Originally Posted by infrequentflyer789
128/0.08 = roughly 1500 times as much data - and hence 1500 times the cost. A satcom phone call is conducted at a rate of about 2.4kbps maybe $1 / min, so that's $50 / flight-minute. Even if I'm out by a factor of 10, that is a significant cost.
Hi
infrequentflyer789
Thanks for a very good post, my friend! I’ve gone over your figures (which are pretty darn accurate I would say) … and, presuming your suppositions are correct, it’s actually closer to 1600 times (rather than 1500 times) the amount of data involved. I also agree that it’s approximately $1.00 per minute for a “sat-phone call,” transmitting approximately 2.4kbps of data each minute. Using that same rate of data transmittal (2.4kbps), it would take approximately 22 minutes (and some 15 seconds) to transmit the data that you describe being regularly gathered each second – or, more precisely, the data that would be transmitted during approximately the first hour of flight would be the data collected only during the first 3 seconds of that flight. On the surface, regularly gathering the data you describe, and then transmitting the next 3-second hunk of data every 22+ minutes, would leave a huge amount of data that has been gathered while the first portion of that data was being transmitted. In this event, the process of transmittal would be ever falling further and further behind … to the point that at landing after an 8 hour flight (which is 480 minutes; or 28,800 seconds) it is likely that only the data for the first 24 seconds of that flight would have been transmitted. Or, said differently, this means that
substantially well less than 1% of the data collected will have been transmitted throughout that 8-hour flight.
Of course, this would not be the case were there a way to increase the data transmission rate. If it is logical (and it may be totally illogical, but…) presume that the transmission rate were to be increased by the amount of data collected in one second - which would mean a transmission rate of 128kbps (128,000 bits per second) – and as you indicated, this is 1600 times (my corrected number) that of the sat phone. If we presume a straight “1 for 1” increase, the transmission of FDR data would be approximately $1600 per flight minute … and again, a flight of 8 hours would cost a mere $768,000. With there being approximately 100,000 airline flights per day, this would net the provider of this service merely $768 million a day, every day of the year – which would generate a mere 280 billion 320 million dollars each year. Anyone care to guess who would wind up actually paying for this? Yeah … the passengers. So … I don’t hold out for any such situation becoming something to consider – unless of course, the transmission rate were dramatically increased, and cost equally dramatically reduced – that might make the process more in line with “cost for value.”