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Missing Airplane Flew On for Hours

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Re: Missing Airplane Flew On for Hours

#91

Post by akiselev »

alexeisadeski3 wrote: post #43
nostrademons wrote: post #39

Earlier quoted context omitted.

The other thing to consider is that there are roughly 90,000 flights/day and 365 days in a year, so even if such an event has a probability of 1 in a billion (that's roughly 9 9s reliability), you'd expect it to happen once every 30 years on average. Extremely unlikely events become plausible when large numbers are involved.

You're showing one botched flight deck O2 tank per 30 years? That's how I read it but I may be wrong. What are the odds that that one botched O2 tank happens to be on a flight with high altitude decompression?

If the cause of the accident is in any way related to "human error" instead of unpredictable failure (unpredictable as in photons causing a bit flip that can't be caught in error correction, not something like a part with a 15 year life span being used for 20), chances are that error is the result of an institutional problem. With 90,000 flights a day I can imagine plenty of people making mistakes during maintenance and flight checks because they're tired, having trouble with at home with the family, etc. but that's why we have so many levels of review and confirmation, checking to make sure it all goes according to plan. If the airline (the asset/floor managers specifically) don't enforce a culture that takes safety and aircraft operation seriously, no amount of reviewers will help them and when things fall apart, they do so in spades.

It's not really a question of "what's the chance that this will break in 30 years." It's a question of the part's function, the added complexity/failure points it adds to the design, and the chances that the added complexity will exacerbate flaws in management when it all goes haywire.

Re: Missing Airplane Flew On for Hours

#92

Post by mrow84 »

mrow84 wrote: post #77
United857 wrote: post #15

Earlier quoted context omitted.

It's possible in some cases for phones to "ring" even if they're off/disconnected, as the tone is generated by the network, not the device itself.

Is there is some sort of timeout after which it gives up, or a reliable upper bound on the time it takes for a network search, and if so, do you know how long either of those two periods are? I presume that if you ring a phone, a search is initiated, which would result either the phone being located or the phone being marked as unavailable, and that once the latter had happened you wouldn't get the ringing tone until…

After some link following to [0] I saw tweet [1], which suggests that the phones wouldn't have been on the network at all. It doesn't really answer my questions, but I think it rules out the phones as a source of information.

That tweet implies that the first order answer to my question 'how long before a search times out' is 'a long time'.

[0] http://mh370lost.tumblr.com/ [1] https://twitter.com/AeroMobile/status/443419690350960640

Re: Missing Airplane Flew On for Hours

#94

Post by TillE »

infinii wrote: post #74
digitalengineer wrote: post #9

So we have a plane that flew to another destination without communication and several people with bogus passports on board. Familymembers have reported cellphones that kept 'rining' instead of going directly to voicemail (as they would have if the plane was at rhe bottom of the ocean). Hijacking looks to me the only reasonable explenation.

So after 5 days, the hijackers are allowing all the hostages to charge their phones?

I don't think this is remotely plausible, but remember that dumbphones can last well over a week between charges.

Re: Missing Airplane Flew On for Hours

#95

Post by omegant »

retrogradeorbit wrote: post #84
nostrademons wrote: post #7

Interesting hypothesis that would square with this: http://www.antipope.org/charlie/blog-static/2014/03/a-hypoth...

The best part of this theory (which I think is good) is: "Losing Helios 552 might be a freak accident, but if decompression and a locked door led to the loss of MA370 as well, then this would be a new threat that will now have killed 360 air travellers—many times more than have died as a result of hijackings since 9/11. Is it appropriate to employ anti-hijacking measures to prevent violent hijackings a couple of time…

There is a code that can be used by the cabin crew to access the cockpit in this cases. It's cancelable from the inside, so if a hijacker tries to use it you can put it of once it starts ringing(it rings for 30 seconds and then opens the door). So this case of pilots unconscious is covered.

Any way I agree that the spending after the 9/11 is insane and unecessary.

Re: Missing Airplane Flew On for Hours

#96

Post by WalterBright »

ekianjo wrote: post #35
Blahah wrote: post #27

Earlier quoted context omitted.

He does reference the case of Helios Airways Flight 522[0], where a similar situation happened as a result of human error (leaving the pressurisation system set to manual). 0. https://en.wikipedia.org/wiki/Helios_Airways_Flight_522

This was not the same place (737 is damn old in design, from the 70s, 777 was designed in the 90s), this was not an international flight (security standards for international flights are stricter), so I'm not sure he even tries to compare both of them. Why not reference a Cessna incident as well ?

The 737 entered service in 1968.

Re: Missing Airplane Flew On for Hours

#97

Post by eklavya »

Crito wrote: post #41
ekianjo wrote: post #29

Earlier quoted context omitted.

I don't know how networks work in your country or where this accident occured, but in Japan when your phone is off, and you try to call it, it does not ring and indeed goes to voicemail directly.

Instead of turning your phone off, so that it can inform the network that it is going off line, try pulling the battery without warning. If I turn off my phone gracefully, the network will send incoming calls pretty much straight to voicemail. If my phones battery has died, or the phone dropped off the network for another reason (went camping?), then the network will have your phone ring as it searches for the phone.

No, you will not hear a ringing. The ringing only starts after the phone you are calling has been contacted. When you pull the battery out, the network will keep on searching for your phone and since no phone replies, it will inform you that the phone is out of coverage area.

Re: Missing Airplane Flew On for Hours

#98

Post by Raptor22 »

brador wrote: post #62

They claim some of the cell phones are still active. Can't they just "traceroute" the call to find the nearest cell tower and search around it?

This blew my mind. Cell phones don't work that far out from range of towers, and they sure as hell don't work at the bottom of the ocean. I heard that those were rumors and that they were false, but if they're true, then that's a major wtf...

Re: Missing Airplane Flew On for Hours

#99

Post by eklavya »

jonah wrote: post #34
sitkack wrote: post #14

Earlier quoted context omitted.

Annnd, why aren't we reading about cell logs of every IMSI of every passenger on board. Isn't this baby stuff? Continually ringing doesn't mean the phone is still on a network.

Continuously ringing means the network still thinks the phone's on the network. When you power down your phone it sends a signal to the network saying it's going off. If you just pull the battery or something else where it doesn't send that signal, the network still assumes (maybe only for a time) that the phone is still on but isn't connected to a tower.

But the ringing only starts once the target phone responds to the paging from network, otherwise the network just keeps on searching and after a timeout informs that the target phone is unreachable or out of coverage area.

Re: Missing Airplane Flew On for Hours

#100

Post by hueving »

mootothemax wrote: post #59
ekianjo wrote: post #35

Earlier quoted context omitted.

This was not the same place (737 is damn old in design, from the 70s, 777 was designed in the 90s), this was not an international flight (security standards for international flights are stricter), so I'm not sure he even tries to compare both of them. Why not reference a Cessna incident as well ?

Edit: deleted hostile, snarky content.

>Can you explain which one it is?

Did it cross your mind that it could be a combination of them? Drop the accusatory tone when you don't understand the content.

International flights have higher standards due to extended distances from emergency landing sites. An old plane is not exempt from the check standards, but the age certainly means that there is an increased probability of failures.

>If so, at what airframe age, or travel standard, or aircraft size does that kick in?

Again, sarcasm is really unhelpful when it's just a result of you lashing out at a comment you didn't understand.

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