So Why Do Planes Need A Black Box?

[RATTER15]

One would imagine that all that is recorded on a black box could be transmitted instantly to wherever, thus, within minutes of an accident this information could be available, ok, so maybe also keep the black box as a backup, but in the era of such amazing technology why cant we do this? or are we to some degree?

[delboy3]

Some airlines do have a live "feed" of their flights back at HQ, monitoring the plane's performance.

[RATTER15]

delboy, that is a bit different than the info being recorded by a black box, but if they can do that they can transmit any info I would imagine!

[delboy3]

I think it is only limited to the basic parameters (altitude, speed, direction). More complex information would only register on the FDR.

[TheChair]

It's estimated that around the world at any one time there 8000-13000 flights in the sky at any one time. Detailed info from one would require quite a bit of bandwidth. Imagine 13000 people all sharing your Internet connection, all trying to upload vast amounts of data.

[RATTER15]

TheChair, I dont think your answer holds any water to be honest. I dont think its a case of bandwidth, surely!

[Old_Geezer]

I'd suspect a non-wireless link more reliable.
Certainly wouldn't want to get rid of them.

[TheChair]

Ratter - bandwidth is certainly a consideration of telemetry. The amount of information that needs to be sent in order to be useful, is pretty vast. The position of each of the control surfaces, the positions of the controls (for example, if the airbrakes are deployed you need to know to what extent and whether this was commanded by the pilot, the autopilot or neither - in the case of the Airbus 320, you also need to know how they were deployed), temperatures and pressures of various systems and subsystems, etc, etc. All this would need to be transmitted by radio, and in such a way that it did not interfere with similar quantities of info being transmitted by the other 12999 planes in the sky). Also, where would it be transmitted to? For many flight paths, the only accessible receiver would be a satellite.

[koster]

I struggle to get a decent Internet signal on the train from Cambridge to London, up above the remote Alps you'd be a long way from the nearest WiFi router!

[ichkeria]

Not sure what difference it would make.
Mercifully air crashes are statistical rarities. In the case of the Germanwings plane - or indeed most other disasters, it is going to be far too late to do anything about it anyway. You just need to know what happened afterwards.

[RATTER15]

I would have thought satallite was the obvious answer. I think it could be done.

[RATTER15]

ichkeria //You just need to know what happened afterwards// I know that. I was just suggesting that if we had all the info sent live and continuously it may mean that when a plane is at the bottom of a very deep ocean or on some inhospitable mountain or in a jungle far from civilisation etc. we would not necessarily need to retrieve the black box.

[237SJ]

That has been suggested before Ratter. It would save a lot of hunting around at the bottom of oceans for evidence. If/when it happens, it would be via satellite with someone like Inmarsat who are starting to get into inflight communications/tracking etc.