Why Are We Still Looking For Black Boxes?

[Huerta88]

Black boxes are small, damageable in the type of violent incidents that lead to their contents being relevant, and (as they are finding out down in the Brazlian waters) not always so easy to find.

Aren’t we at a point where airplanes should instead (or as well) be constantly streaming all the data/voice content that otherwise resides only in the black box to a ground station with a fairly massive server farm that can record the digitized data in real time and overwrite it when the flight lands with no incident?

Yes, I know it’s a lot of information. There are 5,000 flights in the air over the U.S. at any given time (http://www.natca.org/mediacenter/bythenumbers.msp). But, memory is sufficiently cheap that Gmail gives me 7.3 gigs for free. How many gigs of data could be contained on the average black box?

[Bijou_Drains]

Probably just tradition , but also there is no guarantee the streamed data will be OK, there can be radio transmission issues.

[Huerta88]

@Bijou_Drains

Probably just tradition , but also there is no guarantee the streamed data will be OK, there can be radio transmission issues.

Yeah, I thought about that too, which led me to add “as well as.”

[SmackFu]

@Huerta88

Black boxes are small, damageable in the type of violent incidents that lead to their contents being relevant, and (as they are finding out down in the Brazlian waters) not always so easy to find.

The question is whether that is enough of a problem to spend a crazy amount of money to fix it.

[Bijou_Drains]

Yes, do they want to spend a ton of extra money just for 1 plane crash a year?

I believe most crashes are on land because that is where most flights are. Flights over oceans are not a big percent of flights.

[Arkcon]

The wikipedia article on flight recorders suggests that constant data streaming is the wave of the future for aircraft. But of course, there will be a significant lag in the implementation. Years after data downloads are so common, we’ll some day hear of a crash, and say they’re looking for flight recorders, and we’ll all go, “Flight recorders? Didn’t thiose die out back in the 2010’s? Yep. But not for all.”

But constantly downloaded data streams are under consideration, particularly for military planes, which we’d like to have more data in the event of a crash, which have systems in place to download the data (presumably, something like AWACS), and would prefer not to have flight data recorder lying around for the enemy to retrieve. At least, the wikipedia article used to say that, but the text is gone now.

[muldoonthief]

@Bijou_Drains

Yes, do they want to spend a ton of extra money just for 1 plane crash a year?

I believe most crashes are on land because that is where most flights are. Flights over oceans are not a big percent of flights.

Plus, flights where you’re most likely to not find the box, over oceans, are the ones where it’s hardest to transmit data. No receiving station in the middle of the Atlantic, so you have to broadcast to a satellite, which then has to retransmit your data down to a ground station. Which isn’t cheap, or easy, when you’re travelling at 600 kts.

[RedSwinglineOne]

They have to recover the wreckage anyway, so it’s not like their wasting extra time in recovering the boxes themselves.

[J-P_L]

If all the planes in the air were streaming their data non-stop, I would guess that it would represent a lot of bandwidth, possibly enough to overstress such a system.

The better approach would be for for planes to transmit interminately, say once every minute or 2.

Obviously, with this method, with an accident possible at any time, you might miss some critical last second data.
Just my comment!

[Whack-a-Mole]

@Huerta88

Black boxes are small, damageable in the type of violent incidents that lead to their contents being relevant, and (as they are finding out down in the Brazlian waters) not always so easy to find.

They may not always be easy to find but damageable? Not really. The important bits are specifically made to withstand a plane crash.

Testing a CSMU [Crash-Survivable Memory Units]

To ensure the quality and survivability of black boxes, manufacturers thoroughly test the CSMUs. Remember, only the CSMU has to survive a crash – if accident investigators have that, they can retrieve the information they need. In order to test the unit, engineers load data onto the memory boards inside the CSMU. L-3 Communications uses a random pattern to put data onto every memory board. This pattern is reviewed on readout to determine if any of the data has been damaged by crash impact, fires or pressure.

There are several tests that make up the crash-survival sequence:

* Crash impact - Researchers shoot the CSMU down an air cannon to create an impact of 3,400 Gs (1 G is the force of Earth's gravity, which determines how much something weighs). At 3,400 Gs, the CSMU hits an aluminum, honeycomb target at a force equal to 3,400 times its weight. This impact force is equal to or in excess of what a recorder might experience in an actual crash.
* Pin drop - To test the unit's penetration resistance, researchers drop a 500-pound (227-kg) weight with a 0.25-inch steel pin protruding from the bottom onto the CSMU from a height of 10 feet (3 m). This pin, with 500-pounds behind it, impacts the CSMU cylinder's most vulnerable axis.
* Static crush - For five minutes, researchers apply 5,000 pounds per square-inch (psi) of crush force to each of the unit's six major axis points.
* Fire test - Researchers place the unit into a propane-source fireball, cooking it using three burners. The unit sits inside the fire at 2,000 degrees Fahrenheit (1,100 C) for one hour. The FAA requires that all solid-state recorders be able to survive at least one hour at this temperature.
* Deep-sea submersion - The CSMU is placed into a pressurized tank of salt water for 24 hours.
* Salt-water submersion - The CSMU must survive in a salt water tank for 30 days.
* Fluid immersion - Various CSMU components are placed into a variety of aviation fluids, including jet fuel, lubricants and fire-extinguisher chemicals. 

During the fire test, the memory interface cable that attaches the memory boards to the circuit board is burned away. After the unit cools down, researchers take it apart and pull the memory module out. They restack the memory boards, install a new memory interface cable and attach the unit to a readout system to verify that all of the preloaded data is accounted for.

SOURCE: How Black Boxes Work | HowStuffWorks

[ElvisL1ves]

There’s a satellite message system to allow the crew and the company to text each other, and some info is automated. The data from AF447 is frightening - this event took place in stages, apparently.

But I agree with the OP that the technology is available and should be used.

[CurtC]

@J-P_L

The better approach would be for for planes to transmit interminately, say once every minute or 2.

Obviously, with this method, with an accident possible at any time, you might miss some critical last second data.

In a system like that, you’d be guaranteed to collect the vast majority of flight data, but also guaranteed to miss the most important bits.

[muldoonthief]

@Whack-a-Mole

They may not always be easy to find but damageable? Not really. The important bits are specifically made to withstand a plane crash.

Then how come they don’t make the whole plane out of the black boxes?

::d&r::

[Dallas_Jones]

@SmackFu

The question is whether that is enough of a problem to spend a crazy amount of money to fix it.

The queston of why airplanes are not tracked by a GPS location system was raised on a radio news show earlier today, maybe ABC top of the hour report.

They quoted the cost for such a system at $35 billion.

[Waffle_Decider]

I think bandwidth is a big problem. Even just for the cockpit voice recorder alone, you’ll need to be streaming multiple channels of audio. Multiply that by the thousands of flights that are flying at the same time. That is a lot of data to be transferred, with many of them taking place in some very remote region of the world.

I think privacy may also be a concern. Pilots do not appreciate that someone could potentially eavesdrops on their conversations in the flight deck (or, og forbid, their last words in case of an accident) and then post it on the Internet. This can be mitigated by the proper use of encryption, but this is just another layer of complications. With this technology, someone could also start storing a permanent copy of what is said in the cockpit, which is unsettling to some (current CVR always just record over itself in a loop).

[Hyperelastic]

How about a compromise system in which the black box doesn’t dump its data to a satellite until after the crash? That way you have two chances to get the data: by finding the box or from the satellite data dump (which of course would have a nontrivial failure rate.) Also, it wouldn’t require continuous streaming.

Also, when will they start using black boxes that float?

[Whack-a-Mole]

@ghardester

The queston of why airplanes are not tracked by a GPS location system was raised on a radio news show earlier today, maybe ABC top of the hour report.

They quoted the cost for such a system at $35 billion.

Huh?

Here is a map of all Southwest Airlines flights over the US right now.

Looks like they can do it just fine.

Now I am not sure if that is the planes reporting their positions automatically (the planes have GPS and know where they are) or if that is reported from ground radar. If ground radar then there are lots of places over oceans that would not be tracked.

Still, the planes do have an uplink apparently via satellite. I would think it would be trivial for the plane to send its position once every few minutes and have that recorded somewhere (or only when it is out of radar coverage to lighten the load even more).

[Whack-a-Mole]

@Hyperelastic

Also, when will they start using black boxes that float?

I heard or read somewhere that the black boxes are made to sink on purpose. The expert said often the black boxes are pretty banged up by the crash and having it float along in (perhaps) strong wave action getting beat up even more and perhaps dropping pieces along the way is not a good thing. Apparently it is better to let it go to the bottom and stay there.

The box has a pinger that activates when it gets wet and will run for 30 days. I think they have heard the ping of this black box but not sure.

[Really_Not_All_That_Bright]

@Hyperelastic

Also, when will they start using black boxes that float?

The ability to float would necessarily erase the black box’s survivability advantage over the rest of the plane.

[Markxxx]

35 billion isn’t a lot in the bigger picture. Bill Gates alone is worth 45 billion.

Look at the bail out figures.

As a compromise, why not just put the technology on but only turn it on for flights over oceans and such, where it’d be hard to get at the data.

I don’t buy the bandwidth is costly argument. The real argument is if I use the bandwidth for that I can’t sell the same bandwidth so Americans can have a second and third cellphone, another wireless Internet AND a GPS.