Boeing 737 Max design error

What do you expect? If you aren't of this Earth, you have to produce some sort of document.

By all indications it was not a software bug, from everything we've seen the software did what the aerodynamic engineers and others spec'd it to do. And it all was tested, including by test pilots, for certification, including in extreme situations, where MCAS would be involved. Apparently having a stuck AOA sensor wasn't part of the testing.

That's ridiculous and what evidence do you have that the software developers were spaced out? Aeronautical engineers and pilots certainly should have been involved with what MCAS was and the specs for how it should operate. This failure is clearly on them and the FAA. Could some software team people have weighed in on some aspects of it? Sure. Like you'd think someone might have said that part of the software should do a functional test while the plane is still on the ground, to verify that the reading from the AOA is normal there. And maybe they did, we won't know what all went on until it's all been investigated. Also, whoever was writing that code, that code module might not have access to the necessary data to even know if the plane had just been started up, was still on the ground, etc. and without that, you couldn't check.

Bottom line, people that were responsible, were knowledgeable at Boeing and FAA were OK with this half-assed design where a single failed sensor could shove the nose down, repeatedly. They considered it a serious malfunction and evaluated the probabilities of various failures that could cause it, by that measure, it met FAA and industry safety guidelines. Another question in all this is what the root cause failure was? We've heard nothing of that from either crash, which is very weird. These were two sensors in two new planes that someone failed or were damanged, etc. What exactly happened? You'd think they would suspect say a manufacturing defect or something and have out a directive to inspect, replace, all the similar AOAs out there.

Well, thankfully we have plenty of others willing or we'd be screwed.

No

While there certainly was some shystering involved in calling it a university, Trump didn't hand out fake certificates, he never claimed it was an accredited, real university, he wasn't handing out BA, BS diplomas. You'd have to be a real grade A moron to thing a few real estate seminars could be a university degree.

Except of course that the 737 Max and MCAS had been developed before Trump took office. But I agree he is a corrosive effect and like you say, if he can lie and cheat, then why not everyone else? One of his worst moments was when he saluted Manafort, who had just been convicted of among other things, of hiding laundering and failing to pay income tax on $30 mil. He said it was awful what "they" did to him and that he respects him for being strong and refusing to cooperate with the Justice Dept. That was a very, very low point for our country.

When's the last time you heard Trump even use the words deficit or national debt? They were only a big issue when they were under Obama, now that they are his, not a word. In fact, he just had another meeting for a "solution" to a problem. He had Schumer and Pelosi over the the WH and they reached "agreement" to spend $2 tril on infrastructure. The WH admits there was no preparation, no analysis, just Trump winging it. Notably absent was any discussion about how to PAY for it. So, we all know where this "solution" is headed, it was all Kabuki theater.

The birther movement is still alive. And then you wonder why some people say birthers are racist.

On a sunny day (Mon, 6 May 2019 06:27:34 -0700 (PDT)) it happened snipped-for-privacy@optonline.net wrote in :

I have read lately it was, it is anyways in the sense that it did not detect the output to ever tilt the thing more and more. Looks like the dumbest loop you can ever write. It did not check angular position (I think they added that now, only takes a 1$ MEMS chip), and it had no redundancy.

That it did what it did!!!

Yea, that is why so many of those IT projects are a disaster.

CNN had it I think :-0 :-)

That's incorrect. The pilots know that a stall is approaching with the STICK SHAKER and audible alerts.

The issue with the 737 Max is that at high levels of AOA, the plane has a tendency to nose up even further. Part of the certification process is that if you release the controls the plane is supposed to head in a stable direction, not toward instability. That is why MCAS was added.

Wrong again, as proven by the first Lion Air flight that had the same problem the day before the crash. The pilot in the jump seat, who was not one of the crew, correctly identified the runaway trim problem, told the two pilots flying what to do. They turned off the electric trim, used manual trim and the plane flew on to it's destination.

Wrong, always wrong.

And the Lion Air pilot on the flight the day before the crash, did exactly that. He wasn't flying, just catching a rid in the jump seat. When the other pilots couldn't figure it out, he did. This is the most shocking thing. This isn't rocket science and the LA pilots on the fatal crash had ~10 mins to figure it out. Let's see, the plane is porpoising around, driven DOWN by something, then corrected back up by you with the trim buttons. The trim wheels by your seat are noisely spinning back and forth, the indicators showing extreme down and up trim. Hello? You should know that the planes you've flown so many times before, the trim needs to be near neutral. So, get it there and turn off the electric! Trim manually. It's part of basic flight training. In fact one of the things pilots are supposed to have committed to memory is that if all is going screwy, set power to 70%, trim to 3 deg up and the plane will fly.

Yes.

Agree. We really don't know from what limited info the Ethiopians have released. The co-pilot turned off the electric and said that he was trying to trim manually, but could not. But it's not clear if he meant he was trying to turn the wheel or if he meant he was using the button on the controls. It would seem most likely that he was trying to turn the wheel, but could not. If so, that would be another huge problem, one that could extend to all 737s. Is it possible with extreme trim and enough airspeed that you can't turn the wheel? IDK, that seems unlikely, because then any runaway trim could be fatal. Also, someone then turned the electric back on. That would be consistent with not being able to move it by hand, but then you should have the trim UP button pressed on the controls as you turn it back on, get the trim to near neutral, then turn it off again. Instead after it was turned on MCAS was allowed to push it nose down again, this time into the dirt.

I agree. Especially in the case of the LA crash. They had ~10 mins of flying time to figure it out. And they did plenty else wrong too, like keeping the airspeed high, which would just make trying to trim it harder. Also, all the trouble started just as they retracted the flaps. You'd think a last ditch idea might be to try putting the flaps out? That would have disabled MCAS. Still, another question is if this is really a training issue? It's quite possible that they were trained a lot but screwed up anyway. And part of this is so very basic. A plane isn't going to fly right when something is pushing the trim nose down. It flies nice when trim is near neutral. Seems pretty obvious what to do, but maybe in a real crisis, people can't correctly react? That LA pilot had handed over control to the co-pilot as he was flipping through the manuals. Where you'd expect to find a page that covers that problem, IDK. He'd have been better off focusing on very basic flight principles.

Not true. The runaway trim procedure is to turn off the electric trim and then trim manually. MCAS is disabled when the electric trim is off. We have proof of that from the Lion Air flight on the day before the crash that had the same problem. A pilot that happened to be riding in the jump seat told the pilots who were flying what to do, because they could not figure it out. And the cutout switches aren't in some obscure panel somewhere, they are right next to the two trim wheels beside the pilots. The trim wheels spin back and forth, noisely, and indicate the trim position. If you saw the trim going to nose down, driven by something, and the two clearly marked cutoff switches, what would you do? And what to do is part of very basic flight training, it's the runaway trim procedure.

Yes it was, per the above.

Normally manually

You didn't have to know it was MCAS that was causing runaway trim. It could have been an intermittent short, for example. A stuck trim button would force it full nose down too.

That is all that it was. MCAS just uses the electric trim to push the nose down. You'd think that even without training at all, pilots would realize that the plane isn't going to fly right with the electric trim intermittently forcing extreme nose down. But that it will fly all day long with just 4 deg trim and 70% power. Or that if the trim is somewhere near neutral, then you can put enough force on the controls to make the plane do what you want. So? Get the trim back to near neutral and TURN IT OFF.

And we know that following the runaway trim procedure works, because that's what they did on the Lion Air flight the day before the crash. The passenger pilot in the jump seat had to tell the two flying to do it. They did, the flight went on to it's destination.

The cavalier way that was treated is something else that should be looked at and corrected. IDK what procedures any airline has, but you would think that after a plane experienced a severe event like this, the crews that are taking it out subsequently, especially the very next flight, would be informed about the abnormal behavior and what was needed to correct it. What the maintenance crew did with the AOA or whatever else still isn't public. Nor is the root cause of what was wrong with AOAs in two brand new planes? You'd think they would suspect something, eg a manufacturing defect or incorrect installation and there would have been a directive to inspect, replace all similar AOA. But nothing, very weird.

Incorrect. There are two clearly marked cutoff switches for the electric trim, located right at the large trim wheels that are spinning back and forth beside the pilots. Turned off, MCAS can't do anything.

Altitude would not seem to be a parameter in determining if the plane is stalling or not.

Wrong. A pilot on the Lion Air flight with the same problem the day before the crash followed the correct procedure. But he was in the jump seat, not flying. The two flying pilots couldn't figure it out. He told them the procedure, it worked, the plane flew on to it's destination.

You can get abnormal trim from a short or similar component failure. That's why those cutoff switches and manual trim wheels are in all aircraft, not just the Max.

I agree it should have been in the manual. But even there, pilots disagree. After the LA crash, the head of United pilot's union said they were OK with it not being in the manual, that they don't need to know that level of the inner workings. I found that quite stunning, but that's what he said. And we have the Ethiopian crash, in which case those pilots knew about the system and how it worked and it didn't matter. No searching in manuals was required. The runaway trim procedure is very basic and is one of the memory items all competent pilots are supposed to understand.

There is a procedure and it's a MEMORY item of what to do in a run-away trim situation. There are 2 switches, just below the throttle quadrant that cuts out the electric trim (and MCAS). Once turned off the AFM says you do not turn it back on. It stays off until you land. Auto Pilot off Auto Throttles off Auto trim off.

A friend of mine with over 10K hours in the 737 variants explains these are memory items drilled into your head and you practice them every 6 months in the simulator check ride.

In the Ethiopian crash it seems they never disabled the auto throttles and towards the end they re-engaged auto trim (and MCAS). The aircraft was already red-line in speed.

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at the front of the wing. That makes it stall easily. Software cannot fix that

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oesn't.

nothing

I have not seen anything clear or athoritative, but it appears the situatio n is not so simple to diagnose as was initially indicated. When you have a cockpit full of instruments and controls and "something" is wrong and the plane is behaving very erratically, it seems not so simple to do the right thing and know that it was right in the face of the airplane continuing to fly improperly.

There is the main point. It is too early to be making judgements. I like that some consider the problem to be software failures that could have been prevented by using pilots to write code. lol

Serious questions need to be asked about the process that allowed this syst em go so wrong that so many people died in two accidents. This investigati on should be no less rigorous than the investigation into the Challenger ac cident.

On a sunny day (Mon, 6 May 2019 07:26:28 -0700 (PDT)) it happened snipped-for-privacy@optonline.net wrote in :

Yes I did read that.

If that is so then it is indeed strange the pilots did not use those. Maybe it had to do with too much flying on auto-pilot and not enough real flight hours, too much relying on automation, much has been written about that.

You can only get out of a stall by putting the nose down gaining speed if you have any altitude at all. So it the very low altitude situation the system should not interfere in my view (minimum altitude can be calculated I'd think), but simply sound a warning. It is a bit tricky, you can argue that is just where I need that system.

PR s*it because Boeing did not even inform the pilots of the system it seems, and is trying to avoid large damage claims. All the grounded airlines all over the world that now have less income can sue Boeing. That could go into the very high numbers of dollars.

I would not want to fly a plane without knowing what control systems it has. That is a bit tricky too, does a truck driver need to know how ABS works etc... or how the fuel injection computer works? If you say 'no' then having no redundancy is a crime?

I'd imagine they're hiring a lot more of the best legal teams money can buy to fight all the negligence lawsuits heading their way and tie them up in court until about the year 2045 would be my guess.

When Boeing's execs heard an Ethiopian plane had crashed they were like "wtf? what are those monkeys doing running an airline with our planes, anyway? Well we'll just patiently explain to low IQ Americans that the reason it crashed is due to the even lower IQ of Africans. and well I guess we gotta pay something what's a good payout for a shithole country victim, like $25?"

A jet plane is full of software that's critical to flight. The throttles aren't mechanical any more, they send signals to the FADECs. And on and on.

I don't think that your "looking at photos" is solid aerodynamic analysis.

Boeing made some appalling choices with the AOA sensors. Absent those mistakes, the 737 would be fine.

The Board of Directors didn't design the anti-stall system or decide to only use one AOA sensor per flight.

I don't honestly know what a robot needs to go to college for I imagine they could just upload all the data in like a microsecond.

Maybe it's just for personality/backstory reasons. Anyway I went to a liberal arts college and ah just some friendly advice probably best to take your chances with the science-student model.

Very small, minor bug with early liberal arts model which results in occasionally she breaks down your bedroom door with a fire ax at 3 am while asking through sobs if you truly love her even tho she is not a "real girl" YOU DON'T REALLY LOVE ME!!! I would suggest you affirm that you do to the robot-girl with the fire axe if you encounter this definitely-uncommon bug.

When you design a safety system that relies on a single sensor to determine whether the aircraft system is in a safety-critical state that needs action "the AOA sensor indicates the aircraft is in stall", how do you distinguish between a "normal" safety-critical situation "the AOA sensor indicates the aircraft is in stall" where the plane a a whole is in an error state but the safety system itself is still functioning normally, vs. "the AOA indicates the aircraft is in stall...because the AOA sensor is trashed" where the plane is still functioning normally but the safety system is in an error state.

I don't know that I have an answer to that question either other than "don't do that."

The lawsuits from the victims are the least of Boeing's problems. They will wind up paying far more to all the airlines that have grounded

One way would be to look at other data, eg airspeed and attitude and see if that's consistent with a stall. There is going to be a wide range where the plane couldn't be stalling based on the other data. Including the flights that crashed. You'd have to be doing an extreme maneuver to get into a high angle of attack stall. And that is apparently what Boeing is now doing as part of the new software.