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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

#71

Post by curtis »

TylerE wrote: post #52
curtis wrote: post #38

Earlier quoted context omitted.

That may be true of existing black boxes, but a purpose-designed solid-state black box wouldn't have to be very big. Especially if it was optimized for surviving impact with water rather than, for example, a mountain. In fact, I was just thinking about how you could probably put a miniature blackbox in every single airline seat. Airline seats are already designed to float, and you'd only need one of them to be recove…

> Especially if it was optimized for surviving impact with water rather than, for example, a mountain. I think that's a distinction without difference. At 500mph, the water might as well be rock.

I'm not at all certain that's true at the extremes for which black boxes are designed. A difference between thousands of Gs and tens-of-thousands of Gs wouldn't matter for the airplane fuselage, but it might matter for solid-state electronics. I don't know if you'd get that kind of force differential between a water impact and say, slamming into a solid granite wall. But I'm to ready to discount it.

But even if we assume that there really isn't a meaningful difference in the physics of a ground vs. water impact, I think there still might be an advantage to having your conventional black box optimized for maximum survivability and having an auxiliary black box which sacrifices some degree of survivability at the extremes in exchange for improved discoverability after an accident.

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

#72

Post by ghshephard »

joering2 wrote: post #59

The issue here is a monetary one. How many planes go down each year? A few. How many planes are never found (black boxes). One per 10-15 years? An airline, or a company that builds planes would have little to none problem explaining to the judge that benefit-cost analyse make no sense: too much money would be spent for too little benefit (I know lives may be at stake, but that won't convince the judge). Couple years…

"I know lives may be at stake"

What lives are at stake? An enhanced black box won't prevent accidents, and, with very few exceptions, it won't help us find out the cause of accidents. I think your take on the "cost-benefit" analysis made the most sense.

Your 1 in 17 million scenario is interesting - how many times per flight is that scenario evaluated, or is that per flight? If per flight, and suppose we have about 20,000 Boeing flights a day, then we would have a Boeing explosion every 3 years. (Adjust the numbers based on how many Boeing flights there are) - I would say it's worthwhile making the change there.

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

#73

Post by fnordfnordfnord »

mcintyre1994 wrote: post #33
curtis wrote: post #28

Earlier quoted context omitted.

There were certainly parts of Air France 447 that floated. I think the largest piece may have been a section of tail. I don't know if there are parts that reliably float in the case of an accident over water but I'd guess that tail sections and winglets are good candidates.

I was thinking about the added weight of a black box though. My possibly naive assumption is that they're heavy because they're so robust, so would need serious buoyancy. I can't find a weight for them though so I might be wrong.

This one is 8.8 lbs. Not sure if this is the type used in a 777. http://www.uasc.com/documents/products/CVFDR.pdf

TRW makes them as well, but couldn't find data sheets on theirs.

You might also find this relevant. http://www.ntsb.gov/doclib/manuals/FDR_Handbook.pdf

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

#74

Post by pavelrub »

brandon272 wrote: post #7

I'm seeing a lot of armchair criticism aimed at the air travel industry about how these aircraft should be able to be tracked more effectively given "modern technology" and they reference things like broadband in cars, WiFi on flights, etc. What they seem to ignore is that many of these things only work effectively on land in populated areas. Drive your car out to the South China Sea and let me know how well the in-c…

I'm not convinced by your argument. I'm not sure what you mean by 'something catastrophic happens'. 'Something catastrophic' is the result of a certain chain of events. Telemetry data about those events can be sent before they lead to 'something catastrophic' that makes it impossible to send anything further. It is not as if the plane hits a meteor in mid flight and everything suddenly explodes with no prior indication of anything going wrong. And even if that's the case (as being accidentally hit by a missile during training - this happened before) - the lack of telemetry will also tell us something.

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

#75

Post by vinceguidry »

toufka wrote: post #54
michaelt wrote: post #43

Earlier quoted context omitted.

Part of the reason Iridium needs a lot of satellites is because they're in low earth orbit, to reduce latencies (800km instead of 42000km for geostationary orbits means round trip latency of 5ms instead of 280ms). You might be able to lower costs by tolerating increased latency and using higher orbits. You'd still need something for pole coverage, of course.

Those higher orbits are significantly more expensive to achieve.

Sure, but you wouldn't have so many of them.

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

#76

Post by fnordfnordfnord »

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:…

Why use satellites? There is plenty of long-range terrestrial radio tech that could do the job. Land-based and or even cargo ship based listening posts would be much cheaper. Aircraft-to-aircraft comms could also potentially do the job.

Granted, aircraft fly high in the air, but there are no line-of-sight problems as with terrestrial radio links, so even high frequency comms are possible.

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

#77

Post by jarek »

MISTERSASB wrote: post #58

Great discussion. I now understand more about the objections to replacing a black box with satellite streaming data . The two major objections seem to be 1) a catastrophic event could bring external communications to an immediate end and 2) the high data density could make it impractical to link it all to a satellite. As to the first objection, any catastrophe would be preceded by the cause of the catastrophe. This i…

> it could be of great value to have instant access to events just prior.

Why is it a significantly larger value than having access at worst two years later? No plane went down due to the same problem while they were looking for the AF 447 black box.

> Anything that can be done to reduce the time needed to locate passengers who are injured or trying to survive on the ocean or in difficult conditions deserves a look, in my opinon.

Passengers might survive reasonably successful ditchings, after which currently-fitted ELTs activate and transmit location as you expect. An event that results in ELTs not activating is generally not survivable in the first place.

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

#78

Post by aaronbrethorst »

"Your iPhone is more powerful than the evidence-collecting computers in the cockpit."

My iPhone 5s is arguably "more powerful" than the Hasselblad 501cm[1] I currently have sitting next to me. The iPhone has a built-in light meter, flash, and GPS. It can take more than 12 photos without reloading.

But, the Hasselblad was designed to satisfy a different set of criteria than the iPhone. And, for those criteria, it's absolutely perfect. If I want to Instagram something I'll use my iPhone[2]. If I want to shoot a photo I can print at sizes measured in feet, I'll use my Hasselblad.

Is it possible that the airplane black box needs a 21st century rethink? Sure. But to dismiss it in the article subhead does a disservice to everyone who reads the article.

[1] not my blog and not my photos, but representative of the camera: http://blog.mingthein.com/2013/07/27/fd-shooting-with-the-le...

[2] Actually, I'm one of those people who only uploads photos taken with a 'real' camera to Instagram, but you get the idea.

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

#79

Post by gvb »

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…

a) Nobody on the ground knew AF447 was in trouble. The aircraft never broadcast a declaration of an emergency.

b) Even if there was telemetry that sent the aircraft control inputs and instrumentation to the ground, with thousands of aircraft in the air, nobody would have been watching AF447's telemetry, waiting for Something Bad to happen.

c) It was about four minutes between when the aircraft got in trouble and when it impacted the ocean. Even if the aircraft declared an emergency and someone was able to pull up the telemetry for that flight, it is highly unlikely they would have been able to identify the cause before the aircraft impacted.

Ref: http://visual.ly/air-france-flight-447-crash-timeline

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

#80

Post by mpyne »

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 was one of the worst crashes in history and there was never even a problem with the plane.

There were many problems with the plane, including the physical one of the pitot tubes freezing up (despite heating elements installed to prevent that), and the software and design problems relating to silent disengagement of parts of the auto-pilot, silent transfer to different flight modalities by the auto-pilot, and poor affordances in the physical user interface itself.

Certainly the subsequent pilot error did not help, as the flight would have been recoverable if proper action had been taken, but it wasn't just the pilots either.

Either way if you think some random shore sider would have been able to identify the exact pilot fault and clue them in within time parameters even with the inherent latency of satellite comms you more faith than I do.

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