Nightly News | April 08, 2014
>>> search teams off of australia still scanning in the hopes of picking up another possible electronic signature from the black boxes from the missing malaysia airlines jet. the wreckage is likely three miles down. it's all happening as those pingers are quickly running out of battery life if they haven't already which would make this incredibly difficult mission all that much harder. we get our report once again from tom costello.
>> reporter: on this 32 day of searching frustration. after two days the australia american team aboard the ocean she would heard the pings that might have come from the plane's black boxes they have not heard the signals since.
>> if we can get more transmissions, we can get a better fix on the ocean floor . which will enable a much more narrowly focused visual search .
>> reporter: the pinger locator is working at a depth of 4600 feet. "the washington post " illustrated today at 15,000 feet the ocean depth is a huge challenge. the elm pyre state building stands at 1250 feet tall. the maximum depth a sperm whale can dive, 2,200 feet. the "titanic" was found at 12,500 feet. if it's there flight 370 could be 15,000 feet below the ocean surface nearly three miles down. the why are water terrify vein a volcanic plateau known as broken ridge, so deep oceanographers say the area has never been thoroughly charted.
>> are there peaks and valleys that can hide the wreckage, is it soft mud, hard rock . it could be hard to get it off the bottom.
>> reporter: search teams still haven't found a single piece of floating wreckage.
>> if you have a break up you expect to see wreckage. you expect to see debris, cargo. nothing.
>> reporter: the cost of the search so far rough lui $44 million and still no sign of flight 370. tom costello, nbc news, washington.