See here for the long answer - http://www.bbc.com/news/world-asia-pacific-26544554 http://www.bbc.com/news/world-asia-pacific-26544554 The short answer, as I u

See here for the long answer - http://www.bbc.com/news/world-asia-pacific-26544554 http://www.bbc.com/news/world-asia-pacific-26544554 The short answer, as I understand it, is: 1) Most communications technology, including satellites, is focused on where most people are communicating - ie, on land; ie, on 1/8th of the earth's surface 2) As you correctly point out, satellites over water aren't as obvious a problem as, say, mobile phone towers in the Indian Ocean, but the cost to retrofit existing aircraft is considered prohibitive given the rarity of this type of situation (ie, existing communication systems work well, and in this case seem to have been deliberately turned off anyway - so a different system is likely to have proved no more helpful).