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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" ?

#71

Post by HeyLaughingBoy »

dcurtis wrote: post #23
anigbrowl wrote: post #2

From : http://www.eng-tips.com/viewthread.cfm?qid=246491&page=1 Again, any single box is not the problem. It's the receiving end. Picture the FAA receiving 8000 planes worth of a minimum of 88 data streams at 50 Hz at 12 bytes each. That would be a minimum of about 4 Gbps data stream, and allowing for collisions and whatnot, you're around 20 Gbps datastream capacity. Guess where the hackers are going to concentrate t…

You only have to transmit data when something is wrong. You can use software to determine when to start sending updates.

No. Part of failure analysis is understanding what led to the failure in the first place. If you only transmit when something goes wrong, you may end up knowing what went wrong, but not why And why is usually just as important.

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

#73

Post by jonah »

GiraffeNecktie wrote: post #5
anigbrowl wrote: post #2

From : http://www.eng-tips.com/viewthread.cfm?qid=246491&page=1 Again, any single box is not the problem. It's the receiving end. Picture the FAA receiving 8000 planes worth of a minimum of 88 data streams at 50 Hz at 12 bytes each. That would be a minimum of about 4 Gbps data stream, and allowing for collisions and whatnot, you're around 20 Gbps datastream capacity. Guess where the hackers are going to concentrate t…

Sounds like a job for some kind of distributed peer-to-peer (or is that air-to-air?) network. A bittorrent of the skies.

While crossing the ocean aircraft are generally out of easy contact with ground stations for hours at a time. They're using long-range HF radios or even the data-only CPDLC system.

Some comments I've in other discussions brought up plane-to-plane communications, but other craft aren't commonly close enough to have any relevant weather information to share. (I'd extrapolate to think you'd have similar issues reliably transmitting data.)

Some fascinating comments below this post by the way: http://www.weathergraphics.com/tim/af447/

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

#74

Post by gvb »

rbanffy wrote: post #55
rossriley wrote: post #25

Earlier quoted context omitted.

I imagine that if they floated they would be carried far out of the way of the crash scene and thus much more difficult to find.

That's why they have radio beacons

No, no radio beacons. If they are on land, an exhaustive search finds them. For underwater search, they have battery powered "pinger" beacons. That is the cylindrical item in the picture on the Wikipedia page.

http://en.wikipedia.org/wiki/File:Grossi-7.png

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

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

#75

Post by jonah »

jules wrote: post #61
ynniv wrote: post #48

Earlier quoted context omitted.

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 ]

I meant in the situation that black box floats.

I believe they do, but maybe not whatever they may still be attached to.

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

#76

Post by patrickg-zill »

asciilifeform wrote: post #22
cstejerean wrote: post #20

Earlier quoted context omitted.

Probably because the majority of passengers are not trained to operate a parachute, attempting to jump out of a plane at 40,000 ft is likely to be lethal even with a parachute, and that having 200+ people orderly jump out of a plane with parachutes while the plane is crashing out of control is unlikely to work.

A more interesting question is why one is not permitted to bring a parachute on board at one's own expense, and why there are not even token provisions for enabling their use in a situation where they might be helpful. Air travel phobia seems to be rooted in the lack of control experienced by the passenger - specifically, in the anticipation of utter helplessness in the event of a crash. A parachute would help with t…

Parachute use at high altitudes means you have to either depressurize the entire cabin, or else create some sort of airlock which allows you to get into an unpressurized space so that you can open a door to the outside; which would add a large amount of weight and take up expensive space.

The reality is, that you are in fact utterly helpless in the event of a crash.

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

#77

Post by gvb »

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.

Nobody knows how to make a ballistic parachute that will handle a passenger jet, especially not a widebody A330.

Airplane doors CANNOT be opened in flight unless you depressurize the airplane first. Even then, it would probably be difficult. The only airliner (that I am aware of) that could have the rear stairs opened in flight was the 727, which was "fixed" after D.B. Cooper took that way out. (Odds are pretty good he didn't make it, either.)

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

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

#79

Post by asciilifeform »

philwelch wrote: post #68
asciilifeform wrote: post #22

Earlier quoted context omitted.

A more interesting question is why one is not permitted to bring a parachute on board at one's own expense, and why there are not even token provisions for enabling their use in a situation where they might be helpful. Air travel phobia seems to be rooted in the lack of control experienced by the passenger - specifically, in the anticipation of utter helplessness in the event of a crash. A parachute would help with t…

D.B. Cooper. Allowing people the means to parachute from airliners only enables hijacking as a means of escape from the law.

Then why not have garlands of frag grenades hanging on the ceiling as part of every bank's security system? Why should we enable bank robbers to escape from the law when hijackers cannot?

I'd prefer to fly on planes which aren't execution chambers for criminal and witness alike. The market refuses to provide me with this option, however.

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

#80

Post by philwelch »

asciilifeform wrote: post #79
philwelch wrote: post #68

Earlier quoted context omitted.

D.B. Cooper. Allowing people the means to parachute from airliners only enables hijacking as a means of escape from the law.

Then why not have garlands of frag grenades hanging on the ceiling as part of every bank's security system? Why should we enable bank robbers to escape from the law when hijackers cannot? I'd prefer to fly on planes which aren't execution chambers for criminal and witness alike. The market refuses to provide me with this option, however.

"Then why not have garlands of frag grenades hanging on the ceiling as part of every bank's security system?"

Because that would have significant side effects. Since parachutes are pretty much useless on airliners anyway, no significant side effects from banning them.

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