News Ethiopian 737 crashed on way to Kenya, 157 people on-board

MaverickSawyer

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Found this article to be extremely interesting...

http://spectrum.ieee.org/aerospace/...37-max-disaster-looks-to-a-software-developer

Indeed, not letting the pilot regain control by pulling back on the column was an explicit design decision. Because if the pilots could pull up the nose when MCAS said it should go down, why have MCAS at all?

MCAS is implemented in the flight management computer, even at times when the autopilot is turned off, when the pilots think they are flying the plane. In a fight between the flight management computer and human pilots over who is in charge, the computer will bite humans until they give up and (literally) die.

Finally, there’s the need to keep the very existence of the MCAS system on the hush-hush lest someone say, “Hey, this isn’t your father’s 737,” and bank accounts start to suffer.

The whole article is definitely worth a read.
 

Urwumpe

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The whole article is definitely worth a read.


It isn't bad - but contains quite a few weasel words.


Also, one of its questions is easy to tell: What if the hardware of the computer has only access to one sensor at a time?
 

MaverickSawyer

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It isn't bad - but contains quite a few weasel words.


Also, one of its questions is easy to tell: What if the hardware of the computer has only access to one sensor at a time?

Shouldn't be that way. If it is, then that's another case of Boeing being stupid on this.

Honestly, the more I learn about the MAX, the more I want to scream. They've made a disturbing number of poor or questionable design decisions that are now coming back to haunt them. They gambled that they'd be able to cut corners and costs by making the bare minimum of changes, instead of doing the safer (but more expensive) thing and at least re-winging the 737 design, or better yet, a clean sheet design.
 

Urwumpe

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Shouldn't be that way. If it is, then that's another case of Boeing being stupid on this.


Is that really a question now? :lol: The more gets known about the design, the more you wonder who designed it....
 

MaverickSawyer

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Is that really a question now? :lol: The more gets known about the design, the more you wonder who designed it....

I don't wonder, and that's what makes it even more terrifying. It was designed by folks who were willing to cave to management and cut corners in pursuit of profit margins, and by folks whose experience in engineering is likely limited to what they learned in school, which, through second- and third-hand exposure, I know isn't exactly teaching them things they need to know. They have limited to no hands on experience in the practical aspects of engineering and flight
 

steph

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I don't wonder, and that's what makes it even more terrifying. It was designed by folks who were willing to cave to management and cut corners in pursuit of profit margins, and by folks whose experience in engineering is likely limited to what they learned in school, which, through second- and third-hand exposure, I know isn't exactly teaching them things they need to know. They have limited to no hands on experience in the practical aspects of engineering and flight

Not sure how Boeing does the software part, but perhaps they outsourced it to the point that the programmers hardly knew what exactly they were working on, let alone know the safety rules on airplane programming.
 

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I wonder how long the 737 MAX will remain grounded, will it be something that basically makes 737 MAX untenable?
 

MaverickSawyer

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That's a possibility that I wouldn't discount, tbh. Boeing made some choices that left the aircraft reliant on the flight computer for safe flight in certain regimes, which isn't a good idea for an airliner. I mean, if I'm understanding the situation correctly, stalling the MAX is probably going to end really badly.
Personally, I think they should revoke the type certificate for the MAX line.
 

RisingFury

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Among bits and Bytes...
Boeing has decided to blame the pilots. :facepalm::facepalm::facepalm:

"Yes, we know the plane's flight characteristics have changed to the point we need a new undocumented system to correct for fault and yes, we know it's led to one crash before, but we gave you strict rules to follow in the event that our hacked together system malfunctions. So you're to blame!"
 

zerofay32

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I'm surprised Ethiopian Air isn't getting any blame TBH. Both crashes happened in parts of the world that are well known in the industry to have substandard Pilot training. That's on the individual airlines, not Boeing. But the whole deal has revealed flaws in the aircraft, no getting around that.
 

Urwumpe

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I'm surprised Ethiopian Air isn't getting any blame TBH. Both crashes happened in parts of the world that are well known in the industry to have substandard Pilot training. That's on the individual airlines, not Boeing. But the whole deal has revealed flaws in the aircraft, no getting around that.


Because Ethiopian is none of those. It has a very good safety and maintenance standard and a very new fleet - why else do you think are they flying brand new planes and not a 25 year old used 737?
 
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Frilock

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...Both crashes happened in parts of the world that are well known in the industry to have substandard Pilot training. That's on the individual airlines, not Boeing...




Except Boeing went out of its way to convince airlines the pilots didn't need extra training. An airline can have the best training program in the world, but if its not aware that there's something to train FOR I don't see how they could be blamed for not training for it.
 

APDAF

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Ethiopian is the biggest and best airline in africa, it's on par with most European and American airlines.

Likewise their training is also top notch.
 

Urwumpe

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Still - I wonder why the manual trim is unable to work, while the electric system could. Is the electronic torque limiter of the electric system increasing resistance of the trim wheels when powered off?
 

Notebook

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Reading the article it was lucky a previous crew had a jump-seat captain that knew what would work in that situation.
Does the mechanical trim wheel operate the elevator trim tab or the whole horizontal stabiliser?

N.
 

MaverickSawyer

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Reading the article it was lucky a previous crew had a jump-seat captain that knew what would work in that situation.
Does the mechanical trim wheel operate the elevator trim tab or the whole horizontal stabiliser?

N.

I think it moves the entire stabilizer. And in certain situations, you can apply enough aerodynamic load on the stabilizer with the elevators to lock up the jackscrew that serves as the actuator, at least with the amount of torque the crew can provide with the trim wheel. The electric motor on the jackscrew can provide significantly more torque and is basically impossible to lock up, provided the jackscrew is properly maintained.
 

Notebook

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As I understand it, a jackscrew is a mechanically irreversible mechanism? So once the motor has driven the stabiliser to wherever it has been commanded, it stays there till something breaks or changes?
Its odd that this none-reversible mechanism exists only in pitch control, not the others?

N.
 

GLS

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A few days ago I saw the CBS report with the audio, but for some reason it has now been removed from youtube... :shifty:
Here is a similar report from ABC:
 
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