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The Situation Room

New Ping From Flight 370?

Aired April 10, 2014 - 18:00   ET

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

WOLF BLITZER, CNN ANCHOR: Happening now: our special coverage of the mystery of Flight 370.

Air crews are about to return to the search area where another possible signal from the jet's black boxes was detected. Are they getting closer to finding a crash site? We're learning new details about the final moments when the plane vanished, including maneuvers that may have been intended to dodge military radar.

Plus, new confirmation the final message from the cockpit to the tower was spoken by the captain. We will break down all the new information and what it means for the investigation.

We want to welcome our viewers in the United States and around the world. I'm Wolf Blitzer. You're in THE SITUATION ROOM.

ANNOUNCER: This is CNN breaking news.

BLITZER: We're following several breaking developments in the Flight 370 mystery. Right now, experts are analyzing what could be the fifth signal from the missing jet's black boxes. Planes are about to take off for the area in the Indian Ocean where the electronic pulses have been heard.

The search zone is the smallest it's ever been as the crews race around the clock hoping to hear more pings and find actual wreckage.

Our team of experts standing by in THE SITUATION ROOM to help us understand what it means and our correspondents have new information about the search and the investigation.

Let's go first to our aviation correspondent, Rene Marsh, for the very latest -- Rene.

RENE MARSH, CNN AVIATION CORRESPONDENT: Well, Wolf, another day, another potential ping in the same area as the others, but this time it was detected with a totally different piece of equipment.

(BEGIN VIDEOTAPE)

MARSH (voice-over): The search for Flight 370's black boxes intensifies, and the ping count may have gone up again.

An Australian Orion aircraft flying over Ocean Shield dropping sonobuoys into the water below, and at least one of them got a hit, a possible fifth ping detected where Ocean Shield already picked up four. That could be a confidence-builder.

MIKE WILLIAMSON, OCEAN SEARCH SPECIALIST: The fact that it's picked up by a sonobuoy, which is probably less well-equipped to detect that signal than the pinger locator, that would indicate that perhaps it is still a pretty strong signal.

MARSH: The acoustic data is being analyzed but the search coordinator says it's potentially from a manmade source, like a flight data recorder. An underwater listening device is attached to the buoy. An antenna relays what it is hearing to the aircraft. The sensors are deployed at least 1,000 feet underwater, but only work for eight hours.

Sonobuoys, usually used to detected submarines, were not designed for this kind of mission.

MIKE WILLIAMSON, OCEAN SEARCH SPECIALIST: The ones that I'm familiar with generally have very poor response to frequencies as high as 37 kilohertz. They are more used for detecting mechanical sounds of submarines, one kilohertz or lower. But that's not to say that there haven't been some changes made.

MARSH: The search surrounding the Ocean Shield continues to intensify. The British ship HMS Echo has pulled out of its position to the southwest and is now focusing where the pings have been detected.

But crews continue to listen for even more pings to shrink the search zone. A smaller zone is necessary. The underwater vehicle can only search 40 square miles a day. That means the roughly 500-square mile area where the pings were detected over a span of three days would take nearly two weeks for Bluefin to search.

(END VIDEOTAPE)

MARSH: And today, a U.S. Navy supply ship joined the mission for the search of Flight 370. The ship will be used to replenish Ocean Shield and others participating in the search. Essentially, it can supply them with food, water, and fuel, an indication this mission isn't ending any time soon -- Wolf.

BLITZER: That's correct. Stand by, Rene.

I want go to Perth, Australia, and that's the base of the operations for the search.

CNN's Michael Holmes is on the scene for us with more.

What's the latest there, Michael?

MICHAEL HOLMES, CNN CORRESPONDENT: yes, we're going to have the search planes out again, more than a dozen of them, Wolf. They will be leaving in the next few hours.

Also, those ships, again, are going to be scouring the ocean today. Something Rene mentioned is really interesting. The Ocean Shield joined now -- we reported this to you yesterday, that it was headed to the Ocean Shield area, the search area where they have been getting these pings.

Now, HMS Echo, it's a British naval ship. Now, what it is, it has the ability -- it's an oceanography ship. It has the ability to scour the ocean using echo sonar, scouring the floor obviously trying to find evidence of wreckage below. Now, as Rene said, this Bluefin submersible, it's a tedious operation with that.

It goes literally at walking pace, takes a full day to go down, cover some space, come back up. The HMS Echo, though, it's got a two- mile-wide coverage. It's not high resolution like the Bluefin submersible, but way broader brush strokes, if you like, and much faster. We have talked before about the silted bottom down there, perhaps meters of silt at the bottom. That would give off this echo from HMS Echo, it would give a soft signal back, if you like.

Now, that means that if there is a plane down there or wreckage down there, it would give off a hard signal. So it's obviously out there to sort of help now that we know those pings are in that area, going to go do these broad brush strokes and see if they can found wreckage.

Meanwhile, those other ships are a few hundred miles to the west, where experts think any debris from the suspected crash site would have drifted over the weeks since MH370 disappeared, Wolf.

BLITZER: Michael Holmes on the scene for us in Perth. Thank you.

We also have some new compelling details of what may have happened in those first few hours after Flight 370 went off course.

Our senior correspondent, Joe Johns, is joining us from Kuala Lumpur right now, the Malaysian capital, with details -- Joe.

JOE JOHNS, CNN CRIME AND JUSTICE CORRESPONDENT: Wolf, the new details suggest a familiar scenario in crisis management, that in the early hours when Flight 370 disappeared, the Malaysian military could have been acting on information that civilian authorities didn't get access to until later, though the government is already denying it.

(BEGIN VIDEOTAPE)

JOHNS (voice-over): It has been one of the lingering mysteries of Flight 370. What happened in those first few hours after it went off course?

Now we're learning the plane disappeared from military radar for 120 nautical miles after it made that left turn and crossed over the Malay peninsula And new details about what happened in those predawn hours. A senior Malaysian government official and a source involved in the investigation tell CNN the plane must have dipped in altitude to between 4,000 and 5,000 feet, a possible sign the pilots were at the controls. But it's still unclear if the plane was in some sort of trouble, whether they were purposely evading detection, or whether the Malaysian radar system failed somehow.

ANTHONY ROMAN, COMMERCIAL PILOT: It's not telling us very much, other than they may have been switching pilot responsibilities at the time. So whatever event happened, whatever was planned, whether it was nefarious or mechanical, it happened as a result of that transponder and that ACARS getting shut off.

JOHNS: What is clear now, MH370's captain, Zaharie Ahmad Shah, not his co-pilot, was the last person on the jet to speak to air traffic controllers, telling them, "Good night, Malaysian 370," Malaysian sources tell CNN.

The sources said there was nothing unusual about his voice, which betrayed no indication he was under distress, and no third voice is heard.

And just today, more than a month after the flight disappeared, we're learning Malaysian Air Force search aircraft were dispatched soon after the airline reported its plane missing, Malaysian sources told CNN, headed for the Strait of Malacca and South China sea. Malaysian authorities had initially focused their search mostly on the South China Sea.

The search aircraft took off before authorities had corroborated data indicating that the plane turned suddenly westward from its original course. And the Malaysian government denied in a tweet that any Malaysian air force aircraft were scrambled.

ROMAN: I'm suspicious of the information that they have provided. I think the most likely scenario is that they detected them on military radar, they scrambled those jets, and either couldn't locate it or some other problem developed.

JOHNS: But our source says the air force did not inform the rest of the Malaysian government until three days later, March 11, a source involved in the investigation told CNN.

(END VIDEOTAPE)

JOHNS: Malaysian police continue their criminal investigation into the disappearance of the plane and say no conclusions have been reached.

The home minister here reiterated at a news conference on Thursday that 180 people have been interviewed, including family members of the cabin crew -- Wolf.

BLITZER: Joe Johns with the latest on the investigation in Kuala Lumpur.

Let's bring in our panel right now. Our aviation correspondent, Rene Marsh, is back, along with our aviation analysts Miles O'Brien and Peter Goelz and our law enforcement analyst Tom Fuentes. Miles, what do you make of this notion the plane suddenly went down to 4,000 or 5,000 feet and may have been trying to avoid military radar detection?

MILES O'BRIEN, CNN AVIATION ANALYST: There's lots of things wrong with it, Wolf. It just doesn't add up.

The ability to get down to that altitude and back up to another altitude, although I question all the numbers we have gotten, are in question. The fact that it might have been down at 4,000 or 5,000 feet as it potentially crossed the Malaysian Peninsula, which has peaks of 7,000 feet, confused me as well. Is this an above-ground a altitude or above sea level altitude?

There's a lot of questions here. And even with all of that, 4,000 to 5,000 feet is not an altitude where most pilots would expect not to be painted by radar. It doesn't add up. I'm not quite sure what they're trying to say with this.

BLITZER: If it's true, though, Tom, what does it say to you? If a plane is normally supposed to be cruising at 35,000 feet and suddenly goes down to 5,000, what does that say to you?

TOM FUENTES, CNN CONTRIBUTOR: It says it changed altitude, Wolf. We don't know why. We don't know who was at the controls, if it's true. But I'm not buying that yet. I think the reporting on their radar sightings from the beginning of this investigation have changed. Different stories have come out about changes in altitude, direction, speed, and then multiple changes of direction.

So I just -- you know, again, I would like to see proof, and right now what they're offering is that since they don't know for sure what it did, they're assuming that when it went off radar, it must have gone down below the radar. That's not how you arrive at conclusions in an investigation by, because of a negative, you say that the opposite must have happened.

BLITZER: If it did go down to 4,000, 5,000, Peter, what does it say to you?

PETER GOELZ, CNN AVIATION ANALYST: Well, it says somebody was in control of the plane, but I'm with my two colleagues. The Malaysians have not been forthcoming throughout this investigation.

And even in today's report, did they scramble two jets or didn't they scramble two jets? And why are they revealing this 35 days after the accident? This is stuff that should have been clarified within 24 hours after the accident. The radar data should have been looked at within 72 hours.

And people should have had a clearer picture. And this has been a mess from day one.

BLITZER: I want all of you guys to stand by for a moment. I want to bring in another aviation analyst, Geoffrey Thomas, who's joining us from Perth, Australia, right now. He's the editor in chief of AirlineRatings.com.

What are you hearing over there in Perth? You're there where the staging area is. What's the latest on this entire investigation, specifically the notion that the plane at one point may have gone down to 4,000 or 5,000 feet in altitude?

GEOFFREY THOMAS, EDITOR IN CHIEF, AIRLINERATINGS.COM: Yes, Wolf.

Those detail about the change in altitude, we have known about that here for about three weeks. This was -- this came out of Malaysia and some of the Malaysian military failure early on, again, off the record. Now we're getting something more on the record.

And as your panelists have just suggested, the variations in what we're getting out of Malaysia has not been good. It has been inconsistent. It has been contradictory. And that's led to a lot of confusion in the reporting and, more to the point, a lot of confusion in the analysis of exactly what's happened with this airplane.

My sources tell me that there were multiple changes in flight path, direction, and there were a number of changes in altitude. The specifics, we don't have as yet, but clearly this airplane was under the control of somebody. And we're yet to find out exactly who.

BLITZER: We have now confirmed, Malaysian authorities apparently have finally concluded that the voice, the last voice heard from the cockpit was the voice of the captain, not the co-pilot, if you will. What do you make of that?

THOMAS: Well, you're right. They have said that, but was the co-pilot doing all the air traffic control communication up to that point, and then the captain signs off? Because, if the captain signed off, that would indicate that the co-pilot was no longer in the cockpit, back doing something, which would kind of support the captain was the man in control for the rest of the flight theory.

So that detail, I haven't got as yet. I don't believe it's out as yet of exactly what was making all the air traffic control communication up to that point.

BLITZER: Let me bring Rene into this for a moment.

Rene, what are you hearing from your sources about this notion that the pilot actually was the last one who said, "Good night, Malaysian 370"?

MARSH: Well, Wolf, you know, I guess the big question in all of this is, if this is true, if it truly was the captain who said those final words, what does it all mean?

And in the grand scheme of things, we may be able to assume a couple of things. We may be able to assume that if the captain was one who was speaking to air traffic control, perhaps the co-pilot was the one who was in control of the plane, although that isn't necessarily true. It could be that, perhaps, under certain circumstances, the captain needed to be speaking to air traffic control and still be in control of the airplane.

So I guess what I'm getting at is that now that we have this detail, it really doesn't change a whole lot. It really doesn't tell us a whole lot. And it really doesn't move us that much further -- Wolf.

BLITZER: You know, Miles, I think a lot of us would be happy if they released a transcript, the Malaysian authorities, they released a transcript. But why not release the audiotape, so we could all hear those words?

O'BRIEN: Why not? Very good question, Wolf. That's a reasonable thing to expect at this time.

I can't imagine how at this juncture it would in any way impede their ability to conduct the investigation, and it would just be a breath of fresh air for an investigation which has not had anything but secrecy surrounding it.

I understand that when you're conducting particularly the criminal side of an investigation, that you need to keep things privileged, but there's a lot of aspects to this investigation that could be shared with the world, and frankly more ears hearing things, the better.

And just one final thought here. It could have been as simple as the first officer was conducting a public address announcement as they leveled off, and the captain handled that particular radio call. I don't want to put too much into that particular thing.

BLITZER: Yes.

Let me bring Geoffrey back into this.

This fifth ping that they suspect actually came from one of those two black boxes, I know it hasn't been confirmed yet, certainly not as strong as the first four that had been detected. But, Geoffrey, what are you hearing there in Perth, Australia, about this fifth suspected ping?

THOMAS: Yes, well, RWAS (ph) P-3 Orions are dropping these sonobuoys.

Now, the ping will not be as strong because it's a different sort of mechanism to listen for the ping. What it does, the sonobuoy drops on the surface. It deploys a 1,000-foot cable, and on the bottom of that cable is a hydrophone. So, it's listening from 1,000-feet deep, whereas the towed pinger is right down at the bottom.

So it's getting a much, much stronger signal. So the weakness of the signal would be indicative of the fact that its hydrophone is much higher up in the ocean. So this just adds to the number of pings we have had. It seems to corroborate the fact that we're right on where the resting place is of 370.

BLITZER: Peter, it's, what, 35 days. Those batteries are supposed to last a minimum of 30, but sometimes they go longer. We're right now certainly at the tail end of the battery life of those two black boxes. Right?

GOELZ: There's no question the clock's ticking. But, you know, we have had some good luck during the last week. Let's hope we continue to have it. We need to pick up probably four, half-a-dozen more pings to start to narrow that search area down from the 500 square miles that Rene reported it currently is.

BLITZER: And, Rene, you're there for us still. What are you hearing from your sources right now? Do they anticipate that, you know, the next few hours they're going to be able to announce maybe there have been some more pings?

MARSH: You know, at this point, we don't know if there have been any more pings.

We do know that HMS Echo now in the vicinity, Wolf. We know that it has the capability of listening as well. It has passive sonar. It also has the ability to map the ocean floor, although they haven't given us much detail as far as what the specific task of HMS Echo will be in the area.

We know that the Ocean Shield is leading the charge as far as using the pinger locator to pick up more pings. But we will just have to wait. We're hoping to get more information as these press conferences happen midnight for us here. But whether they have detected anything else from the time that they last announced it, we don't know.

It's quite possible. Now you have the pinger locator. You have the sonobuoys in area and you also have HMS Echo, so lots of assets. They are listening for those pings. Will we get some good news later on today? I'm going to bet those search crews are hoping so, Wolf.

BLITZER: You pretty surprised, Miles, that 35 days in, they're still hearing pings?

O'BRIEN: You know, aviation is the kind of thing where there's always margin that is added.

Whatever you build, if the spec is 30 days, the engineers are really building it for 40. That's just how they -- how aviation is as safe as it is, and that's just how engineers who are involved in this business operate.

So it doesn't surprise me too much. You know, Wolf, what I was concerned about was that they operated in the first place. Were they damaged on impact? If the pingers were to start going, the fact that they're going past 30 days shouldn't come as too much of a surprise to us.

BLITZER: All right, guys. Stand by. We have a lot more to assess.

Still ahead, the dangers in the deep -- why the underwater search for Flight 370 is so slow, so risky at the same type.

We will also talk about the enormous challenges of recovering wreckage if and when it's found. It could take years, maybe even decades.

(COMMERCIAL BREAK)

BLITZER: "CROSSFIRE" won't be seen tonight so we can bring you more of our special coverage of the Flight 370 mystery.

We're following the breaking news, a possible fifth signal from Malaysia's Flight 370's black boxes. The air search is resuming right now in the smallest area yet, with ships crisscrossing the area around the clock.

CNN's Tom Foreman is digging deeper into the huge challenges searchers are still facing.

What are you finding out, Tom?

TOM FOREMAN, CNN CORRESPONDENT: Wolf, when you go underwater, that's when it really gets complicated. And here's one way of looking at it.

More people have been to space than have been in the deepest parts of the ocean. And this area with the target zone anywhere from one-and-a-half to three-and-a-half miles down, that absolutely qualifies as deep ocean out there. Comparison, we're talking about an area that is much deeper than where the Titanic is, much deeper than where nuclear subs normally spent their time, deeper than giant squids live.

It's absolutely close to freezing down there. Not quite frozen, but almost icy temperatures down here, complete darkness. And they really don't know much about the ocean floor here, Wolf. They know it's a general slope, but they don't know exactly how steep it is, exactly what features are down there, and what could interfere with the underwater search as they move that direction, Wolf.

BLITZER: Why not send those robotic mapping devices down immediately to start looking around?

FOREMAN: Precisely because they don't have all those other answers. When you bring in these features like the Bluefin, for example, to start mapping down here, it helps if you have an idea where you're sending it, because the closer it can be to the ocean floor, it's using side-scan sonar, the better an image you can get.

You don't want it right on the ocean floor. But you're also functioning here kind of at the limits depending where you are. It's designed for two-and-a-half miles down, 25 hours at a time, using sonar acoustics to take images of the ocean floor. But these are typically used at much more shallow depths.

So, to a degree, any time you put it this deep in the water, there's an experimental edge to it. You're trying something you haven't tried a lot of before. And if you want really higher-quality images like some of the other types of sonar that work closer down here, then you need to know even more, because then you're talking about being maybe three to five yards off the ocean floor, and with an expensive and highly sensitive piece of equipment like this, you don't want it colliding with things, getting stuff and then losing valuable time, Wolf.

So, that's whey they're waiting on that. That's also why they're focusing so much on the work on the surface. The ships like the HMS Echo, what it can do is give them a better picture before they start, Wolf, of what they're taking pictures of, so hopefully when they put the Bluefin down there, it can be the most productive, because it's a big production to get it into the water and get it out safely. They don't want to lose any of that time through bad planning -- Wolf.

BLITZER: It's very, very, very complicated, obviously.

All right, Tom, thank you.

Let's get more now with Colleen Keller. She's a senior analyst with the scientific consulting firm Metron. She worked on the search for Air France Flight 447. And Erik van Sebille, he is joining us from Sydney. He's an oceanographer with the Climate Change Research Center.

Talk a little bit about these waters. How challenging, Erik, are they for searchers?

ERIK VAN SEBILLE, UNIVERSITY OF NEW SOUTH WALES: Well, they are very challenging, and it's indeed because it is just so deep.

Once you get down to the ocean floor, really, we oceanographers, we have only done this for a little amount at a time and we haven't just had time to map everything. And most of our focus has been on the other oceans, not on the ocean here, the Indian Ocean off Australia.

BLITZER: Colleen, you worked on the recovery of the black box from the Air France disaster off the coast of Brazil in the Atlantic ocean. Looking for a small box like that, a flight data recorder, a cockpit voice recorder, even if you have a general area, how difficult would it be in the Indian Ocean right now?

COLLEEN KELLER, SENIOR ANALYST, METRON, INC.: Well, you know, the depth compounds the problem.

It just takes an awfully long time to drop the vehicle down there and then the sensors that you're using aren't like just using your eyesight. You do use cameras, but it's dark. The side-scan sonar, the images aren't like a photograph. They cast shadows. The sound waves cast shadows on things that the waves bounce off of.

So you need somebody to kind of interpret the pictures that result from the side-scan sonar to see if they identify anything manmade. And then there's the whole fact that they don't really know what's down there. So, you know, like what was being said, you have to worry about tangling the Bluefin 21 into something, some wreckage or some kind of features on the bottom.

And if you lose that, then you have lost a whole month to get another submersible out there.

BLITZER: One of the great sub-mysteries of all of this, Erik, if you believe those four pings were from the two black boxes or at least one of them, and now maybe a fifth ping come from one of those black boxes, yet no debris has been found at all on the surface or anyplace else.

What's your assumption? What's going on here, since you know these waters well?

VAN SEBILLE: Yes, so I -- one way that's going to explain this is really the debris has gone into a very different direction. Much of the focus, especially early on in this search, has been about debris moving eastward, moving towards the strait (ph), as you were.

But now that these pings seem to be much further northward, much closer to Malaysia, and the plane maybe hasn't flown that far, it means that the circulation actually would have driven the debris the other way around, much more toward Madagascar, toward Africa, even.

BLITZER: Colleen, here's a mystery that I'd like you to explain to our viewers. The -- the pinging sound that's coming from those two black boxes, they're supposed to be, what, 37.5 kilohertz.

But we're told that it was slightly different the first four pings that were detected, this fifth suspected ping. Not exactly 37.5. How -- if they believe they're coming from the black boxes, what would explain the slight change in the kilohertz?

KELLER: Well, it could be the environment or it could be the box itself. I know that when they recover one of the black boxes from the Air France search and they put it on the bench and they cleaned it up and put a new battery in it and then tested it, it didn't function at the frequency they were expecting. And it also didn't give the correct voltage that they were expecting, which indicated that either the box had suffered some sort of damage -- I'm sorry, the beacon had suffered damage or that it -- it was manufactured incorrectly or had some defect inside.

So it could be any number of explanations, including maybe that the water environment is changing the signal, but I think it's probably more likely it's coming from the box at that frequency. But the manufacturers still seem to think that it's coming from their beacon. So we're going to go with that.

We heard in the last hour, Colleen, from one of the New Zealand air commodores, one of the commanders there who's been involved, that the surface search is now about the size of West Virginia. Looking for debris that may be floating on the surface. But the search underwater, based on those four or five pings, is a lot, lot smaller. How much smaller is it, based on the fact that those pings were found about, what, 17 miles apart? KELLER: Well, you know, we're giving the towed pinger locator a 1- to 2-mile detection range, and actually it might be a little bit more because of the altered frequency that we're hearing. The water actually absorbs that energy less, so it -- so the sound can travel farther.

So maybe the TPLs can see quite a bit differently farther than we expected.

But at any rate, let's say you gave it maybe twice the detection range so they could see 5 miles. Then the pings that we've detected are 17 miles apart and add another 10 miles. We're talking like a 20- to 30-mile area and just guessing that that's a square area. So that's significantly smaller than the air search area for the floating debris.

BLITZER: Having said that, Erik, if you take a look at, you know, 20 or 30 or 50 square miles, 3 miles deep, finding those two small boxes, that would be pretty difficult. You know those waters.

VAN SEBILLE: Yes. Absolutely. A lot of time on the surface, because we can go down there with the submersible, they don't go very fast. You can't go -- you can drive your ship at the same speed as you and drive your submersible or the other way around. So the submersible can only cover a very small amount of distance every day, and every time it has to get back up. So this is going to take even for a relatively small area, this is going to take a significant amount of time. Weeks, months. Something like that.

BLITZER: You were involved in that Air France search, Colleen. Is there anything you think they need right now, all the people involved in this search, that they're not getting?

KELLER: Well, you know, it's kind of strange that we're continuing to search the surface for debris. If we found a piece of debris tomorrow, what would that do for this search?

I know that when we found debris for Air France, and we backtracked it using three different sets of models, bra Brazilian models, French models, U.S. Coast Guard models, they all placed the impact point in a different location, and guess what it? It wasn't where we found the wreckage.

So what I'm trying to say is that if you don't have very good current models, that debris isn't really going to help you find where you should be looking.

So right now I think we should be focusing on the pingers, and we should be localizing while we still can hear them. And then we should just go down right there and start looking with our submersibles.

BLITZER: Colleen Keller, Erik Van Sebille, we'll check in with both of you tomorrow. Thanks very much.

Still ahead, more breaking news coverage of Flight 370 and the smallest search area yet. Our Richard Quest is here. He's standing by with the latest.

Plus, new details of the stamp -- stabbing rampage in a Pennsylvania high school. We're learning more about the teenager accused of the bloody attack.

(BEGIN VIDEO CLIP)

UNIDENTIFIED MALE: Alex, why did you do it?

(END VIDEO CLIP)

(COMMERCIAL BREAK)

ANNOUNCER: This is CNN breaking news.

BLITZER: Getting some breaking news about a major resignation in the Obama administration. Let's go to our Brianna Keilar. She's standing by with details -- Brianna.

BRIANNA KEILAR, CNN CORRESPONDENT: Hi, there, Wolf.

We have just learned from a White House official that Health and Human Services Secretary Kathleen Sebelius is resigning as secretary, that she will be leaving the Obama administration.

As you know, she has been very much embattled over the last several months ever since the rollout of Obamacare, specifically marred by the very poor rollout of the Web site, HealthCare.gov in October.

Well, as you do know, that Web site came to its six-month enrollment process at the end of March. There had been some questions over the last several months about sort of what personnel changes might be made. Many Republicans had called for Kathleen Sebelius to resign and we now understand that she is, indeed, resigning, according to a White House official.

We're also told, Wolf, by that official that she is going to be replaced by Sylvia Burwell, who is the OMB chief, the head of the Office of Management and Budget. So that coming to us just now from the White House that embattled Health and Human Services Secretary Kathleen Sebelius, indeed, leaving the Obama administration.

BLITZER: But she's leaving in a relatively high note for...

KEILAR: That's right.

BLITZER: ... as far as the HealthCare.gov is concerned. Not just 7 million. Today they've announced it's gone up to 7.5 million, seven and a half million people have actually signed up for Obamacare, the Affordable Care Act. So that's a pretty positive note, right?

KEILAR: That's right. That's right. And that's a very important point that you make. A White House official, we're learning today that even just since that 7.1 million benchmark, which was really good news for the White House, saying that 7.1 million people had signed up through that six-month process, which really was the goal, Wolf, that when they were looking at sort of congressional estimates, we had heard that just recently here there were 400,000 more signups.

So that was a feeling that, even since President Obama had addressed that 7.1 million mark, that things had really -- I guess, the profile of the program had even been raised. There had been more interest, and certainly that was something that the White House looked on as very positively.

BLITZER: I just think it's going to go up.

KEILAR: And we're also understanding that -- I should clarify, Burwell is going to be nominated. And obviously, this is a position that will have to be confirmed by the Senate. But that's going to be President Obama's pick to replace Kathleen Sebelius.

BLITZER: There are still a few days left until the 15th of the month. The folks who tried to get on, couldn't get on, they still have a few more days. That 7.5 million number presumably over the next few days, Brianna, is going to go up.

KEILAR: Yes, that's the expectation. And there's always this issue, Wolf, of people who have signed up versus people who have completed the process, right, who have paid their premium and are completely enrolled at this point.

But, yes, no, this is certainly a good marker for the Obama administration. But this has been a very difficult, I would say, six months or so for Kathleen Sebelius. Both in trying to gear up for the rollout of Obamacare, and just dealing with what has been politically a nightmare for the Obama administration, even though recently the tide has turned.

Of course, this is going to be, you know, this is going to be an issue that is very much political fodder in this election year.

BLITZER: Former governor of Kansas.

KEILAR: That's right.

BLITZER: Secretary of Health and Human Services Kathleen Sebelius. Kathleen Sebelius now stepping down.

We're going to continue to follow this story.

We'll take a quick break. Much more on the mystery surrounding Malaysian airliner Flight 370. Richard Quest is standing by. We'll be right back.

(COMMERCIAL BREAK)

BLITZER: The breaking news this hour, we're waiting to hear the results of a new analysis of another signal that may be come from Flight 370's black boxes. It's the fifth possible ping detected by searchers since Saturday. Let's bring in CNN's Richard Quest.

What do you make of this? Maybe five pings. That would be dramatic.

RICHARD QUEST, CNN AVIATION CORRESPONDENT: It would, indeed. And the way this ping was acquired is very different. It wasn't done by the towed locator, the ping locator behind Ocean Shield. This was dropped by an aircraft. It's one of the sonobuoys that's been put into the water and has managed to give a signal.

Now, what we know is the frequency's in the right area. They don't believe it's of natural origin. And they believe it is a mechanical.

But they haven't given us any details. For example, we don't know what the frequency is, we don't know what the repetition rate is. We don't know anything like that. We do know it was at about 1,000 meters.

BLITZER: A thousand meters under the surface.

We also know now for sure, Malaysian authorities have confirmed this that the final words from the cockpit came from the captain, not the co-captain.

QUEST: Well, it's still -- it's still -- yes, it's believed to be. I'm putting it like that.

BLITZER: Because people who know both voices have said that this is the captain's voice.

QUEST: Right.

BLITZER: "Good Night Malaysian 370", the final words from the cockpit. Two minutes before the plane made that left turn.

QUEST: That's according to a source -- yes, that says five people have heard it, five people have confirmed it's the captain. The circumstances under which that was said, of course, remain completely unknown. And one crucial point, who was the pilot flying? Was it the first officer? Or was it the captain? Because whoever wasn't the pilot flying does the radios.

BLITZER: Why is it significant, though, who said the final good night?

QUEST: It's not significant in one sense, yet it's totally significant, because we know after that Malaysian Airline 370, 1:19, whatever happened happened after that.

So whoever was at the helm of the aircraft was either trying to save it or was involved or somehow knows best what took place.

BLITZER: What is a lot more significant potentially is if, in fact, the plane went from its normal cruising altitude of some 35,000 feet down to 4,000 or 5,000 feet as it was supposedly tried to evade Malaysian military radar.

QUEST: Right. This is the story that says it flew across, Malaysia. But remember, it flew across 35,000 feet. So, it's one truly on radar. Then it drops down to 4,000 and then perhaps too early comes back again, so it's picked up on radar. That is 4,000- foot theory.

There are those who choose to believe it and those who says it doesn't hold much weight. We don't know.

BLITZER: What do you think?

QUEST: I am still skeptical. I think there were altitude changes. I think there is no question there were altitude changes. But the levels involved and the severity and destination, because let me put it another way. Why go down when you've already been painted over Malaysia?

BLITZER: Does it give us a clue whether it was a mechanical disaster on that plane or it was a criminal act by someone?

QUEST: The conspiracists will say it can only point to one thing. You know me long enough on this story, Wolf, now. I'm sticking right in the middle.

BLITZER: Richard Quest, good work as usual. Thank you.

We're also just hearing now of an incident involving Hillary Clinton. A woman threw a shoe at the former secretary of state during a speech in Las Vegas.

Our senior political correspondent Brianna Keilar is back. She's working this story for us.

What do you finding out, Brianna?

BRIANNA KEILAR, CNN SENIOR POLITICAL CORRESPONDENT: Well, Wolf, we actually have some video. Before we show it to you real quick, though, we do believe this object was a shoe. And just to tell you what this event was, it was a paid speech that she was giving before the Institute of Scrap Recycling Industries.

So, she was at the Mandalay Bay Hotel and Casino in Las Vegas when this happened, the shoe missed Clinton and she actually joked about it. Take a listen.

(BEGIN VIDEO CLIP)

HILLARY CLINTON, FORMER SECRETARY OF STATE: Recycling about -- what was that, a bat? Was that a bat? Is that somebody throwing something at me? Is that part of Cirque du Soleil?

(APPLAUSE)

CLINTON: My goodness. I didn't know solid waste management was so controversial. (LAUGHTER)

(END VIDEO CLIP)

KEILAR: So you have to say there, Wolf, she handled this pretty well. And we don't know why this happened.

A little bit about what we are learning, according to "The Las Vegas Review Journal", the woman there you see walking away with the blond hair, she said that it was a shoe. We don't know who she is.

We understand from a spokesman for the group before which Clinton was speaking that it's not clear what she was protesting, though she was referred to as a protester. She wasn't credentialed for the event, we're told, that she must have slipped under a rope, which certainly raised some security concerns. You can see she was whisked away there pretty quickly by.

We're not entirely sure who that is. But obviously Secretary Clinton has Secret Service detail because she was first lady before as well.

But, again, she ducks there as the shoe is thrown at her. Sort of a narrow miss. But I'll tell you, wolf, I've been to a number of Hillary Clinton events recently. And this here, this is a pretty supportive crowd. You know, this is a paid speech.

There really hasn't been any blips really in these events. So this is something that is really -- you know, really pretty unusual.

BLITZER: That could be terrifying.

KEILAR: Sure.

BLITZER: That's nothing to laugh about. That could be very, very frightening. That shoe, if it was a shoe, could have hit her in the face, causing serious, serious problems.

All right. Brianna, thanks very much.

Just ahead, new information coming into THE SITUATION ROOM on Flight 370. We're going to bring you the breaking developments on the search and the investigation, right after this.

(COMMERCIAL BREAK)

BLITZER: We're following all the breaking developments in the Flight 370 mystery. We're waiting for results right now of a new analysis on the latest possible signal detected in the Indian Ocean. It could be a fifth ping from the plane's black boxes.

The air search is resuming in the area where those electronic pulses have been heard. Crews are hoping to pick up even more signals, knowing the batteries on the black boxes may die at any moment if they're not dead already. Malaysian sources tell CNN investigators now have confirmed it was the plane's captain who spoke the final words from the cockpit to the tower. Those words, "Good night, Malaysian 370."

Remember, you can always follow us on Twitter. Tweet me @WolfBlitzer. Tweet the show @CNNSitRoom.

Be sure to join us again tomorrow in THE SITUATION ROOM. Watch us live or you can always DVR the show so you won't miss a minute.

That's it for me. Thanks very much for watching. I'm Wolf Blitzer in THE SITUATION ROOM.

"ERIN BURNETT OUTFRONT" begins in 60 seconds.