Telemetry isn't as easy as one might think. Airbus, AFAIK, is one of the pioneering manufacturers in this regard, as we witness in the crash of AF447, but given the amount of data that FDRs record, I'd imagine it wouldn't be a simple feat.
And in part, the reliability of FDRs and CVRs has been such that a comparatively small number of those recovered were void of retrievable information. So my guess is that replacing them would require satellite links (which obviously exist) but 1) have complete coverage of the globe (remember, aircraft like the 777 have a huge range) and 2) would be recording real time flight data for every single aircraft in the air. Then you have the issues of costs, approval from the various industry regulators (FAA, etc), and probably no less than 5-10 years before acceptance. And that's being hugely optimistic. In many ways, there's a point where carting around your telemetry-recording device is actually the cheapest and most effective method. It's counter-intuitive to some, but again: Telemetry isn't easy. Or cheap. And it needs to be reliable.
It does appear that Iridium Satellite is proposing something of the sort [1]. And trawling the Interwebs yields some [2] interesting [3] discussions [4].
But chiefly, I think the limitation is mostly cost, and as objclxt points out, reliability is another issue that would need to be addressed. There are a lot of planes in the sky. [5]
Comments
Telemetry isn't as easy as one might think. Airbus, AFAIK, is one of the pioneering manufacturers in this regard, as we witness in the crash of AF447, but given the amount of data that FDRs record, I'd imagine it wouldn't be a simple feat.
And in part, the reliability of FDRs and CVRs has been such that a comparatively small number of those recovered were void of retrievable information. So my guess is that replacing them would require satellite links (which obviously exist) but 1) have complete coverage of the globe (remember, aircraft like the 777 have a huge range) and 2) would be recording real time flight data for every single aircraft in the air. Then you have the issues of costs, approval from the various industry regulators (FAA, etc), and probably no less than 5-10 years before acceptance. And that's being hugely optimistic. In many ways, there's a point where carting around your telemetry-recording device is actually the cheapest and most effective method. It's counter-intuitive to some, but again: Telemetry isn't easy. Or cheap. And it needs to be reliable.
It does appear that Iridium Satellite is proposing something of the sort [1]. And trawling the Interwebs yields some [2] interesting [3] discussions [4].
But chiefly, I think the limitation is mostly cost, and as objclxt points out, reliability is another issue that would need to be addressed. There are a lot of planes in the sky. [5]
[1] http://www.spaceref.com/news/viewpr.html?pid=6174
[2] http://www.nytimes.com/2010/07/22/business/global/22blackbox...
[3] http://answers.yahoo.com/question/index?qid=20110620151102AA...
[4] http://forum.kerbalspaceprogram.com/threads/58733-Why-plane-...
[5] http://www.youtube.com/watch?v=_NFGD9cglb4&t=43s