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Listening for Pings in MH-370 Search; Australian P.M. Says Confident Pings Are from MH-370; Bottom of Indian Ocean Is a Mystery; MH-370 Family Believes Son Still Alive; Frustrated Families Meet Again with Airline; Malaysia: We Don't Have the Expertise to Open Black Boxes, Download Data; New Violence Erupts in Ukraine

Aired April 12, 2014 - 17:00   ET

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

JIM SCIUTTO, CNN ANCHOR: You are in the CNN NEWSROOM. I'm Jim Sciutto in today for Don Lemon. The two words that sum up the search for Malaysia Airlines Flight 370 this weekend optimism but also patience. Australia's prime minister is the world leader closest to this mission. He says, commanders feel good about the newest clues they're hearing from the ocean floor but warns it could be a long time before we see any concrete results.

One group of people whose patience has already run out long ago is the families of those of those on board the airliner. A group of families met again with airline and Malaysian officials, the mother of a missing passenger is not happy. She says they keep telling her the same thing. Nothing useful. It's still an hour and a half until sunrise in Perth, Western Australia, that's when search planes will take off once again on this the 37th day since Flight 370 took off from Malaysia and vanished.

So, we'll going to straight to Perth right now and CNN's Michael Holmes. He's there. Michael, what can we expect when the sun comes up? Because, you know, I'm getting a sense settling our viewers probably getting a sense as well that was settling into a long slow period in this search then.

MICHAEL HOLMES, CNN CORRESPONDENT: Yes. You're absolutely right, Jim. Yes, those planes will be taking off in the next couple of hours. The first ones are normally the Chinese planes. They're the ones that take off from Perth airport and then Australian and New Zealand planes will take off. Of course, the ships are still out there. They're out there 24/7 at the moment being resupplied by a U.S. naval ship so they can stay out there and continue the search.

You mentioned the Australia's Prime Minister Tony Abbott, yes, repeating on Saturday that he had a high degree of confidence, his words, that those acoustic sounds that they heard in the ocean are from at least one of the two black boxes from the missing plane. Did as you said predict also something that we've been saying for ages that even if those boxes are located, it just begins a massive, massive task of trying to get to them. He also mentioned those families as well and said that if they came to Australia, they would be very welcomed. Have a listen.

(BEGIN VIDEO CLIP) TONY ABBOTT, AUSTRALIAN PRIME MINISTER: We would welcome whenever they wish families of the victims to come to Australia, and they will find themselves in the arms of a welcoming friend.

(END VIDEO CLIP)

HOLMES: Of course, that's the Australian prime minister there. I've been talking to some contacts of mine in the West Australian government here, Perth, and they were telling me, too, that they are already making plans for those families to come here at some point. When we don't know. Most likely when some sort of confirmation of wreckage or those black boxes is made, when the confirmation is made. They say that they're going to have a memorial service here. They're going to provide for those families. Give them those open arms. There's even talk that there might be a permanent memorial placed here in Western Australia or at some point in the future -- Jim.

SCIUTTO: Michael, just a quick question, now that there is concern that the pinger may have run out of batteries and they won't be able to hear those pingers anymore, do they, then, switch to using the sonar where they are looking literally at the bottom of the ocean to try to find signs of wreckage?

HOLMES: Yes, that's exactly what will happen. They've been waiting until the very last minute. Until they absolutely are sure that they won't get another ping, because, of course, the more pings they get, the more they can triangulate where they are coming from from the earlier pings and narrow down that search area as much as possible. The reason for that is the submersible, the blue fin, when it does go down and it has that side scan sonar and looks at the ocean floor, that thing is really slow. It moves literally at walking pace, so they want to make the search area as narrow as possible.

When they have decided those batteries now are gone now and that we won't get any more pings, that's when they'll put that down and they'll start what is a very slow, very tedious process of looking at the ocean bottom. Then if they find something they've got to get other submersibles in that can do some sort of recovery work. They have different vehicles. So, Tony Abbott's right when he says this is a massive, massive operation that is very much far from over -- Jim.

SCIUTTO: Yes, no question, listening for those pings really just the first chapter and then you got to look for the wreckage and then think about recovering the wreckage. Thanks very much to Michael Holmes in Perth, Australia.

I want to bring in now our expert panel, CNN aviation analyst and pilot himself Miles O'Brien, aviation consultant, also a commercial pilot Ken Christensen, CNN aviation analyst, former NTSB inspector General Mary Schiavo and a sonar expert Arnold Carr.

Arnold, I wonder if I can start with you, because just the point I was making with Michael there. The pingers' batteries are supposed to last about 30 days, normally there's an extra time built in, we may be reaching that point now. Do you think that at this point really the last ping was heard I believe on Tuesday, how much longer should search teams, is it worthwhile for search teams to keep on listening for those pings?

ARNOLD CARR, SONAR EXPERT: I would continue to do so. The batteries don't die immediately. They die in a gradual sense. So, maybe they can triangulate a little further. It's really important to tighten up that area and make it as small as possible because as was previously just said, when you use the sonar, the side-scan sonar, which sweeps the bottom very effectively, it's slow, it's tedious.

SCIUTTO: Yes.

CARR: Usually use the sonar first and we get the pings second. As you know. But we're fortunate to have the pings at this point.

SCIUTTO: Yes. As Michael said, it goes at walking pace, so imagine walking an area the size of Arizona or New Mexico. I want to bring in Miles in if I can here. Because let's assume they have as many clues as they're going to get as far as the pings are concerned you. I guess you have four points separated by a dozen miles or so. We talk a lot about triangulation. Can you explain to our viewers how that process works and how much this information can really allow them to find I guess the crossing point where these various signals cross so that you can zero in as to where the black box is?

MILES O'BRIEN, CNN AVIATION ANALYST: My understanding the purest sense of the word is not triangulation, because these are omnidirectional pings. So, you don't have, you know, a beacon that you are homing in on.

SCIUTTO: They just go out in all direction?

O'BRIEN: Yes. It goes all out in all directions. So, what you're doing is you kind of tightening up the box but it's not, it's kind of a technical difference. But the fact is it's tightening up the box. So as they go about that, that obviously eliminates the need for this underwater autonomous vehicle to map and look for the wreckage itself. When we get into that mode and decide no more pings, we're talking about a long period of time to go through that process. It's six or seven times longer to cover any specific square foot of ocean bottom with the -- the UAV as opposed to the device listens for the pingers. They want to use that potential of hearing things up as much as they can.

SCIUTTO: Right. Ken, I wonder if I can bring you in to describe this. Because you have -- it's only directional and it doesn't give you an exact point, but I imagine you then look at the strength of this signal right to get a sense of which one is further away and can kind of guess as to, you know, closer, you know, zero in more on the area. But I also know that the signals are corrupted in effect by temperature in the water, currents, depth, all this kind of stuff, so you also have to interpret -- you also kind to correct for that as well. I mean, this is complicated business.

KEN CHRISTENSEN, AVIATION CONSULTANT: It's complicated but the people who are doing it have that background. And yet, all the points you just made are very correct. So, Terrain just like a radar would bounce off a mountain, sonar acoustics will bounce off an underground mountain ranges under the water. And then they allocate for the signal latency and the strength and they try to keep doing those routes over and over again and then they can get more of a pinpoint like Miles was saying, reduce that area where they -- if they do have to put an underwater sonar in there, that's what they'll do.

SCIUTTO: I mean, it's really complicated. Mary, I wonder if I can bring you in. Mary, you've done a number of investigations for the NTSB. For the sake of our viewers, can you give just sort of an estimate of what they should be prepared for, for how long this search goes now, right? I mean, you got some pings, right? Maybe your last pings. Then you got to go into a really slow sonar scanning and then a slow recovery, assuming you find wreckage. What kind of time period are we talking about here?

MARY SCHIAVO, CNN AVIATION ANALYST: Well, I'll give you some examples based on previous accidents in the Indian Ocean and in the java sea right over there, Adam Air went in the Java Sea and that was in January. They found the wreckage about three weeks later. But they didn't get the black boxes until August. Conversely, South African Airways went into the Indian Ocean, the black boxes were under 16,000 feet of water. And they got one of them. They only found one, but they got it on the second day.

So, the bottom-line on those examples is it could be a very, very long time or they could get very fortunate. They could be -- literally have use some algorithms on those pings to locate a spot and be right on top of it. But unfortunately there's a little bit of luck involved with a lot of algorithms and so, we won't know until they get down there and actually start looking how long it's going to take. It could be a long time.

SCIUTTO: Well, credit is where credit is due, it's already been an incredible detective story here where they determined where this plane likely went around. So, maybe they'll apply some of that expertise as well this time around. Thanks very much to Miles O'Brien, Ken Christensen, Mary Schiavo and Arnold Carr.

There is no sign of the black box but Malaysian police already say they'll need help opening and decoding it if it is recovered. We'll be live from Kuala Lumpur right after this.

(COMMERCIAL BREAK)

SCIUTTO: Welcome back. I'm Jim Sciutto in Washington. At this very moment, ships are scouring the Indian Ocean for pings, if -- and it's still a big if -- Flight 370's black boxes are eventually recovered, it is still unclear who would control the delicate information inside. Malaysia's government admits they don't have the know-how to deal with the black boxes. Our Joe Johns has more from Kuala Lumpur.

(BEGIN VIDEOTAPE)

JOE JOHNS, CNN SENIOR WASHINGTON CORRESPONDENT (voice-over): Over two dozen countries have been involved in the search for the missing plane. Any hope of unraveling the mystery and the fate of its 239 passengers and crew rest in two boxes, the flight and data recorders. ABBOTT: We have very much narrowed down the search area and we are very confident that the signals that we are detecting are from the black box on MH-370.

JOHNS: If they find them, the question remains who gets the black boxes and who will lead the investigation to uncover what really happened to Flight 370. Typically following a crash the country of origin for the airliner, in this case Malaysia, is tasked with taking charge of the investigation. But Malaysian authorities have already asked for help.

KHALID ABU BAKAR, MALAYSIA'S INSPECTOR GENERAL OF POLICE: We don't have the expert to open up the black box and to analyze what are the contents of the datas, the voice data and the flight data. We have to get experts to do it for us.

JOHNS: The U.S. National Transportation Safety Board and the British Air accident investigation branch as well as Australian authorities each have capabilities with sophisticated labs and technicians. But an international working group of experts has also been suggested. If they are found, decoding the black boxes could be complicated. The boxes are built to withstand extreme conditions including fire and heat damage. But depending on the circumstances of the crash, memory chips extracted from the data recorders could still be damaged and might require cleaning until the raw data begins to paint a picture of what happened.

PETER GOELZ, CNN AVIATION ANALYST: We still don't know what condition they're in. And they've been sitting on the bottom of the ocean under extreme pressure for, you know, weeks, perhaps months by the time we get them up. The water could have caused some deterioration of the circuitry. You just need to be careful when you first download it, because if you screw it up, you may lose vital data.

JOHNS: And time is now a vicious enemy.

ANGUS HOUSTON, JOINT AGENCY COORDINATION CENTER CHIEF: The batteries are starting to fade, and as a consequence, the signal is becoming weaker.

(END VIDEOTAPE)

SCIUTTO: I want to bring in Joe Johns, who is live in Kuala Lumpur, Malaysia. Joe, as we know, we've reported on this a lot, Malaysia is taking a lot of heat for its handling of the investigation across the board. Who would they trust with the black box data? You have a real international coalition of countries joining the investigation there.

JOHNS: Jim, the truth is, from what I can tell, the Malaysians have not expressed a preference among those countries I mentioned, the United States, the UK, and Australia. We also know this has been a very collaborative effort throughout, with many nations involved in the search. The Malaysians have also been very careful to try to include Malaysia which is a country they want to maintain good relationships with, and as you know, Jim, more than half of the passengers on the plane were from China. SCIUTTO: All right, well, it's going to be the next step, let's just hope they find those black boxes if they get to that step. Thanks to Joe Johnson in Kuala Lumpur in Malaysia.

Now, the Malaysian government keeps contradicting some of its own information. Ten days ago, Malaysian's police inspector general said all 227 passengers had been cleared in the investigation, but now Malaysian investigators appear to be backtracking. Malaysia's transport minister told sky news quote, "Everyone on board remains under suspicion."

I want to bring our expert panel back with us. And Mary Schiavo, if I can start with you first, has Malaysia signaled that there is any reason why the passengers should again be under suspicion or are they really just kind of covering their bases here, because they don't know, they still don't know what happened to this plane?

SCHIAVO: I think they're just responding to the national -- or the international criticism that they cleared 237 people in a week. And I think skeptics kind of worldwide said, well, that's just not possible. So, they now say, well, they're not cleared and they're under suspicion or suspects. I really think it was just a matter of covering their own, you know, poorly worded initial announcement. I don't think it really signals that they have additional suspects.

SCIUTTO: Miles, as you look, you've been following the ins and outs of this investigation from the beginning, and we talked about, you know, this is a double investigation so you don't want to beat up Malaysian investigators too much. But, you know, as you've watched this, have you seen them getting better at this? Right? More transparent, more thorough?

O'BRIEN: Not so much. What I see is a lot of inconsistencies, a lot of backtracking, a lot of flip-flopping. I mean, at the time they cleared -- magically cleared 237 people, there was a lot of focus among the investigative team on the flight crew in particular the captain. It seemed as if they were rushing to impugn him. And, you know, it's -- that's -- you know, the pilot, the flight crew is the proverbial butler in these cases, you know, it's very simple to blame the flight crew and, you know, and then off you go and we can be done with this investigation. Well, you know, to imagine that 237 people could be completely cleared in that period of time, there's no way that could be possible. We know that. So, the real question is, are they really investigating them or not? And we don't know because these investigations have been opaque from the beginning.

SCIUTTO: Well, there has to be an element they just haven't turned anything up, right? So, you have to come and go back over. Ken, you know, I wonder, you've been watching this, too and then Miles mentions the focus on the pilots, there's a reason for that because they're in the cockpit. Right? But do you think the investigation has been fair to the pilot so far?

CHRISTENSEN: I think initially it wasn't. But now, again, they are backtracking. I agree with Miles. That now they are looking at them again. They didn't get anything substantive out of the flight simulator from his residence and that's very typical that some pilots would have that in their residence. Also not like U.S. pilots but pilots overseas will get some currency training on that instead of going to a larger simulator. That's a little bit different from how western pilots would fly.

SCIUTTO: So, some of the other pilots that we've used as analysts here have mentioned to me, they have simulators on their home computers, they even showed me how easy it was, you just buy a DVD and pop it in and you have a simulated. Although this was more complicated.

Arnold, I wonder if I could bring you in, just switching gears a little bit, because we've talked a lot about these pings. I know that there's great interest, there will be great value in hearing another ping, but as you reach day 37, I mean, how much longer is it worthwhile for that search to continue before, you know, as much as you'd like that extra ping, before you make a switch to a sonar search which as we made the point on the air is a much slower process?

CARR: It appears that the signals are getting weaker, so I would expect maybe just a few days more from what I hear. I would like to comment a little bit on triangulation. If you remember the Chinese working with some handheld devices in shallow water, those are unidirectional. They can really get into a point where the black boxes and the pingers are. When you get into this deep water, you're really looking at omnidirectional, meaning devices that listen for the ping but can't discriminate exactly which direction. So, in this case, what you're doing is you're really looking at the intensity of the ping to try to really relate it down to distance.

SCIUTTO: Got you. Just another step in what's already been a difficult investigation. Thanks very much, Arnold Carr, Miles O'Brien, Ken Christensen, Mary Schiavo putting it into context for us. There is much more on the mystery of Flight 370, had the first developing story as gunman seize building in Ukraine, the escalating crisis and the consequences facing Russia right after this.

(COMMERCIAL BREAK)

SCIUTTO: Welcome back, I'm Jim Sciutto in Washington. And we'll get right back to our continuing coverage of the hunt for Flight 370 in just a few minutes, first, though, here's a few other stories that we're keeping a close eye on.

And we are now following a couple of breaking news stories. The first a huge earthquake has struck the Solomon Islands in the South Pacific and a tsunami warning is now in effect in and around there. This Pacific Nation just North of Australia where that search for Flight 370 is taking place is already suffering in the aftermath of last week's cyclone and deadly flooding. Some 50,000 homes were destroyed in that storm, at least 20 people killed. Today's earthquake is believed to be a magnitude 7.8. That is huge. We'll continue to follow it.

And closer to home in Europe we are following breaking news as well in Ukraine. Within the last hour, the White House responding to rising tensions in Ukraine. A National Security Council spokeswoman releasing a statement saying, quote, "The White House calls on Russian President Putin to cease all efforts to undermine and destabilize Ukraine." The statement went on to say, "We are very concerned about the concerted campaign we see under way in Eastern Ukraine today by pro-Russian separatists."

Meanwhile in Eastern Ukraine, in the city of Kramatorsk, police and activists exchanged gunfire today. And just about 70 miles away from there, gunman stormed two buildings including one belonging to the police. Three officers were hurt.

We have our own Nick Payton Walsh who is live in Donetsk, Ukraine, where some of this violence is escalating now. Nick, as you've watch this, you've been there for weeks following this really from the beginning, is there any doubt that this campaign of violence is being orchestrated by Russia? Is there any doubt to that? The White House clearly is assigning blame. But do you see any doubt of that connection?

NICK PATON WALSH, CNN SENIOR INTERNATIONAL CORRESPONDENT: It's hard to work out how this could be as well coordinated and organized if there wasn't some sort of state actor behind it, but on the ground Jim, you don't see any direct links to Russia. The militants you've seen on the ground have been very well equipped, they've been well organized, they've known where to go and what to do, very aggressive in Slavyanka, the main town, a lot of focus of militant activity today, taking the security service building there and its weapons and the police station there, too, as well.

A lot of locals coming to their help, erecting barricades to aggression towards Western journalists. Another town, we went to talks about Kramatorsk as well, we were there early in the day, it seems as though protesters want to call a referendum to join Russia, they seem to be getting all the police reasonably well but then, as we heard from a witness who saw in some social media video, intense gunfire later on in the evening. And indeed, if there were clashes between police and pro-Russian militants as the interior ministry says, there were, that would be the first since these tensions began -- Jim.

SCIUTTO: It shows you just how easily this could devolve into something more serious. I wonder, Nick, because the U.S. administration's policy as well as the west's policy and this is been to try to deescalate, right, and give Russia an opportunity to deescalate. This very much appears to be an escalation. In fact, I see the Swedish foreign minister just tweeting, he called it a massive escalation of a destabilization strategy by Russia. Is there any sign there that the penalty that have been imposed so far, these economic sanctions, et cetera, are leading to the escalation, that Russia is considering that off-ramp as western diplomats have talked about?

WALSH: No, Jim, there's been a marked worsening of things in the last 24 hours and frankly, Russia seems to be pointing the finger at the west for stirring up trouble rather than looking at itself in this way. I think we're looking now as the White House just themselves in a potential repeat of the Crimea -- where we had popular protests backed up by armed men. It's not clear who these armed men here as it wasn't clear who the armed men who swarmed all over Crimea were over a month ago, so many people deeply concerned about what comes next. We're seeing weapons in a lot of places now. Great heightened tension and I think also a vacuum anyways in response from central government in Kiev. They've had a key meeting of officials in the last few hours or so and we've yet to see many police on the streets at all and certainly not the concerted response from the capital -- Jim.

SCIUTTO: Sobering developments from Ukraine. We'll going to continue to watch them closely, thanks very much to our Nick Paton Walsh who is right in the middle of it there.

Coming up next, Malaysia Airlines Flight 370 as investigators listen for those elusive pings in the hunt, it's definitely not the only thing making noise under the waves. Rosa Flores joins me next, she's listened for a ping signal with an underwater microphone and heard much, much more.

(COMMERCIAL BREAK)

SCIUTTO: In about one hour, as the sun rises in Perth, Australia, search planes will take off once again. Crews will scan mile after mile of ocean on this, the 37th day after flight 370 kept missing. And we keep hearing words like "optimism" and "confidence" related to this search, but the pings that are thought to be from the plane's black boxes have not be detected since Tuesday -- that's five days -- leading to fears the batteries in the data recorders are becoming too weak to transmit.

Now, relatives of missing passengers met today with Malaysian officials. One mother says she feels like the Malaysian government has forgotten about all things connected to flight 370.

Right now, the U.S. Navy's towed ping locator is scouring a narrowed section of the Indian Ocean. Over the past week, four possible black box pings have allowed investigators to narrow the search area somewhat, but so far, they've been unable to relocate those sounds. And one of the reasons is because the ocean is just such a noisy place. Other sounds under the surface could be drowning out any signals coming from those data recorders.

CNN's Rosa Flores took a pinger out on the water to let us hear some of the obstacles they may be encountering.

(BEGIN VIDEOTAPE)

ROSA FLORES, CNN CORRESPONDENT (voice-over): This is what a ping sounds like.

JAMES MILLER, PROFESSOR, UNIVERSITY OF RHODE ISLAND, OCEAN ENGINEERING: Very high frequency.

FLORES: The critical sound searchers are hoping to hear in the deep and rough waters of the Indian Ocean.

MILLER: It's deep and it's dark. It's salty. It's high pressure. It's hard to work.

FLORES: Here in Rhode Island's Narragansett Bay, researchers show us the challenges search crews face as they try to hear the ping from flight 370's data recorder.

MILLER: So, this is a hydro-phone.

FLORES: We drop an underwater microphone off the back of the boat as it moves farther away from a pinger that's already been submerged. And even less than 100 yards away, the ping starts to fade.

Distance isn't the only problem out in the Indian Ocean. There are other noises competing with the sound of the pinger, like sea life. One dolphin species sounds like a black box pinger. And this is the sound of rain underwater.

(on camera): Let me get away from the loudest part of the boat so I can show you one of the biggest obstacles that searchers have in the open sea. Just ship noise. Even here, listen to how loud it is.

(voice-over): They are at a minimum 15,000 ships on the world's motions on any given day, creating even more obstacles in a search that's already daunting.

(END VIDEO CLIP)

SCIUTTO: Rosa Flores joins me now.

Rosa, great piece, because I think, you know, hard for any of us to get a sense of just how weak the signals can be in the ocean. You were dealing in much shallower waters. It's a real lesson about the challenge here, isn't it?

FLORES: It really is. And one of the things I find fascinating, I was asking the researchers, how does the sound travel, because we've been hearing that the ping has a two-mile radius. And here's the easiest way to explain it. Here's how they put it. They said low- pitched sounds travel very far in the ocean. High-pitched sounds don't travel as far. And this pinger, Jim, is a high-pitched sound, and so they say that's why it has this two-mile radius. And then, of course, I had to follow up with this question. I said, because one of the complicating things about the search is just how deep the Indian Ocean is. In parts of the Indian Ocean, it's deeper than two miles. And the oceanographer said, you know, Rosa, on the surface of the water, you'd literally have to be on top of it to hear it. That's why, Jim, it's so important for all of these -- for the towed pinger locator, for example, that dives deep to listen to these sounds carefully, it's because of that, because of the range and because of the depth of the Indian Ocean.

SCIUTTO: Wow. It's incredible. And all those other things, too, temperature, currents, all those things that can be a factor.

Thanks very much to Rosa Flores in New York.

Deeper than where the "Titanic" rests, deeper than where you would find squid. Next, how the search crews are handling the nearly three- miles depths of the Southern Indian Ocean.

(COMMERCIAL BREAK)

SCIUTTO: Welcome back to CNN special coverage on the hunt for flight 370. I'm Jim Sciutto, in Washington.

The ping locator towed by the Australian ship "Ocean Shield" has detected four pings over the past week, all within 17 miles of each other. Australia's prime minister said he is, quote, "very confident" the pings are from the plane's black boxes.

I want to bring in the panel, again, as we talk through the developments.

Ken, I wonder if I can start with you. Confidence is not something we've heard a lot in this search because we're dealing with so many educated guesses. Do you think the prime minister's confidence is well placed?

KEN CHRISTENSEN, AVIATION CONSULTANT: I think so. I think clearly from the first days, the search is narrowing. We still did not see the debris field, but now we're honing in on the signals.

I, for one, still want to see a piece of wreckage, whether that's from SONAR or somebody picking it up. Then we have definitive proof that that, in fact, is the wreckage. But I do share his optimism.

SCIUTTO: That's good to hear.

Miles, I wonder if I can ask you, as we talk about the optimism, and Rosa Flores in the previous block had a piece talking about how, you know, the pings go two miles. So just the natural question is does that mean if they hear the pings they're only two miles away, or no?

MILES O'BRIEN, CNN AVIATION ANALYST: That would seem so logical, wouldn't it?

SCIUTTO: Yes.

O'BRIEN: But the way it works, I'm told -- I'm not an expert on this -- but listening to and reading up on this, basically, underwater acoustics are not like acoustics here in the air. So there's a tendency for thermo climes and the temperature differences to have an impact, as well as the way it bounces off the seafloor, and it can actually propagate farther than the two miles.

SCIUTTO: Right.

Arnold, you're the expert on all things underwater. I wonder if you can pipe in on that as well. How could the signal travel further, in effect, if it's beyond that range of two miles?

ARNOLD CARR, SONAR EXPERT: Well, the key thing is to get your hydrophone or your locator down deep so you are below some density layers that would reflect or mitigate the transmission. So, when it's down and sometimes hitting those density layers, it can travel further.

I'm optimistic for several reasons. One is, they have repeated signals they've detected. And when I say "repeated signal," it's not one pulse. It's pulses -- plural. And the other thing is that they tightened up the area a bit. It still needs to be a smaller area to have effective side-scan SONAR and sonafication.

SCIUTTO: Something I imagine searchers have to prepare for is you don't get another ping. Let's say the batteries are dead. How big an area are they talking about, then, that they -- let's say those are all the pings you hear from the black box. How big of an area do they then have to side-scan or SONAR scan?

O'BRIEN: 17 miles are separating some of these pings so you start doing the math on the radius of that, and that's more math than I'd like to do in public, but that is a much larger area than they'd like to have.

The question is, are -- that's an unusually long distance between pings. And so a lot of people are looking at the outliers and wondering if those are necessarily right. There is one ping that they heard for more than two hours, and there's reason to believe that's the one you should begin with. That's sort of the datum, and begin at that point and move from there.

SCIUTTO: Make it the center of your search area? Is that how it works?

O'BRIEN: Exactly. Well, that's a good solid hit.

SCIUTTO: Ken, even if you move in on that and say that's the center point, because of the way things can travel, it doesn't mean you have to travel 17 miles squared, in effect, because I imagine the area still is going to be a pretty big chunk of the bottom of the ocean.

CHRISTENSEN: Like Miles said, you can go to your origin and maybe you want to do an expanding square.

SCIUTTO: Yeah.

CHRISTENSEN: And then you just keep going in a box and expand out.

SCIUTTO: Yep, yep.

CHRISTENSEN: Or you can do a parallel search, like mowing a lawn, like that. And clearly now, at this point, we're not at a rescue phase. We're at a recovery phase. We have the pingers. We have a general location of it. It's a large area, but that area can be mapped, and it will take time. It will probably take six weeks, eight weeks or more. But that can be mapped. And it's probably going to be mapped because the pingers are going to cease to be operating here in another week or two.

SCIUTTO: And I imagine the pace -- I think Miles made this point -- that it moves as slowly as a walking pace. Imagine walking a chunk of land the size of the area they are talking about. We are talking about a period of time here.

CHRISTENSEN: Yes, absolutely.

SCIUTTO: Thanks very much to Ken and Miles, and Arnold as well. We'll bring you back next hour.

More people have been to space than have explored the depths of the Indian Ocean where this search is taking place, so how are search teams ever going to find these black boxes? Next, the amazing technology that is being used there.

(COMMERCIAL BREAK)

SCIUTTO: Our coverage of the search for Malaysia Airlines flight 370 will continue in a moment.

But first, we want to introduce you to this week's "CNN Hero." She is a Philadelphia fire fighter, Jen Leary, who started a sort of Red Cross for animals.

(BEGIN VIDEOTAPE)

JEN LEARY, CNN HERO: You get to a fire scene and the firefighters are there to put out the fire it the Salvation Army and the Red Cross take care of the people once the fire is out. But there just wasn't anybody there to help the other part of the family.

I would see how upset the people were about their animals. You know, where is my pet? And then where is it going to go. These are people's children. They've just lost everything. They shouldn't, then, be forced to lose their pets as well.

We have a dog displaced by a fire, a Chihuahua. I'm headed to the scene now.

We respond 24/7, 365 days a year. We do for pets what the Red Cross does for people.

We went into the basement, found the dog hiding behind something. Once the fire's under control, we're able to look for the animals and bring them out.

Hi, baby. Come here.

Red Paw headquarters is my house. We've helped close to 1,000 animals.

She's been at my house. The owner said she was pregnant. Everything that their animal needs -- hi, buddy, you hungry? -- we'll handle for free for them.

Good girl, Bella.

When we reunite the families, it's a good thing.

(LAUGHTER) It's like a void has now been filled.

UNIDENTIFIED FEMALE: Hey, Chocolate. Welcome home.

LEARY: My hope is that a fresh start, that they can move forward together.

Nina and Ninda (ph) are home.

After going through such a sad thing, it's so good to have a happy ending.

(END VIDEOTAPE)

SCIUTTO: Do you know someone that deserves this kind of recognition? Please tell us about them, CNNheroes.com.

Now, in the search for flight 370, the task is find the pinger and find the black box. The problem, they could be nearly three miles down.

Tom Foreman breaks down what we do and do not know about the bottom of the Southern Indian Ocean.

(BEGIN VIDEO CLIP)

TOM FOREMAN, CNN CORRESPONDENT: More people have been to space than in the deep ocean. And the search area for plane is quite deep. Anywhere from one and a half to three and a half miles down, depending where you are in the big slope down here. That's deeper than the location of the "Titanic" or where you would typically find nuclear subs or where giant squids may live. And this is a very forbidding environment. It is cold, just above freezing. It's completely dark. And we really don't know much about the ocean floor here.

So you might say why not just drop that robotic SONAR imaging device and let it ride around and start mapping all of this? Well, if you want the best performance out of something like this, you would like to get it as close to the right distance from the floor as possible. And this is right at the range of its functioning level here, two and a half miles down. So they want to make sure that they have a better idea before they turn it loose. What that means is, up on the surface, her going to spend more time with things like the "HMS Echo" trying to get a better map of the ocean floor in general. If they have that, they know where the obstacles, they will know how to place the robot and get better results.

(END VIDEOTAPE)

SCIUTTO: Tom Foreman with the immense challenges for the search of that missing plane.

Now, with not a shred of evidence the families of flight 370 passengers cannot let go.

(BEGIN VIDEO CLIP) AMIRTHAM ARUPILAI, MOTHER OF FLIGHT 370 PASSENGER: Inside Malaysia, they still telling -- still they are lying. All the authorities are lying.

(END VIDEO CLIP)

SCIUTTO: Next, the parents who refuse to believe that their only son is truly gone.

(COMMERCIAL BREAK)

SCIUTTO: The families of those 239 souls aboard flight 370 are holding on to their faith. CNN's Nic Robertson sat down with a mother and father whose only son was on that flight.

(BEGIN VIDEOTAPE)

NIC ROBERTSON, CNN SENIOR INTERNATIONAL CORRESPONDENT (voice-over): Amirtham Arupilai and her husband are in pain watching every newscast, waiting for word on their son.

UNIDENTIFIED MALE: We need to officially to identify the wreckage.

ROBERTSON: The news, the day we arrived, more pings, increasing confidence from searchers, they may be closing in on flight 370.

ARUPILAI: We can't believe it. We have to see him. We can't believe it.

ROBERTSON: Without proof of wreckage, it is too painful to comprehend. For weeks now, they have been telling themselves he's alive.

ARUPILAI: My inside, my heart is telling -- still they are alive. All of the passengers are live.

ROBERTSON: Her son, Pesthamatan (ph), was aboard flight 370. An I.T. specialist heading to Beijing to begin a new job, married with would young sons.

To his parents, he is everything.

"He provides for us both of takes care of us," his father says. "What do we do now? Just the two of us in our 60s."

They do all they can do, which is wait and hope.

ARUPILAI: They are telling, wait, wait.

ROBERTSON: On television, it is government officials keeping their hopes alive.

HISHAMMUDDIN HUSSEIN, ACTING MALAYSIA TRANSPORT MINISTER: I always said, especially for the families, miracles do happen. We are still hoping against hope. You need to hope and pray for survivors.

ROBERTSON: On this day, that faith helping them, calling her son for the first time in days, reaching his voice mail.

A sign they believe he must be safe.

ARUPILAI: So ironic. My son is somewhere. I got it.

ROBERTSON: This was this morning.

ARUPILAI: This morning, today morning.

ROBERTSON: One day soon, though, the news of the other end of the phone may be a lot harder to bear.

ARUPILAI: We hope he comes back to me. I have only one son. So he has to come back.

ROBERTSON: Nic Robertson, CNN, Kuala Lumpur, Malaysia.

(END VIDEOTAPE)