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let me finish your summary: ... but the aerodynamics were changed in the process and they fixed it with software, which was bad.

by hn3333 6y ago

throwaway0a5e 6y ago
Would have been fine if they hadn't fixed it with crap software that was incompatible with the pilots existing runaway trim checklist.
- raxxorrax 6y ago
  I bet if we look at the requirements analysis of MCAS, the developers just met the specification. I think the article makes to much assumptions about the state of the industry and developer hubris, but the decision of system design of the plane was probably decided before it reached developers. They might also just have a perspective of this one system, so the result is as expected.
  - throwaway0a5e 6y ago
    Yup. The UX guys didn't apreciate how critical the software was and how half-baked it was going to be (and therefore require pilots to need to interact with it requiring good UX). The software guys didn't know that the pilots weren't gonna know how to turn off the software so they didn't know they couldn't half bake it. The engine guys didn't know the software guys were gonna half bake it. The AOA guys retired in the 1990s and had no idea the system was gonna be used for anything more than warning lights. Everyone did their job as it exists on paper but... https://youtu.be/452XjnaHr1A?t=20 https://youtu.be/452XjnaHr1A?t=20
- jki275 6y ago
  It was perfectly compatible with existing runaway trim checklist. The problem was that the pilots didn't recognize it as runaway trim, in part due to pilot error and in part due to the fact they weren't told the capacity for this system to create a runaway trim situation existed.
MaxBarraclough 6y ago
Fixing aerodynamics with software is nothing new, and isn't always a mistake. The F-16 (a multirole fighter from the 70's) does this. https://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting_Falcon#Negative_stability_and_fly-by-wire https://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting...
- jki275 6y ago
  Every modern fighter jet does this, because they're all aerodynamically unstable.
  - rightbyte 6y ago
    And fighters fall out of the sky quite ofent for no good reason. Luckely the pilots can shoot them self out.
    - liability 6y ago
      > And fighters fall out of the sky quite ofent for no good reason What do you mean by that? That they're crashing for unknown reasons? Because that's generally not true. A lot of effort is put into figuring out the causes of crashes. If you're insinuating that the software is generally to blame, I'd like to see your sources for such a claim. The first F-35 to crash was due to a faulty fuel tube. Was that "for no good reason" or does that count as a "good reason"?
      - rightbyte 6y ago
        I mean "good reasons" as in storms, collisions with birds or trees etc. No I didn't mean software issues or the F-35 in specific, but fighters in general compared to passenger airplanes. I didn't find any specific statistics, but I remember reading it in a book about the Swedish airforce some years ago that fighters just crash alot. They seem to just be way more prone to crashing due to their combat agility need. E.g.: https://economictimes.indiatimes.com/news/defence/13-fighter-jets-crashed-from-2017-18-to-november-2019-government/articleshow/72475143.cms https://economictimes.indiatimes.com/news/defence/13-fighter...

let me finish your summary: ... but the aerodynamics were changed in the process and they fixed it with software, which was bad.

by hn3333 6y ago

let me finish your summary: ... but the aerodynamics were changed in the process and they fixed it with software, which was bad.

throwaway0a5e 6y ago

Would have been fine if they hadn't fixed it with crap software that was incompatible with the pilots existing runaway trim checklist.

raxxorrax 6y ago
I bet if we look at the requirements analysis of MCAS, the developers just met the specification. I think the article makes to much assumptions about the state of the industry and developer hubris, but the decision of system design of the plane was probably decided before it reached developers. They might also just have a perspective of this one system, so the result is as expected.
- throwaway0a5e 6y ago
  Yup. The UX guys didn't apreciate how critical the software was and how half-baked it was going to be (and therefore require pilots to need to interact with it requiring good UX). The software guys didn't know that the pilots weren't gonna know how to turn off the software so they didn't know they couldn't half bake it. The engine guys didn't know the software guys were gonna half bake it. The AOA guys retired in the 1990s and had no idea the system was gonna be used for anything more than warning lights. Everyone did their job as it exists on paper but... https://youtu.be/452XjnaHr1A?t=20 https://youtu.be/452XjnaHr1A?t=20
jki275 6y ago
It was perfectly compatible with existing runaway trim checklist. The problem was that the pilots didn't recognize it as runaway trim, in part due to pilot error and in part due to the fact they weren't told the capacity for this system to create a runaway trim situation existed.

MaxBarraclough 6y ago

Fixing aerodynamics with software is nothing new, and isn't always a mistake. The F-16 (a multirole fighter from the 70's) does this. https://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting_Falcon#Negative_stability_and_fly-by-wire https://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting...

jki275 6y ago
Every modern fighter jet does this, because they're all aerodynamically unstable.
- rightbyte 6y ago
  And fighters fall out of the sky quite ofent for no good reason. Luckely the pilots can shoot them self out.
  - liability 6y ago
    > And fighters fall out of the sky quite ofent for no good reason What do you mean by that? That they're crashing for unknown reasons? Because that's generally not true. A lot of effort is put into figuring out the causes of crashes. If you're insinuating that the software is generally to blame, I'd like to see your sources for such a claim. The first F-35 to crash was due to a faulty fuel tube. Was that "for no good reason" or does that count as a "good reason"?
    - rightbyte 6y ago
      I mean "good reasons" as in storms, collisions with birds or trees etc. No I didn't mean software issues or the F-35 in specific, but fighters in general compared to passenger airplanes. I didn't find any specific statistics, but I remember reading it in a book about the Swedish airforce some years ago that fighters just crash alot. They seem to just be way more prone to crashing due to their combat agility need. E.g.: https://economictimes.indiatimes.com/news/defence/13-fighter-jets-crashed-from-2017-18-to-november-2019-government/articleshow/72475143.cms https://economictimes.indiatimes.com/news/defence/13-fighter...