| ▲ | quantummagic 4 days ago |
| Limiting the devices to two per person seems nonsensical to me. The devices are either dangerous, or they're not. If they're dangerous, two is too many. And if they're not, then why limit them only to two? |
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| ▲ | nharada 4 days ago | parent | next [-] |
| > The devices are either dangerous, or they're not That's not actually how it works though, it's all a risk and percentages. Nobody says "driving is either safe or it's not" or "delivering a baby is either safe or it's not" |
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| ▲ | SilasX 4 days ago | parent | next [-] | | Correct, but I agree with the parent that this is a dubious case to apply that reasoning. To make it clearer, imagine another context: "It's dangerous for a passenger to have a gun on board. Therefore, we're strictly limiting passengers to only two guns." Like, no. The relevant sad case is present with one gun just as with two. Of course, what complicates it is that these power banks present a small but relevant risk of burning and killing everyone on board. So yeah, you might be below the risk threshold if everyone brought two, but not three. So it's not inherently a stupid idea, but requires a really precise risk calculation to justify that figure. | | |
| ▲ | _moof 4 days ago | parent [-] | | That's not really how risk is managed in aviation. ICAO will have made a list of all possible ways a power bank could create a hazard. Then for each failure mode, they'll come up with two numbers: probability, and severity. There's a formula to combine those two numbers into a single risk score. Any risks over the acceptable threshold (varies depending on the circumstances and I can't remember what it is for human-rated transport) must be mitigated. A mitigation is anything that reduces the probability or the severity of a risk. There are different categories of mitigation, some of which are more robust than others. Once the risk score moves below the acceptable threshold, the risk is satisfactorily mitigated. Example: Rapid depressurization. Without mitigation, the risk of rapid depressurization is unacceptably high. So we mitigate the probability by requiring sensitive inspections for metal fatigue, and we mitigate the severity by providing oxygen masks, a standard flight crew procedure for making an emergency descent, and regular training on that procedure. (Plus a bunch of other things I'm not thinking of off the top of my head.) Assuming ICAO did their due diligence - and I don't have any reason to think they didn't - they would've assessed the probability and severity of all of the ways a consumer power bank might fail. That analysis is the rationale for both the number of power banks allowed on a flight and what you're allowed to do with them. And yes, they will have considered the probability of people not following the rules (which is the reason, btw, that airplane lavatories have enormous "no smoking" signs right above an ash tray). | | |
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| ▲ | quantummagic 4 days ago | parent | prev [-] | | That's not actually how it works though. There's a reason we restrict people to zero bombs allowed on board. | | |
| ▲ | thih9 4 days ago | parent [-] | | Only because bombs don’t charge as well. Aerosol cans and flammable liquids (e.g. alcohol) are allowed; in small quantities - just like power banks. | | |
| ▲ | quantummagic 4 days ago | parent | next [-] | | This is the first decent answer, which I appreciate. And while my comparison to a bomb may have been over the top, I don't think a comparison to shampoo is fair either. And in any case, I'm not so sure whether the limit on toiletries is all that sensical either. | | |
| ▲ | thih9 4 days ago | parent [-] | | > I don't think a comparison to shampoo is fair either I’m not sure what you mean; when I Ctrl+F “shampoo”, this is the only hit I see. |
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| ▲ | majorchord 4 days ago | parent | prev [-] | | There are non-rechargeable power banks too though. |
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| ▲ | avidiax 4 days ago | parent | prev | next [-] |
| Maybe it's a sort of build-quality proxy. Someone bringing 150 "lipstick" single-cell promotional chargers -> bad Someone bringing one phone and one laptop battery pack -> OK If you are limited to two, you are probably not bringing anything that is near e-waste quality. |
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| ▲ | tristanj 4 days ago | parent | prev | next [-] |
| These items are dangerous. The FAA limit for power bank capacity is 100Wh (~27000mAh), which is 360kJ of energy. A hand grenade has approximately 700-800 kJ of energy. Two powerbanks contain the same amount of energy as a hand grenade. |
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| ▲ | drum55 4 days ago | parent [-] | | That's a kind of meaningless comparison. Peanuts are about 8kJ per gram supposedly, by your measure we should ban even small amounts of peanuts on planes because 100 grams of them contain more energy than a hand grenade. Without talking about the time frame over which the energy can be released you'd have to make sure that everybody went onto the plane completely naked lest their clothes ignited. | | |
| ▲ | SoftTalker 4 days ago | parent [-] | | Not good enough, body fat contains about 35kJ per gram. So nobody with over 1lb of excess body should be allowed on board. People are known to occasionally spontaneously combust. | | |
| ▲ | fragmede 4 days ago | parent [-] | | I thought that was proven to be people falling asleep with a cigarette in their hands and lighting a blanket on fire. |
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| ▲ | bryant 4 days ago | parent | prev | next [-] |
| More batteries, more likely that you'll have even just one of them fail. Since even one of them (to your point) failing is enough of a reason to divert the flight, better to start by reducing the probability of that happening in ways people can swallow. |
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| ▲ | quantummagic 4 days ago | parent [-] | | So having 500 batteries on board is okay.. but 750 is too risky? I just have a hard time believing that the math is actually mathing in this case. Maybe you're right, and this is just a first step to get people to gradually accept more restrictions. |
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| ▲ | ddalex 4 days ago | parent | prev | next [-] |
| Quantity is a quality of its own. Maybe there is enough plane onboard capacity to deal with just 50 batteries, let's say; multiply the failure rate expected and the pax capacity of the plane and you get how many batteries you can afford to have onboard and still be able to deal with worst case scenario. |
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| ▲ | dataflow 4 days ago | parent | prev | next [-] |
| If one power bank has independent probability p of failure, then n of them have probability 1 - (1 - p)^n of failure. What you're saying is equivalent to claiming that this quantity is somehow independent of n. |
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| ▲ | hollerith 4 days ago | parent | prev | next [-] |
| Way to lean into binary thinking. |
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| ▲ | quantummagic 4 days ago | parent [-] | | Do you save your snark for batteries only, or are you equally liberally minded with your non-binary thinking about the number of bombs allowed on board? | | |
| ▲ | unethical_ban 4 days ago | parent [-] | | You've now used this fallacious analogy twice. Clearly, battery packs have more legit utility for more people at much lower risk than a bomb. | | |
| ▲ | pocksuppet 3 days ago | parent | next [-] | | Maybe he has one of those rare laptops that's powered by a portable black hole. I think I saw them in the Apple store. | |
| ▲ | quantummagic 4 days ago | parent | prev [-] | | > You've now used this fallacious analogy twice. It's not fallacious, it focuses the issue, and in this particular case shows that it's not about "binary thinking" it's about risk. And my original puzzlement continues. At what level of risk, does limiting the number of devices on board to 500 or even more, actually accomplish anything? If they're not all that dangerous, then why limit them at all? And if they're dangerous enough to limit at all, why in God's blue sky, would you allow that many of them on a plane? We don't limit people to 1 knife per person, even though knives have utility to a lot of people who carry one with them every day. | | |
| ▲ | majorchord 4 days ago | parent | next [-] | | > why limit them at all Because it's a numbers game... the original order itself even acknowledges that the problem is not unique to power banks, but that what makes power banks unique is the amount of increased risk they pose compared to other devices, due to a higher ubiquity of them in general, and of low-quality unsafe ones. If laptops were catching fire with the same frequency, they'd ban those too, but they're not. They technically can be made just as unsafe as power banks, but they usually aren't, and this directive is based on the frequency of occurrence of a particular type of device, not a general "what if" strategy. Banning all electronic devices would be extremely unpopular and possibly tank their sales. They're trying to balance safety with convenience at a level that is acceptable to most people. | |
| ▲ | unethical_ban 4 days ago | parent | prev [-] | | If there are 20 battery banks on board a plane, each possessed by a different person: * Less likely to be of the same low quality * Less likely to all go off * Less likely that someone is doing something malicious/suspicious with it vs. someone who has 20 power banks themselves in a bag, in which case if one of them catches fire unexpectedly, they will probably all go up at once and create a cumulative effect much more dangerous than 20 individuals. |
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| ▲ | 4 days ago | parent | prev [-] |
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