Re:737 Max Explanation by a Software Engineer
by JorgeGT on Monday March 18, 2019 @06:17AM
(#19419900)
In that sense, I agree with you. I meant to say that this wasn't a software bug or programmer's fault like "oh, someone wrote max_authority = 6º instead of 0.5º in line 8745679", but something bigger: the very design and specs of the system and a certification process that didn't challenge those aspects.
Re:737 Max Explanation by a Software Engineer
by sgustard on Monday March 18, 2019 @02:51AM
(#19419138)
I have to agree. If you're saying "the software is working to spec, but the specs are bad," then you're still describing a software problem.
Re:737 Max Explanation by a Software Engineer
by speedplane on Monday March 18, 2019 @02:59AM
(#19419159)
> If you're saying "the software is working to spec, but the specs are bad," then you're still describing a software problem.
This is a pretty bold statement. The spec includes many non-software related features.
Re:737 Max Explanation by a Software Engineer
by cashsterling on Monday March 18, 2019 @05:25PM
(#19425479)
In aerospace, lack of proper requirements in the flight software would be a system engineering problem... a semantic difference really, but important nonetheless.
System engineering and validation has a metric ton of 'tools' to catch bad system design and improper algorithm implementation...
I really question what the hell happened here: - Did they just pencil whip the FMEA on this or what? (failure mode and effects analysis)
- What happened with the Hardware-in-the-loop flight simulation when they tested the scenario where the AoA sensor givesg spurious data, both high and low (but especially high)? I mean... they did test this, right?
> Nowhere in here is there a software problem.
I worked on the design of the 757 stab trim system, am trained in aerospace engineering, and am a programmer. I'm not a pilot. I am not explicitly familiar with the 737 stab trim system.
It is indeed at least partially a software problem. I had thought of two possible improvements: one is to limit the authority of the MCAS's commands to the trim, and the other is to not issue further commands if the pilot fights the trim commands. I read today that Boeing's proposed software fix includes both of those.