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Doesn't the incidental damage like blowing out a cargo door suggest that, while they expected to push the plane to close to it's limit, that prior to the test t
by abeppu 7y ago
Doesn't the incidental damage like blowing out a cargo door suggest that, while they expected to push the plane to close to it's limit, that prior to the test they assigned very low probability to this kind of failure? Even if this barely-a-failure isn't on its own evidence of a practical safety risk, anytime you're surprised by new data, it does suggest something about your model needs to be updated.
- lisper 7y agoIt is possible to design systems that fail in predictable ways (tear-strips on consumer packaging are an example of this) but airplanes aren't designed that way. It just doesn't matter how the plane fails when it reaches its structural limits, so no design effort is put into this. So no, it is not at all surprising that the energy dissipated in unexpected ways. That's one of the reasons they ran the last test past 100% so they could find out how it would fail because no one knew.
- scoot 7y ago> tear-strips on consumer packaging are an example of this The ring pull on a can might be a better example. Tear-strips are notoriously unpredictable.
- leobakerhytch 7y agoNice video on the design and manufacturing of aluminum drinks cans here: https://youtu.be/hUhisi2FBuw https://youtu.be/hUhisi2FBuw The whole thing is pretty ingenious, but the way the internal pressure helps vent the can while the tab is acting as a second class lever, then as soon as it’s vented becomes a first class lever to push the scored section of the top into the can — that’s great engineering.
- jacquesm 7y agohttps://news.ycombinator.com/item?id=8098146 https://news.ycombinator.com/item?id=8098146
- Pinus 7y agoIsn't there an ancient joke about an aircraft manufacturer having problems with the wings breaking off, and some engineer suggesting performating the wing roots, because have you ever seen toilet paper actually tear at the performation?
- aunty_helen 7y agoThat's not true at all. A good example of this would be the requirement that under a blade out condition on an engine it remains contained. They even test this, https://www.youtube.com/results?search_query=ge90+blade+out https://www.youtube.com/results?search_query=ge90+blade+out
- inferiorhuman 7y agoThat's not true at all. A good example of this would be the requirement that under a blade out condition on an engine it remains contained. They even test this About that… https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380 https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380
- WalterBright 7y agoNot always. The pins that hold the engines on to the wings are "fuses" in that they are designed to break away if the engine is vibrating violently, before it breaks the wing.
- awalton 7y agoSure. They'll update their models saying "yeah, this can happen sometimes at 148.5% of max designed wing load. So... don't fly the plane into any >F5 tornadoes." These max overload wing tests are scary dangerous, but they don't represent real flight situations. 99% of their target safety factor is within the margin of error for manufacturing variance. While they'll most certainly investigate the causes of the damage down the fuselage from the wing rupture, it's not likely much of it will be unexpected - if a plane experienced that load, the plane is considered a Loss of Hull even if it lands successfully somehow. I'm immensely paranoid about flying on planes, I have a terrible fear of heights... and nothing I've read in that article bothers me in the slightest.