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Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

bbc.co.uk

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Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#51

Post by cdolan »

sundvor wrote: post #23
bobcostas55 wrote: post #15

Earlier quoted context omitted.

The software did what it was supposed to, the issue was the specification necessitated by the design change.

Yep, the issues started way earlier than the software. In fact the software is at the very end of the chain here, unless you also want to insert "no training". It all started when they wanted those big engines crammed into an airframe not designed to hold them, so as to try to quickly catch up to shifting market demands being met by Airbus.

How can you say “no training” caused this second crash after reading the article? Did you read the article?

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#52

Post by Pyxl101 »

DanielBMarkham wrote: post #16

There you have it, folks, programmers killing people. No, it wasn't on-purpose, but that doesn't mean it didn't happen. This, of course, has been happening for a long time, it's just getting more and more obvious now. I feel strongly that AF 447 was an example. It's important to understand that this is the natural result of two trends. One, software/hardware systems continue to become more and more complex, many time…

How can we be sure that this is programmers killing people, and not merely a busted angle of attack sensor, or an inadequate specification for how the plane should be designed (number of sensors or sensor robustness) or how the software should behave? This conclusion feels premature.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#53

Post by jfk13 »

vfinn wrote: post #46

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would eject the cabin as a parachute module or something. Yes, I'm sure this is naive, but why? Edit: My point is that almost anything is better than crashing down with the plane.

Can you imagine the scale of parachute that would be needed to safely bring an airliner cabin to earth? Could a parachute on that scale actually be made sufficiently strong (and light), and successfully deployed? I doubt it.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#54

Post by lm28469 »

pjc50 wrote: post #28
deepstream wrote: post #11

pilots should not have to fight the system. can there not be a simple button, "switch to manual"?

Naive question, but is the plane actually possible to fly in "manual"?

Not sure about that particular plane, but it should be. Contrary to jet fighters they are made to be aerodynamically stable.

You can fly (glide) them and even land with most systems switched off, including engines and main power.

https://www.boldmethod.com/learn-to-fly/aerodynamics/3-types...

https://en.wikipedia.org/wiki/Gimli_Glider

https://en.wikipedia.org/wiki/British_Airways_Flight_9

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#55

Post by agumonkey »

vfinn wrote: post #46

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would eject the cabin as a parachute module or something. Yes, I'm sure this is naive, but why? Edit: My point is that almost anything is better than crashing down with the plane.

costs and motivation I suppose

some air vehicles have whole frame parachutes but not the scale of 737.

I was wondering if a plane could not be made out of separate cabins coupled together (I can hear engineers die of laughter) so that they could be break loose with their own parachute.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#56

Post by milgrim »

bobcostas55 wrote: post #15
WheelsAtLarge wrote: post #6

This is a software screwup. It's buggy software due to rush to market. I hope they do an analysis of the whole project. We can all learn from it.

The software did what it was supposed to, the issue was the specification necessitated by the design change.

I just sounds like nobody really thought about the consequences of MCAS triggering due to faulty AOA sensor input. There should be a dedicated switch to disable MCAS without completely disabling the electric trim motors.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#57

Post by nl »

bobcostas55 wrote: post #15
WheelsAtLarge wrote: post #6

This is a software screwup. It's buggy software due to rush to market. I hope they do an analysis of the whole project. We can all learn from it.

The software did what it was supposed to, the issue was the specification necessitated by the design change.

The software did what it was supposed to

I'm pretty sure that it's a reasonable assumption that an implies requirement of any type of aircraft control software is "don't fly the aircraft into the ground"

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#58

Post by jakecopp »

vfinn wrote: post #46

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would eject the cabin as a parachute module or something. Yes, I'm sure this is naive, but why? Edit: My point is that almost anything is better than crashing down with the plane.

Hard engineering problem - where do you open up the fuselage to get the people out? It's a tube so you can't weaken it.

You also can't open a hole at the back and let them slide out backwards, you'd need a cylindrical tube in a tube which can then slide out. That's a HUGE amount of extra weight and complexity.

Planes are so so much safer than cars. Before we parachute people out of passenger planes we should be ejecting people out of the roofs of cars if an imminent collision is detected :)

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#59

Post by sundvor »

lysp wrote: post #13
mhandley wrote: post #7

Will be interesting to see the details when the report is actually public. It does sound like the scenario that Mentourpilot explored in the simulator is close to what happened, namely: Bad AoA probe causes MCAS to trim down, and also to indicate IAS disagree. Pilots increase throttle as per non-normal checklist to reduce the risk of stalling due to unreliable airspeed. Pilots disable electric stabilizer trim, as per…

Does anyone have a mirror of that video?

Not that video, but at least it shows the automatic trim system in action - and is rather educational:

https://youtu.be/l62NvkRWa5E .

Even better: https://youtu.be/xixM_cwSLcQ

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#60

Post by quickthrower2 »

WheelsAtLarge wrote: post #6

This is a software screwup. It's buggy software due to rush to market. I hope they do an analysis of the whole project. We can all learn from it.

Not really, see https://news.ycombinator.com/item?id=19570691 for a good analysis
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