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Erin Burnett Outfront

Search Area For Flight 370 Shrinks Dramatically; 24 Injured In High School Stabbing Attack

Aired April 09, 2014 - 19:00   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

ERIN BURNETT, CNN HOST: Next, breaking news in the search for Malaysia Airlines Flight 370. A massive change just announced in the search area and two new signals that could be from the black box.

Plus, the man who discovered the Titanic wreckage. Does he think this is it?

And our other breaking news story tonight, more than 20 students stabbed at a Pennsylvania high school. We have new details coming in at this moment about the teenage suspect. That's coming up. Let's go OUTFRONT.

Good evening. I'm Erin Burnett. OUTFRONT tonight, breaking news in the hunt for Malaysia Airlines Flight 370, searchers are closing in, just announcing the search area has changed dramatically. This is a huge change. It was 29,000 square miles. It's now 22,000 square miles. That drop in just one day. The search area is now roughly the size of West Virginia.

Yes, still huge, but remember, we were talking about a search area originally bigger than the continental United States. And they have picked up new signal that they say could be from the plane's black boxes. It had been two days, as you know, where they said look, we're feeling worse about this and worse about this. We haven't reacquired the signal.

Now they have two more times. Could this be it? The question is time is running out. It is day 34 of the search. The batteries in the black boxes are fading more as each day passes. It's pretty incredible if in fact they are still working at this point.

The Australian ship, "Ocean Shield" I was just showing you first picked up two sets of underwater pings on Saturday, and now reacquired the signals twice Australia time Tuesday. All four signals detected within 17 miles of each other on the surface that could mean a lot of things when it gets to under the water but on the surface.

Michael Holmes is in Perth tonight for us. So Michael, how close do they think they are to finding the plane?

MICHAEL HOMES, CNN INTERNATIONAL CORRESPONDENT: Well, you know, Erin, it's interesting listening to the man who is heading up this search effort, Air Chief Marshal Angus Houston. He did say the wreckage needs to be identified before any certainty that this is indeed the area where the plane is. But, you know, what was interesting is he said the pings were sustained and consistent with a flight recorder. Not random or natural marine noises.

And why it's interesting to me certainly is this is a man not given to hyperbole or raising hopes. This is a very cautious man and for him to say as he did yesterday that he is optimistic, not cautiously optimistic, but optimistic that the wreckage will be found is really quite something. We're waiting for the planes to head out today.

More than a dozen planes going out. A dozen ships out there. As you said, the search area has been shrunk. But it's interesting too where the four pings were, they're trying to triangulate those. They're looking for more pings. It's sort of like a cell towers, pinpointing where a cell phone is. The machine, the U.S. Navy machine that is going along behind that Australian Navy vessel, the ping locator, it's not directional.

So it doesn't get the ping and tell you exactly where these things are on the bottom. It's omnidirectional. So they're trying to triangulate those pings and shrink that search area down even more. Of course, that's really just the beginning. Then they're going to send the Bluefin submersible down to try to map that ocean floor and see if they can find the wreckage.

And then they'd have to get the sort of underwater vehicles that could recover things like black boxes. It could take weeks and weeks and weeks, even if this is the right location -- Erin.

BURNETT: All right, Michael, thank you very much. Michael mentioned the Bluefin, how crucial that's going to be. We have the CEO of Bluefin on later this hour. And a special report coming up OUTFRONT, investigation on exactly how that triangulating will be happening.

But joining me now is Bob Ballard, the underwater explorer who found the wreckage of the Titanic. Bob, it's great to have you with us. You know more about this than anyone. You've recently, in fact, even just have gotten planes out of the water. So here is the bottom line question, do you think that they are now looking in the right spot?

ROBERT BALLARD, DISCOVERED TITANIC WRECKAGE: Yes. It looks like the search area is collapsing to a square that you can now mount the next vehicle system. What they want to do now is take advantage of the pinging to make that search area smaller. Eventually they'll be happy with the size of the box or the pinger will stop pinging. They're also trying to find out whether they're listening to two different pingers. They're in the end game. This has been very encouraging.

They now have the AUV, the autonomous vehicle, very similar to the ones that were used on the French Airlines. As far as I'm concerned, they're in the end game. I would be surprised if they're not able to begin launching the AUV within a matter of days once they have closed the box.

BURNETT: Wow. We'll see what the Bluefin tells us. Bob mentions two pingers, there should be two, a cockpit voice recorder and a flight data recorder. Now, Bob, assuming they are in the right location, I just want to show this to our viewers because this is where no one knows this better than you. The wreckage is going to be so far down if that's what they find.

Empire State Building used to be the tallest building in the world, but that would be 1250 feet down. So everyone, you can see that. The Titanic, which is the one Bob discovered, 12,451 feet down. Almost 3 miles, everyone. The Bluefin underwater device, which bob just mentioned can work in a maximum depth of 14,763 feet, very specific level.

The 14,800 feet is the depth at which the pinger signal so far has been detected. So Bob, when you're talking about distances this deep beneath the water, pressure that increases exponentially when you're talking about a few hundred feet. Are they going to be able to get down that far?

BALLARD: I don't think that's going to be the issue. The Bismarck we found was deeper than that. It was 16,000 feet. The Yorktown from the battle of Midway was in 18,000 feet. Most oceanographic organizations design to 20,000 feet because that gets you 98 percent of the world's oceans. Yes, it's deep, but it's certainly depth that we've worked in. It's not an insurmountable. The real challenge is going to be once it's located is recovery. That -- those depths are very difficult depths to recover from. It's not that you can't do it. It just takes more time and special assets.

BURNETT: So let me ask you. You've talked about all these different situations. You've done. This you recently just pulled a plane out of the water off the coast of Syria, a fighter jet that had been shot down. What do you think this plane is going to look like, especially given the fact that at least at this point, there has been no evidence of debris on the surface?

BALLARD: Well, first place, I would be absolutely surprised if there was any debris floating on the surface in the search area right now. That's long gone. This has been a month. That's been carried away. We've had typhoon go through that area. I would not expect any debris on the surface. So I'm not really focusing on that right now. I'm focusing on the pinger from the black box. It's not moving and it's really going to tell you where it is.

Also, if there is two pingers, let's say that in earlier reports we heard that they were picking up both pingers, and that both pingers were a distance apart that means that the plane fragmented. To get two pingers a distance apart that is greater than the length of the airplane means that it's busted up. There is some good news if there is any good news in this kind of tragedy is that the more fragmented it is, the easier it is to find.

So what we'll want to be listening to, are they hearing two pingers, two distinct pingers? What's their distance? That's what they're going to do right now until they finally run out of battery power. They know what they're doing. These guys, I'm watching them. They're pros and they're following the book. So I'm very confident you have the best people in the world on the game. BURNETT: Interesting you think it broke up. Bob is going to be with us later on in the program because we want to talk about the other problem here, which is they have no idea what it look likes underneath the surface here. Is there a mountain range? I mean, it's pretty incredible we don't know.

OUTFRONT next, though, breaking news coverage continues. The two new signals Bob just mentioned, possibly from Flight 370. So how is each signal helping out on the search? That crucial triangulation and special investigation OUTFRONT.

Plus, we're going to go to the deepest depths of the ocean and show you how an underwater drone would be used to find Flight 370, Bluefin on this show.

And more than 20 people allegedly stabbed by a teenager armed with kitchen knives today. A shocking story. We are learning new details about the suspect tonight. We'll be back.

(COMMERCIAL BREAK)

BURNETT: Breaking news, the search area for missing Malaysian Flight 370 narrowing dramatically, shrinking 7,000 square miles. At this hour, 14 planes going into the area, 13 ships already aiding the search, two new signals, this is huge, have been picked up. Officials say this could be from the plane's black boxes. You now have four times the signals have been picked up in the same general area.

We've played this for you person after person. No way this could be anything but man made, this is a big, big event. Officials say each new signal is helping them zero in on exactly where it is because you say we have four in the general area. Just go down there and get it. No. It is not anywhere near that easy, as we have all learned.

Tom Foreman is OUTFRONT. Talking about how they're going to find this, all four search areas within 17 miles of each other. It could mean a lot of things, right? How much closer could these new pings get us in terms of the space?

TOM FOREMAN, CNN CORRESPONDENT: It means you are closer than you were when you had three million square miles. It's not nearly as close as you want to be. Look at how they got to these things because it's really quite fascinating. This is the big arc described by the satellites that we talked about so much. As you move in on that, you can see the actual path that the "Ocean Shield," that ship followed out here. It looks something like a mess.

And look at where the pings show up along this path. All four of them there. As I said, it looks like a mess, but it's not really. First of all that, satellite path we're talking about, it runs right across here. So very close to where these pings are found. And if you look at the pattern they were actually building here, it's based upon a grid.

The idea is you take the ship in and go back and forth one way and get every hit you can. Then you go the other way and get every hit you can. Then you look at the strongest ones and how they are located toward each other and hopefully what you get out of that is a much smaller box than the big box you started with, Erin. That's what they're doing now. That's why they keep doing, this even though they've had some good pings.

BURNETT: All right, so, we've been told at least these pinger signals only travel a couple of miles. How are they getting hits over what seems to be larger distances than that?

FOREMAN: This is a great question, because I felt the same way, Erin. I was saying how is this possible this we've been told over and over again it can't happen? Well, the understanding, as we're told, is like this. Imagine that there are layers of water in here that are warmer than others. They're called thermal climes.

If you have the warmer layers than others and create barriers in here, the idea we're told by the searchers, people who are involved is that they think that essentially the signal is bouncing between different layers and just doing odd things. So it may be coming up much further away than you would expect, and it makes it harder to find.

This is the kind of thing that happens with radio waves sometimes, and it's possible here. The bottom line here is everyone says and they know that sound does strange things underwater. So you have a box right now that is about 17 miles long. Overall, you've got about 560 miles search area, square miles. They're just trying to crush that down by trying to get rid of the anomalies. Get as many direct signals as they can, Erin and then maybe a much smaller box.

BURNETT: All right, Tom, thank you. That of course is why they're rushing to race against the clock, why what they have now isn't enough. They need more. They need more to get this exactly right.

Richard Quest joins me along with Anish Patel, the president of Dukane Seacom, the largest manufacturer of black box pingers. Authorities have confirmed at least one of this pingers was on board Flight 370. So Anish, let me start with you. They're saying the signals they picked up are weaker than what they got over the weekend. Now we're possibly past the battery life of the pinger. How much longer do you think the batteries have?

ANISH PATEL, PRESIDENT, DUKANE SEACON, BLACK BOX PINGER MANUFACTURER: Well, we build in a design margin of about 10 percent. So we think they're going to go a few days longer than 30. After that, we call it bonus time. The battery is going to start to degrade. It sounds like we're in that period right now. So it could be a matter of days. In the lab we have experimented with this under laboratory conditions. We can get a very faint signal out to about 40 days. But again, you got to be right on the top of the unit to hear it at 40 days.

BURNETT: And we're at 34 right now, so we are getting there, Richard. So we're getting there. Are we going to get enough to triangulate the exact distance? I think we have made the point to people that yes, you may be hearing something, but that doesn't mean you can dive down and look around and it's there. RICHARD QUEST, CNN AVIATION CORRESPONDENT: Angus Houston said last night, he is the man in charge of the search operation, Houston said, there is no second chance, meaning he's got to keep the search, the mowing of the sea, as Tom Foreman was showing. He has to keep that going until he is absolutely certain that there is no battery life left, that there is no pings. A quick question, Anish?

BURNETT: Yes, of course.

QUEST: How many days would you give it from not picking any pings or any acquisition before you would say with certainty they're dead. We can put the underwater stuff in, do you think?

PATEL: I wouldn't go much beyond day 40.

QUEST: Right. But if you haven't heard anything for two or three days, would you say that's it? It's over. Let's go and put the other stuff in?

PATEL: That's a fair assumption. Right now they're continuing to hear pings. Let's see what happens today. But definitely day 40, I would call it quits.

BURNETT: And it's a good point Richard raises, because obviously, as everyone you may know when they first heard the signal this weekend, there was a two-day break before they heard the other signal. So that has happened before. Anish, Australian figures say we know very little underneath the ocean floor, pretty incredible in general. But a silt, a mud-like substance that is even more thick and solid than mud would ever be could be muffling the signals and causing all parts of problems. Does that worry you in terms of locating them?

PATEL: Well, now that we've got a few more hits, I feel a lot better that we have done or our pinger has done its job in terms of signalling where they ought to be looking. Hopefully we get a few more days out of it to help them narrow this box and we can do our small part in helping bring some closure to these families.

BURNETT: Anish, before we go, what is the pressure like if you're looking at almost 3 miles under on your little pinger? What is the pressure on that thing?

PATEL: We certify it to 8700 psi. I think it's a little less than that here but it's a lot.

BURNETT: What is that like? I mean, the truck sitting on a bug? I mean, I'm trying to imagine.

PATEL: Well, we've been able to crush ours at about 10,000 psi, literally crushes like an aluminum can.

BURNETT: Wow. All right, thank you very much. We're going to be back. Richard will be with us as Bob Ballard comes back as we talk with the CEO of Bluefin when they put that down exactly what it's going to do. OUTFRONT next, we're going to go into the ocean and show you how that underwater drone could actually acquire, bring up this plane if that's what is down there and actually see what happened and find out the mystery.

And chaos and panic at a Pittsburgh high school as a student stabs 20 people.

(BEGIN VIDEO CLIP

UNIDENTIFIED CALLER: Jake, I'm in the front door the first hallway in the front halfway down. We've got multiple victims here. We need ambulances here as soon as possible.

(END VIDEO CLIP)

BURNETT: And now to our other breaking news story, tonight, a 16- year-old high school student has been charge as an adult with attempted homicide after allegedly stabbing more than 20 people at his school. The school is in Murrysville, Pennsylvania, about 18 miles outside of Pittsburgh. Pamela Brown is there. Pamela, what else can you tell us about the suspect and what happened?

PAMELA BROWN, CNN CORRESPONDENT: Well, we're learning his name, Erin. His name is Alex Hribel, according to the criminal complaint. He is a 16-year-old male sophomore here at the school. These are the charges that he faces. Four counts of criminal attempt, criminal homicide, 21 counts of aggravated assault, and one count of weapons possession on school property. That's according to the criminal complaint.

Right now authorities are going through the computer that was retrieved from his home during a search today, trying to figure out what set him off to come in to school and prompt this attack and stab so many of his fellow classmates. We've learned from authorities that he had no prior run-ins with law enforcement before. And those that knew him said that he was a quiet student and he kept to himself.

So this really has a lot of people baffled. Here is what we do know, Erin, from authorities that he walked in around 7:00 a.m. this morning into school. This was before classes started and he was wielding two steel kitchen knives about 8 inches long. And according to witnesses, he just started stabbing anyone that he could find. And this was a period of time where there were a lot of students at their lockers.

And so that could potentially be one big reason why so many people were hurt, 24 injuries we're told, one adult and the rest were classmates. And also authorities saying that the crime scene was about 200 feet. And it was one wing of the school, a long hallway and several classrooms. Here is what the police chief had to say about.

(BEGIN VIDEO CLIP)

CHIEF THOMAS SEEFELD, MURRYVILLE POLICE: The hallway that was pretty much in chaos, as you can imagine. A lot of evidence of blood on the floors in the hallway. We had students running about, trying to get out of the area. (END VIDEO CLIP)

BROWN: And some of those injuries, Erin, were life-threatening. Some of the students remain in the hospital with critical injuries, although some have been discharged with some minor injuries. A lot of them were at the torso, the lower abdomen, and the back, but I can tell you, just being out here today, this has really shaken up this community.

BURNETT: And what about the heroes who stopped the attack from getting worse? This could have been so much worse, I know.

BROWN: This could have been. And we heard authorities talk in the press conference that we probably could have seen a lot more injuries or even deaths if there weren't some heroes, some quick-thinking people who jumped into action. We've learned that the assistant principal here at the school, Sam King, tackled the alleged attacker.

Also, the school resource officer and a security guard known as Buzz here at the school also helped and jumped in to subdue the attacker. And we also heard about cafeteria workers, teachers, fellow students coming to the aid of those that were wounded. So certainly a lot of heroes here today -- Erin.

BURNETT: All right, Pamela, thank you very much. Pamela Brown covering that story for us in Murrysville.

And still to come, the breaking news as investigators pick up two fresh signals that could come from Flight 370's black boxes. And dramatically narrow the search area. So the question is how will they actually reach the plane? Well, the company that is going to be doing that is on the show tonight.

And the husband of a Flight 370 passenger is OUTFRONT. This is about people and the people on that plane. He is going to react to tonight's breaking news.

(COMMERCIAL BREAK)

BURNETT: More of our breaking news tonight on the disappearance of Flight 370.

Officials zeroing in on what could be the missing Malaysian airliner. They have just moments ago right before this program slashing the size of the search area, and they say they have identified two more sets of pings. That brings it to four total that they say they believe at this point is from that plane's black box.

The latest developments mean investigators could be just days away from taking the search to the next level, which means going under the water and trying to find what is there.

Our Rosa Flores begins our coverage on this with a first look at that search.

(BEGIN VIDEOTAPE) ROSA FLORES, CNN CORRESPONDENT (voice-over): Four times investigators have heard pings that are consistent with the signals coming from the missing jet's data recorders.

ANGUS HOUSTON, AIR CHIEF MARSHAL: I believe we're searching in the right area, but we need to visually identify aircraft wreckage.

FLORES: That's where this probe comes in. It was sent to the Indian Ocean to scour the ocean floor.

(on camera): It's called an AUV, an autonomous underwater vehicle. And it uses side scan sonar. You can see it right here, to create that picture. It's also equipped with a GPS system. You can see it right over here. And, of course, that lets the crew know where this probe is at any point in time.

It has been used before to identify and help recover plane wreckage. It would be able to narrow the debris field. For demonstration purposes, it's tethered. That would not be the case, of course, in the Indian Ocean. Once this launches on to the water, you're going to see it kind of floats. It's buoyant.

CHRIS MOORE, PHOENIX INTERNATIONAL: Our particular AUV has about a 20-hour endurance. To get down to a depth of 4,500 meters, it takes about two hours.

FLORES: This is an AUV made by Bluefin robotics, as it searches underwater. It's the same AUV that is in the Indian Ocean, ready to dive more than 14,000 feet in search of the mission 777.

This animation shows how it moves along the ocean floor, as if it were mowing a lawn, creating a map of potential plane debris. The AUV is also equipped with a still camera, essential to the search.

PAUL NELSON, PHOENIX INTERNATIONAL: So, once we get a debris field, we'll have the AUV run a pattern over the debris field with photographs, and that will pretty much identify the airplane for sure.

UNIDENTIFIED MALE: Are you getting the signal on the ROV beacons as well?

FLORES (voice-over): If they find Flight 370, this remotely operated vehicle, an ROV, can retrieve the black boxes from the ocean.

UNIDENTIFIED MALE: You put your two cameras here on our pilot monitor and your copilot monitor.

FLORES: The ROV can operate in the deep sea where humans can't, and may be the only chance of recovering the flight data recorders and any evidence of what happened to MH370.

Rosa Flores, CNN, New York.

(END VIDEOTAPE)

BURNETT: All right. David Kelly is the president and CEO of Bluefin Robotics.

Good to have you with us, sir. Appreciate it.

So, as you know, obviously, right now, they're still searching with the towed pinger locators. But those only hear a black box. Your Bluefin can see a box, see the wreckage.

When it is time to put the Bluefin in the water to answer the question of whether this is the plane?

DAVID KELLY, BLUEFIN ROBOTICS CEO: The Bluefin can search about 40 square miles a day. And so the appropriate time would be when they had narrowed the search area enough that that coverage would give them data that they need to resolve the mystery.

BURNETT: So it sounds like you're saying a few days away, if they were to continue to acquire the signal and triangulate more, you would still wait a few days?

KELLY: You know, the people on the site, we salute their efforts in trying to resolve this mystery. Phoenix International that owns the Bluefin-21 has done multiple of these types of missions. They know what they're doing, and I trust their judgment on when to put the vehicle into the water to conduct the search.

BURNETT: And what about whether how deep it can go? I know at least the specification say, what, 14,763 feet. But obviously, the ocean at this point could be a little bit deeper than that. It's not fully mapped. So they don't know.

So, I know any change in depth at that far below the surface, it could be an incredible change in pressure.

Is the Bluefin able to operate outside its formal range if it needed to?

KELLY: Yes. The Bluefin standard 21 that Phoenix has is rate to 4,500 meters. And as you noted, that's about two and a half miles down. At that depth, the pressure is equivalent to having the weight of a Cadillac Escalade on your thumbnail. It's also slightly above freezing at that depth and it's pitch-black.

We are looking, following good engineering practice, we do have design margin on that vehicle. We're reviewing the data now to look at any possible extension of the operating depth that the vehicle could be worked at.

BURNETT: Well, all right. Stay with us. I want to bring in Bob Ballard now back, the underwater explorer who discovered the wreck of the Titanic and our own Richard Quest.

Richard, first, react to what David said. I mean, that's incredible. I was trying to understand, the pressure of a Cadillac on a thumbnail.

RICHARD QUEST, CNN AVIATION CORRESPONDENT: Not only the pressure, but it's the mechanism by which it has to do it. Untethered, down below -- David, it's untethered, it's down blow. It's slow. It has to bring its pictures back up again. It then has to be analyzed.

So, you don't really embark on something like this until you're really ready. You don't think oh, we'll lower the Bluefin today to see what's down there.

BURNETT: You can't just go down and look around and come back up.

Now, Bob, what about what this means? I mean, we've got video of the wreckage of the Titanic when you went down there and used these kinds of vehicles, went down there yourself. That was 12,500 feet down, about what we're looking at now.

But when you went down, how much did you know about what the ocean floor would look like down there, or were you, similar to this situation, kind of going down not knowing what the surface would be like?

ROBERT BALLARD, DISCOVERED TITANIC WRECKAGE: We had better maps. We actually had a better idea of the terrain that the Titanic was lost in. There was a canyon running through the area. So, we knew pretty much the topography we were up against.

Here, as far as I know, they don't have the kinds of maps that we have when we've done previous searches. And what they're going to be doing now is trying to narrow the box, but there are also assets not far away that can actually come in and make detailed maps.

But I think the point is that this is a very slow process. When you're operating at those depths, the time to get down, the time to get up, we call it the elevator time, can be very long, a couple of hours in this case for this vehicle. But, you know, we have the assets in place for this phase. We'll then move to the second phase, then the third phase.

This takes a multiphase of operations that quite honestly dependent upon where the assets for the next phase are located can be weeks. And certainly, a recovery could be months.

BURNETT: So, David, what about in terms of what it's going to be able to see if it goes down? Let's assume you get to the point you know you're in the right place. The Bluefin goes down. It's looking around. They're saying in terms of what they do know, which is very little here. I mean, what are we looking at?

There are so many things we don't know. But there could be hundreds of feet of silt at the bottom of this. Just, I mean, you know, that's an enormous amount. You're going to be able to see through that, see what's there wreckage-wise?

KELLY: The Bluefin-21 sonar payload that is on this particular vehicle has three different sonars. It has a side-scan sonar, which provides imagery of the bottom, can cover roughly a little over half a mile in swath. It has a multi-beam echo sounder, which will give depth information and telemetry (ph) information.

You also can do some coarse level imagery with that. And finally, it does carry a sub bottom profiler, which depending upon the bottom type, it can see some depth into the sediments on the bottom.

BURNETT: So, Richard, all the reporting you have been doing in terms of what's down there, if the plane is there, this issue of there being no debris on the surface, you heard Bob Ballard. It makes total sense to him with the typhoon and the time that's happened that there is no debris no matter how this plane went under the water.

But this whole question people have asked of whether it's intact or how many pieces it's in. Do we have any information or any guesses about that?

QUEST: No, we don't. The experts are telling me that bearing in mind what we know so far, that there is a realistic possibility that it is in major pieces.

BURNETT: OK.

QUEST: Note I'm not saying --

BURNETT: They don't know, right.

QUEST: I'm not saying it's intact, not in some sort of movie, it's all sitting there on the bottom of the ocean. But it could be in major identifiable looks like a plane.

BURNETT: OK. Now what about this issue of the black boxes themselves? Because everyone keeps saying, they record over themselves. So, every couple of hours --

QUEST: The CVR.

BURNETT: The cockpit voice recorder. If someone in that cockpit, whoever it was, pilot, crew, whoever else was in that cockpit, was in charge did this on purpose, it is possible that they didn't want anyone to ever know and you're going hear two hours of silence?

QUEST: It's not possible. It's highly likely. Unless the plane --

BURNETT: So, what I'm saying is you could find this plane and this mystery of why this plane is there may not be solved?

QUEST: No. Because you will get sufficient information from the flight data recorder about the implements and the instruments and who was doing it. You may not know who is doing it, but you'll know what was being done.

BURNETT: So, Bob, what do you think about this issue? Because again, for our viewers who are just joining, Bob not only found the Titanic, he brings planes up from underwater. Recently, you just brought up a fighter jet off the coast of Syria that had been shot down. Do you think that if a person in charge here -- again assuming intent if that is indeed the case, didn't want us to know what happened, that we would be able to find out from those recorders?

BALLARD: Well, the first place, he certainly picked the best place to hide his plane. I mean, it looks like this individual was actually going out as a way to hide the plane. But we can find it. And I'm very confident.

I don't think the silt issue is an issue, you know. I've -- like I said, I've seen debris fields from the thresher and the scorpion where they drop nuclear reactors. So, yes, the very, very heavy objects will go into the bottom to some degree. But engines, for example, from the Turkish Phantom 5 were sitting right on the surface of the ocean.

You couldn't have had a heavier object hit a soft bunch of mud. So, I don't believe this thing is buried. Certainly, the fact that you can hear the pinger, it's not buried.

So, I think you're going to find a large debris field. You'll be able to figure out by its density where things are. And you slowly collapse it, collapse it, and collapse it. And then you finally set up shop.

And when you set up shop in 15,000 feet of water, it's not that big an issue. The big issue is how much of this airplane do you want to bring up.

BURNETT: And how do you bring it up? That's the other question, right? I mean, it's not like you can just stick a crane down three miles and pull it up.

BALLARD: There is all sorts of recovery devices. It also depends upon how big the objects are. I think they're going to obviously want to get the black boxes. That should not be difficult. It's a question of how much of this plane do you bring up to reconstruct it to understand what happened, and that is all going to be on what you finally end up encountering.

I suspect there are some very, very large pieces. I would have -- I would be surprised if there is an intact airplane sitting on the bottom of the ocean. But we have found intact airplanes sitting on the bottom of the ocean.

So until we can collapse the box, until we can actually get into the debris field, there is a lot of possibilities. But the good news is I think we're going to home in on this guy.

BURNETT: David, quickly, before we go, what level of detail can you see when you go under? I mean, you see big objects. Are you going to be able to see what it looks like on that plane, the seats, all the detail?

KELLY: There is three different sensor resolutions that would be involved. In the first broad area search, the objects that could be detected would be about a meter in size and larger. And it's also important to remember when you're looking in a sonar image, you're looking at sound waves imaging an object, not light.

BURNETT: Understood.

KELLY: And so the objects will look different than when you look at a camera. There is a higher frequency sonar that then can be deployed that can see objects about a half meter and larger. And then there is the high definition black and white camera, which would see obviously optical level of resolution.

BURNETT: All right. Well, thanks very much to all three of you.

And still to come, more on the search for Flight 370, the families with this development. What do they think? We're going to be joined by the husband of someone on that plane.

And Oscar Pistorius in his own words, with a tearful defense.

(COMMERCIAL BREAK)

BURNETT: I want to check with Anderson with a look what's coming up on "AC360".

Hey, Anderson.

ANDERSON COOPER, CNN ANCHOR: Hey, Erin.

Yes. We have breaking news on two fronts tonight. Tragedy and heroism at a high school outside of Pittsburgh. You're going to meet Gracie Evans (ph) who helped save her friend's life after he put his on the line standing between Gracie and the knife-wielding suspect who allegedly stabbed more than 20 people in the school.

Also tonight, breaking news on the search for Flight 370. Four signals now in a 17-mile area, but there is still no confirmed debris in the surface. Still no visual sighting under water. We'll speak with Commander William Marks aboard the U.S. Navy command ship, the USS Blue Ridge. And we'll take you down to depths of the ocean floor.

This is what it looks like 9,000 feet down in the area where search efforts for Flight 370 are centered. The plateau are closed to double that if you can imagine.

Gary Tuchman shows what researchers are up against, mapping the unknown depths. That's all at the top of the hour, Erin.

BURNETT: All right. Thanks, Anderson, see you in just a few minutes.

And our breaking news coverage continues on Malaysian Flight 370. As I mentioned, the headline at this point is that search crews are zeroing in on the wreckage, what they think could be the wreckage. They reduced the size of the search zone overnight dramatically by about 20 percent in one day after locating two more signals that could be pings from the black boxes.

But the families of those missing, though, they are so many hard questions. They want answers. They want the truth. But do they really want this to be the plane?

It could finally provide a bit of closure after 34 days for some. Earlier, I spoke to KS Narendran. His wife, Chandrika Sharma was onboard Flight 370. She was her way to a U.N. conference in Mongolia. Regular viewers of our program met Naren the other day and heard about Chandrika.

Tonight, I started by asking Naren if he's hopeful search crews have found the plane in this spot.

(BEGIN VIDEOTAPE)

KILAPANDAL SANTHANAM NARENDRAN, HUSBAND OF MH370 PASSENGER CHANDRIKA SHARMA: I frankly don't know what to expect or to (INAUDIBLE). If it is the plane indeed, then I suppose the last word is more or less not too far off. And one has to accept the reality and the finality of the goal, that things have come to an end.

And if it is not the plane, then it's equally difficult and equally traumatic, because then the wait just continues for much longer, and I don't know if that's any better. So, either way I think from a personal standpoint it doesn't take away the pain, the waiting, the agony of simply not knowing. And the -- what shall I say? -- the extreme difficulty of the continued absence of somebody who is very much an integral part of one's life.

BURNETT: And, you know, when you -- Chandrika and you had had a wonderful life together. You know, the last time we spoke, you said you didn't believe in miracles. You were very pragmatic about what might have happened. And now, of course, we could be days away from learning if it was the plane, and you know, you're saying, look, I don't know if it is or if it isn't. But you wanted an answer.

Are you really, though, prepared to hear the answer?

NARENDRAN: It's like this. We've been married now -- this year would have been the 25th year of our marriage, yes. So we have been together 25 years in married life. So it has been a long time. And so, it is a little hard to imagine what life might be in her absence, if she is forever gone.

And at the same time, it's hard to imagine what it would mean to actually claim her if she is indeed at the bottom of the ocean. And I dread the prospect of having to go to the court and go through some process of identification. That is the part that is quite dreadful and I can't imagine what that might be. So, I'm not sure what I really wish to look forward to in any case.

BURNETT: Naren, do you think you'll ever get the answers about what happened?

NARENDRAN: My belief is that eventually, we'll get around to that. But it is going to take a while. It is going to take us a long time. And it is going to require a lot more people to become a lot more candid, up front and forthcoming with what they know already and what they discover in due course of time.

BURNETT: And, Naren, you talked about how this would have been your 25th anniversary with Chandrika. And her birthday, of course, was March 30th, which you had to commemorate without her with you.

What are you going to do to honor her and to celebrate her in your life together?

NARENDRAN: So, imagine the best way for us to commemorate her and her life would be to continuously strive to see that we, as a global community, as mankind at large, look at the ways in which we create our own difficulties. And find some common ground where we can discover sources of our own wellbeing.

BURNETT: Naren, thank you very much. It's good to talk to you again.

NARENDRAN: Thank you very much. Thanks for your time.

(END VIDEOTAPE)

BURNETT: OUTFRONT next, we have the latest on the Oscar Pistorius trial.

(COMMERCIAL BREAK)

BURNETT: A tense day of testimony as Oscar Pistorius took the stand for a third day. The prosecution's chance to grill the one-time Olympian.

Robyn Curnow again OUTFRONT in Pretoria.

(BEGIN VIDEOTAPE)

OSCAR PISTORIUS, CHARGED OF MURDER: I'm here to tell the truth as much as I can remember on that night.

ROBYN CURNOW, CNN CORRESPONDENT (voice-over): Oscar Pistorius undergoing an aggressive cross examination during his third day on the stand.

PISTORIUS: My mistake was that I took Reeva's life, my lady.

GERRIE NEL, PROSECUTOR: You killed her, you shot and killed her. Who will take responsibility for that?

PISTORIUS: I did, my lady.

NEL: Then say it then. Say yes, I killed -- I shot and killed Reeva Steenkamp.

PISTORIUS: I did, my lady.

CURNOW: The Olympic runner says the shooting was an accident, but the prosecution says it was murder.

PISTORIUS: I shot because I was -- at that point, with that split moment I believed somebody was coming out to attack me.

CURNOW: Prosecution then played a video of Pistorius firing shots at a watermelon just months before shooting.

NEL: You know the same happened to Reeva's head, it exploded.

CURNOW: Things quickly became heated when the prosecution asked Oscar Pistorius to look at a crime scene photo of Reeva's bloody head.

PISTORIUS: I've taken responsibility, but I will not look at a picture where I'm tormented by what I saw and felt that night.

As I picked Reeva up my fingers touched her head. I remember. I don't have to look at a picture. I was there.

CURNOW: The prosecution accused Pistorius of not answering the questions directly.

PISTORIUS: My lady, if I was sitting here and I wouldn't think of every implication of what I say, it would be reckless, my life is on the line.

NEL: But Reeva doesn't have a life anymore because of what you have done.

(END VIDEOTAPE)

CURNOW: At the end of a combative day of cross examination, Oscar Pistorius saying that he didn't think before he shot. The state responding they will prove that he was lying.

Erin back to you.

BURNETT: Robyn, thank you.

And President Obama and the first lady in Fort Hood to pay tribute to the three people killed and 16 injured in last week's shooting rampage.

(BEGIN VIDEO CLIP)

BARACK OBAMA, PRESIDENT OF THE UNITED STATES: To the parents of these men, as a father, I cannot begin to fathom your anguish.

(END VIDEO CLIP)

BURNETT: And Lieutenant General Mark Milley spoke about each soldier who lost his life.

(BEGIN VIDEO CLIP)

LT. GEN. MARK MILLEY, U.S. ARMY, FORT HOOD COMMANDING GENERAL: Staff Sergeant Carlos Lazaney-Rodriguez, came from a close knit family from Aguadilla, Puerto Rico. During almost 20 years of selfless service, he earned numerous decorations including the Combat Action Badge. And on April 2nd, he was tragically just months away from a well-earned retirement.

Sergeant Timothy Owens was from Effingham, a small town in central Illinois. And he loved baseball and football and wrestling and taekwondo, so much so that he became a black belt and taught martial arts before joining the Army in 2004.

Sergeant First Class Daniel Ferguson grew up in small town Mulberry, Florida. In high school, he was an outstanding athlete. Sergeant Ferguson died a hero. He was shot as he held a door closed to protect a roomful of other soldiers. He put himself in the line of fire to save them.

(END VIDEO CLIP)

BURNETT: All three soldiers were fathers, all three had served tours in Kuwait and Iraq. These men and their families are in our thoughts.

Anderson begins now.