it's maximum operating depth. that's what happened in this case. the charted sea floor depth that we have for this area is between 4200 and 4400 meters and 5 x 8 kilometer square or rectangle that it's searching. we hate deeper spot than we initially planned so we got to bring it up, reprogram it, shift it a little away from that deeper area and adjust our search pattern. >> the air chief marshal said the bluefin is being used in the most likely spot. i just was wondering about that. what makes that the most likely spot? is it in relation to the four sets of ping or other data? >> well, the information that tells us is the most likely location is the nature of the detection from the tow pinger locator we had in that area. it was the site of the highest signal strength or the loudest received signal. it was also where we had an increase in signal strength as