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Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

theguardian.com

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Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#61

Post by adanto6840 »

melling wrote: post #39
Zancarius wrote: post #27

Earlier quoted context omitted.

> Btw, what's the transmission range of a black box? If it's 10,000 ft down, how close do you have to be to hear it? Apparently 2-3 kilometers according to [1], which I found in the comments from here [2]. [1] http://www.hydro-international.com/issues/articles/id1098-Ai... [2] http://www.aticourses.com/blog/index.php/tag/side-scan-sonar...

So, if the plane is traveling at 13 km a minutes and you have a 20 minute window, it's going to take a long time to find it. Doesn't the technology exist to detect low power signals from a much greater distance? The US military must be able to do it?

I'm more surprised that there isn't a single (imagery-related) satellite that would, over the last 24 hours or so, have taken imagery (or been able to be re-assigned to do so) of the area(s) of interest.

If for nothing else than to rule out some areas / possible outcomes... But yeah, very far out of my realm of expertise, though I do hope to finish my PPL fairly soon & am an avid AVHerald & LiveATC follower! :-)

http://www.liveatc.net/forums/

http://www.avherald.com/

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#62

Post by jarek »

m4x wrote: post #34
objclxt wrote: post #15

Earlier quoted context omitted.

I pointed this out somewhere else, but satellites aren't particularly helpful because you won't be able to transmit to them when you most need it , which is when there are problems with the plane. It's still highly likely that you're still going to end up with planes going 'off the grid' so to speak. You could lose power, stopping you from transmitting telemetric data. Or there could be a cabin depressurization or br…

Real time telemetry via satellite could definitely be useful in some situations. The Air France crash could have been prevented if somebody on the ground had taken a look at the data from the plane, realised that the junior pilot has been pulling up the whole time, and made the crew aware of it. That was one of the worst crashes in history and there was never even a problem with the plane. All they needed to save the…

Presumably you've read the story of what went on in the AF 447 cockpit - do you suppose adding one more voice to the cacophony of warnings would really have helped? Two seasoned pilots that were in the cockpit didn't fully realize what was happening - there's no guarantee a remote overseer dealing with incomplete and inconsistent data would have either.

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#63

Post by confluence »

We really don't. Satellite uplinks don't have enough bandwith for every plane's black box data, and the data we would get wouldn't be useful, since you need the data when things go wrong, and I doubt you'll maintain a connection when everything goes wrong. Furthermore this article illustrates why I try not to read the news at all. The journalist has absolutely no idea what he's talking about - which is the norm for most stories. Film streaming is done from an on plane cache and in air WiFi is more often than not provided by ground cellular networks, falling back to satellite, which is unusable most of the time.

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#64

Post by [deleted] »

SnowProblem wrote: post #41
objclxt wrote: post #15

Earlier quoted context omitted.

I pointed this out somewhere else, but satellites aren't particularly helpful because you won't be able to transmit to them when you most need it , which is when there are problems with the plane. It's still highly likely that you're still going to end up with planes going 'off the grid' so to speak. You could lose power, stopping you from transmitting telemetric data. Or there could be a cabin depressurization or br…

But if you were broadcasting location and velocity at all times, even if an aircraft lost power, you could project where the "unplanned water landing" would occur. That seems helpful. I wonder if Google's Project Loon [1] would be of any use here. [1] http://www.google.com/loon/how/

[deleted]

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#65

Post by ars »

tobiasu wrote: post #51

Before you waste time with better data logging, please install an ejection seat, parachute, and a built-in life support system. That's much more useful than sensors that record the demise of the passengers to satisfy the bloodlust of news corps. Or rationally, don't change a damn thing. Airliners are fine. Any other form of transportation (maybe with the exception of trains) is many times more deadly and we cope with…

> That's much more useful

Not really. The hard part is knowing when to use such a system. In most of the catastrophic crashes I've heard about no one knew they were in danger till they were dead.

> to satisfy the bloodlust of news corps

That's not what it's for, that's horrible thinking. It's for determining what happened so we can prevent it from happening again!

> Any other form of transportation (maybe with the exception of trains) is many times more deadly and we cope with that risk just fine.

Because of those same data recorders you denigrate! And now that we've reached a plateau of sorts, it's time to move to the next level.

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#66

Post by gvb »

yaakov34 wrote: post #20

Let's start estimating the technical challenge here (we're supposed to be techies, after all). Bandwidth: quick googling shows that a flight data recorder records between 64 and 256 12-bit words a second, i.e. 1-3 kbps. Browsing http://en.wikipedia.org/wiki/Bit_rate shows that another 2-8 kbps is needed for voice recording (from one microphone). Let's call it 10 kpbs all together. Number of simultaneous connections:…

How many aircraft are lost that satellite link "crash data" would have been useful? I recall three, MH370 would make four. I imagine there are more, but compared to the number of aircraft that don't crash, the total is a rounding error.

http://en.wikipedia.org/wiki/TWA_Flight_800

http://en.wikipedia.org/wiki/China_Airlines_Flight_611

http://en.wikipedia.org/wiki/Air_France_Flight_447

Of the three, TWA flight 800 is the only one whose cause is controversial, and in-flight data transmission likely would not have helped identify the cause of that crash.

Of all the above accidents, the causes are understood and have not been repeated. In fact, the cause of Air France 447's instrumentation failure was understood before the crash - there was an an active airworthiness directive to fix the pitot icing.

Extraordinary expense with no(?) payback.

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#67

Post by hga »

m4x wrote: post #34
objclxt wrote: post #15

Earlier quoted context omitted.

I pointed this out somewhere else, but satellites aren't particularly helpful because you won't be able to transmit to them when you most need it , which is when there are problems with the plane. It's still highly likely that you're still going to end up with planes going 'off the grid' so to speak. You could lose power, stopping you from transmitting telemetric data. Or there could be a cabin depressurization or br…

Real time telemetry via satellite could definitely be useful in some situations. The Air France crash could have been prevented if somebody on the ground had taken a look at the data from the plane, realised that the junior pilot has been pulling up the whole time, and made the crew aware of it. That was one of the worst crashes in history and there was never even a problem with the plane. All they needed to save the…

That's demanding rather a lot from a human on the ground.

The Boeing (and I'm sure others) design philosophy is "unsynchronized joysticks ARE A TERRIBLE IDEA", and if Airbus and Air France had use the normal synchronized yokes, the problem of the brain wedged junior pilot would have been quickly apparent.

Can you think of other examples?

BTW, it's guessed that iced up pitot tubes caused the autopilot to disengage.

You're also assuming the pilots would listen to a kibitzer from afar while struggling to fix their plane. Plus a hell of a lot of expensive technology to support all that. And expensive kibitzers looking over the pilot's shoulders, which the latter wouldn't like.

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#69

Post by jusben1369 »

dap wrote: post #49
yeukhon wrote: post #40

Earlier quoted context omitted.

How many fatal crashes of commercial airliners with black boxes have ultimately not been root-caused? I am not sure what you are trying to say. The blackbox is like your log file on a server: the flight recorders (flight data recorder and cockpit voice recorder) in aircraft, (wiki). So if you want to know what happened to the aircraft, whether after a fatal crash or after a hijack or after emergency landing, the blac…

I'm saying that if black boxes are sufficient to root-cause the vast majority of commercial airline crashes, what problem are we trying to solve by "rethinking" them? The only one I can think of is speeding up the process, but it's not clear that that's actually a real problem rather than just disappointing to someone in the news industry who wants answers within a few news cycles.

Yes I think you're on to something. The complaint is how long it takes to have a definitive answer. But I'm not sure how significant a problem that is. For relatives and friends it may create a little closure but probably not much given it doesn't change the main issue. It's possible that there could be data collected that, if modified on other planes, would reduce or remove the chance of a similar tragedy. It doesn't seem though like that is the case in any disaster to this point.

Re: Malaysia Airlines flight MH370 makes it clear: we need to rethink black boxes

#70

Post by jusben1369 »

tobiasu wrote: post #51

Before you waste time with better data logging, please install an ejection seat, parachute, and a built-in life support system. That's much more useful than sensors that record the demise of the passengers to satisfy the bloodlust of news corps. Or rationally, don't change a damn thing. Airliners are fine. Any other form of transportation (maybe with the exception of trains) is many times more deadly and we cope with…

The problem here is that the blackbox should continue collecting data to the very last second until it no longer can. So trying to time it to get it out before the "end point" undoubtedly reduces the value of what it's collecting.
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