let's bring in our invitation correspondent renee marsh. airline technologies, they are outdated. what's the problem here >> here's the bottom line. in talking to a lot of people this is it. the thing is unless it's mandated many airlines won't go ahead and take it upon themselves to make the changes on their own. if it's mandated they will do it, if not they won't. you mentioned the pilots union are asking for stronger transmitters, better battery life. i think after this people will revisit those issues and perhaps we'll see some changes. plans as far as batteries on those pingers that's something we've been talking about and should be extended beyond the 30 days. >> batteries on these pingers on those two black boxes they may not have been properly installed. >> cnn read out to the manufacturer of these pingers and said look they were due for an overhaul, a maintenance overhaul to change out the batteries and essentially give this thing a new look because they were due for that in 2012. it didn't happen. now that could mean one of three

renee marsh joins me from washington.e new rules. >> carol, the first one you spoke about, no pilot or first officer is allowed to be alone in the cockpit. the reason behind that is, for example, if one pilot has a health issue, you always want someone who is able-bodied to be in the cockpit to fly the plane or if a pilot has sinister intentions, you wouldn't want it that person in the cockpit alone. here in the united states, a pilot is never alone in the cockpit. before they leave the cockpit, they have to receive verification that it is clear for them to come out. when they do come out, we know that the door is blocked. if someone is at the cockpit door, for example, and wants to get in, the pilot must make a visual contact through that little peep hole before opening the cockpit door. we also know that in the united states, pilots don't get served the same meal in the event, let's just say, the chicken that's being served is tainted. each one is going to get a different meal if they are in the cockpit. here in the uni

thank you, to rene marsh. coming up, more on rene's reporting.at the airline industry is doing now to make sure it never loses a plane again. stay with us. the day we rescued riley was a truly amazing day. he was a matted mess in a small cage. so that was our first task, was getting him to wellness. without angie's list, i don't know if we could have found all the services we needed for our riley. from contractors and doctors to dog sitters and landscapers, you can find it all on angie's list. we found riley at the shelter, and found everything he needed at angie's list. join today at angieslist.com with olive garden's new cucina mia for just $9.99. italian dinner first, choose unlimited soup or salad. then create your own pasta with one of five homemade sauces. and finish with dessert. three courses, $9.99. at olive garden. [ male announcer ] when fixed income experts... ♪ ...work with equity experts... ♪ ...who work with regional experts... ♪ ...who work with portfolio management experts, that's when expertise happens. mfs. because there is no

let's begin our coverage this hour with our aviation correspondent rene marsh. renee? >> we know there have been about 133 missions, and australian authorities say they are just as intense today as they were on day one. now you're about to hear for yourself the audio of the pinging sound search crews detected for a substantial amount of time. the problem is, they've lost contact with it. it's the sound crews onboard the ocean shield are desperately trying to find again, the australian defense department released audio of the possible black box signal the towed pinger detected twice over the weekend. despite a continuous effort to recapture it, still nothing. >> as the hours pass, we are -- our optimism is fading away ever so slightly. >> if it is flight 370's black boxes, finding it again is the only way to pinpoint its location. the ocean shield moves about two miles per hour, tracking back and forth around the clock. the towed pinger measures intensity, but not position, so multiple hits are crucial in triangulating a smaller search area. >> until we stop the pinger

tonight, he says he agrees with the australian prime minister, as our aviation correspondent renee marsh reports, seems almost certain that the pings in the water are coming from the black boxes. >> reporter: another day of searching above and below the water for signs of flight 370 is now under way. forget cautious optimism, the australian prime minister, tony abbott, is oozing confidence. >> 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. >> we are confident that we know the position of the black box flight recorder to within some kilometers. >> reporter: his tone stronger and more upbeat compared to the careful wording two days ago from the man coordinating the search. >> i think we're looking in the right area, but i'm not prepared to confirm anything until such time as somebody lays eyes on the wreckage. >> reporter: but with rumors flying, the black boxes were located overnight. angus houston released a statement saying quote, there has been no major breakthrough in the search for mh-

at this hour we're waiting the results of the analysis on that as our renee marsh reports. the team came by the latest break in the mystery using very different, perhaps even more efficient technology. >> reporter: the search for flight 370's black boxes intensifies and the ping count may have gone up again. an australian orion aircraft over the ocean shield, dropping sonobuoys. and at least one of them got a hit. a possible fifth ping detected where the ocean shield already picked up four. that could be a confidence builder. >> the fact that it is picked up by a sonobuoy which is probably less well equipped to detect that signal than the pinger locater, that would indicate that perhaps it is still a pretty strong signal. >> reporter: the acoustic data is being analyzed but they say it is potentially from a black box source. the sensors are deployed at least a thousand feet under water but only work for eight hours. sonobuoys usually used to detect submarines were not designed for this type of mission. >> the ones that i'm familiar with generally have very poor response to

let's go first to our aviation correspondent, rene marsh for the very latest. rene? >> 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 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 uoys in the water below and at least one got a hit. a possible fifth ping detected where ocean shield already picked up four. that could be a confidence builder. >> the fact that it's picked up by a sonabuoy 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. >> reporter: 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's hearing to the aircraft. the sensors are deployed at least 1,000 feet under water but only w

let's go to our aviation correspondent, rene marsh, first, for the very latest. rene? >> well, wolf, i can tell you a significant strategy in the search here, shift in the search. crews have moved from listening under water to looking under water and this new phase could be a long haul. taking weeks, even months. a strategy shift in the search for flight 370's black boxes. >> it's time to go under water. >> reporter: and possible new evidence. >> an oil slick in the same vicinity, so we will investigate those to their conclusion. >> reporter: it's been six days since the last pings were detected in the south indian ocean. searchers believe the pinger batteries are probably dead. so they've retired the pinger locator and launched bluefin-21. the underwater vehicle will scan the sea floor for wreckage. >> i would caution you against raising hopes that the deployment of the autonomous underwater vehicle will result in the detection of the aircraft wreckage. it may not. >> reporter: bluefin is concentrating on a roughly 500 square mile area where the four pings were detect

let's bring in rene marsh. this is one of the most encouraging signs we've seen yet but searchers are really under the gun now. >> they absolutely are under the gun. we are already two days past the required shelf life of the batteries. there's really no guarantee at this point how much longer they will last. but here's why authorities are cautiously optimistic. while there's still no sign of wreckage, there was a distinct sound coming from under water. as we speak, they are trying to determine if it's flight 370's black boxes that are calling. it's the sound search teams have desperately been trying to find and now they just may have. the pinger locator towed behind the "ocean shield" detected distinct sounds that may be from the black boxes. >> the first detection was held for approximately 2:20. the ship then lost contact. the second detection on the return leg was held for approximately 13 minutes. >> reporter: the detections about a mile apart in water more than 14,000 feet deep. on one occasion, two separ

. >> thank you, rene marsh. and what about this australian big announcement coming up.et into that when we come back. ♪ norfolk southern what's your function? ♪ ♪ hooking up the country helping business run ♪ ♪ trains! they haul everything, safely and on time. ♪ tracks! they connect the factories built along the lines. and that means jobs, lots of people, making lots and lots of things. let's get your business rolling now, everybody sing. ♪ norfolk southern what's your function? ♪ ♪ helping this big country move ahead as one ♪ ♪ norfolk southern how's that function? ♪ >>> welcome back to "the lead." the australians have called it the most difficult search in human history. a ship with advanced u.s. technology will finally arrive and help searchers locate the black box recorders from flight 370 which disappeared 28 days ago. by the time it arrives, the batteries in the pingers will nearly be out of power, if there is anything left at all. let's talk about this with miles o'brien and jeff wise. what can you tell us about what that means? >> it's to go out and to listen es

rene marsh, appreciate your reporting there. let's bring in our cnn aviation analysts, miles o'brien, david soucy. good to have you both back. miles, what do you make of this new emphasis on the malaysian airline on cockpit security, that month one pilot could ever be alone up there? is that a law already in the states? >> it is. that's standard operating procedure, post 9/11 procedure in the u.s., the reinforced cockpit door. anytime the flight crew leaves the cockpit for any reason, another crew member, a cabin person, or another person, a backup pilot, would go on board and be on the flight deck. for security, this is to help see when he comes back to the door to identify the right person a is at the door and open the door for that person. this is surprising to a lot of us who follow aviation that malaysia had not followed that procedure up until now. this tells us there's a lot of focus on a deliberate act. was there a passenger, another crew member who commandeered and got into the flight deck alone or in fact one of the fl

they had to make adjustments because as our own aviation correspondent rene marsh reports, the first dive came to an abrupt and unexpected end. >> reporter: after an abbreviated first launch, bluefin-21 is back in the water and searching. but so far, no trace of flight 370. extremely deep water caused it to abort its first mission. >> the one condition that causes it to abort its dive is if it reaches its maximum depth. >> reporter: bluefin can operate in water almost three miles deep but it turns out the search area was deeper than expected. bluefin was pushed to its limit. it should have spent two hours diving to the ocean floor, 16 hours searching for wreckage and two hours resurfacing. instead, it only spent 7 1/2 hours in the water. >> once it hit that max depth, it said, hey, this is deeper than i am programmed to be so it aborted the mission. >> reporter: the bluefin did collect data which included first ever images of the seafloor but they showed nothing of images that crews consider to be the most promising. as for the oil slick spot 3d 1/2 miles away, they are still chasing

cnn aviation analyst miles o'brien, and cnn regulation and government correspondent rene marsh back with and cnn correspondent richard quest. miles, let me start with you he here. if i told you that the ship would find the ping without finding the debris first, what would your reaction be? >> my first reaction would be what are the un -- nonpublic satellite images that got them on target, if you will. i suspect the chinese have employed a lot of assets that they don't want to talk about to assist them in locating this particular find, if it is indeed a find, and i think that they have been playing independently, autonomously outside of the investigation, because of the concerns about their sharing some of the methods for gathering secret information. and also, frankly, because of the acrimony that we have docume documented thoroughly here on cnn between the malaysians and the chinese as this investigation has progressed. so, that is what is sort of p my first inclination is that the chinese know something they have not shared, and that should not come as much of a surprise to us. >> no,

. >> i want to bring in our aviation correspondent, rene marsh. if they find what they think they are on to, of course that means that all hope is lost and the families have bad news. >> it is, jake. you know, it's really tough because as much as these families want to know what happened to their loved ones, if and when those black boxes are found in the bottom of the indian ocean, their worst fear will be confirmed. and speaking of the black boxes, australian prime minister tony abbott in china today to update china's president on the search for flight 370 but it's abbott's tone about how things are progressing that's receiving a lot of attention. forget cautious optimism. australian prime minister tony abbott is oozing confidence. >> 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. >> we are confident that we know the position of the black box flight recorder to within some kilometers. >> reporter: his tone stronger and more upbeat compared to the c

>> rene marsh, thanks. we'll talk about the families' concerns in a couple of minutes. let's turn to the search, after its second aborted mission, u.s. search officials said the underwater drone search for flight 370 could take months. so, why isn't there an entire fleet of bluefins to cover the search area? tom foreman in our virtual studio to answer that question for us. >> jake, when you think about what happened on top of the water, that's exactly what we had, dozens of planes, dozens of ships looking everywhere. so why can't you do that below the water? why can't you go down there and put in not one or two but maybe a dozen or 20 different bluefins going through all at one time? think about it. right now, with just one down there, it's basically having to mow the lawn, as they describe it. that means a piece at a time, it's got to go back and forth, just like we're showing here. even if everything goes right, it's going to take six weeks to two months to get it done. so, why not kick in with more? bring in more here and have them all work together to get the job do

aviation correspondent rene marsh is with us as well as aviation analyst mark wice and peter goles and law enforcement analyst tom fuentes. how chose are they, mepeter to finding the two black boxes and plane? >> they're closer but not close. this is still a long struggle. four pings 17 miles apart. they've still got to narrow it down. if the pings die out, we're in for a long slog. so i'm optimistic as the vice air marshal is. we're in for a long fight. >> you think this could take weeks if not months to locate the two black boxes. assuming they locate the black boxes, they're assuming there might be wreckage there as well. >> if they can see them. the silt could be thick enough the box has sunk into it and the currents maybe washed over. it's almost like finding buried treasure on top of everything else they're looking for. >> are you hearing, rene, that the pings are coming from the flight data recorder, not the cockpit voice recorder? just just one of the two boxes? earlier a few days ago we heard authorities say that australia they think they had two separate pings which would ind

let's go to aviation correspondent rene marsh for the very latest. >> wolf, as you said, to hear him tell it, prime minister of australia, you'd think a breakthrough is right around the corner. tony abbott is in china to update china's president on the search for flight 370, but it's his tone about how things are progressing that's receiving a lot of attention. forget cautious optimism. australian prime minister tony abbott is oozing confidence. >> we have very much narrowed down the search area, and we are very confident that the signals that we are directing are from the black box on mh-370. >> we are confident that we know the position of the black box flight recorder to within some kilometers. >> reporter: his tone stronger and more upbeat compared to the careful wording two days ago from the man coordinating the search. >> i think that we're looking in the right area, but i'm not prepared to say, to confirm anything until such time as somebody lays eyes on the wreckage. >> reporter: but with rumors flying, the black boxes were located overnight, angus houston released a statemen

let's bring in our aviation and government regulation correspondent, rene marsh. walk us through some of the details we've learned from this transcript, which has just been released. >> right. you know what, wolf, we have learned that communications between the cockpit and air traffic control was pretty normal up until it disappeared. so this is the transcript here. just a little bit over two pages long. and we're going to pull from it. we know that at 12:40, according to this transcript here, the tower instructs 370, it is clear for takeoff from runway 32l, then says good night. then the cockpit repeats the runway, 32r, cleared for takeoff, mass 370. thank you, bye. then in the minutes that follow, nothing out of the ordinary. at 1:19 a.m., the last time anyone would hear from the plane, as it was leaving malaysian air space, heading to vietnamese air space, the tower says, "malaysia, 370, contact ho chi minh 120.9," good night. and then someone in the cockpit says "good night, malaysian 370." the only thing that was missing, the pilot didn't repeat the frequency

aviation correspondent renee marsh for the very latest. >> wolf, it's down to the wire for these crews're now two days past the required shelf life of these batteries. there's no guarantee how much longer they will last if they haven't died already. but tonight, authorities are cautiously optimistic. there's still no wreckage, but there was a distinct sound coming from under water, and as we speak, they are trying to determine if it's flight 370's black boxes. they haven't been able to recapture that sound just yet. it's the sound search teams have desperately been trying to find. and now they just may have. the pinger locator towed behind the ocean shield detected distink sounds over the weekend that may be from the black boxes. >> the first detection was held for approximately 2 hours and 20 minutes. the ship then lost contact. the second detection on the return leg was held for approximately 13 minutes. >> reporter: the detections about a mile apart in water more than 14,000 feet deep. on one occasion, two separate pings were heard which only heightened the excitement because the co

get the very latest now from our aviation correspondent, rene marsh. >> wolf, as much as we've focused on the search at the heart of all of this are the families of the people onboard who 40 days in know nothing other than the plane that's carrying their loved one is missing. some of those families are now at an emotional boiling point. >> you're all bloody liars and you're lying to us again now. >> reporter: families explode in anger and storm out of a briefing in beijing. after technical glitches prevented a promised video conference with malaysian officials. >> translator: we will request our team of experts to come to beijing to conduct face to face communications and fulfill their commitment. what is the truth? what problem do they want to cover up? >> reporter: meanwhile, the search in the indian ocean remains stop and two wigo with second setback in as many days for the bluefin-21. the underwater robot's 24-hour mission cut to about 11 hours after an oil used to protect its electronic components from saltwater ran low. data collected again showed no sign of flight 370. mission t

our aviation correspondent renee marsh has been watching. >> they feel as if whatever they found, itinvestigating. others are skeptical. also, never before released information about flight 370 in its last moments finally shared with the families of passengers on board. newly released images from private australian company geo geo resonance. it has found something in the bay of bengal where searches ended six weeks ago. >> we have identified technical elements of materials that might make up a boeing 777. >> reporter: the company uses technology intended to detect nuclear, biological and chemical weapons below the sea. that applied that same strategy to search for the plane four days after it disappeared. soon after, they detected titanium, aluminum, steel, and copper in this area. materials that make up a 777. they say they notified search officials a month ago, but went public monday after getting no response. >> if you rewind to march 5th, georesonance have information to say those materials were not in that location. so that to me is a corroboration as to why we should be pursuin

let's bring in rene marsh, she's got the latest. >> just for perspective here, it was four weeks agold got the news malaysia airlines flight 370 with 239 people on board vanished from radar never to be seen again. and at this four-week mark, search crews continue to make only educated guesses about where this plane is. it's a shot in the dark and search teams need a stroke of luck. that's the hunt for flight 370 one month in. overnight the search dramatically changed, moving under water off the west coast of australia. >> that area is being pinged because -- picked because on the basis of the analysis and on the six hours of pings we have the exchange between the satellites, the inmarsat state and the aircraft. >> two ships the australian "ocean shield" and the british "hms echo" are scanning a track of deep blue sea around the clock inching along at about two to three miles per hour. they'll eventually converge. the "shield" is equipped with a pinger locator which the towed behind the vessel. it detects pings from the black boxes in water as deep as 20,000 feet. >> i remain cautious

so rene marsh in washington, this chinese claim raising a lot of key questions. for one, could this really be an indicator of the black box? >> right. so fred, like you said, along with the developments come a lot of these key questions. so could it be? well, the manufacturer of the pingers today did tell us that this frequency is so very unique. there's not many things that this could be, but now, behind that is this chinese television reporting that the signal was detected every second for 1:30 seconds. that's the part that makes us scratch our heads a bit, because the manufacturer says if these pingers are working, they're constantly pinging. possible explanation for why this sound was only detected for that short period of time? well, perhaps the ship was moving away, or it could also be that the signal was disrupted by silt or debris. also, there are two beacons. one is attached to the cockpit voice recorder, the other attached to the data recorder. however, we're only hearing a report of one ping. we know that the two beacons ping independently and not at t

rene marsh, thank you. watch more of your reporting at 5:00 eastern here on cnn tonight. >>> coming up next, minutes from now, again, i'm live in boston, an emotional silence will be covering the city. live pictures as people are lining boylston street for the moment, at 2:49 p.m. eastern, a moment of silence will be observed, raising of flags and church bells chiming. and we will all pause, and remember what happened one year ago today. all stations come over to mission a for a final go. this is for real this time. step seven point two one two. verify and lock. command is locked. five seconds. three, two, one. standing by for capture. the most innovative software on the planet... dragon is captured. is connecting today's leading companies to places beyond it. siemens. answers. i dbefore i dosearch any projects on my home. i love my contractor, and i am so thankful to angie's list for bringing us together. find out why more than two million members count on angie's list. angie's list -- reviews you can trus

>> rene marsh, many things. back in a minute. repared. fancy feast elegant medleys.hes like primavera, florentine and tuscany. fancy feast. a medley of love, served daily. [ female announcer ] we eased your back pain, you turned up the fun. tylenol® provides strong pain relief while being gentle on your stomach. but for everything we do, we know you do so much more. tylenol®. i'm on expert on softball. and tea parties. i'll have more awkward conversations than i'm equipped for, because i'm raising two girls on my own. i'll worry about the economy more than a few times before they're grown. but it's for them, so i've found a way. who matters most to you says the most about you. at massmutual we're owned by our policyowners, and they matter most to us. ready to plan for your future? we'll help you get there. transferred money from his before larry instantly bank of america savings account to his merrill edge retirement account. before he opened his first hot chocolate stand calling winter an "underserved season". and before he quit his friend's leaf-raking business for

renee marsh, thanks so much. i want to bring bang our panel. t renee said, want won't this help us keep better track of planes and why isn't it in place now? >> absolutely help us keep better track of planes. remember, as we fly now and been flying literally since orville and wilbur, we fly on highways in the sky and basically planes have to get in line and air traffic controllers have to see them. next jen gets rid of the highway in the sky and run air traffic control through a series of satellites that literally will circle the globe. the planes will talk to the satellite. the planes will talk to each other and they can perfectly sequence their traffic in a way that a human being couldn't even begin to do. but everyone has to have this quip. it's called a vsb. the system's costing $40 billion and the office of inspector general, my old office, says it is not going to be done until probably 2035. and then the air lines have to buy another $7 billion of equipment. here's the rub. congress and the faa have not required all planes to have this equ

joining us now is aviation correspondent rene marsh and justice reporter evan perez and law enforcementfbi assistant director tom fuentes. rene, let's start with the new information that we're getting on the last person to speak the final words heard from the cockpit to ground control. tell us about that. >> well, wolf, we are now told by a source in malaysia that it was actually the captain who spoke those last words, "good night malaysia 370" as it was leaving malaysian air space and going into vietnamese air space. quite a difference from what we heard originally. before we were told by authorities that it was the co-pilot who spoke those last words. so now this changes things quite a bit as to who was on the radio and who was communicating in the air with air traffic control. we also know from this same source that it was five malaysian airlines pilots who were allowed to listen to the air traffic control radio transmissions to make the determination that it was the captain and not the co-pilot, as we had heard before, wolf. >> tom, what's the significance if it was either the pilot

rene marsh has been watching this story for us. rene whar rene, what's going on?wolf, i just got off the phone with the faa. here's what we know. very little bit of information at this point. we are seeing that ground stop there because of a problem, a computer problem, a technical issue at the l.a. center essentially that is not lax but a center, a facility that handles safely spacing out the aircrafts at high altitude. they're having a computer problem there. in order to address the computer problem, they're essentially just slowing down and stopping traffic because the problem is you want to be able to -- you don't want to have a situation where you can't safely space these planes apart. that's why we're seeing that ground stop while they deal with, again, this computer issue which is at a facility in los angeles. again, they deal with spacing out these planes at high altitude. that's information we have now. >> and this air traffic control center in los angeles, it could impact other cities as well. we know burbank, for example, there's been a stoppage in burb

our rene marsh has all of the latest. >> reporter: a strategy shift in the search for flight 370's blackoxes. >> it's time to go under water. >> reporter: and possible new evidence. >> an oil slick in the search vicinity. we'll investigate those to the conclusion. >> reporter: it's been six days since the last pings were detected in the south indian ocean. searchers believe the pinger batteries are probably dead. so they've retired the pinger locator and launched bluefin-21. the underwater vehicle will skin the sea floor for wreckage. >> i'll caution you to not raise hopes that the deployment of the autonomous underwater vehicle will detect aircraft wreckage. it may not. >> reporter: bluefin is concentrating on a roughly 500-square mile where the pings were detected. but the process is slow. it takes two hours to reach the ocean floor, 16 to scan the area, two hours to return, and about four hours to download data, which includes high-resolution 3-d maps like this. the other development, an oil slick discovered nearly 3 1/2 miles away. a sample was collected for testing. but if it's beli

cnn aviation correspondent rene marsh has more. >> reporter: it's the sound crews on board the "oceang to find again. the australian defense department released audio of the possible black box signal the towed pinger detected twice over the weekend. despite a continuous effort to recapture it, still, nothing. >> as the hours pass, our optimism is fading away ever so slightly. >> reporter: if it is flight 370's black boxes, finding it again is the only way to pinpoint its location. the "ocean shield" moves about two miles per hour tracking back and forth around the clock. the towed pinger measures intensity, not position. so it's crucial to triangulate a smaller search area. >> it will be several more days now until we stop the pinger search we will not deploy the submersible. is that clear? we will not deploy it unless we find -- unless we get another transmission. >> reporter: this is the submersible. bluefin-21, the underwater. it's at a lower transmission frequency than the standard 37.5. a change possibly due to environmental factors. >> if there's a change in pressure on the ocea

. >> let's go straight to renee marsh. you heard him.debris is found, the search teams will obviously have to re-evaluate what their next step is. what happens if the plane is never found? >> you know, that is a question we ask as we enter week four. what if this plane is never found? if that is the case, there could be safety and security implications for people who fly on airplanes every day. and that's because many of the safety and security regulations are currently in place, they came about as a result of a crash or an incident involving an aircraft. september 11th, for example, hijacking. that led to the cockpit doors. the shoe bomber. that led to shoe checks at the airport. in 1996, if you remember, hazardous cargo onboard value jet flight 592. that caught fire. 110 people died in that crash when it went down in the florida everglades. that crash, that led to new cargo hold safety rules. so you can see how these crashes lead to changes within the industry. but if we don't find flight 370 or its data recorders, it really could be a

. >> thanks renee marsh. the company that made have found the plane, is it a legitimate lead? let bring in our analyst. tim taylor is president of sub sea services and he himself is a sea operations specialist. david let start with you. i want to talk about -- geo renaissance said they were rebuffed by the australian-led searching team. now they put out a center. quote the australian search is relying on information from satellite and other data to determine the missing aircraft's location. the location specified by the geo residence report is not in this data. it's satisfied that the final resting place of the missing aircraft is in the southerly portion of the search arc. do you think -- they're just dismissing it saying it's false. what do you think? >> i don't think they should be dismissing it completely. i still feel very confident the pings came from the aircraft. here's the space situation. how many hours and millions of dollars were spent trying to find debris on top of the ocean because we wanted to

rene marsh is here in "the situation room" with all the new developments. >> they're being pretty tight-lipped about this news conference that we're expecting to happen here. will it be another announcement about a new search zone or will they announce more refined data analysis. we just don't know. but we do know in week four not one piece of this plane has been found. and australian officials warn there's no guarantee it will be found. a new ship searching for new leads. the british ship "hms echo" will do a specific search friday. it's unclear what they're zeroing in on. but what this ship can do is detect pings from the flight data recorders and take detailed images of the ocean floor like these. it detected something thursday. but it was a false alarm. after nearly a month, the search zone continues to shift. >> it is a very difficult search. the most difficult in human history. >> reporter: the prime ministers of both australia and malaysia standing side by side in perth. the center of the search operations. both vowing to keep looking. but a distinct shift in australia's tone suggests h

aviation correspondent rene marsh has all of the latest developments. >> reporter: the search for flight black boxes intensifies and the ping count may have gone up again. an australian orion aircraft over the "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. >> 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. >> reporter: 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 and an antenna relays what it is hearing to the aircraft. it is deployed at least 1,000 feet under water but only works for eight hours. schl onobuoys were not designed for this kind of mission. >> the ones that i'm familiar with generally have very poor response to frequencies as high

our aviation correspondent renee marsh is back. a lot of people are wondering if this search will winds up finds nothing thing. >> right. as we move into week four it's a question that you can't help but ask, what if flight 370 is never found. one thing seems apparent. proof that flight 370 had mechanical problems would likely lead to safety improvements, proof it was hijacked would lead to security improvements. with proof of nothing and a whole lot of speculation no changes may come out of this. as searchers race to find any wreckage of flight 370 the cost of not finding the plane could impact the safety of future flights. accidents equal safety and security improvements. in 1983 a fire broke out in a laboratory on air canada flight 797. the plane landed but 23 people on board died. after that smoke detectors and automatic fire extinguishers were mandated in aircraft lavatories. in 1996 hazardous cargo on a flight caught fire. the plane crashed in the florida everglades. 110 people died. it led to new cargo hold safety rules. but

cnn aviation correspondent rene marsh explains the controversy. >> reporter: australian company releasedbe wreckage from flight 370 in the bay of bengal. 3,000 miles from the current search zone. skepticism is high, but so is curiosity. two navy ships from bangladesh are en route to investigate. but in a new interview the man in charge of australia's search efforts rejects the company's claim. he's confident the best experts in the world have led his team to the right place. >> on the basis of their analysis, is that the aircraft appears to have entered the water in the indian ocean. >> reporter: within hours, the malaysian government is expected to release to the world a preliminary report on the investigation into flight 370's disappearance. the routine report is expected to include factual details, like a time line. but will not make any conclusions about the cause of the plane's disappearance. meantime, flight 370 families are learning even more in a second day of in-depth briefings, malaysian authorities went through detailed questions line by line. many questions on the plane's eme

renee marsh, cnn, washington. >>> 12 hours ahead of the eastern time zone, long past the dawn. as many as 13 airplanes and 13 ships are taking part in what is now a 24/7 effort. let's go to our own michael holmes live in perth. shrinking that search area really seems like a very positive sign. >> yeah, it does. jake, the search area down from 72,000 or so square miles down to 60,000 or so it is interesting when you look at that. as you say that is a massive, massive area. sorry i was saying square kilometers, actually less in miles, down to 22,000 square miles. but when you look at the pings, what they're trying to do if you look at a cell phone trial, you triangulate between them. that is why they want to get more pings. they're out there dragging that ping locater so they can do that. narrowing down that search area. and as renee pointed out in her piece, that is really just the beginning. and it can take a full day to get the data back by the time it has gone down and up. and even if they find wreckage, you have to get the other sub mersibles, you heard from the man, angus h

aviation correspondent rene marsh has the latest. >> the manufacturer of the pinks believe this is itralian authorities have gone as far as they can without actually saying they found it it. 34 days since flight 370 went missing and crews now finally believe they are searching the right area. >> reporter: after 67 hours of silence, came five minutes of hope. >> ocean shield has been able to reacquire the signals on two more occasions. >> reporter: the elusive pings, they've been desperately trying to recapture, detected again tuesday, once for five minutes and then again for seven. ocean shield has now picked up a total of four pings in five days. all near the arc where the plane made its last satellite connection. >> i'm now optimistic that we will find the aircraft, or what is left of the aircraft, in the not too disstant future. >> reporter: detections boosted optimism but crews are listening for even more to narrow the search arrir area, and they're borrowed time. >> given the guaranteed shelf life of the pink batteries is 30 days, and it's now 33 days since the aircraft went miss

let's bring in our panel, aviation correspondent rene marsh, peter goels, and tom fuentes. peter, this bluefin-21, is that the best option right now available to try to find the two black boxes or any wreckage that may be on the floor of the ocean? >> i think it's the only option they've got right now. there are other options tethered deep dive remote vehicles, but right now we've got the bluefin and that's what we're going to use. >> what about those other options? we've been hearing there are these other options, more guarantee that these other options can go deeper than the bluefin-21. >> that's right, but remember, when they first deployed bluefin-21, we still didn't even know what was going to be the focus of our search. we thought at one point it was going to be in point a, then point b, so they didn't know that. they didn't know what they know now, which is how deep this water is. so you're right, there's other equipment that could go a lot deeper, but it would take days for this boat to travel back to the port to switch out and get another piece of equipment which i

cnn aviation correspondent rene marsh has more for us. r, as the ship moves under water, two ships the australian "ocean shield" and "hms echo" are inching along at 2 to 3 miles per hour. "the ocean shield" is equipped with a pinger locator which is towed behind the vessel. it detects pings from the plane's black box's in water in as deep as 20,000 feet. but this specific mission could be futile. the manufacturers of the black box tells cnn they were due for a maintenance overhaul and new batteries in 2012 but they were never returned for the fix. now, that could mean three things, malaysia airlines replaced the old pingers, had the maintenance done some place else or had outdated pingers. if they were outdated, they'd have a shorter battery life and wouldn't last 30 days as required. >> rene marsh there for us. rene, thank you so much. >> and searchers, as you know, are hoping to find flight 370 deep under the indian ocean and using different perspectives to do so today. >> if they do, how hard will it be to bring the wreckage to the surf

let's bring in rene marsh for the very latest. >> as crews gear up for another day of searching, a new search zone is in focus after the old one turned up nothing. as for the criminal investigation and who may be responsible for the missing plane, officials now say some people have been ruled out while others remain under the microscope. 25 days in and malaysian police say they remain focused on the pilots and anyone who had contact with flight 370 before takeoff. ranging from those who prepared on board food to ones who packed the cargo. >> this is a criminal investigation. it is ongoing. we have not concluded the whole thing. >> reporter: malaysian investigators have been treating the disappearance of flight 370 as criminal since march 16th. four areas of interest -- hijacking, sabotage and personal or psychological issues. so far police say all passengers have been cleared in those four categories. as for mechanical failure, it's still on the table. aviation authorities are investigating that. meantime, the search zone shifted yet again. ten planes and nine ships are now zeroing in

christi, victor. >> renee marsh reporting for us here.ee, thank you. >>> we have new information, we'll go to our live reporter in perth, australia, in just a moment. stay with us. the conversation about her mortgage didn't start here. it began on her vacation in europe. someone stole her identity and opened some credit cards in her name. checking her experian credit report and score allowed her to better address the issue...and move right in. experian. so i can reach ally bank 24/7, but there ar24/7.branches? i'm sorry, i'm just really reluctant to try new things. really? what's wrong with trying new things? look! mommy's new vacuum! (cat screech) you feel that in your muscles? i do... drink water. it's a long story. well, not having branches let's us give you great rates and service. i'd like that. a new way to bank. a better way to save. ally bank. your money needs an ally. lactaid® is 100% real milk? right. real milk. but it won't cause me discomfort. exactly, because it's milk without the lactose. and it tastes? it's real milk! come

our renee marsh joins us now from washington.se ship is the standard frequency from the pingers at least from what's being reported and this doesn't necessarily mean it's a slam dunk and there's a lot of skepticism. why? >> there is a lot of skepticism. this report has really peaked our interest simply because of that key information coming from chinese tv in that the sound was that standard frequency of the pinger 37.5 kilohertz. you have the manufacturer on our air saying this tre quency is unique to these pingers and there's not a lot in nature that mimics this sort of frequency so there aren't many things that this could be. that said, we do know chinese television is reporting that signal was detected every second for only about a minute and a half. so here's what's leading us to scratch our heads just a little bit here. according to the manufacturer, those pingers, if it's working, it's constantly pinging. it doesn't ping for just a short period of time. it continues to ping, so now the question is why did they only detect