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Delays in Boeing Max Return Began with Near-Crash in Simulator

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Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#51

Post by LanceH »

dtwest wrote: post #48
joobus wrote: post #15

Earlier quoted context omitted.

Boeing makes up 8.8% of the Dow right now, the largest component. There is a lot of pressure from the finance community and the government to get this recertified to keep the stock market from going down.

I had to comment, nobody in finance pays attention to the Dow. It's a meaningless index. Look into how it is constructed if you're curious as to why. But to your point, it makes up 0.78% of the S&P500 which is not insignificant for sure.

It makes up a far larger portion of US influence on aviation, which might bring the real push from the government.

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#53

Post by jackhack »

akersten wrote: post #2

These should not fly for a decade. They're rewriting the avionics from scratch. This should require a years-long process of testing, external auditing, and approvals. I'd even go so far as to say in flight, we should require competitor review. That's right, no trade secrets. If you want your Hello World up in the air, you better let your competitor vet the source code. This is an engineering boondoggle and an embarra…

>>Software does not need to be this complicated. >>Design a damned airframe that's airworthy without needing stabilization hacks.

In effect you are stating that you understand better than the hundreds of engineers involved with this project why these design trade-offs were made. Careful with that line of thinking. You're nearly guaranteed to be wrong.

There are a host of reasons for the design in place: Efficiency, ease of implementation, familiarity with the components/technology, reliabilty of subsystems, availability of components, cost, maintenance complexity, etc. etc. etc.

And, don't forget, efficiency standards. As the whole world freaks out about CO2 and global climate change/cooling/warming, and the insta-crowd 'air travel shames' those who use these magnificent machines, it's important to realize that some of these design decisions maximizing efficiency are the hereditary descendants of cultural pressures, too.

Not to excuse any engineering f-ups, but there's a lot more to it than just 'build a simple tube with wings and an engine.'

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#54

Post by kejaed »

danso wrote: post #10

FWIW, the near-crash in the simulator was apparently not directly related to MCAS, but occurred when Boeing "simulated what would happen if gamma rays from space scrambled data in the plane’s flight-control computers." > In one scenario, the plane aggressively dove in a way that mimicked what happened in the crashes on the grounded jetliner, the people said. While such a failure had never occurred in the 737’s histor…

Single Event Upsets are a real thing and if they had a failure mode that missed that, it's a problem that needs to be fixed.

https://en.wikipedia.org/wiki/Single-event_upset

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#55

Post by kejaed »

rootusrootus wrote: post #52

> simulated what would happen if gamma rays ... So now I am curious. How do other airliners (newer Boeings, Airbus, etc) fare when subjected to the gamma ray test? I would like some context.

The article could have used the industry term, Single-Event Upset, rather than use the more eye catching gamma ray term over and over. It's a failure mode that aircraft and spacecraft have to deal with.

You keep CRCs of data in critical areas of memory and constantly check them to make sure you are only processing valid data, or use equivalent of ECC memory.

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#56

Post by chkaloon »

They're redesigning the architecture and expect to be done by the end of the year? That is insane. The MCAS change was a patch of one fairly isolated system as I understand it. Redesigning the entire architecture of the flight controls seems like a years long process. Is this article correct? If so, I don't think I'll be riding on a MAX any time soon.

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#57

Post by chkaloon »

zaroth wrote: post #12

The can of worms has been officially opened, and this may turn out to be a case study in how bad software and outsourcing your centers of excellence can bankrupt a company. If TFA is to believed, Boeing has embarked on a project to take what is currently a master-slave failover design and jury-rig it into a master-master real-time system. This is based on bad performance in the simulator—not because of MCAS—but while…

That, or this article missed the boat somehow. I find it hard to believe that a total redesign is happening and that they expect to be done by the end of the year. Either this article is wrong, or something is terribly wrong at Boeing.

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#58

Post by SkyBelow »

eigenvalue wrote: post #45
joobus wrote: post #15

Earlier quoted context omitted.

Boeing makes up 8.8% of the Dow right now, the largest component. There is a lot of pressure from the finance community and the government to get this recertified to keep the stock market from going down.

That is incredibly misleading. The Dow is not representative of the entire stock market anymore. The S&P 500, which is only the 500 largest public companies by market cap, has a combined market capitalization of ~$25+ trillion. Boeing has a market cap of ~$200b, so that represent 0.8% of the total. If you include the top 3,000 public companies (i.e., the Russell 3000), the combined market capitalization is over $32 t…

>The idea that regulators at the FAA are going to let them fly a dangerous plane "because of the stock market" is absurd.

They already let fly a dangerous plane. Given they have already done so, an explanation like 'stock market pressure' is no longer absurd.

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#59

Post by joobus »

eigenvalue wrote: post #45
joobus wrote: post #15

Earlier quoted context omitted.

Boeing makes up 8.8% of the Dow right now, the largest component. There is a lot of pressure from the finance community and the government to get this recertified to keep the stock market from going down.

That is incredibly misleading. The Dow is not representative of the entire stock market anymore. The S&P 500, which is only the 500 largest public companies by market cap, has a combined market capitalization of ~$25+ trillion. Boeing has a market cap of ~$200b, so that represent 0.8% of the total. If you include the top 3,000 public companies (i.e., the Russell 3000), the combined market capitalization is over $32 t…

You can argue for days about your favorite index, but the Dow is printed on every financial news channel, every newspaper, every finance and trading site, every evening news show. You are naive if you think the Dow doesn't matter, or that the largest military supplier doesn't have large influence over government and finance.

Re: Delays in Boeing Max Return Began with Near-Crash in Simulator

#60

Post by linuxftw »

imglorp wrote: post #44
xvf22 wrote: post #39

Earlier quoted context omitted.

A split brain in a plane is a bit of a nightmare. I'm not sure how they can work around it with just two computers.

Big "disagree" alarm for the pilots and let them decide to keep either computer or go direct. Airbus has the concept of flight control laws, surfaced and changeable by the wet backups. http://www.airbusdriver.net/airbus_fltlaws.htm

Which computer calculates that there's a disagreement, and how can we ensure it's not indicating a false negative?
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