81–90 of 93 posts
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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
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Why do you think that it doesn't?
I don't know whether it does, but it would be stupid to let it sink and send a signal.
Sending a signal makes it easier to find - that's not stupid whether or not it sinks.
Sinking means that it doesn't move much. However, since it's attached to the plane, it's likely to go down with the airplane whether or it it would sink on its own, whether or not it sinks on its own is irrelevant.
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 distribute…
Good question. Likewise, I've always wondered why don't they have parachutes in aeroplanes :(
HALO jumpers breathe pure oxygen onboard and jump with oxygen tanks. A single breathe during the transfer is enough to return your nitrogen levels to normal and cause blackout on egress. Any kind of medical condition, even anxiety or exhaustion can dramatically affect your susceptibility to hypoxia and normal clothes would not save you from frostbite.
By the way, 747's cruise at up to 40k altitude and 565mph. Jumping out is not a good idea.
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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.
The aircraft itself will also carry an underwater acoustic beacon (pinging at about 40KHz) or two so that underwater wreckage can be located once the general area has been established by the ELT that should have been jettisoned on impact. Both items (the ELT and the UAB) have limited battery life -- they pump out huge signals relative to their size. By convention, the UAB is located in the same general area as the FDR and CVR longitudinally.
In the case of the Air France flight incident, it would seem that the ELT did not work or was at a significant distance from the crash site by the time the search reached the position. That the black boxes (the FDR and CVR) are expected to be recoverable at this point seems to indicate that the UAB did work (it would have been detected by a sonobuoy dropped by the search airplane, which looked to me like it was equipped with anti-submarine warfare equipment, judging by the MAD boom on the tail).
Why don't they make black boxes floatable?
Better yet, why don't they make them orange?
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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
Wow! Why no radio beacon?
http://en.wikipedia.org/wiki/Emergency_Position-Indicating_R...
The ELT is to locate the debris field. (OK, it is officially to locate the survivors, but they tend to be in the debris field.) If the crash is on land, another radio to locate the black box is unnecessary. If it is in the water, a radio transmitter is useless, but a pinger is very useful (see other debate threads why floating black boxes aren't a good idea, and impractical to boot - the armor is very heavy).
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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.
What are you talking about? The market already provides that option in several forms:
1. Learn to fly and fly yourself. 2. Rent a pilot and a plane and get to where you want to be.
You might not be able to afford those options, but they are there.
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Let it send a signal.
Aircraft have floating, jettisonable radio beacons (Emergency Locator Transmitters) that transmit on the international guard frequency 121.5MHz (with intentional harmonic distortion that allow reception on the military guard frequency of 243MHz). That frequency is monitored by SARSAT (Search and Rescue Satellite) in North America -- the middle of the South Atlantic may not be monitored, since the automated search not…
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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.