car. Then one day someone realized that somehow the design had a mode where the thing could get stuck and effectively reverse it's action, ie the plane had hard right rudder, the pilots are trying to make it go left, but to solve it, you had to instead do the opposite, use more right rudder! How it could take years to find that, IDK, nor did anyone ever explain it.

But the problem there is that every plane with an electric trim system, which is all commercial aircraft can get into similar runaway trim emergencies due to an electrical failure in those systems, eg short, stuck switch, etc. All pilots are supposed to be trained on that. It's why they have the switches to turn it off right at the trim wheels by the pilots. And even without training, you;d know that the plane flies perfectly fine with 4 deg nose up trim. So, suddenly trim is being driven to absurd, nose down by *something*. The 6" in diameter trim wheels, that make noise, are spinning right next to you, to nose down by *something*, then back to normal trim by pilot action on the trim buttons. The switches to turn off the electric are right there and then you can set it by turning those wheels by hand. Hello? What this shows is that there are some really incompetent pilots out there, some with thousands of hours and that's scary.

The LA pilots flew for about 10 mins and still couldn't figure it out. And again, this is supposed to be part of very basic pilot training, because runaway trim is very dangerous and needs to be solved immediately. But pilots keep screwing up. Sadly it happens a lot. They train for engine failure on takeoff on twin engine prop planes too. Over and over. Yet in a lot of cases, when it actually happens, the pilots screw that up, one classic way is they identify the wrong engine and perform the shutdown and feathering on the working one.

Yes, that's a big remaining mystery, what they actually did or didn't do. And we still don't know the root cause, ie is it actually the AOA sensor, the wiring, the interface in the instrumentation, etc. And if it's the AOA, what was the failure in these brand new sensors? Why no notice to inspect or replace them? Inspect and replace *something*? Makes you wonder if they really know exactly what happened. Is it possible it's something else, eg a still unidentified flaw in the software?

But they didn't have to know about MCAS at all to identify what was happening, which was the electric trim was running amok. A wiring short or stuck switch in any aircraft with electric trim could do similar.

It still didn't matter! After the LA crash in October, Boeing put out an urgent directive explaining what happened and what to do. The Ethiopian Airline says their pilots were informed and knew about it. The LA crash, of a brand new Max was all over the news and you'd think all Max pilots, if they gave a damn, would have followed it too. Yet the Ethiopians had the same thing happen and failed to follow the basic procedure.

Reply to
trader4

This is an interesting question of responsibility between the FAA and Boeing. According to some reports, FAA had preliminary approved some of the activity of MCAS. Then Boeing made the system 3 times more aggressive that had been told to FAA without telling about the change to FAA. I guess some heads will roll at Boeing for this change.

Reply to
upsidedown

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

Now think about the device that relies on.

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@optonline.net wrote in news:1a04bb5a-360c-46d7-9960- snipped-for-privacy@googlegroups.com:

No, idiot. The module incorporated could have a rod entry port that allows the pilot to tweak it from within the cockpit.

You are one thick f*ck.

And if you were actually literate, you stupid piece of shit, you would have noted where I said that a solenoid could be built into it that actuates an arm to make sure it is operating freely.

Maybe you could take your head out of your ass and go find yourselfa nice tall building to jump off the roof of.

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@optonline.net wrote in news:9ea95eb8-ead3-424b-818c- snipped-for-privacy@googlegroups.com:

I was talking about AOA indication. Boeing stopped including it in NUMEROUS planes.

Learn to read, s*****ad. And while you are at it, GROW THE FUCK UP.

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@optonline.net wrote in news:dbc6c11c-b680-49d9-85a1- snipped-for-privacy@googlegroups.com:

They ALSO do not include an AOA indicator on other 737 and other Boeing models.

Like I said... they quit including it because NO large craft really needs it. PILOTS never put their craft into such a situation so never need to refer to in indicator that merely takes up space on the instrument panel or a display.

That is one reason also why it was an option.

Reply to
DecadentLinuxUserNumeroUno

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

No. The software did what it was programmed to do. That program is in error becdause it NEVER 'decided' to relenquish control after deciding that it was not properly assisting.

The new code changes the trim rate and the rules for releasing its control and the rules for deciding whether it is recieving valid data from its sensor(s).

"the software, written by software engineers"

Are you really so thick as to think they do not know anything other than byte snippets?

ALL of the control code gets fully reviewed by ALL of the engineering staff. Sure "it did what it was supposed to do".

Sorry you have reading issues, but I refer to the "what it is supposed to do" as in PROGRAMMED to do, as being what is wrong, as in the choices made at particular event moments. The code works... It fires every transistor it was told to. That does not mean it cannot be 100% flawed in the decisions made to how it operates.

Maybe one day you will get it.

Reply to
DecadentLinuxUserNumeroUno

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

No shit, dumbfuck!

Reply to
DecadentLinuxUserNumeroUno

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

Sure, but in this case, the decisions to what to put in to the software is flawed, and sorry but that carries on intot the software.

Flawed is flawed, just like your mindset. Flawed.

Reply to
DecadentLinuxUserNumeroUno

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

You are an abject idiot.

Sure they are. They are right there in the same development group and provide input to the creation of that decision engine. It is a group effort.

Gert off you little hobby horse, noy.

Reply to
DecadentLinuxUserNumeroUno

Winfield Hill wrote in news:q7tpv3014r2 @drn.newsguy.com:

You spelled "point WHY" wrong. ;-)

Reply to
DecadentLinuxUserNumeroUno

Are you as sure of that as you were that:

The AOA display was standard in the 737 Max, not an option?

That the AOA is derived inside the plane via inertial reference, not by a vane in the airstream?

That Boeing has identified the root cause of the failure that caused the incorrect AOA reading?

That the two crashes were caused by bad software, as opposed to a bad system design?

As to your latest BS claim, that AOA isn't necessary in planes today, the NTSB that actually investigates accidents and knows how planes and crews operate, would disagree:

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Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Require that all t ransport-category aircraft present pilots with angle-of-attack info in a vi sual format, and that all air carriers train their pilots to use the info t o obtain maximum possible airplane climb performance.

Reply to
trader4

Again, one more time, software programmers are not the ones that decide what to use to determine that an aircraft is stalling, what to do about it, for how long to keep doing it, etc. Those are system design issues, presumably decided by aeronautical engineers, pilots, FAA, etc. The software which is part of it is then written to those specs. So far, there is zero evidence that the software was not written as specified.

No shit Sherlock. The aeronautical engineers and similar CHANGED THE SYSTEM CHARACTERISTICS, the system specs and software engineers wrote new software that conforms to it, just like they initially wrote code that implemented the original reqts.

You're the one that claims the software engineers made aeronautical system decisions. You seem to think that's how it works, so you show us your evidence. Of course you're also the one that told us:

The AOA is not a vane, it's done inside the airplane by inertial reference

The AOA is displayed as standard eqpt, it's not an option

Boeing has identified the specific root cause of the two failures. (BTW, since you know what it is, why haven't you shared that? And no, "it;s the AOA sensor" is not an acceptable answer because, A - Boeing has not said that, and B - even if is the AOA, it's still not the root cause. A root cause would be incorrect installation, a manufacturing defect, paint that stopped it from moving, etc.)

Presumably, that's true. But Boeing screwed the pooch badly here, we really don't know who reviewed what. We do know that the FAA didn't review it properly because apparently Boeing did not tell them that they had changed the system to exert 3X the trim force that the FAA was told.

And again, it did what it was programmed to do, it did what the system was designed to to, it did it exactly.

as

Maybe one day you'll get the concept that software engineers generally write code to the system requirements and those aeronautical specs are the expertise of aeronautical engineers, test pilots, the FAA, etc. You come to me and tell me you want software that when switch A and B are closed, applies 1000V to your balls for ten minutes. I write it. Someone closes the two switches. It may come as a shock to you, but it's not my fault, the software did what you told me to make it do. It's not a software flaw, it was a stupid system design.

Reply to
trader4

snipped-for-privacy@optonline.net wrote in news:e3bdffe7-1dc4-40c3-911c- snipped-for-privacy@googlegroups.com:

No. I am saying that Boeing quit puttin AOA in their planes. All of their planes. That is what I read.

The max did not have it. It was an option as was the disagreement indicator.

There is still no need for an AOA readout on modern large craft. Which is why it is an option.

If there were no MCAS in place, the pilot would trim out a nose up tendency and keep flying.

Because there are major competitors like Airbus in play, this boo boo could very well take Boeing all the way down in the passenger jet channel.

The dang thing also adds weight in the rear of the craft very likely moving the center of gravity back even further yielding an even greater nose up tendency.

Reply to
DecadentLinuxUserNumeroUno

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