Except rumors from media there is no clear explanation about what is going on inside Boeing. I just hope Boeing management is not the old Microsoft management.
737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
51–60 of 133 posts
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#52Mass media in general is stressing too much the fact that 737 MAX is allegedly based on dated designs. I think it's fair to say that MAX versions present some compromise solutions (like the now-infamous MCAS, which is there to compensate for the "unnatural" bigger engines). But I think that is not the main point. They would be good solutions it they worked as intended. There are some other more fundamental and more d…
>Like, why does such a critical system like MCAS take only a single AoA sensor as input
The classic approach is to have three sensors, so in case one fails you can know which one. Having two only indicates something is wrong but is not useful on the fly.
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#53Earlier quoted context omitted.
"Figure out a way to fly the thing in the new, crippled configuration" is hard. Figure out a way that's better than what the human pilot came up with may be even harder.
It's hard, but it's a very measurable problem. You randomly deform the airframe in a physics simulator, then get a real pilot to try to fly the simulated damaged airframe to the nearest airport. You then get an AI to try doing the same. As soon as the AI manages to get to the airport more often than the human, the tech will save lives, on average. My guess is a PhD student could come up with an AI passing the above t…
The political problem is that people still trust humans a lot more than they trust machines. So passengers would be nervous about being flown by an AI, even if the AI was safer.
There's some weird psychology behind this: human pilots/drivers/etc are seen by passengers as a personal proxy, with agency over any situation.
If you take away the proxy you take away the illusion of agency. Humans really do not like being put into situations where they believe they have no agency at all.
As AI gets smarter, this will become more and more of a problem, until there some kind of cultural shift because AI is obviously safer it's not even a question any more.
This may or may not happen.
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#54Why exactly does this author think an airplane needs a lot of computing power? Airplane software does not deal with especially large amounts of data or intense computations. Faster hardware does not provide an inherent safety benefit. There is a large degree of coupling between avionics hardware and software amd updating that software is prohibitively expensive. There's just no point in doing it unless you get a tang…
Yes, the 486 or 586 are far more powerful processors than what you would actually need for everything but the cockpit UI. You could probably get away with a Z80 or something similar. The flight control computers in our space probes frequently have a similar level of functionality simply because it's more than enough.
The only thing a more modern processor buys you is more memory, a faster tick rate for your RTOS, potentially an MMU if it doesn't cause substantial timing skew, and high-precision floating point. In the case of an avionics system I would imagine the requirements for fixed-point arithmetic are very well-understood at this point, so floating point doesn't buy you a whole lot and potentially creates new and exciting problems.
So I would say that 90's-era computers are plenty powerful for what they're used for.
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#55Why exactly does this author think an airplane needs a lot of computing power? Airplane software does not deal with especially large amounts of data or intense computations. Faster hardware does not provide an inherent safety benefit. There is a large degree of coupling between avionics hardware and software amd updating that software is prohibitively expensive. There's just no point in doing it unless you get a tang…
We sent people to the moon in 1969. We can definitely live with 90s computing power when it's enough.
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#56Mass media in general is stressing too much the fact that 737 MAX is allegedly based on dated designs. I think it's fair to say that MAX versions present some compromise solutions (like the now-infamous MCAS, which is there to compensate for the "unnatural" bigger engines). But I think that is not the main point. They would be good solutions it they worked as intended. There are some other more fundamental and more d…
>Like, why does such a critical system like MCAS take only a single AoA sensor as input, when there are two sensors available? Specially considering that the inputs from both are hardware-available to MCAS (the new software version is going to take data from both).
Are you saying the answer in the article didn't give enough information?
"Airbus addressed this potential problem on some of its planes by installing three or more such sensors. Former Max engineers, including one who worked on the sensors, said adding a third sensor to the Max was a nonstarter. Previous 737s, they said, had used two and managers wanted to limit changes.
The angle of attack sensor, bottom, on a Boeing 737 Max 8.CreditRuth Fremson/The New York Times “They wanted to A, save money and B, to minimize the certification and flight-test costs,” said Mike Renzelmann, an engineer who worked on the Max’s flight controls. “Any changes are going to require recertification.” Mr. Renzelmann was not involved in discussions about the sensors."
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#57Earlier quoted context omitted.
That article says that other plans will display the error and the recommended checklist automatically, which certainly seems faster than flipping through a bunch of books trying to find a specific page based off of some lights.
A lecturer of mine once said - knowing what kind of people we teach here for programmers, I am scared of going to the doctor. The less software is in something(and less cloudy/iot) the better. And the more I program the more I prefer stupid and mechanical things when reliability is on the line. A paper manual is always there for you.
>A paper manual is always there for you.
Then have the paper manual as a choice and/or backup.
If the programmers working on aircraft are so incompetent that they can't get a the digital manual correct, than they have no business programming any of the other multitude of systems that are critical to fly-by-wire systems.
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#58Mass media in general is stressing too much the fact that 737 MAX is allegedly based on dated designs. I think it's fair to say that MAX versions present some compromise solutions (like the now-infamous MCAS, which is there to compensate for the "unnatural" bigger engines). But I think that is not the main point. They would be good solutions it they worked as intended. There are some other more fundamental and more d…
>Like, why does such a critical system like MCAS take only a single AoA sensor as input The classic approach is to have three sensors, so in case one fails you can know which one. Having two only indicates something is wrong but is not useful on the fly.
Three with a disagree algorithm is definitely what I’d expect out of such a critical system, but two with signal averaging would still be much better than just one.
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#59Three angle of attack sensors should have never been something that could be overridden by cost savings measures. The engineers wanted three sensors and the management said no without ensuring all planes sold had sufficient mitigating controls. We need justice.
Re: 737 Max: 1960s Design, 1990s Computing Power and Paper Manuals
#60I'd rather take a well tested i386 than a new processor that crashes Linux with microcode errors.
Paper manuals actually instill confidence. Should pilots contact Stackoverflow in an emergency?