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FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

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Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#191

Post by agumonkey »

th0ma5 wrote: post #51
rjvehn wrote: post #27

There are a myriad of issues that put the planes at risk, but I think that the fact that when the control system (MCAS) is engaged causes it to ignore feedback is the biggest issue of all. "But with the MCAS activated, said Fehrm, those breakout switches wouldn’t work. MCAS assumes the yoke is already aggressively pulled back and won’t allow further pullback to counter its action, which is to hold the nose down. Fehr…

To be fair, ignoring user input could have potentially have saved Air France 447... I mean I actually can't think of an automated fool proof system that would've fixed 447, but incorrect input was a major factor.

After so many decades, there's no golden rule here ? (genuine question).

A principle of zero automation fallback in case of confusion ? something that is hardcoded deep in the design so that people in charge (pilot crew) can know for sure that whatever happens is in their hands ?

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#192

Post by SmellyGeekBoy »

blackflame7000 wrote: post #16
mevile wrote: post #2

I wonder if they're just now finding new things by simply running the software in a simulator, what more will they find, and what does this say to their continued assurances as to the safety of this plane?

On the flip side, all airplanes have flaws to some degree or else they would never crash. A deep audit of everything in the end should make things safer. And Boeing also has a solid safety record on their other models 777 and 767

> Boeing also has a solid safety record on their other models 777 and 767

You seem to be overlooking the 787 - a few early models set on fire. Sure, nobody died, but that was more luck than judgement.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#193

Post by SmellyGeekBoy »

jonknee wrote: post #138
jussij wrote: post #84

Earlier quoted context omitted.

Hence the reason I said time will tell. But there are also many examples of aircraft with terrible early safety records that never recovered from their bad start.

> But there are also many examples of aircraft with terrible early safety records that never recovered from their bad start. From Boeing? They have a history of sorting their shit out. Maybe this time is different, but I doubt it.

It's a shame so many people have to die for them to "sort their shit out". Maybe they shouldn't make idiotic design decisions and lie to regulators in the first place?

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#194

Post by SmellyGeekBoy »

jussij wrote: post #37
333c wrote: post #26

Earlier quoted context omitted.

How can you practically avoid a model of plane, other than avoiding all airlines that operate them?

Just visit a flight tracking website before booking. In addition I'm sure airlines not flying the MAX will be using that fact as a marketing tool (i.e. we only fly Airbus etc) so you could limit your bookings with just those airlines. As an example of this, here in Australia I know one of the carriers is planning to fly the Max some time next year. If they go ahead with that plan, I will be making sure not to book wi…

> Just visit a flight tracking website before booking.

I always do this anyway just out of curiosity. Also if it's a plane I enjoy flying on it makes me look forward to the trip that much more. I have to admit that if I spotted "737 MAX" on there I seriously doubt I would book that trip, even after these issues are eventually resolved.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#195

Post by SmellyGeekBoy »

qrbLPHiKpiux wrote: post #13

The computers are all part of the problem with this and it's a trend I've noticed for a long time now. Regarding critical output and human input.

Not "the computers" but the software running on those computers. Software that was specced and implemented by humans.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#196

Post by dandare »

238475235243 wrote: post #178
dandare wrote: post #175

As a web/game developer, one thing I never understood is the alleged complexity of these control systems. There is no image/voice recognition, no graphics engine, no rocket science. What are they even doing? Or is it all a big lie? Lines of code, from the internet[1]: Pacemaker: 100k Boeing 787: 5M Chevy Volt: 10M Modern car: 100M [1] https://www.visualcapitalist.com/millions-lines-of-code/

There's a number of pieces: * Writing everything three times for three different computers with three different architectures in three different ways (e.g. numerical vs symbolic integration) * Using obsolete programming languages for the same reasons doctors use latin * Has to be usable by poorly trained pilots, while tired, on the other side of the planet in complete darkness with half the systems failing. * Nobody…

Writing everything 3 times: I believe this is not the case for a car or pacemaker. For the Boeing: 5M/3 = 1.3M lines of code. Still makes no sense.

Obsolete languages: Old language (or Latin) does not bloat the size of your code astronomically.

Usability in specific conditions: does not apply to a car or pacemaker. Yes, for an airplane, it can make the design phase lengthy and difficult but the actual size of the code will not bloat astronomically.

From some of the discussions I have seen on HN, writing safety-critical software is not a question of adding millions of lines of code - to the contrary, safe software must be clean and readable.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#197

Post by [deleted] »

rfugger wrote: post #59

I'd be pretty comfortable flying it after all this attention and review. It will probably be the best reviewed passenger plane software developed in America, if not the world once this is over. Boeing deserves a 9-figure fine though, and its shareholders should lose massively to make sure this doesn't happen again.

[deleted]

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#198

Post by grenoire »

aivisol wrote: post #144
jbigelow76 wrote: post #119

Earlier quoted context omitted.

So the FAA says "this is fucked" and and the EASA says "they're all good bro"[1], who do you side with? [1] feel free to flip flop regulatory agencies if you so desire.

It is like with two AoA sensors: if they disagree, there is the problem.

Too soon...

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#199

Post by tremon »

cmurf wrote: post #122
teh_infallible wrote: post #97

I hate the fact that all discussion focuses on the software and ignores the airframe.

What's the problem with the airframe? What's the problem with the larger engine nacelle causing a different pitching moment? I've yet to read either of those violate any portion of FAR 25. There is still an open question whether the MAX should have or will have a separate type certificate from other 737's, thereby requiring pilots of a type rating to fly the MAX, thereby requiring full disclosure and training on all…

What's the problem with the airframe?

The #1 problem with the airframe is that it is not identical to the original 737 airframe. Therefore it shouldn't have been certified as a 737, and it should have required pilot training.

Boeing has been using software to emulate a 737 airframe to avoid the pilot training costs. This approach itself is fraught with problems, and I hope the FAA puts a hard stop to these non-solutions.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#200

Post by acqq »

EdwardDiego wrote: post #125
halter73 wrote: post #103

Earlier quoted context omitted.

IIRC, the cockpit voice recording included a comment from one of the co-pilots about how pulling back on the yoke couldn't cause a stall. The assumption was that the Airbus's fly-by-wire system would prevent it and ensure the aircraft still climbed as long as the pilot held back on the stick. The co-pilot apparently didn't realize that the sensor issue that disabled the autopilot also disabled the stall prevention. A…

Exactly - the computer had switched contexts, but the pilot hadn't. And expecting pilots to switch their mental map of expected behaviour when the computer does (and did so with, from the accounts I read, very minimal indication that it had done so) during a high stress situation, is asking for trouble.

The indications were different alerts continuously sounding. It’s a complex problem, there’s a lot that can go wrong at once.
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