Originally Posted by
mixture
So to sum up .... I'm right. There IS
insufficient bandwidth.
Iridium and INMARSAT both have sufficient connections for every passenger aircraft in the world with more than say 80 seats to have their own 'private' connection to the satellites. They
could give that bandwidth to low sample rate DFDR/CVR recording but although the bandwidth is available it would be a waste of bandwidth as the number of times it would be needed is extremely small. Not only that in line-of-sight of land the aircraft would more sensibly use higher bandwidth protocols such as WIMAX to ground communications stations.
From a commercial point of view there is more benefit in provision of streaming broadband Internet to the pax. (Note this streaming broad band internet is what is planned; there is lots of bandwidth).
Therefore, the most likely commercial and engineering option is for the bandwidth to be used to allow pax to use the Internet in flight but with an emergency capability for that bandwidth to be taken by the live streaming of DFDR/CVR data if the aircraft automatics sense a probable emergency condition or if the pilot selects to stream. Probable emergency conditions could be extreme turbulence or g above a certain level, extremes of climb/descent or speed, unusual positions, pressurization failures, fire of engine(s) and/or fuselage, some avionics failures etc., etc..
This approach would also remove the concern often expressed by crew that they don't want management electronically watching 'over their shoulders' in real time; it's bad enough with FOQA.
Bandwidth is not an issue, using it for something else for the more than 99.999% of the time that makes the company money and only allocating it for emergency use in the 0.001% of the time that use is actually needed is an engineering solution.
