On 3/26/2014 4:37 AM, Keith Willshaw wrote:
1) The Indian Ocean is BIG
2) Nuclear Submarines typically operate submerged with no radar working
3) DE Submarines tend to lurk around main shipping routes and also
practise EMCON

Correct me if I'm wrong, but:

Listening for a "ping" is a passive operation. Simply listening
involves no emissions of any kind from the submarine. Still, given the
published 2 KM range of the black box's pinger, the chances of a
submarine blundering close enough to detect it are small given the vast
search area.