Vooke, your understanding of the 'pings' are completely misguided. You're talking about 2 separate things here, let me explain this to you so you will no longer write erroneous things like your previous comment. There were handshake signals, also being referred to as 'pings,' that were picked up by Inmarsat. These were hourly packets of data recorded from the interaction between the plane, a satellite, and a ground station. These pings contained information on only the frequency shift of the plane relative to the satellite, and the time for the signal to get back to the ground station. These pings were heard hourly for 6 hours after the plane lost contact with radar, and analysis of this data led investigators to believe that the plane flew for 6 additional hours and most likely flew in the southernly direction. This combined with estimated groundspeed led them to search in the South Indian Ocean. The 2nd set of pings were initially heard once the search team started searching the South Indian Ocean, and were heard from underwater devices that pick up sounds from underwater. When planes crash, there black boxes emit signals which help the search team locate the black box. The search team picked up 4 different underwater signals, and initial analysis of the signals led them to conclude that they were most likely from the plane's black boxes. However, just a few days ago, all 4 of these underwater signals were completely discounted as having come from the plane. They are no longer part of the search evidence. So the only thing they are going with at this point in time are the Inmarsat handshake pings, which are a bit ambiguous in their own right. The search team is positive that the Inmarsat signals came from MH370, and these are the ones that were picked up for 6 hours. Just wanted to clear that up with you.