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Hmm. Not sure it’s really necessary. They’re talking about live transmission of all the telemetry data. Seems like an unnecessary complication of a system that’s still working quite well. It’s not like there’s a big problem with recovery of black boxes. They are almost always found, and soon enough to be useful. Now there would have to be an additional powerful transmitter sucking amps from the plane, and somewhere somebody would have to be listening and recording all this stuff. Then there would have to be redundant systems to back that all up in case of failure.

I’m not sure investigators really gain much for all that.

Not that well. When Air France 441 went down off the Latin American coast, nobody had any idea of what had happened to it.

Now there would have to be an additional powerful transmitter sucking amps from the plane, and somewhere somebody would have to be listening and recording all this stuff. Then there would have to be redundant systems to back that all up in case of failure.
I’m not sure investigators really gain much for all that.

I disagree.
First of all, this system would only need to save data for no more than 24 hours, and we're talking about two totally distinct and separate sets of data : Engine and flight parameters, and position/speed/bearing data.

The former can be complex, comprehensive and is useful to determine the cause of the accident after the fact. The latter is a much simpler set of data used exclusively to locate the aircraft, even after breakup, if the recording medium and its power source is an integrated unit, and well protected to survive the accident.
No transmission of anything is essential, so long as the system is designed to be ejected and also to resist impacts and in the case of over-water flights, to float.

I scratch my head at the repeated objection to the cost of installing this equipment on all airliners. It is probably cost effective to install on all transoceanic-capable airliners.

After all how much does a search like the ongoing one for Flight MH370 cost? How many aircraft would that amount equip with the locating equipment?

Hmm. Not sure it’s really necessary. They’re talking about live transmission of all the telemetry data. Seems like an unnecessary complication of a system that’s still working quite well. It’s not like there’s a big problem with recovery of black boxes. They are almost always found, and soon enough to be useful. Now there would have to be an additional powerful transmitter sucking amps from the plane, and somewhere somebody would have to be listening and recording all this stuff. Then there would have to be redundant systems to back that all up in case of failure.

For General Aviation, you currently have tracking packages which use the existing satellite phone infrastructure. In places like Alaska, usage of such a system is mandatory. The Iridium satellite people have a package that costs $995 for the unit, plus between $15 to $85 per month depending on usage. Figure for a commercial airliner it would be more like $300/month.

The data doesn't need to be as much as what the black box records. Just GPS position, airspeed, and altitude, transmitted once per minute would be good enough to find the plane, and have some idea of when it got into trouble. Ideally, they would put the unit somewhere it cannot be tampered with while in the air.

Now there would have to be an additional powerful transmitter sucking amps from the plane, and somewhere somebody would have to be listening and recording all this stuff.

Adding to what I said in my prior post: all you would need is a PC accepting the data packets from the various planes in the airline, matching them up against the filed flight plan, and issuing an alarm message if the plane position deviated from the flight plan by some pre-set amount, or if its airspeed or altitude dropped below what it should be for the current point in its flight plan.