There have always been two issues in play...one is "where is the aircraft?", and the other is "what were the critical parameters indicating at the time of the disappearance?", (a basic set could be decided upon quite easily).
The first can be addressed (and is being so) with available technology.
The second is a far larger question concerning a concept for data transmission which I think is unnecessary for the reasons given above.
However, there is a way forward if over time it is decided that some "critical path" flight & system data is necessary to at least shorten the time between the disappearance and original causes, if only for humanitarian reasons. This would certainy apply to MH370.
If I understand the basics behind the B787s data recording process, (I am a (retired) pilot and a flight data analyst, not an engineer or statistician!), there are so many parameters that the recording system data capture process "skims the surface" so to speak but when something out of "normal" occurs, the "focus" shifts towards more parameters for affected systems, (and perhaps at greater resolutions and capture rates?).
The notion is, when normal boundaries of controlled flight are exceeded or are in the process of being exceeded, (phase advance process...), the primary recording system bursts data to the deployable recorder in preparation for deployment. If things continue towards pear-shape, the little recorder with a powerful locater transmitter is deployed/parachuted/ballooned etc.
One objection voiced elsewhere is, how to keep such a heavily-reinforced, crash-protected device afloat?
But the whole idea behind such a deploying recorder is that it isn't at the scene of the crash so it can be light, like the aircraft's QAR, and still powerful with today's battery technology, and it can contain gigabytes of data for later examination.
Just protect it sufficiently against normal touchdown 'g' forces and the elements, (water, ice, rocks, jungle, mud, etc).
The alternative is, instead of, or in addition to a deploying recorder, the aircraft's normal recording system sends the several-GB burst of data to the satellite and thence to the dedicated airline, perhaps through the SITA system, or other such position-tracking satellite carrier. Such technology is already in use and available, and though presently expensive, would shift to lower costs as the system gained widespread use.
Wholesale data transmission is far too complex both technically and industrially, (someone brought up pilot concerns with off-site data and believe me, they are very real concerns), it's expense is unwarranted and the capability is unnecessary.
Last edited by PJ2; 15th Jan 2015 at 03:11.