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Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

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Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#91

Post by manigandham »

contravariant wrote: post #86
manigandham wrote: post #80

Earlier quoted context omitted.

There's no fundamental design flaw, the aircraft is sound. The problem came from using software systems to artificially make the plane behave like older designs to avoid entirely new training and certifications. Even that would've been acceptable and similar systems are already in use in other planes but it was the inadequate info, redundancy, warnings and controls to disable the system that created the problem. It's…

This is pretty far from my area of expertise but I if it was behaving as the older designs did then why did it crash? As far as I can tell there are definitely some flaws, which seemed to have crept in as a result of the attempt to make them behave like older designs, but it seems optimistic to assume you can simply remove the flaws by sacrificing on that point.

It crashed because the system that was making it behave that way failed. The MCAS did not get correct data, did not react well, was not easily deduced to be the problem, and was not easily disabled.

Training and technical improvements can resolve these problems and it's ready to fly. If that's still deemed too risky then Boeing can remove the behavior modifications with training and certification as a completely new design. It was this cost that they were trying to avoid through emulation but clearly not done in a safe enough manner.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#92

Post by [deleted] »

samstave wrote: post #84
manigandham wrote: post #80

Earlier quoted context omitted.

There's no fundamental design flaw, the aircraft is sound. The problem came from using software systems to artificially make the plane behave like older designs to avoid entirely new training and certifications. Even that would've been acceptable and similar systems are already in use in other planes but it was the inadequate info, redundancy, warnings and controls to disable the system that created the problem. It's…

Exactly. Structurally it is sound. Tear out the MCAS and get the bodies in the air. Period. However, fuck boeing's engineering team on this one. They should pay a price. Fuck you for downvoting, be informed: https://www.vox.com/videos/2019/4/15/18306644/boeing-737-max...

[deleted]

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#93

Post by an_account_name »

djsumdog wrote: post #30
acidburnNSA wrote: post #25

Earlier quoted context omitted.

The Nuclear Regulatory Commission is doing just fine in their function.

True, but I also doubt we'll see new nuclear facilities in the US any time soon.

Some of these applications have been withdrawn, but there are in fact some in flight.

https://www.nrc.gov/reactors/new-reactors/col/new-reactor-ma...

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#94

Post by cm2187 »

djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

A brand new design would probably introduce more serious flaws than an interation of a mature design, so I am not sure it would be safer.

In term of public perception, it is a PR disaster but not unprecedented. The DC-10 went through a similar rocky start where passengers just wouldn't want to board it. But after the flaws were fixed it turned out to be quite reliable.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#95

Post by cm2187 »

blattimwind wrote: post #56
staunch wrote: post #47

Earlier quoted context omitted.

Now imagine if Boeing had created a brand new design instead of the 737 MAX and it had some mysterious fatal flaw as well? Second System Syndrome is something every engineer should understand. There's just no good reason to suspect a brand new design would've been bug free or easier to debug than the 737 MAX. The 787s or A320neos could start dropping out of the sky at any minute. Maybe their carbon fiber panels start…

> There's just no good reason to suspect a brand new design would've been bug free or easier to debug than the 737 MAX. A brand new design actually supporting the engines used would not have aerodynamic issues that place the airframe outside the limits set forth by regulations.

I think the point if the OP isn't that a new design would have the same flaw, but rather that it would possibly introduce many other flaws. I think the analogy to a full software rewrite vs fixing a bug in a battle tested software is relevant.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#96

Post by erentz »

deskamess wrote: post #57
erentz wrote: post #32

Earlier quoted context omitted.

Had Boeing built the 737 at the time Airbus built the A320 they would've had a taller undercarriage also. For example the narrow body 757 built around the time of the A320 does have this. When the 737 was built back in the 60s it was intended to be a small regional jet, not the continent and ocean crossing aircraft it evolved into over the years since. It originally came with a retractable staircase for passengers to…

Why would they not have gone with a, say, 757 MAX - it seems to fit the bill spec wise. Is it that global pilot pool is not as great for the 757 as 737?

I’m not an expert, but the 757 was a larger and heavier plane which changes the economics a lot. It also stopped production over a decade ago so restarting production would’ve been a challenge. On top of that as you said airlines wanted to maintain the 737 type rating so pilots didn’t need retraining.

The 797/NMA program Boeing is proposing is a replacement for the aging 757 and 767 fleets.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#97

Post by skybrian »

owenversteeg wrote: post #90
skybrian wrote: post #49

Earlier quoted context omitted.

It's rather weird to ask a huge number of mostly-good airplanes to be thrown away for PR reasons, rather than fixing them. (Not to mention that these planes have never crashed in most countries, even with an admittedly serious bug.)

>(Not to mention that these planes have never crashed in most countries, even with an admittedly serious bug.) In... Most countries? That's such a weird standard to hold an aircraft to. Even very serious aircraft issues before typically only resulted in crashes in a handful of countries! Did I read that wrong or do you want 100+ of the 200ish countries in the world to have experienced a 737 MAX crash before scrapping…

Just putting the safety record into context.

Actually, I think if the planes can be fixed (and I'd be shocked if they couldn't), the two crashes before the fix will no longer be relevant for assessing safety.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#98

Post by hirowan »

cm2187 wrote: post #94
djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

A brand new design would probably introduce more serious flaws than an interation of a mature design, so I am not sure it would be safer. In term of public perception, it is a PR disaster but not unprecedented. The DC-10 went through a similar rocky start where passengers just wouldn't want to board it. But after the flaws were fixed it turned out to be quite reliable.

> A brand new design would probably introduce more serious flaws than an interation of a mature design

As evidenced by the ever-crashing 787s and A350s.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#99

Post by skybrian »

nikofeyn wrote: post #52
skybrian wrote: post #49

Earlier quoted context omitted.

It's rather weird to ask a huge number of mostly-good airplanes to be thrown away for PR reasons, rather than fixing them. (Not to mention that these planes have never crashed in most countries, even with an admittedly serious bug.)

it’s not just pr reasons. they tried to hot patch this airplane design with software, and now they are hot patching that fix. it seems it is a fundamentally flawed design that they tried to hide and get away with rather than doing the right thing. i know i don’t want to fly on a 737 max ever, and this whole ordeal with boeing and the faa has made me less confident in the airline industry as a whole. your parenthetica…

The fix taking a while to get right is not evidence for "fundamentally flawed".

You have a strange idea about how to assess risk. It's like faults are somehow contagious.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#100

Post by hirowan »

manigandham wrote: post #80
djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

There's no fundamental design flaw, the aircraft is sound. The problem came from using software systems to artificially make the plane behave like older designs to avoid entirely new training and certifications. Even that would've been acceptable and similar systems are already in use in other planes but it was the inadequate info, redundancy, warnings and controls to disable the system that created the problem. It's…

MCAS has absolutely nothing to do with maintaining commonality. An aircraft with decreasing stick force on approach to stall in its normal mode of operation would've never been certificated.
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