Why Planes Vanish

PBS Airdate: October 8, 2014

NARRATOR: It seems unthinkable.

AIR TRAFFIC CONTROL: Malaysia 370 is cleared to Beijing.

NARRATOR: In a world of smart phones and G.P.S.,…

MALAYSIA AIRLINES 370 COCKPIT: Malaysian 370, contact Ho Chi Minh, 120 decimal 9. Good night.

NARRATOR: … a 270-ton passenger jet…

AIR TRAFFIC CONTROL: Goodnight, Malaysia 370.

NARRATOR: …vanishes into thin air. What happened to Malaysia Airlines 370? Was it a catastrophic accident…

JOHN GOGLIA (Former National Transportation Safety Board Member): It's not a good idea to fly lithium batteries on a passenger airplane.

NARRATOR: …or something more sinister?

JEFF WISE (Journalist and Author): It was intentional. Some humans did this.

JOHN GOGLIA: The dots don't line up. It doesn't make sense.

NARRATOR: Could the plane have been hijacked?

JEFF WISE: You can basically remove control from the cockpit.

NARRATOR: What are the weak links in the system…

JEAN-FRANCOIS LEPAGE (NAV CANADA): This is a flight that we are not 100 percent sure is there.

NARRATOR: …that allow a plane to disappear without a trace?

MALAYSIA AIRLINES SPOKESPERSON: We have not found any wreckage, no wreckage whatsoever.

NARRATOR: And how can we make sure it never happens again? Why Planes Vanish,…

MARY SCHIAVO (Former United States Department of Transportation Inspector General): Everything that we needed to avoid this has already been invented.

NARRATOR: …right now, on NOVA.

The international Airport in Kuala Lumpur is one of the largest and fastest growing in Southeast Asia. Thirty-five-million passengers transit its terminals every year. March 7, 2014, begins like any other day here. The captain and first officer of a Malaysia Airlines red eye flight to Beijing make their way through security.

Do either or both of them know what will unfold? Or are they simply two more victims of the most inexplicable mystery in airline history, the flight that vanished and stunned the world?

This is the story of that flight, the flaws in the system that it exposed, and the technological solutions that would ensure it could never happen again.

AIR TRAFFIC CONTROL: Malaysian 370, request level.

MALAYSIA AIRLINES 370 COCKPIT: Three-seventy, we are ready. Malaysian requesting flight level 350 to Beijing.

NARRATOR: It begins as all airline flights do: a rote ritual exchange of jargon between crew and air traffic control, captured on these recordings.

AIR TRAFFIC CONTROL: Malaysia 370 is cleared to Beijing.

LES ABEND (Boeing 777 Captain): It absolutely was a normal flight.

AIR TRAFFIC CONTROL: Malaysian 370, taxi to holding point Alpha 11.

MARY SCHIAVO: It's very seasoned pilots. The communications seemed completely normal.

AIR TRAFFIC CONTROL: Three-seventy, 32 right, cleared for takeoff. Good night.

MALAYSIA AIRLINES 370 COCKPIT: Thirty-two right, cleared for takeoff. Malaysia 370, thank you, bye.

NARRATOR: At 12:41 a.m. local time, now March 8th, the Boeing 777 lifts off, 227 passengers and 12 crew members aboard.

MARK WEISS (Retired Boeing 777 Captain): The pushback, the taxiing, the takeoff, the departure all seemed normal.

LES ABEND: Just a mundane, cruise-level trip to the destination of Beijing.

NARRATOR: Les Abend and Mark Weiss are both veteran 777 captains. They show us what it's like to fly the airliner, in a sophisticated simulator that looks and flies, virtually, like the real thing. Like most pilots who fly the 777, they sing its praises.

LES ABEND: This airplane is one of the most sophisticated in the world.

MARK WEISS: It's a well thought out airplane, system-wise. It's a very stable platform, a very forgiving airplane. Probably the nicest airplane I've ever flown.

NARRATOR: The Boeing 777 fleet began passenger service in 1995. The $270-million airliner can fly and even land itself, yet pilots still like the way it handles when they take the controls.

LES ABEND: It's a pilots' airplane, regardless of the fact that it's an electronically controlled flight system. It's built for pilots.

MARK WEISS: Once you understand how the systems work, it's user-friendly. So, you put the information in, and it does what you want it to do.

NARRATOR: The plane is equipped with eight ways of communicating with the ground, while in flight. There are five very-high-frequency and high-frequency radios, two transponders and a satellite transceiver that can transmit and receive text messages and phone calls.

MARK WEISS: All of those systems…each one is a layer of protection, an electronic cocoon around the airplane to let somebody know who you are, where you are and where you're going. And that really is the important thing that you want to have air traffic control know. Somebody should be following you. Somebody should know where you are at all times.

NARRATOR: The air traffic control system is designed to know where planes are at all times, but it works on the assumption that aircraft want to be seen. A trip begins with approval of the intended route: the flight plan.

MARK WEISS: The flight plan is downloaded into the flight management computers. Now you've got a route, like a highway in the sky, and the computers onboard the aircraft are programmed to fly that route.

NARRATOR: Less than a minute after takeoff, air traffic controllers modify the route, to give MH370 a little shortcut.

AIR TRAFFIC CONTROL: Climb flight level 180, cancel SID, turn right, direct to IGARI.

MALAYSIA AIRLINES 370 COCKPIT: Okay, level 180, direct IGARI, Malaysia 370.

NARRATOR: IGARI is not a real place. It is just a code name for an intersection of longitude and latitude, one of thousands that dot aviation charts to make it easier for air traffic controllers and pilots to navigate safely and efficiently.

MARK WEISS: Direct to IGARI, 180.

LES ABEND: One-eighty, direct to IGARI please.

AIR TRAFFIC CONTROL: Malaysian 370, climb flight level 350.

MALAYSIA AIRLINES 370 COCKPIT: Flight level 350, Malaysian 370.

NARRATOR: Twenty-six minutes after takeoff, at 1:07 a.m., local time, the plane transmits a text message, via satellite, to the airline operations center. It appears to confirm MH370 is bound for Beijing.

At IGARI, responsibility for air traffic control shifts from Malaysia to Vietnam. The control sectors are, in part, defined by the range limits of radar. This 1940s technology remains a mainstay of air traffic control in the 21st century.

Rick Castaldo is a former F.A.A. radar engineer, with 40 years of experience. He gives us a primer on radar at the F.A.A. Technical Center, in New Jersey.

RICK CASTALDO (Former Federal Aviation Administration Radar Engineer): This is an airport surveillance radar, currently in use in many parts of the world.

Radar is an acronym, stands for Radio Detection and Ranging. Hasn't changed much in 40 years. It's gotten a little bit better, it's gotten a little bit cheaper, it's gotten a little bit more reliable, but the fundamental principles are the same.

NARRATOR: There are actually two kinds of radar used in air traffic control. Primary radar emits a powerful electromagnetic pulse that bounces off the curved antenna, called a “sail.” An aircraft in flight, as far as 200 miles away, will reflect that pulse back to the sail. The time it takes for the signal to make that roundtrip defines the distance between the antenna and the aircraft.

RICK CASTALDO: The limitations of primary radar are, one, you don't know who you're seeing, and there's no altitude information.

NARRATOR: That's where secondary radar comes in. It turns a simple blip into something much more useful for air traffic controllers.

RICK CASTALDO: On top of this radar, is mounted another antenna. It is the secondary radar.

NARRATOR: Secondary radar sends out a signal that interrogates a device installed on the aircraft, called a “transponder.” The transponder then transmits a pulse back, indicating the altitude, along with a four digit code or “squawk” that is assigned to the aircraft. This is so important, commercial airliners carry two transponders in case one malfunctions.

RICK CASTALDO: You join the secondary return from the transponder with a primary return, and that's what goes on a controller screen.

AIR TRAFFIC CONTROL: United 96, contact tower heading 112.

NARRATOR: It gives radar a third dimension, altitude, and it makes it much easier to identify and track a flight.

As MH370 approaches IGARI, it levels off at 35,000 feet. Air traffic controllers in Kuala Lumpur are still tracking the flight on secondary radar. They tell the crew to switch radio frequencies and check in with the control center in Ho Chi Minh City, Vietnam.

This is the final exchange between the crew and a Malaysian controller.

MALAYSIA AIRLINES 370 COCKPIT: Malaysian 370, contact Ho Chi Minh, 120 decimal 9. Good night.

AIR TRAFFIC CONTROL: Goodnight, Malaysia 370.

NARRATOR: Three minutes after that call, at 1:22 in the morning, both transponders on the Boeing 777 go silent, and so does the crew. Air traffic controllers in Ho Chi Minh City, monitoring the frequency MH370 was assigned, never hear from the crew.

MARK WEISS: That electronic cocoon around the airplane—that device that emits a signal so air traffic control knows who you are, where you're going, how high you are—that went blank. You've now become lost in the abyss.

NARRATOR: Somehow, in the handoff between control centers, MH370 vanishes. As day breaks, rescue crews immediately begin searching for wreckage of a crash, in what seems like the logical place: the South China Sea, near IGARI, where the plane was last seen by air traffic controllers on secondary radar. But there is nothing there.

MALAYSIA AIRLINES SPOKESPERSON: We have not found any wreckage, no wreckage whatsoever.

NARRATOR: For the families of those on board, it is too much to bear: the sudden loss, the unanswered questions. Malaysian authorities seem overwhelmed and unresponsive.

The dreadful images ricochet around the world, as the mystery deepens. More than 6,000 miles away, in London, one man turns on the evening news and starts thinking outside the box, way outside the box.

ALAN SCHUSTER-BRUCE, BBC: BBC News at 11 o'clock. The Malaysia…

ALAN SCHUSTER-BRUCE (Inmarsat, P.L.C.): I heard the news about the loss of the aircraft, I think it was on the 11 o'clock BBC News.

NARRATOR: Alan Schuster-Bruce is a senior engineer with a company called Inmarsat, which operates a ten-satellite voice and data communication network for ships at sea and airplanes in flight, including MH370.

The satellite transceiver on the plane provides a link to the Inmarsat system, the satellite checks in with the transceiver periodically, much like a cell tower would ping a mobile phone.

ALAN SCHUSTER-BRUCE: After 60 minutes of inactivity, the station sends a signal to the aircraft, which says, “Are you still there?” And then the aircraft just replies, “Yes.” And these are what we call the “handshakes” or the “pings.”

NARRATOR: Alan pulls the plane's communication log. He is startled to see that even though all seven other means of communication on the plane were non-responsive, the Inmarsat transceiver continued responding to the handshakes, in effect saying, “Yes, I am here.”

The log documents seven handshakes, or pings, between the satellite and the airliner; about one an hour. All of them occur after the plane had vanished.

Alan Schuster-Bruce had made a shocking discovery about what happened after the last contact between air traffic control and MH370 at IGARI in the South China Sea: the airplane continued to fly for at least seven more hours.

ALAN SCHUSTER-BRUCE: At that point, it was quite clear something strange had happened, because the plane had flown on for all those, all those many hours.

NARRATOR: The largest search in aviation history is already underway in the South China Sea, but are they in the wrong ocean?

Meanwhile, investigators are rolling up their sleeves. Was there a mechanical failure of some kind? Or does the evidence point to something deliberate, sinister?

The sudden radio and text message silence, the disappearance on secondary radar screens, combined with a plane that is able to fly unseen for seven more hours, present a riddle wrapped up in an enigma.

John Goglia is a 40-year veteran of the aviation industry. He was the first and only Airframe and Powerplant mechanic appointed to the National Transportation Safety Board.

JOHN GOGLIA: Accident investigators are trained to follow the facts. You want to know all the facts, and you let the facts lead you around to connect the dots. This accident is unique, because there's very little factual information. We don't have any wreckage. We have a lot of missing links, if you will.

NARRATOR: They have to consider every possible scenario, beginning with sudden, serious events: was there a major mechanical failure? A fast moving fire? Or a bomb?

JOHN GOGLIA: An airplane that suddenly disappears would require a catastrophic failure, something that happened so quick that the crew couldn't communicate, the automatic systems on the airplane couldn't communicate and, in this case, where it just disappeared from radar for a little bit, one would assume something happened in-flight to take it down. It could be a catastrophic failure of the fuselage, where the pressurization blows it apart. It could be a fire onboard and a device. Those are the big hitters that investigators would look at, right off the bat.

NARRATOR: And one of the first places they would go is to the cargo manifest. It indicates MH370 was hauling electronics and lithium ion batteries in two containers, weighing a total 2,400 kilograms, or 5,300 pounds: highly volatile if not packed properly.

JOHN GOGLIA: It's not a good idea to fly lithium batteries on a passenger airplane. In the U.S., we don't do that. We put them on cargo airplanes, and there's even some talk about changing that, as well.

NARRATOR: Like so many things in aviation, the rule has roots in a tragedy. In 2010, a U.P.S. 747 hauling lithium batteries caught fire soon after departing Dubai. The crew declared an emergency and told controllers there was thick smoke in the cockpit. The plane crashed as they tried to reach the airport. Both pilots died.

JOHN GOGLIA: If you have a fire inside the airplane, you're going to have fumes from both what's burning and fumes from what's being burned on the airplane. If the temperatures are too high, it would compromise the structure of the airplane.

NARRATOR: For John Goglia, any fire big enough to wipe out communications and prevent a Mayday call would bring the plane down right away. But the Inmarsat data is firm: the aircraft stayed aloft for seven more hours.

JOHN GOGLIA: If there was a fire on this particular airplane, caused by these lithium batteries, the airplane wouldn't have flown for the next seven hours. The dots don't line up. It doesn't make sense.

NARRATOR: If it wasn't a fire, could there have been some kind of failure of the plane's pressurization system that turned MH370 into a ghost plane? If so, it would not have been the first time. In 2005, a Helios Airlines 737 stopped responding to air traffic control while en route from Cyprus to Athens.

The pressurization system was improperly set. As the airliner climbed to cruise altitude, the cabin air became too thin to support human life.

JOHN GOGLIA: If you have a loss of pressurization, for any reason, at altitude, you can't breathe. You only have nine seconds to 30 seconds, depending on where you are and how healthy you are, before you pass out. And you just sort of fall asleep and you don't wake up.

NARRATOR: The Helios plane flew for three hours on autopilot, and eventually crashed, killing all 121 people on board. Some fear MH370 had seen the same fate.

But then comes a bombshell. The Malaysians reveal that primary military radar, which does not rely on a transponder, had tracked MH370 for an hour after the plane had gone silent. The path it took deepened the mystery.

Just after passing IGARI, when MH370 should have checked in with air traffic control in Vietnam, the plane banked hard to the left, flew back across the Malaysian peninsula, then turned right to the northwest, threading the needle between Malaysian and Indonesian air space.

NAJIB RAZAK (Prime Minister, Malaysia): These movements are consistent with deliberate action by someone on the plane.

NARRATOR: Attorney and author Mary Schiavo is a former Inspector General for the U.S. Department of Transportation.

MARY SCHIAVO: If you believed the Malaysian military radar, you have to believe that someone was still alive and manipulating the controls up and around Indonesia. At that point, who knows? But somebody had to manipulate those controls to go around the northern tip of Indonesia.

NARRATOR: At Inmarsat, in London, Alan Schuster-Bruce is hard at work trying to determine how far the plane flew. He knows exactly where the Inmarsat satellite is: in a geosynchronous orbit more than 22,000 miles above the Indian Ocean. And he knows how long it took for a signal to travel between the satellite and the aircraft. So, he does some relatively simple algebra, to determine how far away the plane was from the satellite when the seven handshakes occurred. His conclusion: each handshake must have happened when the aircraft was somewhere on one of these seven circles on the surface of the earth.

A last, and incomplete, handshake came in at 8:19 in the morning.

ALAN SCHUSTER-BRUCE: We obviously knew that that was most likely indicative of the time the aircraft was lost.

NARRATOR: It was the loss of another airliner that made this exercise possible.

NEWS BROADCAST: French investigators say they have recovered 400 pieces of debris from Air France Flight 447. They say the wreckage comes from all areas of the plane.

NARRATOR: Air France Flight 447 disappeared in the middle of the Atlantic Ocean in 2009. Back then, Inmarsat did not keep track of the precise time it takes for the signal to travel between the airplane and the satellite.

Alan suggested they start doing that, and the company agreed.

ALAN SCHUSTER-BRUCE: I was thinking we might need it one day. Might be useful, might not be useful, but I'd no idea that it would, essentially, be, really, the only evidence in town.

NARRATOR: Using that information, the Inmarsat team further narrows the search zones: eliminating the portions of the final handshake circle that were beyond the range of the plane, leaving two huge swaths of the planet where it could be, more than 2,000,000 square miles in all: to the north, all the way to Kazakhstan; or in a place about as close to nowhere as anyplace can be, the southern Indian Ocean.

ALAN SCHUSTER-BRUCE: We had two possible scenarios. It could've either, sort of, turned left and gone south or could turn right and go north, and we didn't know which one.

NARRATOR: The evidence is sparse, but it leads investigators to an almost inescapable conclusion: whatever happened on MH370 was likely deliberate.

JOHN GOGLIA: It's pretty clear that it had to be human intervention. Every step of the way, someone was doing something to this airplane.

NARRATOR: This odd change of course, immediately after the transponder ceased transmitting, during an air traffic control handoff, has all the hallmarks of someone who wanted to make the aircraft vanish.

MARK WEISS: If you wanted to time something on when would be the most reasonable time for me to succeed—When am I out of radar contact? When am I going to be in between air traffic control sectors?—where I can take that airplane and make it silent, turning off a transponder and maneuvering so that I'm now out of radar coverage.

NARRATOR: And it's not just the strange maneuverings of MH370. Buried in the Inmarsat data log may be more proof that this was a deliberate act. It shows the satellite transceiver stops operating sometime after the last text transmission at 1:07 and the next scheduled handshake with the satellite at 2:03. But then, at 2:25, three minutes after MH370 is out of range of primary radar and completely invisible, the satellite transceiver, for some unknown reason, comes back to life.

JEFF WISE: I think we can just unequivocally say it was not mechanical failures; a string of unfortunate accidents did not happen; it was intentional. Some humans did this.

NARRATOR: But which humans?

Jeff Wise is a pilot and aviation journalist who edits a blog that has become a focal point for experts outside the investigation trying to solve the mystery.

JEFF WISE: Who amongst the passengers could have done it and why? Was it the pilot? Was it just suicide?

People have flown their planes into the ground to kill themselves. Nobody has ever done it by flying until it runs out of fuel, but maybe he killed himself and then let the plane fly itself to the end. It's possible. But it's a super-weird way of committing suicide, because it involves all these strange behaviors.

NARRATOR: The timing of events, the specific electronics that went silent, and the flight path itself, all point to someone who knew a lot about aviation, in general, and the Boeing 777, in particular. But did it have to be the flight crew?

JOHN GOGLIA: I don't have enough facts to say who it was, but it was somebody that either studied an awful lot about the airplane or who flew the airplane, to make the airplane do what it did.

NARRATOR: Malaysian investigators claim they pored over the passenger manifest, finding two Iranians traveling on phony passports, but say there was no evidence suggesting they, or anyone else on the plane, were hijackers.

JOHN GOGLIA: Who knows? It could have been anyone, there was a lot of people on this airplane.

NARRATOR: Prior to the disappearance of MH370, Malaysia Airlines had reportedly not adopted cockpit security protocols mandated in the U.S., after 9/11. Before he retired as a 777 captain for a major U.S. airline, Mark Weiss served as the vice chairman of the National Security Committee for the Allied Pilots Association.

MARK WEISS: That airline had a history of, basically, a porous cockpit door—that they've allowed people who really had no authorization to be in the cockpit to be allowed to come into the cockpit, for whatever reason.

NARRATOR: But what if a hijacker or hijackers seized control of the plane without ever setting foot inside the cockpit? It would not be easy, but it is possible.

PILOT IN IN-FLIGHT TOUR VIDEO: Now we're going to show you the electronic compartment of a 777.

NARRATOR: This video was shot in 2006, for aviation enthusiasts. It can be purchased as a D.V.D. online, and portions are available on YouTube. It offers an in-flight tour of a 777, operated by Brazil's Varig Airlines.

This is the hatch to the electronic and equipment bay. It is just outside the cockpit door, near the forward galley.

PILOT IN IN-FLIGHT TOUR VIDEO: We pilots do not use this in flight. It's just for ground maintenance. But it is huge.

NARRATOR: Airlines have the option to purchase a lock kit from Boeing, but there are no regulations that require this, and the hatches are commonly unsecured. Malaysia Airlines would not comment.

PILOT IN IN-FLIGHT TOUR VIDEO: This is the electronic equipment compartment.

JOHN GOGLIA: It is a room unto itself. Devices start at the back; they're in the middle; they're in the front.

PILOT IN IN-FLIGHT TOUR VIDEO: That's the nose of the plane.

JOHN GOGLIA: It's very, very large.

NARRATOR: The emergency oxygen tanks for the pilots are here. And so are electronics and circuit breakers associated with every major system: radios, navigation devices and the computers that are the brains of the fly-by-wire aircraft.

PILOT IN IN-FLIGHT TOUR VIDEO: This is the Portable Maintenance Access Terminal. This is the place where the ground crew, the mechanical group, engineers, access the main computers.

JEFF WISE: There's a device, the E.E. bay, and you can, basically, do anything to the plane, move the ailerons, load software. It can even remove control from the cockpit, so that you can make the cockpit helpless. You don't even need to go into the cockpit.

NARRATOR: Or there is a circuit breaker in here for the cockpit door lock system. When it is de-energized, the door unlocks.

PILOT IN IN-FLIGHT TOUR VIDEO: That's it. Let's go back to the flight deck.

NARRATOR: NOVA asked Boeing about the potential vulnerability of the 777 electronic and equipment bay. A spokesman said the company “would not comment on matters relating to an open investigation.”

But even if it were possible to hijack a plane this way, the question remains: why would terrorists execute such an elaborate plot and not tell anyone?

MARY SCHIAVO: It's difficult for me to see a hijacking scenario, because we haven't come up with any suspects. A terrorist group would have had to invest a lot of money and a lot of time planning this operation, for no apparent result. I mean, I don't see what they got out of it.

NARRATOR: Back at Inmarsat headquarters, in London, engineers are still at work. Is it possible there are more clues buried in the data? Is there a way to narrow it down? At the very least, determine what hemisphere the plane might be in?

Engineer Chris Ashton takes on this challenge.

CHRIS ASHTON (Inmarsat, P.L.C.): The big question is which route was taken?

NARRATOR: Besides the timing of those handshakes, there is another trove of data stored in the logs: minute changes in the frequency of the signals received by the satellite from the plane.

CHRIS ASHTON: We had a northern and a southern route that were so very different, so very far apart, the frequency information at that stage was something that was probably going to be good enough to discriminate between those two routes.

NARRATOR: The frequency of a signal that a satellite receives from an aircraft changes, depending on the plane's speed and direction. It's called the Doppler effect. It's what makes a train whistle change pitch as it passes by. The transceiver on the plane is designed to correct for this, so that the frequency received by the satellite stays within a narrow band.

But its calculations assume the satellite is in one place, and the Inmarsat satellite used by MH370, 3 F1, was launched in 1996 and was designed to last 13 years. Now, it is low on fuel and no longer holds a fixed latitude over the equator. It moves back and forth in a north-south direction every day. The satellite was accelerating southward, as MH370 disappeared from primary radar.

So, if the plane's track took it to the southern hemisphere, the satellite would be moving towards it and the frequency of the signal received would increase. If the plane's track took it north, the satellite would be moving away, and the frequency would decrease. The shift would be subtle, just parts per billion, and masked by other factors.

So was it even possible to tease out the signal from the noise? Could Inmarsat engineers create a mathematical formula, feed in the subtle frequency changes and determine the direction the plane had gone?

They start crunching the numbers.

CHRIS ASHTON: We'd attempted this calculation two or three times and abandoned it. We were working at it for a long time and not getting a good match between the measured data and the predicted data.

NARRATOR: They are comparing Doppler shift data logged during that fateful night to various other flight paths in the northern and southern hemispheres.

CHRIS ASHTON: We'd been working on the Doppler analysis all day long, at the end of a week of investigating and collecting data. Quite late on the Friday night, about 8 o'clock in the evening, suddenly the graphs matched, the data worked, the calculation was solved.

That was quite a nice feeling, that it…we'd got the calculation to work. And then I checked to see which of the flight paths it was, and we then identified it was, in fact, the southern route.

We can identify the path that matches exactly with all those frequency measurements, and with the timing measurements, and lands on the final arc at a particular location, which then gives us a, sort of a hot spot area on the final arc, where we believe the most likely area is.

NARRATOR: The subtle changes in frequency left a virtual trail of breadcrumbs that lead, almost certainly, to an end in the ocean.

CHRIS ASHTON: Then there's, of course, the realization that this is the, this is not good news for the people on the plane. This isn't “the aircraft is hijacked and is flying up to Kazakhstan, landing safely and everybody's in a hangar.” You feel the, the depth of this, the severity of it. It means very little chance for the people on the aircraft.

NARRATOR: Inmarsat sends the evidence to Malaysian authorities.

MALAYSIA AIRLINES SPOKESPERSON: According to this new data, Flight MH370 ended in the southern Indian Ocean.

NARRATOR: The search along the southern arc is a test of persistence and patience. Despite 345 flights, covering nearly 1.7-million square miles of open ocean, searchers from 26 nations see nothing but a lot of floating trash.

If they can find some wreckage, it could lead them to the black boxes: the flight data and cockpit voice recorders, which are designed to emit pinging noises for 30 days, when submerged.

A month after the disappearance, a device designed to hear the pings detects what seems like a promising lead. But after searching more than 300 square miles of ocean bottom for two months, with an underwater autonomous vehicle, they turn up nothing.

The pings were, most likely, malfunctioning detection equipment.

DAVID GALLO (Woods Hole Oceanographic Institution): It was sad, because it took up time. It got everyone's hopes up, and it was a big letdown. We thought we were days away, maybe hours away from locating the plane, the pingers at the bottom.

NARRATOR: David Gallo is Director of Special Projects at the Woods Hole Oceanographic Institution. In May of 2011, he co-led the team that found the wreckage of Air France Flight 447.

Air France had paid for more frequent and detailed satellite text messaging. It provided investigators position reports right to the end.

DAVID GALLO: There was debris being picked up a week after the plane hit the water, so there was no question that there was a plane somewhere in that neck of the woods.

NARRATOR: They were able to narrow the search area to a circle, 90 miles in diameter. And yet it still took nearly two years of searching with autonomous underwater vehicles to find the wreckage.

DAVID GALLO: It's not putting on scuba gear and just going down to the bottom. You're talking about going miles into the deep, into the darkness, where there is no G.P.S., and there is no power, and you have to bring everything with you and start from scratch. It's incredibly difficult terrain, mountains as steep as any mountains we have on Earth.

NARRATOR: The area that Inmarsat has defined and searchers are pursuing in the hunt for MH370 is about the size of the state of West Virginia, four times greater than the Air France 447 search zone. It would take an autonomous underwater vehicle nearly a thousand days of operation to cover an area that size.

DAVID GALLO: The haystack is enormous right now. And there's a lot of doubt about whether there's actually a needle in that haystack. There's not a single bit of tangible evidence that a plane impacted the water in the southern Indian Ocean. It doesn't mean it didn't, but there's nothing that has showed up. Not a flight magazine, not a seat cushion, nothing in that area that says, “There's a plane here, someplace.”

We're right on the hairy edge right now of uncertainty about whether there's actually going to be a needle in that haystack.

NARRATOR: What if the haystack is nowhere near here?

Inmarsat's ability to use a communication system as a positioning tool was ingenious, but how accurate can it possibly be?

MARY SCHIAVO: I do think it's premature to say that they're exactly in the right spot, because there were so many assumptions that they had to make to get to this spot.

NARRATOR: Investigators estimated various speeds and altitudes that the missing plane might have flown. Those factors, along with the amount of fuel and the winds aloft, are crucial in determining where the plane might be along the last arc, where it is presumed the tanks ran dry.

Taking all these variables into account, they generated thousands of possible routes, then compared them to the Doppler and timing data.

The cluster of routes considered most likely defined a 400-mile-search-zone.

JEFF WISE: The method itself just has severe limitations. You cannot pinpoint the location of a plane using their algorithm and using their data. The numbers don't let you do that. It just gives you a range of possibilities and unfortunately that range is quite huge.

But we can't figure out what the truth is, because we have so little to go on and what we do have is ambiguous.

Nothing really makes any sense when you look at MH370.

NARRATOR: But did the tragedy of MH370 have to be such a mystery? Maybe not. It turns out, the absence of evidence, elaborate math and tormented families all could have been avoided without inventing anything new, just implementing some proven technology to bring airplane tracking into the 21st century.

RICK CASTALDO: What we have here is a chart. And it describes the various types of radars that exist and the boundaries that define the radar coverage.

NARRATOR: There are gaps, sometimes large, between radar coverage areas. Any aircraft that flies over the ocean more than 200 miles from land is not tracked on air traffic control radar screens.

RICK CASTALDO: The fact that you have areas of this geographical space that is not covered by radar is not unusual.

In this country, United States, we have around 500 radars. We do not cover all of our own space. The thought that you can see airplanes everywhere on a radar is fiction. I would say maybe two or three percent of the earth's surface is covered by some form of radar, and the rest is wide open.

NARRATOR: There is a way to track aircraft with much greater precision and without blind spots, by transforming the technology of air traffic control from spinning radars to orbiting satellites.

In the U.S., it is called the Next Generation Air Transportation System, or NextGen.

North of the border, in Hudson Bay, the Canadians were early adopters. This is one of the busiest air corridors in the world and one of the biggest radar blind spots.

JEAN-FRANCOIS LEPAGE: Between 200 and maybe 300 aircrafts are flying over Hudson Bay every day. Most of them are aircrafts coming from Europe or going to the western coast of the United States, and the rest of them are coming from North America, going to Asia over the North Pole.

NARRATOR: Until 2009, air traffic controllers here had to rely on pilots to report their positions.

JEAN-FRANCOIS LEPAGE: The orange one is a flight that is not, at the moment, captured by radar, so this one, at the moment, we are not 100 percent sure is there.

NARRATOR: Here, they are using a technology called Automatic Dependent Surveillance Broadcast, or ADS-B. It is the keystone component of NextGen.

An Aircraft outfitted with this system determines its location, using G.P.S., and transmits that data back to controllers by radio, which has a greater range than radar. But still, when an aircraft flies over the ocean, it will be out of range.

So the industry is testing a space-based system, where planes would report their locations via satellite, wherever they are in the world. There are numerous technical details that need to be worked out, but ADS-B could eventually make blind spots a thing of the past.

JEAN-FRANCOIS LEPAGE: We have currently one aircraft under ADS-B coverage at the moment. This is a United Flight from Chicago, going to Beijing.

NARRATOR: The aircraft depicted in white is using ADS-B to broadcast its exact G.P.S. location, automatically, once a second.

JEAN-FRANCOIS LEPAGE: We see the aircraft. We know it's there. We know exactly where the aircraft is at all times.

NARRATOR: MH370 was equipped with ADS-B and was broadcasting its position that night. At the time, Malaysia had two active ground stations. But the technology still relies on a transponder, so when those devices stopped transmitting, the 777 was invisible, no matter what the surveillance technology.

So why not make it impossible to turn off a transponder?

RICK CASTALDO: There's really no good reason to turn the transponder off. You have two on a plane. If you really need to recycle one, just switch to the alternate transponder, and that doesn't require powering anything on or off.

MARY SCHIAVO: At a certain point, you do have to trust the person driving the bus, but if you are at all concerned that they can be hijacked or suicidal or incapacitated, then simply make it so it can't be shut off.

NARRATOR: But many pilots oppose that idea.

LES ABEND: Maybe it's archaic thinking, but anything electronic in the airplane, we need the capability of turning it off directly or from our circuit breakers, because it's an electrical system. I mean it's a very traditional way of thinking, but then again, it's important to be able to turn…

MARK WEISS: There are times you have to isolate a system because of a malfunction, whether it's a fire or another type of an emergency.

NARRATOR: But when the air traffic control system has fully implemented NextGen, there will be much less primary radar coverage and the transponder will become even more crucial than it is today.

MARY SCHIAVO: When we get NextGen, it has to be a system that you can't turn off, because that's going to be all we have, and there is too much of a risk of mid-airs and runway incursions, et cetera. If you fly in the NextGen without it, it's havoc.

NARRATOR: If NextGen can take care of tracking the location of planes, is there any way of knowing not only where the plane is, but what's happening on board? The kind of information investigators today must glean from the black boxes?

MIKE DALTON (First Air): Okay, so this is the e-bay of the 767, and this is really the heart of the electronics for the aircraft. The data is fed from all the various sensors and equipment to the flight data recorder. What's unique about what we've done is we've added this unit here, which is the “AFIRS.”

NARRATOR: The Automated Flight Information Reporting System monitors what the flight data recorder is seeing. It starts transmitting key information automatically when it senses trouble, at the command of the flight crew or dispatchers on the ground.

MIKE DALTON: This is actually analyzing the data as it's going into the box, so it's actually reading the files. It's looking at them and seeing what's happening with this airplane. Is everything working correctly? And if it's not, it tells people. It lets people know that.

COMPUTER VOICE: Flight C.F.F.N.E., flight stream activated.

NARRATOR: True to its name, Canada's First Air is among the first airlines to equip its fleet with AFIRS, which costs $100,000 per plane—worth it for an airline that flies remote routes in the Arctic Circle, where radar and radio coverage is sparse.

RICK CASTALDO: If you wanted to stream data from an airplane everywhere in the world, it might be expensive. However, you've spent $50-million looking for the Malaysia flight.

NARRATOR: If all airliners were equipped this way, we could know a flight was in trouble, even if the crew could not communicate by other means. It could make searching for the black boxes a thing of the past.

JOHN GOGLIA: Over 15 years, the N.T.S.B. has long tried to get flight data recorders to be streamed. It is an excellent idea, it's actually one whose time has come. And I think we are about to see some changes in the international community, requiring some sort of reporting of the airplanes all the time.

NARRATOR: After MH370, The International Air Transport Association announced new tracking mandates for member airlines, but there are no plans to require streaming data.

MARY SCHIAVO: There are lots of things that we can solve and lots of recommendations that need to come out of this and change. And I hope that those don't wait on finding the plane, because there's just no need to wait.

A nation has to make it mandatory to have streaming data that cannot be turned off, in order to operate in their air space. Then there's a chance that we'll get streaming data that can't be turned off for the whole world.

NARRATOR: The sea does not give up its secrets quickly, but after so many months, so many missions, so many eyes scanning the horizon, with no sign of the missing plane, it is hard to fathom why, especially for families left behind.

MARY SCHIAVO: They want answers and they want results. And now they're told that it could be another year just in mapping the floor and searching. They're just in total limbo, and it's just heartbreaking.

NARRATOR: And the experts are as mystified as the rest of us.

RICK CASTALDO: It's hard to believe that there's no trace of it. Very difficult to believe, if it did, in fact, impact in the ocean, that something's not floating somewhere. It's very difficult to believe that it just disappeared off the planet.

NARRATOR: But somewhere out there lays the wreckage, the black boxes and hopefully, the answers.

JOHN GOGLIA: Airplane accident investigators are very much like cold-case investigators. They do not give up. We can't let it stand that we didn't find the cause. We will find the airplane. It might take a year, two years, it might be next week, but there's a lot of effort going on out there. Sooner or later, the secrets will be given up.

NARRATOR: But maybe not all the secrets.

MARK WEISS: It's still going to be a true mystery. There's no black box for a human brain.

JEFF WISE: The worrying truth that MH370 pointed up is that this kind of thing can happen, and we don't why, and we certainly haven't prevented it from happening again, because we don't know what it is that we need to prevent. We don't know what MH370 was.

NARRATOR: Whatever happened to Malaysia Airlines flight 370, there is no good reason that a modern airliner should be allowed to vanish.

DAVID GALLO: It's the wrong thing to do, to let a plane go into the water without knowing where it is. It's a…shame on us, you know? Not good, not good.

And I hope that this time, we learn about airplanes and tracking them, so we know where they are, what they're doing. And if they should go into the water, God bless them, we know where that happens.