# Why don't "black boxes" float? **URL:** \ **Category:** Factual Questions\ **Created:** [June 2, 2016, 10:38pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345 "2016-06-02T22:38:18Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [June 4, 2016, 6:03am UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/21 "2016-06-04T06:03:25Z")
So if they aren’t helping locate airliners, it probably comes down to the whole “crashing into the ocean” factor of a non-ideal operating environment. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [June 4, 2016, 12:11pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/22 "2016-06-04T12:11:59Z")
> [@Raguleader](#): > > Perhaps, though aside from any environmental concerns that for the purpose of discussion I presume we would have resolved before employing these dye packs, there is the practical issue of the volume of water in question. The oceans are very big, and depending on where you are and how deep you end up, the water is very cold. The first means the dye will be more diffused, the latter means the dye packs might not dissolve at all since cold water doesn’t dissolve as effectively. > > Maybe an audio beacon to supplement any other location aids? There are all manner of submarines and sonar arrays and such in various parts of the ocean. I’m pretty sure they already have a locator beacon that anything passing nearby can pick up. As for dye packs, if they can make it up to the surface, similar things are already used in other cases. They have dye available for people taking out small boats or diving out in the middle of nowhere in case they lose their bearings. It’s easier to see [neon green or orange](http://www.smh.com.au/content/dam/images/g/m/x/k/x/5/image.related.articleLeadwide.620x349.gmxkp2.png/1455782050607.jpg) than a black neoprene diver or upside boat. I’m not sure how widely used it us, but I heard about it a long time ago and it wasn’t that hard to find now, so I’m guessing at least some people must keep it on them when they go out. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [June 4, 2016, 2:41pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/23 "2016-06-04T14:41:51Z")
> [@Richard\_Pearse](#): > > [INMARSAT coverage.](http://www.inmarsat.com/wp-content/uploads/2013/11/I-3-satellite-coverage-November-2013.jpg) Oceanic regions have plenty of coverage, the only bits that don’t have coverage are close to the poles. > > Sat-phones are common on airliners and other aircraft. Ever wondered how wifi works on a plane? [Satellite antenna on an aircraft.](http://aviation.stackexchange.com/questions/14849/how-does-wifi-work-on-an-aircraft) Once you know what they look like you’ll realise that whole fleets of aircraft have them. > > It matters because we need to learn what happened so we can try not to let it happen again. Aviation is relatively safe because we go to great lengths to work out why crashes occur. I agree to some extent that it is a solution in search of a problem. It is very rare to not retrieve the flight data recorders. The system currently in place is adequate, so expect any improvements to come slowly and only once it is cost effective. I’ll just add that it’s not mandatory that this this system be used. If Aircraft were required to continuously broadcast their position plus the status of the plane then it would much easier to find the wreckage and determine what happened. ---
**Author:** ![UberArchetype](https://avatars.discourse-cdn.com/v4/letter/u/2bfe46/32.png) [@UberArchetype](https://boards.straightdope.com/u/UberArchetype)\ **Post date:** [June 4, 2016, 2:53pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/24 "2016-06-04T14:53:18Z")
> [@Dingbang](#): > > Why don’t “black boxes” float? Because that would make them even harder to find. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [June 4, 2016, 4:25pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/25 "2016-06-04T16:25:50Z")
> [@Richard\_Pearse](#): > > The 406 MHz beacons work world wide. Except in the South China Sea, apparently. I could see the value in a breakaway floation beacon on craft used for longer over-water flights. Something that breaks loose at a certain shock impact or other conditions, floats, and has a powerful if short-term radio beacon. There’s no way to make it stay in place, but even initial indication of crash location to a 10-mile radius would speed getting to the site and the data recorders. ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [June 4, 2016, 4:30pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/26 "2016-06-04T16:30:20Z")
> [@Amateur\_Barbarian](#): > > Except in the South China Sea, apparently. Aside from the possibility of the transmitter being damaged in the crash (which also happens in land crashes), seawater plays merry hob with attempts to propagate radio waves due to it being conductive. The same basic principle is how Faraday Cages work to isolate equipment from outside RF interference. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [June 4, 2016, 4:38pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/27 "2016-06-04T16:38:59Z")
> [@Raguleader](#): > > Aside from the possibility of the transmitter being damaged in the crash (which also happens in land crashes), seawater plays merry hob with attempts to propagate radio waves due to it being conductive. The same basic principle is how Faraday Cages work to isolate equipment from outside RF interference. I know, was just poking fun at an unqualified statement. It’s my belief that the pilot of 370 did everything he could to put the plane down as gently as possible, so that it would sink intact, losing little if any float-able pieces. That only a few pieces that would tear loose from a belly landing at ~100kt or so have been found tends to support my notion. ---
**Author:** ![Dingbang](https://avatars.discourse-cdn.com/v4/letter/d/ac8455/32.png) [@Dingbang](https://boards.straightdope.com/u/Dingbang)\ **Post date:** [June 6, 2016, 2:38pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/28 "2016-06-06T14:38:36Z")
> [@UberArchetype](#): > > Because that would make them even harder to find. Why? At worst, it seems to be a trade off – boxes sitting still on the very deep ocean floor, eventually not sending a locator signal anymore, probably difficult to retrieve if ever found vs. containers bobbing on the surface and subject to drift but easily recoverable when found. Even the drifting could be addressed by including a spooling anchor that stops or slows the movement from the crash area. (This is all assuming you can overcome the other practical issues discussed here. I’m just addressing the “harder to find” question.) Reminds me of the last-ditch emergency measure by a WW2 era submarine that is sinking. They could release a large buoy that would float to the surface. It had a metal plaque attached to it saying something like, “If you’ve found this buoy, there is a U.S. submarine attached to it at the bottom of the ocean in distress. Please contact authorities for rescue.” I’ve seen one in the water at the Navy museum in Charleston, SC. Pretty chilling to think of having to release that buoy. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [June 6, 2016, 2:46pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/29 "2016-06-06T14:46:44Z")
> [@ThelmaLou](#): > > In past discussions like this, I’ve suggested why not just continuously stream data via satellite. But if that’s not feasible for some reason… In the past, it wasn’t. But now that airlines are putting active WiFi on all their planes, offering 12 Mb/s speeds to each passenger at once, it doesn’t look like data transmission is the problem. Even sending ALL of the plane’s digital data, plus cockpit audio, in real time, would be nothing compared to one passenger watching a streamed video. So we are left with airlines just not wanting to install something they can’t charge for. It does occur to me that they could piggyback on the WiFi stream and not have to install more equipment, but I haven’t seen that proposed yet. ---
**Author:** ![Channing\_Idaho\_Banks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/channing_idaho_banks/32/250_2.png) [@Channing\_Idaho\_Banks](https://boards.straightdope.com/u/Channing_Idaho_Banks)\ **Post date:** [June 6, 2016, 2:58pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/30 "2016-06-06T14:58:00Z")
How about redundant black boxes? The first set of black boxes are secure on the plane, while the second set of black boxes is located near the exterior of the fuselage, and breaks away on crashes. What if the planes were equipped with some kind of float away beacons on the exterior of the plane so that when the plane crashes they would be a series of floating beacons that would guide Rescuers to the source of the crash. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [June 6, 2016, 3:02pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/31 "2016-06-06T15:02:08Z")
One problem with all these solutions is that ANYTHING added to an aircraft, especially a commercial transport, has to be over-engineered and re-engineered and tested, lather rinse repeat, specifically to ensure that it won’t cause any problems with flight or safety systems. You can’t just stick another box somewhere and run some wires to it. So multiply all this (essentially nonproductive) development, engineering and testing by the eventual cost of putting a validated system on every airliner… and it’s no longer a simple, “Daddy, why don’t they…” ETA: said testing having to be done, to some degree, on every separate platform - approval for a 737-500 doesn’t mean the FAA will let Southwest bolt one onto a 737-800, and certainly not a nearly identical A321. All to partially fix a once-in-ten-million-flight hours issue. ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [June 6, 2016, 5:31pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/32 "2016-06-06T17:31:57Z")
> [@Musicat](#): > > In the past, it wasn’t. But now that airlines are putting active WiFi on all their planes, offering 12 Mb/s speeds to each passenger at once, it doesn’t look like data transmission is the problem. Even sending ALL of the plane’s digital data, plus cockpit audio, in real time, would be nothing compared to one passenger watching a streamed video. Tangent: Do they let passengers watch streamed videos now? They didn’t the last time I flew on a plane with in-flight wifi, but then I fly steerage. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 6, 2016, 5:51pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/33 "2016-06-06T17:51:30Z")
[QUOTE=Musicat] But now that airlines are putting active WiFi on all their planes, offering 12 Mb/s speeds to each passenger at once, it doesn’t look like data transmission is the problem. Even sending ALL of the plane’s digital data, plus cockpit audio, in real time, would be nothing compared to one passenger watching a streamed video. [/QUOTE] Data transmission IS the problem. Commercial airliners are probably using services from outfits like Gogo or ViaSat. As a general rule, satellite-based data service is wildly asymmetrical. One real-world review I came across for Gogo is that it delivers around 25 Mbps down and .5 Mbps up. Note that this is also for the most part, over land. Over the oceans, the “build-out” is rather less comprehensive. There is truly global coverage but far slower service available from companies such as Inmarsat. Their BGAN service offers up to 468 Kbps downlink anywhere other than at the north or south poles, and that’s the fastest one I could find on a quick scan. And then, once you have a means to shoot all that data out of an airplane, multiply that data by all the other planes in the sky. An article in the [IEEE Spectrum](http://spectrum.ieee.org/aerospace/aviation/beyond-the-black-box)describes it as hundreds of gigabytes per day. I guarantee “feature creep” will result in demands to manage terabytes of data per flight once the ability to reliably archive any amount of in-flight data is developed. What do you do with it all? Who is responsible for collecting it from multiple receiving stations? How long do you keep it? Where do you keep this international data? (Think of something like a British Airways flight heading to New York crashing over Canada - there’s three countries involved.) Do you keep it all or just whatever looks important at the moment? Another article in the [New York Times](http://www.nytimes.com/2010/07/22/business/global/22blackbox.html?_r=0) describes the problem as not one of hardware, but the phone bill - in 2010, the cost to transmit this data was pegged at $3-5 per minute. Again, multiply that by the number of planes in the sky, and ponder what service they’ll remove to make up the difference. We’ve already lost free bag check, snacks, meals, pillows… At the end of it all, incidents where the recorders are not located are exceedingly rare. Overall, it’s about ten in the past 40 years. How much money are you willing to spend to overcome such infinitesimal odds? ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [June 6, 2016, 8:12pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/34 "2016-06-06T20:12:30Z")
Something I always wondered would be how difficult it would be to have some sort of system on aircraft to release some kind of tiny GPS enabled buoy upon submergence that could connect to a satellite network and transmit its coordinates of where it came to the surface. It certainly wouldn’t always give the exact position of the plane, but it would at least give the searchers something other than a very vague idea of where to search. I mean, even if the buoy wasn’t released until the plane hit the bottom (not the ideal situation), it would likely still surface fairly quickly before currents could blow it off course. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [June 6, 2016, 8:23pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/35 "2016-06-06T20:23:03Z")
Something like that was mounted aboard a U.S. Navy Trident sub in the James Cameron movie _The Abyss_, but for all I know it was pure fiction. > [@Velocity](#): > > Also, imagine if some fisherman or other unrelated sailors find and take your floating black box home. Maybe offer a reward for its return if the box was found by a civilian? ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 6, 2016, 8:58pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/36 "2016-06-06T20:58:49Z")
[QUOTE=bump] Something I always wondered would be how difficult it would be to have some sort of system on aircraft to release some kind of tiny GPS enabled buoy upon submergence that could connect to a satellite network and transmit its coordinates of where it came to the surface. [/QUOTE] An EPIRB for airplanes? Yes, the idea has come up, but there are several obstacles… [ul] [li]They will cost money to install and maintain - someone has to periodically change batteries, ensure the ejection mechanism is functional, etc.[/li][li]Where will the engineers find a space to install it? [/li][li]Who will accept liability if the thing doesn’t eject and activate after a crash?[/li][li]Who accepts liability if the thing ejects when it shouldn’t and kills a baggage handler?[/li][li]Every separate kind of airplane will need a unique design and more importantly, a unique certification by the FAA. There is no one size fits all here - what you may think of as an Airbus A320, for example, may actually be an A318, A319, A321, A320E, A320neo… Each of these will need its own design and certification process.[/li][/ul] Not saying EPIRBs for airplanes aren’t a great idea. It’s just that doing anything to change an airplane isn’t taken lightly. And yes, in the past, various crash sites have been robbed by the locals, confounding the investigators. For the TANS-Peru 204 crash in 2005, investigators had to offer a $500 bounty to get the flight data recorder back from a Peruvian scrapper, and looters scavenged pretty much everything that wasn’t on fire from the 2014 wreck of Malaysia M17 in the Ukraine. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [June 6, 2016, 9:02pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/37 "2016-06-06T21:02:33Z")
> [@gotpasswords](#): > > And then, once you have a means to shoot all that data out of an airplane, multiply that data by all the other planes in the sky. An article in the [IEEE Spectrum](http://spectrum.ieee.org/aerospace/aviation/beyond-the-black-box)describes it as hundreds of gigabytes per day. I guarantee “feature creep” will result in demands to manage terabytes of data per flight once the ability to reliably archive any amount of in-flight data is developed. What do you do with it all? Who is responsible for collecting it from multiple receiving stations? How long do you keep it? Where do you keep this international data? (Think of something like a British Airways flight heading to New York crashing over Canada - there’s three countries involved.) Do you keep it all or just whatever looks important at the moment? > > Another article in the [New York Times](http://www.nytimes.com/2010/07/22/business/global/22blackbox.html?_r=0) describes the problem as not one of hardware, but the phone bill - in 2010, the cost to transmit this data was pegged at $3-5 per minute. Again, multiply that by the number of planes in the sky, and ponder what service they’ll remove to make up the difference. We’ve already lost free bag check, snacks, meals, pillows… All readily solvable problems. Asymmetrical data? That’s because most ISPs still cling to the outmoded notion that all everyone does is send a tiny request up and get a flood of data down. Since that does define many customers who are ignorant of it, ISPs can get by with limited service. If the airlines are able to offer high download speeds (relative to the plane), and if they are using satellites, nothing prevents them from offering high upload speeds. The satellite doesn’t care which direction it is going, and it doesn’t take an unreasonable amount of power (that might be only available on the ground). Storing data, multiple planes, cost per byte, etc. – all very solvable problems. You could make the same objections 20 years ago to claim that HD video streaming would never happen – too much data, too slow, too high a cost. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [June 7, 2016, 11:57am UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/38 "2016-06-07T11:57:11Z")
> [@Amateur\_Barbarian](#): > > One problem with all these solutions is that ANYTHING added to an aircraft, especially a commercial transport, has to be over-engineered and re-engineered and tested, lather rinse repeat, specifically to ensure that it won’t cause any problems with flight or safety systems. You can’t just stick another box somewhere and run some wires to it. So multiply all this (essentially nonproductive) development, engineering and testing by the eventual cost of putting a validated system on every airliner… and it’s no longer a simple, “Daddy, why don’t they…” This is the correct answer to any proposed solution to the problem of black boxes going to the bottom of the ocean with the plane. Virtually any solution that reliably prevents the black boxes from sinking with the fuselage is going to be very expensive, and will only add value in a tiny percentage of all plane crashes, i.e. the handful that go down in deep water. Admittedly we’ve had an unusual number of these types of crashes in the past few years, but this is a random cluster and not cause for spending many tens of millions of dollars on the R&D, FAA red tape, installation, inspection, and maintenance necessary to fit (and retrofit) the entire commercial passenger jet fleet. ---
**Author:** ![KSDeputy](https://avatars.discourse-cdn.com/v4/letter/k/ba8739/32.png) [@KSDeputy](https://boards.straightdope.com/u/KSDeputy)\ **Post date:** [June 7, 2016, 7:53pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/39 "2016-06-07T19:53:06Z")
I just wish they would stop calling them black boxes, when they are orange. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [June 7, 2016, 8:04pm UTC](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345/40 "2016-06-07T20:04:15Z")
> [@KSDeputy](#): > > I just wish they would stop calling them black boxes, when they are orange. Didn’t you get the memo? Orange is the new Black. [Previous page](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345.md?page=1) [Next page](https://boards.straightdope.com/t/why-dont-black-boxes-float/756345.md?page=3)