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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" ?

#51
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.

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

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

#52
post #47

Earlier quoted context omitted.

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?

Based on the article, I'm guessing large passenger jets are some time off. BRS is currently working on systems for very small business jets.

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

#54
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.

Satellite transponder space is expensive, and you would need a whole lot of it. Even if you somehow got the capacity, who would pay for it, and who would collect the data? There's also the problem that satellite communication is difficult to get right (to the level of reliability required by FAA regs) with any degree of consistency. It's also worth mentioning that when a plane is in a state that you'd want the uplink to work, it's generally not flying in a level straight line - it will be experiencing huge turbulence, buffeting winds, and random dives and climbs - which would make keeping an uplink very difficult.

There's also a practicality argument: when a plane is flying along normally, you don't need consistent satellite information - you've got radio communication, radio data-links, and controllers watching. So the usefulness of a satellite uplink only comes when something is not right with the plane.

If we're in that situation - that there's something wrong enough with the plane that you'd want to know about it via the uplink - what makes you think the uplink will still be working? Air planes are designed with huge levels of redundancy and overengineered margins: are you going to take all that, double it, and then put it into a satellite transmitter (which probably won't have that much data to send anyways if the plane is in that state)?

So no, I don't think we need constant satellite uplinks. Black boxes (especially ones of the newer generation) are very well-engineered, and the NTSB guys are masters at getting things off broken ones.

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

#56
post #19

Why don't they make black boxes floatable?

Flight recorders, along with being incredibly durable, are also incredibly heavy. It would be difficult to provide a remotely reliable method of having the device float.

On the other hand, you could make the whole plane float and just let the blackbox sink ;-)

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

#57
post #23

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.

When a plane is flying and not transmitting anything, is the reason that nothing's wrong, or that the system that sends updates when something goes wrong (possibly among others) is broken?

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

#58

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

Assuming that there was a part of the plane that could open to create a viable jump platform (which there isn't in current designs), it would seem that the situations the plane has a problem, but it's stable enough that you and your 2-500 friends can get out your chute, read the instructions, put it on correctly, get to the exit point, and safely jump out and your plane has enough of a problem that you'd want to jump out are mutually exclusive.

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

#59
I was wondering the same thing myself today. My first argument would be that if data is getting into a black box, there's no reason it couldn't also get into a satellite transmitter and out into space in the same amount of time and with the same reliability. As for available bandwidth, how unrealistic is that bandwidth availability? How much data is being fed into a black box during a flight?

The idea of a distributed network among commercial aircraft and ground stations as a method of transmitting the data also seems like an exciting prospect, and perhaps less expensive than relying on satellite communications, though I know nothing of the range or viability of such a platform.

In any case, a system to complement a black box would require large expenditures by governments and airlines. But, how valuable is that data? Pretty valuable, I think.

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