CNN Anderson Cooper 360 April 1, 2014 00:24:00
>> initially where the search area was a few weeks ago, wasn't so bad. now it's moved into a tricky place with a lot of steep cliffs, lumps and bumps, you could hide it behind one of those and never hear it. >> the sound can play tricks on you? >> sure. it can be bent by topography. can you have thermal layers that would attenuate the sound. all sorts of ways to lose that pinging sound. and especially distance. it may not even be close to it. air france, the pinger itself was at a depth of two and a half miles, so it was quite deep. you had to be right on top of it to hear it. >> the pinger lo...