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As a passenger, if these were the trade-offs Boeing made, my stomach just dropped. I don’t consider myself naive as to which trade offs corporations might consi

As a passenger, if these were the trade-offs Boeing made, my stomach just dropped. I don’t consider myself naive as to which trade offs corporations might consider fair game to increase profits, but if,,, changing engine placement in spite of impact to stability and such.... can anyone else talk to this. I’m actually bothered by this. This sounds like dangerous engineering.

asynchronous13 8y ago
Everything in engineering is a trade off. The changes that were made were not inherently dangerous, but the certification process on those changes fell apart for a variety of reasons. If the certification process had been followed correctly, these planes would be flying safely. The FAA is underfunded. A pro-business administration applied pressure to help Boeing certify more rapidly. Due to time and money pressures, many things that should have been performed by the FAA safety inspectors were actually performed by Boeing engineers. The safety assessment was performed on incorrect numbers! (Boeing estimated some parameters and performed safety assessment. Then those parameters were updated after flight testing, but the safety assessment was not re-performed with the updated numbers! That's a huge problem in the process.)
- Gibbon1 8y ago
  > Everything in engineering is a trade off. A trade off too far is real a thing. > The changes that were made were not inherently dangerous A few hundred dead people and hundreds of grounded planes say no to this. > The FAA is underfunded. This is a feature not a bug. Under the neoliberal orthodoxy this is as things should be. The free market is the most effective and efficient way to regulate corporations. The FDA is a drain on the economy.
ajross 8y ago
It's not, really. Not technically. All of those tradeoffs and vastly more are made all the time, when certifying a new aircraft. There's nothing wrong with relaxed stability, autopilots are 60 year old technology and have been keeping people safe since our grandparents were flying. And the certification process has for the most part produced very safe aircraft. But in this case, the certification process was seen as too expensive. Boeing wanted to market a tweaked, high-efficiency 737 with newer engines, and didn't have the time to spend on certifying a whole new aircraft. So it used the same old one and the faster regulatory process. But that assumes that the regulatory process worked. Clearly that cascade of changes was not in the spirit of "just small modifications to existing designs". But the FAA didn't squawk and certified it anyway. And as it happened, just one of those choices (using the trim for stability control) turned out to be unsafe in unexpected ways. One was that the AoA sensor driving the thing was glitchy. But more importantly, the trim was originally certified on the assumption that a trim control failure could be overridden by the pilot, but no one realized that pilots weren't trained to think of trim as being a computer controlled thing and didn't understand what was happening when the MCAS started fighting them.
- asynchronous13 8y ago
  > But in this case, the certification process was seen as too expensive. Not just that, but also pilots would need new training if it were a new type certificate. This was a huge marketing advantage for Boeing because their end customers could avoid the cost of re-training their pilots on a new airplane.
  - paulryanrogers 8y ago
    And the lives lost an unforeseen externality. One would hope a company in such a safety critical industry would err on the side of caution. Or are they so strapped for cash they can't afford it?

asynchronous13 8y ago

Everything in engineering is a trade off. The changes that were made were not inherently dangerous, but the certification process on those changes fell apart for a variety of reasons. If the certification process had been followed correctly, these planes would be flying safely. The FAA is underfunded. A pro-business administration applied pressure to help Boeing certify more rapidly. Due to time and money pressures, many things that should have been performed by the FAA safety inspectors were actually performed by Boeing engineers. The safety assessment was performed on incorrect numbers! (Boeing estimated some parameters and performed safety assessment. Then those parameters were updated after flight testing, but the safety assessment was not re-performed with the updated numbers! That's a huge problem in the process.)

Gibbon1 8y ago
> Everything in engineering is a trade off. A trade off too far is real a thing. > The changes that were made were not inherently dangerous A few hundred dead people and hundreds of grounded planes say no to this. > The FAA is underfunded. This is a feature not a bug. Under the neoliberal orthodoxy this is as things should be. The free market is the most effective and efficient way to regulate corporations. The FDA is a drain on the economy.

ajross 8y ago

It's not, really. Not technically. All of those tradeoffs and vastly more are made all the time, when certifying a new aircraft. There's nothing wrong with relaxed stability, autopilots are 60 year old technology and have been keeping people safe since our grandparents were flying. And the certification process has for the most part produced very safe aircraft. But in this case, the certification process was seen as too expensive. Boeing wanted to market a tweaked, high-efficiency 737 with newer engines, and didn't have the time to spend on certifying a whole new aircraft. So it used the same old one and the faster regulatory process. But that assumes that the regulatory process worked. Clearly that cascade of changes was not in the spirit of "just small modifications to existing designs". But the FAA didn't squawk and certified it anyway. And as it happened, just one of those choices (using the trim for stability control) turned out to be unsafe in unexpected ways. One was that the AoA sensor driving the thing was glitchy. But more importantly, the trim was originally certified on the assumption that a trim control failure could be overridden by the pilot, but no one realized that pilots weren't trained to think of trim as being a computer controlled thing and didn't understand what was happening when the MCAS started fighting them.

asynchronous13 8y ago
> But in this case, the certification process was seen as too expensive. Not just that, but also pilots would need new training if it were a new type certificate. This was a huge marketing advantage for Boeing because their end customers could avoid the cost of re-training their pilots on a new airplane.
- paulryanrogers 8y ago
  And the lives lost an unforeseen externality. One would hope a company in such a safety critical industry would err on the side of caution. Or are they so strapped for cash they can't afford it?