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Ask HN: Why do airlines still use "black boxes" ?

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Re: Ask HN: Why do airlines still use "black boxes" ?

#41

Post by noonespecial »

jdbeast00 wrote: post #37
noonespecial wrote: post #33

Earlier quoted context omitted.

The percentage of actual crashes in which a parachute would do anyone any good is likely vanishingly small. You can't use them when too high up (not enough O2) or too low (not enough time to deploy). Most crashes take place on takeoff or landing. Of the problems that do happen that would take you through a "jumpable" altitude, you can only make the jump if you 1) have time, 2) have enough airplane left to jump out of…

i'm sorry but i just don't buy the 'chutes aren't worth it / wouldn't work' argument. i'm confident that in the next few decades we'll have better safety systems in planes, it will just take a few really smart engineers. people will still die in planes, sure, but in the cases where chutes or whatever will help, there will be huge benefits.

Strangely chutes on planes might be worth it, but maybe not like you think.

http://en.wikipedia.org/wiki/Ballistic_Recovery_Systems

Re: Ask HN: Why do airlines still use "black boxes" ?

#43

Post by wglb »

Consider the fact that aircraft/control tower conversations are done over AM radio, a very ancient technology as these things go. Why so old, you might ask, in the vein of your question. First, there is an infrastructure cost--towers everywhere, airplanes everywhere have AM transmitters and receivers already.

Probably the only viable alternative that is still reliable would be single sideband (SSB), but that would be a infrastructure change as well.

If you consider what is required to do a digital encoding including handshaking, synchronization and the like, you are less likely to have a less reliable system. If in the midst of an AM transmission you get a static crash, it likely deletes one word. In a digital system, you might well have to resync, like a modem.

So some of these systems need to be very reliable under all sorts of harsh conditions. The questions I would ask, is 1) do the satellites already exist 2) how many of them and 3) are they visible everywhere there are airflights? and finally 4) how expensive is this network to maintain?

My guess is that the cost of such a network is a lot greater than a few black-box searches. Additionally, for really difficult crashes, they retrieve every possible piece of the airplane, at an expense that makes finding the black box seem small: http://en.wikipedia.org/wiki/TWA_Flight_800

Re: Ask HN: Why do airlines still use "black boxes" ?

#44

Post by anigbrowl »

jdbeast00 wrote: post #37
noonespecial wrote: post #33

Earlier quoted context omitted.

The percentage of actual crashes in which a parachute would do anyone any good is likely vanishingly small. You can't use them when too high up (not enough O2) or too low (not enough time to deploy). Most crashes take place on takeoff or landing. Of the problems that do happen that would take you through a "jumpable" altitude, you can only make the jump if you 1) have time, 2) have enough airplane left to jump out of…

i'm sorry but i just don't buy the 'chutes aren't worth it / wouldn't work' argument. i'm confident that in the next few decades we'll have better safety systems in planes, it will just take a few really smart engineers. people will still die in planes, sure, but in the cases where chutes or whatever will help, there will be huge benefits.

For this to be true everyone would have to wear one, and the plane would have to break open in mid-air. Obviously, structural integrity is an asset more often than a disadvantage. You won't be able to engineer this unless everyone sits in mini capsules and the plane like a ballistic missile with MIRV. The costs (in planes accidentally exploding over false positives and spewing out their encapsulated passengers) vastly outweigh the benefits.

Re: Ask HN: Why do airlines still use "black boxes" ?

#45

Post by raquo »

jules wrote: post #36
aconbere wrote: post #28

Earlier quoted context omitted.

I suspect that a floating object increase the range over which you have to search. If you object sinks to the bottom, at least you know about where it ended up.

Let it send a signal.

It does, and I think it is easier to pick up signal of a floating object than of an object 2 miles below sea level...

Re: Ask HN: Why do airlines still use "black boxes" ?

#47

Post by tdupree »

noonespecial wrote: post #41
jdbeast00 wrote: post #37

Earlier quoted context omitted.

i'm sorry but i just don't buy the 'chutes aren't worth it / wouldn't work' argument. i'm confident that in the next few decades we'll have better safety systems in planes, it will just take a few really smart engineers. people will still die in planes, sure, but in the cases where chutes or whatever will help, there will be huge benefits.

Strangely chutes on planes might be worth it, but maybe not like you think. http://en.wikipedia.org/wiki/Ballistic_Recovery_Systems

This is an intriguing idea, has anybody heard of any research done for this regarding passenger airplanes?

Re: Ask HN: Why do airlines still use "black boxes" ?

#48

Post by ynniv »

jules wrote: post #36
aconbere wrote: post #28

Earlier quoted context omitted.

I suspect that a floating object increase the range over which you have to search. If you object sinks to the bottom, at least you know about where it ended up.

Let it send a signal.

Radio doesn't work underwater. At 20 meters depth, a submarine can receive a 35 byte-per-second message using a long antenna, but it cannot transmit. [ http://en.wikipedia.org/wiki/VLF ]
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