Transcript for Running Out of Time in the Search for Flight 370
Now, we're going to turn to Steve ganyard, ABC news aviation consultant. Steve, with this dramatic reduction in the search area, and I'm going to put the map up once again, is this search more doable? It is more doable, Diane. It's a good news/bad news story. We've narrowed the search area to come down quite a bit. But the problem is, it's still such an unbelievable large part of the ocean that we have to search. The Australians said today, it will take weeks just to look at this smaller search area. And can the search planes see deeply into the ocean? And how deep is the ocean right there? No, unfortunately, the planes can't see under the ocean. If we're going to find something, it's going to have to be on top of the surface, still floating. Something they can see, perhaps some of the radar can see some reflection. But it has to be on top of the water. They can't see down the bottom of that ocean. As we've talked about all week, this is 10,000 to 15,000 feet. And there's some trenches out there, to 20,000 feet in the search area they're looking. And remind us again how far the ping can be heard on the black boxes? Optimally it can be heard five to ten miles. But if it's at the bottom of the ocean, you have to be almost right on top of it. This is why it's so important to get to the wreckage as soon as we can and get a ship out there to hear the pings before the battery on that black box gives out. The race against time continues. Thank you again, Steve ganyard.
This transcript has been automatically generated and may not be 100% accurate.