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Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

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Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#41

Post by Maakuth »

thelittleone wrote: post #39
aurelwu wrote: post #4

Earlier quoted context omitted.

That sounds like adding a heuristic which works most of the time which is something I can see myself doing to cover some pathfinding issue in a game where it's sufficient if it works 99,9% of the time or when working on a simulation where I can look on the result data afterwards and can see if something looks highly unusual despite the heuristic and improve it iteratively - a luxury you don't get with air planes, at…

Wasn’t aware the compute power was low on the 737. Interested if you have some more info? Always thought they would spec a substantially more processing capability than required. I understand economics are a factor but surely it’s not through necessity to save power?

Here's an article about it. According to this piece, 737 avionics run on a pair of 80286s.

https://www.moonofalabama.org/2019/06/boeings-software-fix-f...

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#42

Post by throwaway082729 »

std_throwaway wrote: post #33
Aloha wrote: post #7

Imagine if your bugfix process was broadcast to the world, every new IN added to spirateam et al, every new crash condition found by test/QA, every time the software failed in test, it got printed by news organizations the world over. This is world the 737MAX software people are living in, for this alone, they have my utmost respect.

> Imagine if your bugfix process was broadcast to the world Have you heard of the site called github?

Heard of a private GitHub?

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#43

Post by zwaps »

goodcanadian wrote: post #38
pcl wrote: post #2

> Because the fault was triggered by specific streams of erroneous flight data, a new software patch can be devised that monitors the computer for that highly unusual condition and prevents movement of the stabilizer when it occurs, one of the people said. Oh man. That sounds like a mess.

Sounds like a running joke at my work. Any hardware problem or design failure: you can fix it in software!

Do you work at Boeing? ;}

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#44

Post by std_throwaway »

throwaway082729 wrote: post #42
std_throwaway wrote: post #33

Earlier quoted context omitted.

> Imagine if your bugfix process was broadcast to the world Have you heard of the site called github?

Heard of a private GitHub?

Yes, for those who need to hide their code from public scrunity.

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#45

Post by hef19898 »

Aloha wrote: post #11
toyg wrote: post #10

Earlier quoted context omitted.

Imagine if your software had already killed a few hundred people. Boeing developers have been put in an untenable position and should consider walking out until management does the right thing and kills the plane.

The plane has no fundamental mechanical flaw, it has a software bug. The only flaw the plane had was being treated as 'just another 737'

It is an old air frame, and one hard mechanical fault that is impossible to solve without a completely new air frame is the ground clearance. The low ground clearance prevents new and larger engines to be used without completely ruining the aerodynamics of the 737 airframe itself.

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#46

Post by aurelwu »

thelittleone wrote: post #39
aurelwu wrote: post #4

Earlier quoted context omitted.

That sounds like adding a heuristic which works most of the time which is something I can see myself doing to cover some pathfinding issue in a game where it's sufficient if it works 99,9% of the time or when working on a simulation where I can look on the result data afterwards and can see if something looks highly unusual despite the heuristic and improve it iteratively - a luxury you don't get with air planes, at…

Wasn’t aware the compute power was low on the 737. Interested if you have some more info? Always thought they would spec a substantially more processing capability than required. I understand economics are a factor but surely it’s not through necessity to save power?

The issue is (from what I understand as layman) that to avoid recertification they kept their old computer hardware from earlier 737 generations, and added more and more tasks to do for it.

https://www.nytimes.com/2019/06/26/business/boeing-737-max-f... (somewhere in the middle: "The issue discovered last week is linked to the data-processing speed of a specific flight control computer chip, according to the two people with knowledge of the matter. In the test, the F.A.A. pilot encountered delays in executing a crucial step required to stabilize an aircraft." )

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#47

Post by comex »

tus88 wrote: post #28
burfog wrote: post #18

Earlier quoted context omitted.

It's proper. This is exactly how you do things with life-critical embedded software. You detect when things are crazy, which of course shouldn't happen but nevertheless does, and you react in a way that is hopefully not disastrous. The alternative is to ignore the problem. Sensors go bad. Actuators go bad. Voting hardware goes bad. Message routing goes bad. Even the RAM sometimes goes bad. When the hardware is failin…

The way I read it they are not detecting malfunctioning sensors, but essentially a computer fault caused by it's inability to deal with erroneous input. Rather than fixing the computer, they are essentially wrapping a great big try/catch around it....good God.

That interpretation seems like a stretch to me.

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#48

Post by selestify »

comex wrote: post #47
tus88 wrote: post #28

Earlier quoted context omitted.

The way I read it they are not detecting malfunctioning sensors, but essentially a computer fault caused by it's inability to deal with erroneous input. Rather than fixing the computer, they are essentially wrapping a great big try/catch around it....good God.

That interpretation seems like a stretch to me.

The way it's worded, that's exactly the interpretation that a lot of us in this thread get. If this is not actually the case, they should really word it differently.

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#49

Post by sundvor »

Aloha wrote: post #7

Imagine if your bugfix process was broadcast to the world, every new IN added to spirateam et al, every new crash condition found by test/QA, every time the software failed in test, it got printed by news organizations the world over. This is world the 737MAX software people are living in, for this alone, they have my utmost respect.

I picture a labyrinth of outsourced spaghetti, with no real ownership anywhere.

Would be very happy to be corrected here.

Re: Latest 737 Max Fault That Alarmed Test Pilots Rooted in Software

#50

Post by iguy »

alexis_fr wrote: post #31
Aloha wrote: post #19

Earlier quoted context omitted.

I think you underestimate Boeing size, wealth, and importance to the federal government.

This. - Boeing is certainly well financially engineered in many financial vehicles, - It’s alone the #1 net exporter of USA, - USA needs Boeing, whether it exports or not. Boeing also funds candidates, just mentioning. - Existing conpanies need to maintain their existing planes, and they need Boeing’s consultancy for that, - I’d say even Airbus needs their competitor, or they would fall in a dangerous monopolistic po…

But in the days of de Havailland & McD-D, there were maybe half a dozen companies which made airliners. That's a much more Adam-Smith world than when there are exactly two.
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