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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" ?

#61
post #48
post #36

Earlier quoted context omitted.

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 ]

I meant in the situation that black box floats.

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

#63
post #8
post #3

There is constant data sent out by most aircraft already. The black box is for when shit goes very wrong, like when a plane is on fire, out of power, with a big hole in it, falling like a rock and spinning like a top.

I still don't see why only a black box should be used for that. As long as a satellite uplink is powered by a separate external power source, none of these factors will stop a transmission.

Really? I think "falling like a rock and spinning like a top" would cause problems with your satellite uplink.

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

#64
post #3

There is constant data sent out by most aircraft already. The black box is for when shit goes very wrong, like when a plane is on fire, out of power, with a big hole in it, falling like a rock and spinning like a top.

A black box captures human perspective of extreme conditions. Telemetry, flight control, and maintenance data is more than enough to figure out what happened to an aircraft. But, they don't tell why it happened? Data in a black box answers a critical question: "Is it human error?"

Having said that, your question does resonate well with me too. How much data does a black box store that we can't send it over satellite (or even to other aircraft nearby-- think of a distributed storage) in real-time or near real-time? The purpose of such distribution is purely redundancy. I haven't seen any concrete numbers or engineering barriers against this idea, yet.

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

#65
post #51

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.

Yes, but you could put a radio beacon on a floating box. This seems like a good idea, possibly for a secondary box.

Or even better, you could have them produce a sonar ping that search and rescue could listen for... which is what they already do. :-) [ http://trueslant.com/milesobrien/ ]

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

#66

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.

There is a small aircraft manufacturer, Cirrus that puts a parachute recovery system right on the aircraft itself.

Notably, reviews have been mixed. http://en.wikipedia.org/wiki/Ballistic_Recovery_Systems

Cirrus, it should be noted has an below average crash rate compared to other aircraft in class. Clearly, the small total of 18 deployments compared to the crash rate leaves a lot of work to be done.

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

#67

Good question. Likewise, I've always wondered why don't they have parachutes in aeroplanes :(

There are a number of reasons. I will list some here:

1. Operational knowledge is lacking.

2. 300 people trying to jump from a plane through 2 3 foot doors will probably cause a crash alone.

3. Pointless at > FL 10. There is no oxygen up there.

4. It's also about -50C ish > FL 10. You would fall as a frozen popsicle.

5. Would add about 1000lbs of weight to the aircraft.

6. People floating around in the Atlantic isn't really an improvement.

7. 95% of all aircraft failures result in a safe landing. Only a small percentage result in crashes at the commercial aircraft level.

8. People hanging in trees all over the province of Alberta isn't really an improvement.

9. People landing in traffic in Denver isn't really an improvement.

I think you get the point. The answer is that parachutes are completely impractical for 90% of all aviation uses.

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

#68

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…

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

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

#70
post #19

Why don't they make black boxes floatable?

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.

Surface shipping already uses something similar, mounting buoyant distress/telemetry beacons which automatically deploy in an emergency (I don't know the exact mechanism, but I'd assume it's triggered by water pressure or something similar).

Some modern recorders on board aircraft can apparently do similar tricks, but I'd imagine it's more difficult to make it work reliably; the stresses involved in a plane crash are likely far greater, and I'd suspect the number of places from which a device could both survive and get free to deploy is much smaller.

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