[MISTERSASB]

Great discussion. I now understand more about the objections to replacing a black box with satellite streaming data . The two major objections seem to be 1) a catastrophic event could bring external communications to an immediate end and 2) the high data density could make it impractical to link it all to a satellite.

As to the first objection, any catastrophe would be preceded by the cause of the catastrophe. This is what one would hope to capture. I'm not sure if that covers every possible case but I it could be of great value to have instant access to events just prior. As to the second objection, intelligent systems can make useful decisions about which data to transmit and about how long a burst of information should be sent.

Anything that can be done to reduce the time needed to locate passengers who are injured or trying to survive on the ocean or in difficult conditions deserves a look, in my opinon.

[jarek]

> it could be of great value to have instant access to events just prior.

Why is it a significantly larger value than having access at worst two years later? No plane went down due to the same problem while they were looking for the AF 447 black box.

> Anything that can be done to reduce the time needed to locate passengers who are injured or trying to survive on the ocean or in difficult conditions deserves a look, in my opinon.

Passengers might survive reasonably successful ditchings, after which currently-fitted ELTs activate and transmit location as you expect. An event that results in ELTs not activating is generally not survivable in the first place.

[Alphasite_]

Well, for example if it was design issue they could pull all effected aircraft immediately, rate than waiting for the next one to crash over and and getting the blackbox then.

[jarek]

In practice, that's just not an issue these days.

Most crashes are due to human error or complex system problems that often include already known issues rather than a single thing failing catastrophically. Airbus put out a maintenance bulletin about pitot tubes freezing before AF 447 crash, and cockpit/crew management, concentration and problem solving while startled, and computer mode confusion were all known. The most recent example of one solid hardware problem are the 787 batteries and thanks to QA systems we know they are problematic but, fingers crossed, so far they haven't gotten bad enough to kill people. If a 787 goes down you know this will be the first thing looked at even without instant access to logs.

A new airplane entering production with a flaw that will go unnoticed until it suddenly starts crashing planes en masse is just incredibly unlikely. On balance of probabilities, we're better off focusing on existing known problems rather than coming up with super high tech monitoring schemes.