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Whether this feature has been battle tested by a two hundred million hours running failure-free in production is beside the point. The point is to categorically

by ajxs 7y ago

Whether this feature has been battle tested by a two hundred million hours running failure-free in production is beside the point. The point is to categorically eradicate the potential sources of failure in the aircraft's engineering. The point of regulation is not to arbitrarily erect hoops for manufactures to jump through. It's to ensure that aircraft are built as safe as possible. If one of my loved ones died due to this defect, as unlikely as that would be, I would not be satisfied with the explanation that "It never happened before in the previous 200 million hours, so no one deemed it worthy of fixing".

avalys 7y ago
The point is not make airplanes “as safe as possible.” It’s to make them safe, while also balancing cost, fuel economy, maintenance, payload, etc. In this case, it is not clear that the actual safety risk is severe enough to justify the significant expense required to resolve it.
AnimalMuppet 7y ago
> The point is to categorically eradicate the potential sources of failure in the aircraft's engineering. Then walk. Seriously. If you want to totally eliminate the potential sources of failure from flying, then walk. Drive. Take a rowboat. But don't fly, because you can never categorically eradicate the potential sources of failure in an aircraft - any aircraft. > If one of my loved ones died due to this defect, as unlikely as that would be, I would not be satisfied with the explanation that "It never happened before in the previous 200 million hours, so no one deemed it worthy of fixing". You probably also wouldn't be satisfied with "In our best estimate, fixing it was likely to introduce more problems than it solved", even if it was precisely the truth. But put yourself in the other position: If one of your loved ones died due to this fix, would you be satisfied with "But we eliminated the original failure possibility"? Somehow, I doubt it...
- ajxs 7y ago
  > Then walk. Seriously... I'm not an idiot. I understand that there is always some risk in flying. My point was that the idea is to eliminate risks to the best of our ability. That should have been obvious by my post. If we know there's a preventable risk, prevent it. > You probably also wouldn't be satisfied with... If that was the recommendation of the regulators, I'd accept that. I don't like the idea of manufacturers policing themselves. We have regulatory bodies precisely because we don't want companies making 'cost effectiveness' a factor in deciding which safety features to implement. Boeing attempting to circumvent regulations is how they ended up in this bind to begin with, resulting in many deaths. > If one of your loved ones died due to this fix... In what world would this be satisfactory at any level? I'm not sure exactly what your point is here. If the company is ordered by regulators to retrofit the aircraft to comply with new safety regulations we expect them to do it in a competent manner, don't we? That's not to say that I expect them to retrofit every existing 737... That's another matter entirely.
  - AnimalMuppet 7y ago
    In software, one more-or-less generally-accepted result is that, when you fix a big, the probability of introducing new bug is somewhere between 20 and 50%. One would hope that it's much less for critical software, but it's not zero. In the same way, what's the probability of introducing a new defect when replacing the wiring harnesses? It's not zero. It's never zero. So the answer to "should we fix this issue?" is not "yes, of course". It's "will the fix make things better, or worse?" And of course, you don't know with certainty, but you make your best estimate of the probability of the new problem being worse than the old, and then you decide. So even if "eliminating risks to the best of our ability" is in fact the right goal, that doesn't always equate to "eliminate this risk", even if we can do so. > I don't like the idea of manufacturers policing themselves. Here I agree with you completely. We've seen that movie; let's not watch it again.
- rbanffy 7y ago
  > you can never categorically eradicate the potential sources of failure in an aircraft But you can make sure that the known potential sources of failures are dealt with.
  - ajxs 7y ago
    That was exactly my point. Thank you.

by ajxs 7y ago

avalys 7y ago

The point is not make airplanes “as safe as possible.” It’s to make them safe, while also balancing cost, fuel economy, maintenance, payload, etc. In this case, it is not clear that the actual safety risk is severe enough to justify the significant expense required to resolve it.

AnimalMuppet 7y ago

> The point is to categorically eradicate the potential sources of failure in the aircraft's engineering. Then walk. Seriously. If you want to totally eliminate the potential sources of failure from flying, then walk. Drive. Take a rowboat. But don't fly, because you can never categorically eradicate the potential sources of failure in an aircraft - any aircraft. > If one of my loved ones died due to this defect, as unlikely as that would be, I would not be satisfied with the explanation that "It never happened before in the previous 200 million hours, so no one deemed it worthy of fixing". You probably also wouldn't be satisfied with "In our best estimate, fixing it was likely to introduce more problems than it solved", even if it was precisely the truth. But put yourself in the other position: If one of your loved ones died due to this fix, would you be satisfied with "But we eliminated the original failure possibility"? Somehow, I doubt it...

ajxs 7y ago
> Then walk. Seriously... I'm not an idiot. I understand that there is always some risk in flying. My point was that the idea is to eliminate risks to the best of our ability. That should have been obvious by my post. If we know there's a preventable risk, prevent it. > You probably also wouldn't be satisfied with... If that was the recommendation of the regulators, I'd accept that. I don't like the idea of manufacturers policing themselves. We have regulatory bodies precisely because we don't want companies making 'cost effectiveness' a factor in deciding which safety features to implement. Boeing attempting to circumvent regulations is how they ended up in this bind to begin with, resulting in many deaths. > If one of your loved ones died due to this fix... In what world would this be satisfactory at any level? I'm not sure exactly what your point is here. If the company is ordered by regulators to retrofit the aircraft to comply with new safety regulations we expect them to do it in a competent manner, don't we? That's not to say that I expect them to retrofit every existing 737... That's another matter entirely.
- AnimalMuppet 7y ago
  In software, one more-or-less generally-accepted result is that, when you fix a big, the probability of introducing new bug is somewhere between 20 and 50%. One would hope that it's much less for critical software, but it's not zero. In the same way, what's the probability of introducing a new defect when replacing the wiring harnesses? It's not zero. It's never zero. So the answer to "should we fix this issue?" is not "yes, of course". It's "will the fix make things better, or worse?" And of course, you don't know with certainty, but you make your best estimate of the probability of the new problem being worse than the old, and then you decide. So even if "eliminating risks to the best of our ability" is in fact the right goal, that doesn't always equate to "eliminate this risk", even if we can do so. > I don't like the idea of manufacturers policing themselves. Here I agree with you completely. We've seen that movie; let's not watch it again.
rbanffy 7y ago
> you can never categorically eradicate the potential sources of failure in an aircraft But you can make sure that the known potential sources of failures are dealt with.
- ajxs 7y ago
  That was exactly my point. Thank you.