4 ms·

It sounds additionally like the bug, caused by the issues presented in the tweets, made it past the usual safeguards and into production because of an abnormal

It sounds additionally like the bug, caused by the issues presented in the tweets, made it past the usual safeguards and into production because of an abnormal certification process: https://www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/ https://www.seattletimes.com/business/boeing-aerospace/faile... So there were failures at almost every level it seems.

JorgeGT 8y ago
Wow... thanks for the link. The details are highly troubling. They assessed the safety of the MCAS based on a statement saying it had max. authority of 0.6º, being thus permissible to rely on a single sensor for this system. But in fact it had an initial authority of 2.5º, which is already pretty high by itself, and then that authority increased after each activation until full stabilizer deflection. That they implemented such a high authority system without triple sensor redundancy and without briefing the pilots is just insane.
- im_down_w_otp 8y ago
  Yeesh. If true, it seems like it should have been a 3oo4 system, with added heuristics for handling soundness of the sensor inputs, and with easy override defaults (e.g. control surface override) and auto-disable on disagreement. What I don't get is how this drifting compounding boundary condition wasn't caught during formal modeling?
  - sitkack 8y ago
    We don't do enough adversarial testing. We are increasingly reliant on systems that have poor closed loop behavior with little to no memory. We need to design systems that are redundant, that have short and long term memories and have domain knowledge to compare their internal understanding of the universe with. And these autonomic systems need to alert the operators on what they are doing, why they are doing it and how to turn it off.
e40 8y ago
> So there were failures at almost every level it seems. They aren't failures, they were designed in. There are forced at work, since the 80's, that have been trying to kill effective government institutions because they are seen anti-free market (the exact quote was "My goal is to cut government in half in twenty-five years, to get it down to the size where we can drown it in the bathtub."[1]). This is the end result, as are E-coli outbreaks, etc. The government is being made ineffective so people can stand and point "see, I told you so, and we need to move this to the private sector were it will be done properly." [1] https://www.brainyquote.com/quotes/grover_norquist_182534 https://www.brainyquote.com/quotes/grover_norquist_182534
- thatoneuser 8y ago
  To be fair there has been plenty of incompetence in the government. I mean as this or the 2008 financial crash shows us - total free market is folly, but there's some back and forth discussion to be had on how much government is good.

JorgeGT 8y ago

Wow... thanks for the link. The details are highly troubling. They assessed the safety of the MCAS based on a statement saying it had max. authority of 0.6º, being thus permissible to rely on a single sensor for this system. But in fact it had an initial authority of 2.5º, which is already pretty high by itself, and then that authority increased after each activation until full stabilizer deflection. That they implemented such a high authority system without triple sensor redundancy and without briefing the pilots is just insane.

im_down_w_otp 8y ago
Yeesh. If true, it seems like it should have been a 3oo4 system, with added heuristics for handling soundness of the sensor inputs, and with easy override defaults (e.g. control surface override) and auto-disable on disagreement. What I don't get is how this drifting compounding boundary condition wasn't caught during formal modeling?
- sitkack 8y ago
  We don't do enough adversarial testing. We are increasingly reliant on systems that have poor closed loop behavior with little to no memory. We need to design systems that are redundant, that have short and long term memories and have domain knowledge to compare their internal understanding of the universe with. And these autonomic systems need to alert the operators on what they are doing, why they are doing it and how to turn it off.

e40 8y ago

> So there were failures at almost every level it seems. They aren't failures, they were designed in. There are forced at work, since the 80's, that have been trying to kill effective government institutions because they are seen anti-free market (the exact quote was "My goal is to cut government in half in twenty-five years, to get it down to the size where we can drown it in the bathtub."[1]). This is the end result, as are E-coli outbreaks, etc. The government is being made ineffective so people can stand and point "see, I told you so, and we need to move this to the private sector were it will be done properly." [1] https://www.brainyquote.com/quotes/grover_norquist_182534 https://www.brainyquote.com/quotes/grover_norquist_182534

thatoneuser 8y ago
To be fair there has been plenty of incompetence in the government. I mean as this or the 2008 financial crash shows us - total free market is folly, but there's some back and forth discussion to be had on how much government is good.