Originally Posted by
EsherFlyer
One (speculative) suggestion I'll offer is that although each arc may have an amount of error if you assume a constant speed then that will help 'respace' them. So if the hourly arcs were notionally 420, 460 and 450 nautical miles apart you could calculate an assumed average speed of ~435knts and replot the lines to fit that assumption.
Has anyone see a 'back plot' from Ocean Shield's search position across the satellite arcs at various speeds to see if it leads back to the right origin?
Alternatively, as I think we mentioned above, I wouldn't be surprised if a submarine from some nation or other had passed by the area in the last month and detected something to help direct the surface search.
In the JACC press conference The naval rep said their sub was "not equipped" for this kind of search.
About the location, Angus said they acted on the belief that the seventh 'half' ping was at the time and point of impact. That seems to be correct. With a time of impact they were able to calibrate a line back through the other ping arcs to get an approximate landing coordinate. That would be the 'back plot' you are asking about.
Angus also said that quiet operation was the key to hearing a weak signal and separating it from noise. Only Ocean Shield will be in the water at the search site. They will drop up to 85 microphones that will listen at a depth of 1000 m. The intent is to get a geographic picture of the sound sources.
I am hoping for the best, although I wonder if all those mics hanging 1000 m down won't interfere with the 4000+ meter cable towing the TPL.
Angus was asked about the discrepancy between the 37 KHz frequency of the FDR and the 33 kHz that was detected. He didn't provide an explanation but he said they were satisfied that they had probably detected the right signal.
The question that immediately popped into my mind was whether the sono-buoy mics were re-calibrated to the actual frequency that is being sent. The sensitivity is given as 37 +/- 1khz which seems like it would tune out the actual frequency of 33khz.
I have a lot of confidence they are doing this correctly. The Ocean Shield detected the signal very soon after they started searching. Inmarsat's ping arcs and the calculation of speed and fuel used from the earlier radar hits was spot on. This is absolutely amazing and shows how technology has moved ahead since the Air France crash.