1 00:00:09,480 --> 00:00:14,320 NARRATOR: It's the greatest aviation mystery of all time. 2 00:00:14,360 --> 00:00:19,160 PILOT: Malaysia 370 contact Ho Chi Minh on 120.9 Good night. 3 00:00:19,200 --> 00:00:25,200 NARRATOR: How can a Boeing 777 with 239 people on board 4 00:00:25,240 --> 00:00:29,440 simply vanish without a trace? 5 00:00:32,240 --> 00:00:37,000 The answer lies somewhere at the bottom of the Indian Ocean. 6 00:00:39,320 --> 00:00:46,040 Imagine if we could empty the oceans, letting the water drain away to reveal the secrets 7 00:00:46,080 --> 00:00:48,400 of the sea floor. 8 00:00:48,440 --> 00:00:52,160 Now we can. 9 00:00:54,200 --> 00:00:59,000 Using the latest underwater scanning technology, piercing the deep oceans, 10 00:00:59,040 --> 00:01:04,920 and turning accurate data into 3D images. 11 00:01:09,960 --> 00:01:13,120 key mysteries of Malaysia Airlines 370. 12 00:01:14,720 --> 00:01:19,040 What lessons lie amid the wreck of previous air disasters? 13 00:01:21,080 --> 00:01:25,800 Can Cold War technology extract vital clues from the deep ocean 14 00:01:31,600 --> 00:01:37,000 And if the plane is found, what secrets could lie hidden in the tangled wreckage? 15 00:02:11,160 --> 00:02:17,640 March the 8th 2014, Malaysia Airlines flight 370 departs Kuala Lumpur, 16 00:02:17,680 --> 00:02:20,600 on a six-hour flight to Beijing 17 00:02:29,120 --> 00:02:34,080 NARRATOR: As the Boeing 777 enters Vietnamese airspace 18 00:02:34,120 --> 00:02:37,640 it suddenly drops off air traffic control radar. 19 00:02:45,080 --> 00:02:51,080 A modern commercial airliner, carrying 239 people, has just vanished. 20 00:02:55,080 --> 00:03:01,080 There's no mayday call and no wreckage at the point of last radar contact. 21 00:03:11,080 --> 00:03:15,520 Aviation authorities struggle to understand. 22 00:03:15,560 --> 00:03:19,080 REPRESENTATIVE: We believe family members should prepare themselves for the worst. 23 00:03:19,120 --> 00:03:22,920 [crying] 24 00:03:22,960 --> 00:03:26,040 NARRATOR: Families left behind demand answers. 25 00:03:26,080 --> 00:03:31,080 WOMAN: [Speaking in Mandarin] 26 00:03:31,120 --> 00:03:34,600 NARRATOR: The Malaysian government launches an investigation. 27 00:03:34,640 --> 00:03:38,760 It will be the largest and most expensive in aviation history. 28 00:03:40,600 --> 00:03:46,560 With multiple dead ends, false leads, a deluge of speculation, 29 00:03:46,600 --> 00:03:49,080 but only a handful of real clues. 30 00:03:51,080 --> 00:03:53,840 One of the first comes from the Malaysian military. 31 00:03:57,080 --> 00:04:03,040 Powerful defence radar has detected the plane, turning back across Malaysia, 32 00:04:03,080 --> 00:04:09,280 heading northwest up the Strait of Malacca, then disappearing out of range here, 33 00:04:09,320 --> 00:04:11,600 just north of Sumatra. 34 00:04:12,800 --> 00:04:15,480 It's a shocking discovery. 35 00:04:15,520 --> 00:04:19,920 After it disappeared from civilian radar, it didn't crash 36 00:04:19,960 --> 00:04:23,160 It continued flying. 37 00:04:23,200 --> 00:04:29,080 JOHN: Initially when the airplane made a turn without talking to air traffic control, 38 00:04:29,120 --> 00:04:31,880 in my mind, all bets were off. 39 00:04:31,920 --> 00:04:36,680 It could be a terrorist event. It could be a deliberate act by a crew member, 40 00:04:36,720 --> 00:04:39,960 it could be a mass failure in the electrical system. 41 00:04:44,520 --> 00:04:49,160 NARRATOR: The next clue comes from space. 42 00:04:49,200 --> 00:04:56,040 Although lost to radar, MH 370 continued to exchange what are called 'heartbeat' signals 43 00:04:56,080 --> 00:04:59,880 with an Inmarsat satellite above the Indian Ocean. 44 00:05:01,240 --> 00:05:05,080 The heartbeats come once an hour. 45 00:05:05,120 --> 00:05:11,440 Frequency changes in the signals help experts calculate its direction of travel 46 00:05:11,480 --> 00:05:15,160 and reveal something extraordinary. 47 00:05:15,200 --> 00:05:25,120 After its initial track to the northwest, MH370 turned south and flew for six more hours. 48 00:05:25,160 --> 00:05:29,880 From the travel time of each signal investigators also calculate the plane's distance 49 00:05:29,920 --> 00:05:31,680 from the satellite. 50 00:05:31,720 --> 00:05:35,080 These lines are called arcs. 51 00:05:35,120 --> 00:05:41,040 Using the fuel load and cruisin speed, they can recreate a rang of possible flight paths 52 00:05:41,080 --> 00:05:43,640 as the plane crosses each arc. 53 00:05:45,080 --> 00:05:50,080 The final, or seventh, arc is deep in the Indian Ocean. 54 00:05:50,120 --> 00:05:54,040 There are no more heartbeat signals beyond this point. 55 00:05:54,080 --> 00:05:58,080 PETER: The data was extraordinary in as much as you're trying to establish 56 00:05:58,120 --> 00:06:03,760 an aircraft's position based on information that was never intended for that purpose. 57 00:06:04,520 --> 00:06:08,000 NARRATOR: It's the biggest breakthrough so far 58 00:06:08,040 --> 00:06:16,520 instantly shifting the search 3,000 miles south of the last military radar contact 59 00:06:16,560 --> 00:06:20,880 taking it into the jurisdiction of the Australian government, 60 00:06:20,920 --> 00:06:23,960 and accident investigator Peter Foley. 61 00:06:24,000 --> 00:06:29,080 PETER: This is something extraordinary that was captured by Inmarsat at the time 62 00:06:29,120 --> 00:06:36,200 the aircraft was in the air, which very few people knew about and which is absolutely key 63 00:06:36,240 --> 00:06:40,000 to the search and working out where to look for that aircraft. 64 00:06:42,240 --> 00:06:44,800 NARRATOR: They start looking here: 65 00:06:44,840 --> 00:06:50,920 a swathe of ocean running seven hundred miles along the seventh arc. 66 00:06:50,960 --> 00:06:55,680 They estimate that the plane could lie 140 miles either side, 67 00:06:55,720 --> 00:06:59,320 the maximum glide range of a 777. 68 00:07:05,080 --> 00:07:11,680 The seventh arc is over 1,500 miles from the nearest land. 69 00:07:11,720 --> 00:07:15,720 It will take two days for Australian search vessels to get there. 70 00:07:16,920 --> 00:07:21,920 Two powerful storms have swept through since MH 370 disappeare 71 00:07:21,960 --> 00:07:25,200 making the job of spotting debris even harder. 72 00:07:26,760 --> 00:07:34,160 22 aircraft and 19 surface vessels look for wreckage, and possibly even survivors. 73 00:07:34,960 --> 00:07:40,360 PETER: When an aircraft enters the ocean with energy, you expect to see a potential oil slick; 74 00:07:40,400 --> 00:07:44,880 you expect to see all sorts of objects, actually, which are buoyant, 75 00:07:44,920 --> 00:07:48,840 which are released from the aircraft as debris. 76 00:07:48,880 --> 00:07:53,520 NARRATOR: Surface debris is normally the first step to finding a missing aircraft, 77 00:07:53,560 --> 00:07:56,160 but it's not a guarantee. 78 00:07:56,200 --> 00:08:01,680 Before MH370, the largest and most expensive search in aviation history takes place 79 00:08:01,720 --> 00:08:08,800 here, 8,000 miles away in the Atlantic Ocean 80 00:08:08,840 --> 00:08:14,120 hunting for the wreck of Air France flight 447. 81 00:08:14,160 --> 00:08:20,000 What lessons lie amid this tangled wreckage, for those searching for MH370? 82 00:08:27,160 --> 00:08:33,080 On June the 1ST, 2009, Air France 447 leaves Rio de Janeiro, Brazil, 83 00:08:33,120 --> 00:08:41,080 carrying 216 passengers and 12 crew to Paris. 84 00:08:41,120 --> 00:08:45,640 Weather reports indicate severe thunderstorms along the flight path. 85 00:08:47,320 --> 00:08:52,160 Three hours and 45 minutes into the flight, as the plane nears the equator, 86 00:08:52,200 --> 00:08:56,680 its on-board computers send a burst of emergency warnings 87 00:08:56,720 --> 00:08:59,160 then falls silent. 88 00:09:04,640 --> 00:09:09,160 Olivier Ferrante is in charge of the French search team. 89 00:09:10,120 --> 00:09:13,160 The warning signals are his first clue. 90 00:09:13,200 --> 00:09:16,720 OLIVIER: Some maintenance messages, and an important position message, 91 00:09:16,760 --> 00:09:21,120 which was very useful for our search. 92 00:09:21,160 --> 00:09:27,960 NARRATOR: It is a deep and remote stretch of ocean, but th search team has every advantage 93 00:09:28,000 --> 00:09:30,600 A known flight path. 94 00:09:30,640 --> 00:09:32,720 An accurate final position. 95 00:09:32,760 --> 00:09:37,560 And then, surface debris found within five days. 96 00:09:39,520 --> 00:09:46,600 And yet, despite initial optimism, it takes two years, four expeditions, 97 00:09:46,640 --> 00:09:50,560 and forty million dollars to find the plane. 98 00:09:50,600 --> 00:09:54,840 OLIVIER: Yes I remember that moment when we found the wreckage. 99 00:09:54,880 --> 00:10:01,520 I was very careful, because we've had false alerts before and then it turned out to be 100 00:10:01,560 --> 00:10:07,000 geology or not what we were looking for. 101 00:10:07,040 --> 00:10:10,360 NARRATOR: Why does it take so long? 102 00:10:10,400 --> 00:10:15,040 Using the data meticulously collected by the search team, combined with the latest 103 00:10:15,080 --> 00:10:21,280 visualisation technology, It is possible to drain the Atlantic Ocean 104 00:10:21,320 --> 00:10:27,000 revealing the hostile world that faces every deep-water search effort. 105 00:10:28,160 --> 00:10:30,200 Immense water pressure. 106 00:10:30,240 --> 00:10:35,920 Freezing cold, total darkness, and hidden dangers everywhere. 107 00:10:37,080 --> 00:10:40,960 Finally, at 12,800 feet 108 00:10:41,000 --> 00:10:45,040 the shattered remains of Air France 447. 109 00:10:47,040 --> 00:10:54,680 Engines, wheel assemblies, and other heavy items lie together 110 00:10:54,720 --> 00:10:59,960 their twisted remains a testament to the force of the impact. 111 00:11:02,280 --> 00:11:07,520 Smaller, lighter, objects stretch along more than a third of a mile of sea floor, 112 00:11:07,560 --> 00:11:11,640 equivalent to ten New York city blocks. 113 00:11:11,680 --> 00:11:19,200 And a critical realization: the seabed wreckage is nowhere near the surface wreckage. 114 00:11:19,240 --> 00:11:22,880 It's almost 24 miles away. 115 00:11:22,920 --> 00:11:29,200 Investigators have wasted years searching directly underneath the surface debris 116 00:11:29,240 --> 00:11:37,400 not realizing that ocean currents have carried it far away from the crash site. 117 00:11:37,440 --> 00:11:42,800 The long and frustrating search for the French aircraft carries a warning. 118 00:11:42,840 --> 00:11:49,560 Even with debris and an accurate final position, when a plane goes into deep water, 119 00:11:49,600 --> 00:11:51,280 it's very hard to find. 120 00:11:54,200 --> 00:11:59,040 A sobering thought for the team searching for MH370. 121 00:11:59,080 --> 00:12:05,600 OLIVIER: Air France was very difficult with our area of 17,000 square kilometres. 122 00:12:05,640 --> 00:12:14,360 But it's nothing compared to the the surface that the search teams have to for MH370. 123 00:12:14,400 --> 00:12:16,800 It's much more difficult. 124 00:12:19,600 --> 00:12:25,680 NARRATOR: In the southern Indian Ocean, investigators loo for surface debris for over two weeks. 125 00:12:26,680 --> 00:12:31,480 Even with the aid of satellites, they find nothing. 126 00:12:31,520 --> 00:12:37,400 JOHN: One of the greatest initial mysteries and that has transcended the entire 127 00:12:37,440 --> 00:12:42,560 period of time that we have been looking for this airplane, where is the debris? 128 00:12:46,320 --> 00:12:50,520 NARRATOR: With no debris they need to find another way to narrow the search. 129 00:12:53,760 --> 00:12:59,480 So they focus on MH370's 'black box' data recorders. 130 00:12:59,520 --> 00:13:04,440 Each has an underwater locater beacon or ULB. 131 00:13:04,480 --> 00:13:11,280 In water they emit an electronic 'ping' with a range of just over a mile. 132 00:13:11,320 --> 00:13:14,640 Find the beacons and you find the plane. 133 00:13:15,480 --> 00:13:18,240 But time is running out. 134 00:13:18,280 --> 00:13:21,920 PETER: Battery life on the ULB's is only 30 days. 135 00:13:21,960 --> 00:13:25,600 Although they do last longer they fade out. 136 00:13:25,640 --> 00:13:29,280 NARRATOR: By the time specialist pinger locater technology reaches the search 137 00:13:29,320 --> 00:13:33,800 zone, there are just three days of battery life left. 138 00:13:38,240 --> 00:13:44,160 [music] 139 00:13:44,200 --> 00:13:46,880 O'DELL: Steer 319. OFFICER: Steer 319. 140 00:13:46,920 --> 00:13:52,200 NARRATOR: Investigators have only a few days to locate MH 370's black boxes, 141 00:13:52,240 --> 00:13:55,680 before their locater batteries run out. 142 00:13:55,720 --> 00:14:01,240 Faced with a vast search zone, they decide to focus on commonly used air routes. 143 00:14:01,280 --> 00:14:07,920 PETER: It was thought that if the aircraft had been in distress and was trying to make 144 00:14:07,960 --> 00:14:11,520 to complete a flight for example to Perth, there was some recognized air routes. 145 00:14:14,280 --> 00:14:19,000 NARRATOR: Australian navy vessel Ocean Shield steams to the point where the air route 146 00:14:19,040 --> 00:14:22,040 to Perth intersects the seventh arc. 147 00:14:30,240 --> 00:14:37,680 The team looking for Air France 447 also used pinger locaters i an attempt to discover the cras site. 148 00:14:43,200 --> 00:14:47,160 They begin listening for signals within days of the plane's disappearance. 149 00:14:48,160 --> 00:14:53,960 OLIVIER: In most cases the pinger locaters work, and that was our assumption before 150 00:14:54,000 --> 00:14:55,960 Air France 447. 151 00:14:56,000 --> 00:15:03,120 NARRATOR: Ships scour the search area for forty days but hear nothing. 152 00:15:03,160 --> 00:15:08,640 The hunters wonder: are the locater beacons lost, or destroyed? 153 00:15:12,120 --> 00:15:17,760 Returning to the remarkable drained seascape of the Air France 447 wreckage reveals 154 00:15:17,800 --> 00:15:21,080 the scale of the problem. 155 00:15:21,120 --> 00:15:28,280 The sea floor here is 12,800 feet below the surface 156 00:15:28,320 --> 00:15:33,440 deep in the mid-Atlantic ridge. 157 00:15:33,480 --> 00:15:39,840 And here amid the wreckage, nestling in the remains of the tail plane, the black boxes, 158 00:15:39,880 --> 00:15:43,600 one with its locater beacon still attached. 159 00:15:43,640 --> 00:15:49,520 A search ship passed directly over here, but detected nothing 160 00:15:49,560 --> 00:15:54,240 The metal wreckage may have blocked the signals, or they could have been damaged 161 00:15:54,280 --> 00:15:57,040 by the sheer force of the impact. 162 00:15:57,080 --> 00:16:02,000 OLIVIER: I think they were unfortunately damaged, at that stage. 163 00:16:06,840 --> 00:16:11,320 NARRATOR: Investigators listening for the MH370 black boxes can only hope 164 00:16:11,360 --> 00:16:14,520 they'll have better luck. 165 00:16:14,560 --> 00:16:20,000 They monitor the ocean for fifteen days, using three ships equipped with sensitive 166 00:16:20,040 --> 00:16:26,920 listening technology, and military aircraft launching sonar buoys. 167 00:16:26,960 --> 00:16:33,040 They do detect some signals, but conclude it's just random interference. 168 00:16:35,080 --> 00:16:36,760 It's another disappointment. 169 00:16:39,120 --> 00:16:44,240 But at this low point there's a dramatic new lead. 170 00:16:48,160 --> 00:16:53,800 A team from Curtin University in Western Australia runs a network of sensitive underwater 171 00:16:53,840 --> 00:17:03,760 microphones called hydrophones positioned all around the Australian coast. 172 00:17:03,800 --> 00:17:11,320 They're designed to monitor earthquakes, Antarctic ice and wildlife and, remarkably, 173 00:17:11,360 --> 00:17:16,040 one of them has picked up an unusual noise 174 00:17:16,080 --> 00:17:25,000 1 hour and 14 minutes after MH370's last communication with the Inmarsat satellite. 175 00:17:25,040 --> 00:17:30,880 ALEC: When we looked at the data from that hydrophone we found one signal that looked 176 00:17:30,920 --> 00:17:35,040 as though it had interesting characteristics. 177 00:17:35,080 --> 00:17:40,000 NARRATOR: Is this the actual sound of MH370's final moments? 178 00:17:48,200 --> 00:17:51,160 Alec Duncan's team look for other audio recordings, 179 00:17:51,200 --> 00:17:55,480 so they can calculate a geographical fix. 180 00:17:55,520 --> 00:18:00,200 ALEC: One hydrophone does tell you a certain amount about the source of the signal, 181 00:18:00,240 --> 00:18:04,120 so you can tell whether it's a whale, you can tell whether it's a snapping shrimp, 182 00:18:04,160 --> 00:18:10,360 you can tell whether it's just noise from the mooring, but you can't tell direction. 183 00:18:12,240 --> 00:18:16,560 NARRATOR: Fortunately, other agencies are listening too, 184 00:18:16,600 --> 00:18:22,160 [explosion sound] 185 00:18:22,200 --> 00:18:26,000 for the sound of illegal nuclea tests 186 00:18:28,120 --> 00:18:32,240 with technology that can accurately pinpoint the source. 187 00:18:35,200 --> 00:18:40,800 Just of the coast of Cape Leeuwin in Western Australia the Comprehensive Nuclear Test 188 00:18:40,840 --> 00:18:49,160 Ban Treaty Organisation runs a listening post specifically designed to detect and locate 189 00:18:49,200 --> 00:18:51,120 illegal nuclear tests. 190 00:18:53,120 --> 00:19:01,080 The station has three hydrophones set one and a quarter miles apart. 191 00:19:01,120 --> 00:19:07,120 They can determine the direction of a sound to within half a degree 192 00:19:07,160 --> 00:19:12,000 and calculate the distance to the source, over thousands of miles. 193 00:19:14,600 --> 00:19:21,800 And astonishingly, this network has detected the exact noise heard by the team from Curtin University. 194 00:19:25,880 --> 00:19:31,080 ALEC: The analysis of the data from Cape Leeuwin told us that that signal had come 195 00:19:31,120 --> 00:19:36,720 from the northwest and gave us a fairly accurate bearing 196 00:19:36,760 --> 00:19:40,400 along which the source of the signal must have been. 197 00:19:41,960 --> 00:19:44,040 NARRATOR: It's a tantalizing clue 198 00:19:44,080 --> 00:19:49,200 and the sound does come from th direction of the seventh arc. 199 00:19:49,240 --> 00:19:57,080 But when the scientists crunch the numbers, the source of the sound is far to the northwest 200 00:19:57,120 --> 00:20:03,040 so far beyond the current searc area that it's considered not worth further investigation. 201 00:20:04,120 --> 00:20:10,160 ALEC: Our conclusion was that he signal was most likely to be of geological origin, 202 00:20:10,200 --> 00:20:14,240 such as a small under sea earthquake but we can't completely rule out 203 00:20:14,280 --> 00:20:18,320 the possibility that it came from something to do with the aircraft. 204 00:20:24,480 --> 00:20:30,320 NARRATOR: Faced with a new disappointment, the search team moves to a different approach: 205 00:20:30,360 --> 00:20:37,160 searching the sea floor itself, using towed sleds carrying sonar scanners. 206 00:20:42,120 --> 00:20:46,160 It will be the largest undersea hunt in history. 207 00:20:46,200 --> 00:20:51,760 But before it can even start there's a new problem. 208 00:20:51,800 --> 00:20:57,360 This part of the Indian Ocean has never been surveyed in detail. 209 00:20:57,400 --> 00:21:04,640 The sleds will be close to the sea floor and no one knows exactly what is down there. 210 00:21:05,760 --> 00:21:09,080 PETER: We knew we'd be operating vehicles very close to the sea floor, 211 00:21:09,120 --> 00:21:12,840 which necessitated knowledge of what was down there and 212 00:21:12,880 --> 00:21:16,840 so that we could avoid collisions with terrain. 213 00:21:16,880 --> 00:21:24,240 NARRATOR: The MH370 team need a simple way to create a snapshot of the sea floor across the vas search area. 214 00:21:26,880 --> 00:21:29,600 They find help in an unexpected place. 215 00:21:36,200 --> 00:21:40,320 [music] 216 00:21:40,360 --> 00:21:49,840 The team hunting MH370 across 463,000 square miles of Indian Ocean, face one big problem. 217 00:21:49,880 --> 00:21:55,680 WALTER: More than 99 percent of the sea floor area in this region has not been covered by 218 00:21:55,720 --> 00:22:00,760 ships with modern equipment, satellite navigation, multibeam echo sounding. 219 00:22:00,800 --> 00:22:05,840 NARRATOR: Geophysicist Walter Smith thinks he might be able to fill in the blanks, 220 00:22:05,880 --> 00:22:07,720 using satellites. 221 00:22:11,040 --> 00:22:15,360 WALTER: The satellites actually cannot see the bottom, they're not seeing the ocean floor, 222 00:22:15,400 --> 00:22:20,440 what they're doing is using radar to measure variations in the sea surface height. 223 00:22:20,480 --> 00:22:24,680 NARRATOR: It's possible, thanks to gravity. 224 00:22:24,720 --> 00:22:29,800 Mountains on the sea floor create their own gravitational attraction. 225 00:22:29,840 --> 00:22:37,400 Surrounding water is drawn towards the mass, creating measurable changes on the surface. 226 00:22:37,440 --> 00:22:43,120 WALTER: The smallest ones I can resolve are a kilometre or less in height and they move the sea 227 00:22:43,160 --> 00:22:47,840 surface about 5 centimetres and the satellite has no problem resolving that. 228 00:22:47,880 --> 00:22:51,760 NARRATOR: It doesn't have the resolution to spot the wreckage of an aircraft, 229 00:22:51,800 --> 00:22:59,280 but it's enough to help create a basic map of the sea floor and identify hazards in the MH370 search zone. 230 00:23:01,960 --> 00:23:05,120 What does the data reveal? 231 00:23:05,160 --> 00:23:11,720 Using the exact information gathered by Walter Smith's team it's possible to drain away 232 00:23:11,760 --> 00:23:17,120 the Indian Ocean to show what the ocean floor actually looks like. 233 00:23:19,320 --> 00:23:24,720 As the water flows away it exposes a world no human has ever seen before. 234 00:23:25,960 --> 00:23:32,720 Dramatic cliffs, more than twice the height of the Empire State Building. 235 00:23:32,760 --> 00:23:37,840 Fault lines plunging almost 20,000 feet deeper than any canyon on land. 236 00:23:41,960 --> 00:23:47,720 A volcano-dotted valley running for a hundred miles. 237 00:23:47,760 --> 00:23:53,320 Operating underwater scanning vehicles in this terrain will take a huge amount of skill 238 00:23:53,360 --> 00:23:54,680 and luck. 239 00:24:00,760 --> 00:24:07,880 Armed with their new map of the sea floor, the search team deploys the latest in subsea technology. 240 00:24:07,920 --> 00:24:13,000 Travelling deep underwater, these towed sleds begin to scan the sea floor. 241 00:24:14,720 --> 00:24:18,760 And they will be guided by a game-changing new clue. 242 00:24:21,160 --> 00:24:28,760 It comes from further detailed analysis of the final Inmarsat signal from MH370. 243 00:24:28,800 --> 00:24:33,840 Engineers crunch the numbers, and discover something shocking 244 00:24:33,880 --> 00:24:39,320 In its final moments, the plane descends rapidly, almost certainly because after 245 00:24:39,360 --> 00:24:43,040 seven and a half hours in the air, it's run out of fuel. 246 00:24:45,360 --> 00:24:51,480 Boeing engineers then simulate what happens when a triple seve exhausts its fuel 247 00:24:51,520 --> 00:25:00,600 making it possible for the firs time to recreate the likely final minutes of MH370's mysterious flight. 248 00:25:02,120 --> 00:25:07,160 The right engine flames out first. 249 00:25:07,200 --> 00:25:11,520 The autopilot compensates for the imbalance with a hard left turn. 250 00:25:16,160 --> 00:25:19,480 Minutes later the second engine flames out. 251 00:25:21,840 --> 00:25:30,160 With no power, the autopilot switches off, leaving MH370 in a long spiral decent. 252 00:25:44,200 --> 00:25:47,240 [crashing sound] 253 00:25:58,600 --> 00:26:06,520 In every Boeing simulation, the crash site lies within 29 miles of the seventh arc. 254 00:26:09,520 --> 00:26:14,640 These dramatic new insights immediately reduce the size of the search area, 255 00:26:14,680 --> 00:26:21,520 from 463,000 square miles to just 23,000. 256 00:26:21,560 --> 00:26:28,760 But that's still three and a half times the size of the search area for Air France 447. 257 00:26:28,800 --> 00:26:30,600 ANDY: This is a massive search area. 258 00:26:30,640 --> 00:26:35,040 It's magnitudes larger than any previous search I have ever worked on. 259 00:26:35,080 --> 00:26:39,080 NARRATOR: Deep sea salvage expert, Andy Sherrell analyses all the data 260 00:26:39,120 --> 00:26:41,520 that's being gathered underwater. 261 00:26:41,560 --> 00:26:46,360 ANDY: Oddly enough when I first heard about MH370's disappearance, 262 00:26:46,400 --> 00:26:50,200 my wife was in labour with our first child. 263 00:26:50,240 --> 00:26:54,520 The news came on about the disappearance of the flight and my wife looked at me and she said, 264 00:26:54,560 --> 00:26:57,920 'well that's a job you are not going to be involved with.' 265 00:26:57,960 --> 00:27:02,000 NARRATOR: Andy has been involved ever since. 266 00:27:02,040 --> 00:27:05,760 Using his knowledge from six previous investigations, 267 00:27:05,800 --> 00:27:10,160 including a search for Amelia Earhart's Lockheed Electra. 268 00:27:17,600 --> 00:27:23,920 As soon as the underwater scanning begins, it identifies shapes that could be manmade. 269 00:27:23,960 --> 00:27:28,120 ANDY: So when you are reviewing the side scan sonar it comes down in a waterfall display 270 00:27:28,160 --> 00:27:34,400 and you can see the different intensities of, you know soft sand versus hard rock. 271 00:27:34,440 --> 00:27:41,440 NARRATOR: Guided by the scans, the team investigate 80 locations in detail 272 00:27:41,480 --> 00:27:44,560 but find no trace of MH370. 273 00:27:46,560 --> 00:27:52,960 Then in May 2015, the sonar picks up something new and exciting. 274 00:27:53,000 --> 00:28:00,000 ANDY: It was a typical looking debris field that definitely warranted more investigation. 275 00:28:04,240 --> 00:28:13,960 NARRATOR: The debris field covers an area similar in size to the wreckage of Air France 447. 276 00:28:14,000 --> 00:28:18,120 Could this finally be the remains of MH370? 277 00:28:20,200 --> 00:28:22,880 PETER: Sonar paints a very good picture of the sea floor, 278 00:28:22,920 --> 00:28:27,080 and what you've got there but it's not perfect. It's not good enough to say with certainty 279 00:28:27,120 --> 00:28:31,240 that a certain item might be an aircraft debris field. 280 00:28:31,280 --> 00:28:34,000 You actually have to investigate with visual means. 281 00:28:37,440 --> 00:28:39,920 NARRATOR: They launch an autonomous underwater vehicle, 282 00:28:39,960 --> 00:28:43,800 armed with state of the art sensors, to take a closer look. 283 00:28:46,640 --> 00:28:52,120 Using the actual data it recorded that day, it's now possible to drain away the wate 284 00:28:52,160 --> 00:28:59,920 from over the site, revealing the most hopeful discovery so far in the hunt for MH370. 285 00:29:02,120 --> 00:29:05,720 At one end a pile of chains. 286 00:29:05,760 --> 00:29:10,120 Then a 23 foot long metal box 287 00:29:10,160 --> 00:29:15,640 rusted machinery and finally three metal anchors. 288 00:29:17,120 --> 00:29:25,240 They've found a shipwreck, its wooden hull long rotted away. 289 00:29:25,280 --> 00:29:30,360 The site strewn with coal, probably cargo, on its final voyage. 290 00:29:32,120 --> 00:29:38,280 They haven't found MH370, but in these dark uncharted depths they're casting light on 291 00:29:38,320 --> 00:29:40,800 tragedies from a different age. 292 00:29:45,400 --> 00:29:48,880 The investigators discover three other wrecks 293 00:29:54,240 --> 00:30:00,160 Including this iron hulled sailing ship upright on the seabed. 294 00:30:05,400 --> 00:30:11,120 And a modern fishing trawler, nets stretched out across the sea floor 295 00:30:12,160 --> 00:30:19,080 proving that their technology can locate and retrieve objects as small as a piece of coal. 296 00:30:23,040 --> 00:30:29,520 After fifteen months of detaile scanning, covering 23,000 square miles of sea floor, 297 00:30:29,560 --> 00:30:32,720 there's still no sign of the missing plane. 298 00:30:34,280 --> 00:30:38,960 ANDY: We have a very high confidence that we would have detected the plane in that search area. 299 00:30:39,000 --> 00:30:45,760 So all of these factors gives us really high confidence that the airplane debris field is not in that area. 300 00:30:49,240 --> 00:30:55,200 NARRATOR: The investigation continues, still guided by just two key pieces of evidence: 301 00:30:55,240 --> 00:31:01,520 the Inmarsat calculations and Boeing's flight performance data. 302 00:31:01,560 --> 00:31:06,080 Then, suddenly, a third line of inquiry brings hope of a breakthrough. 303 00:31:08,680 --> 00:31:13,360 On a remote island on the other side of the Indian Ocean, 3,000 miles 304 00:31:13,400 --> 00:31:18,320 from the search area, a piece of metal washes up on a beach 305 00:31:18,360 --> 00:31:21,120 and it looks like it comes from an aircraft. 306 00:31:24,440 --> 00:31:30,240 [music] 307 00:31:30,280 --> 00:31:35,360 NARRATOR: In July 2015, a council worker on Reunion Island, 308 00:31:35,400 --> 00:31:42,600 a French territory in the Indian Ocean, stumbles upon an unusual object on a beach. 309 00:31:42,640 --> 00:31:46,160 It's called a flaperon. 310 00:31:46,200 --> 00:31:56,280 There is one on each wing of a Boeing triple seven part of the mechanism that makes it rise or fall. 311 00:31:56,320 --> 00:32:03,560 Boeing quickly confirms that its serial number matches that of the missing plane. 312 00:32:03,600 --> 00:32:11,120 It's the first piece of physical evidence that MH370 ended its flight in the ocean. 313 00:32:11,160 --> 00:32:18,280 OFFICER: It is my hope that this confirmation will at least bring certainty to the families 314 00:32:18,320 --> 00:32:19,400 and loved ones. 315 00:32:23,120 --> 00:32:28,040 NARRATOR: The suffering of the families attracts the attention of amateur wreck hunter 316 00:32:28,080 --> 00:32:35,080 Blaine Gibson and sets him off on a remarkable personal quest. 317 00:32:35,120 --> 00:32:40,720 BLAINE: I was very, very touched, very moved and realized that I needed to go do 318 00:32:40,760 --> 00:32:46,520 what I could to solve this and what I learned, what that niche was, 319 00:32:46,560 --> 00:32:55,360 was that there was no official search for debris that washed ashore. 320 00:32:55,400 --> 00:33:02,240 NARRATOR: Blaine consults ocean drift experts, who direct him to Mozambique 321 00:33:02,280 --> 00:33:05,000 where he makes an immediate discovery. 322 00:33:07,600 --> 00:33:13,720 BLAINE: It was a triangular grey shaped piece of debris that said 'no step' on it. 323 00:33:13,760 --> 00:33:16,600 Clearly aircraft. 324 00:33:19,240 --> 00:33:28,560 I felt an enormous sense of responsibility because I realised that I had just found 325 00:33:28,600 --> 00:33:35,040 the second piece of debris in the greatest aviation mystery in history. 326 00:33:35,080 --> 00:33:40,480 NARRATOR: Boeing confirms that the "no step" debris is from MH370. 327 00:33:40,520 --> 00:33:48,160 Blaine has found it 4,350 miles away from the main search zone. 328 00:33:52,840 --> 00:33:56,080 Still acting alone, he continues to search. 329 00:33:59,360 --> 00:34:04,520 BLAINE: We just found on Raike Beach this piece of debris. 330 00:34:04,560 --> 00:34:06,200 We have not picked it up yet. 331 00:34:08,520 --> 00:34:14,720 NARRATOR: Almost thirty pieces of debris thought to come from MH370 are recovered. 332 00:34:14,760 --> 00:34:18,920 All on the western side of the Indian Ocean. 333 00:34:18,960 --> 00:34:22,160 Blaine Gibson finds fifteen of them. 334 00:34:23,200 --> 00:34:26,160 One piece stands out from the rest. 335 00:34:26,200 --> 00:34:31,440 BLAINE: The most significant to me, and also to the investigation, 336 00:34:31,480 --> 00:34:38,320 was the case around the TV screen on the back of the seat in front of you. 337 00:34:38,360 --> 00:34:41,960 This is the one that brought tears to my eyes. 338 00:34:42,000 --> 00:34:46,480 This is perhaps the last thing that somebody saw. 339 00:34:46,520 --> 00:34:52,560 This is what anyone who flies on a plane would recognize. 340 00:34:52,600 --> 00:34:56,240 NARRATOR: Debris like this, fro inside the passenger cabin, 341 00:34:56,280 --> 00:35:01,240 confirms that MH370 hit the water hard. 342 00:35:01,280 --> 00:35:07,080 PETER: Some of the items indicates that there was quite a large amount of energy 343 00:35:07,120 --> 00:35:10,680 at the time the aircraft entered the water. 344 00:35:10,720 --> 00:35:15,120 NARRATOR: Another piece of debris helps resolve a key question. 345 00:35:15,160 --> 00:35:19,040 Investigators already believe the plane ran out of fuel. 346 00:35:19,080 --> 00:35:26,000 But as it fell towards the ocean, was someone trying to save it with a controlled ditch 347 00:35:26,040 --> 00:35:32,120 PETER: This section of main flap was found in Tanzania, Pemba Island in 2016 and 348 00:35:32,160 --> 00:35:38,000 when imagery was passed to us we realized it was pretty significant. 349 00:35:38,040 --> 00:35:42,120 NARRATOR: The flap extends on an internal support track. 350 00:35:42,160 --> 00:35:48,200 Investigators discover that the track has left impact marks inside the flap. 351 00:35:48,240 --> 00:35:54,320 That can only happen if it is in a retracted position strong evidence that the plane was 352 00:35:54,360 --> 00:35:58,640 in its normal cruising state as it fell towards the sea. 353 00:36:02,440 --> 00:36:04,760 PETER: It's been the subject of a lot of debate. 354 00:36:04,800 --> 00:36:10,000 The hard physical evidence and our analysis showed that it wasn't a controlled ditch, 355 00:36:10,040 --> 00:36:14,200 or there wasn't active control from the cockpit extending the flaps at the time 356 00:36:14,240 --> 00:36:17,320 the flaps separated from the aircraft. 357 00:36:20,000 --> 00:36:24,840 NARRATOR: The flap supports the theory that the plane ran out of fuel and suggests that 358 00:36:24,880 --> 00:36:28,880 no one at that point was trying to ditch or save it. 359 00:36:35,080 --> 00:36:41,240 But the debris doesn't only confirm how MH370 crashed. 360 00:36:41,280 --> 00:36:47,960 It opens up a new and exciting line of enquiry that could narrow the search area. 361 00:36:52,280 --> 00:36:56,040 DAVID: I think it's enormously important to find the plane, 362 00:36:56,080 --> 00:37:00,200 because while planes crash routinely, 363 00:37:00,240 --> 00:37:05,640 they don't just disappear and I think this terrifies people. 364 00:37:05,680 --> 00:37:10,800 NARRATOR: Oceanographer David Griffin believes that the very first piece of debris recovered 365 00:37:10,840 --> 00:37:15,440 the flaperon on Reunion Island, may be the key. 366 00:37:15,480 --> 00:37:17,000 SKIPPER: This'd be a good spot, I reckon. 367 00:37:17,040 --> 00:37:20,160 The wind's probably a bit stronger, I guess. Yep. 368 00:37:20,200 --> 00:37:25,760 DAVID: This is a Boeing 777 flaperon off another aircraft, not MH370. 369 00:37:25,800 --> 00:37:28,960 SKIPPER: We use this anchor to sink it again, alright? 370 00:37:29,000 --> 00:37:33,880 NARRATOR: David Griffin is trying to recreate the journey of the flaperon across the ocean, 371 00:37:33,920 --> 00:37:38,000 in the hope this will pinpoint the crash site. 372 00:37:42,560 --> 00:37:46,680 He compares the flaperon's movement to these buoys. 373 00:37:46,720 --> 00:37:54,240 Known as ocean drifters, they'r used daily all around the world to monitor ocean currents. 374 00:37:54,280 --> 00:37:57,960 DAVID: We very quickly determined that these replica flaperons moved about 375 00:37:58,000 --> 00:38:04,160 10 centimetres per second faster downwind than an oceanographic drifter. 376 00:38:05,400 --> 00:38:09,680 NARRATOR: That may not sound like much, but when he compares it to known data about 377 00:38:09,720 --> 00:38:14,840 the currents in the seventh arc on the day of the crash it help him estimate the flaperon's 378 00:38:14,880 --> 00:38:18,480 travels during the 500 days it was afloat. 379 00:38:25,000 --> 00:38:30,440 It's an extraordinary discovery 380 00:38:30,480 --> 00:38:34,360 To narrow the search zone even, further David Griffin investigates 381 00:38:34,400 --> 00:38:38,160 another strange feature of the debris. 382 00:38:38,200 --> 00:38:43,560 DAVID: In addition to knowing where things are found in Africa, 383 00:38:43,600 --> 00:38:48,840 the other key thing is where things have not been found and that's Australia. 384 00:38:48,880 --> 00:38:53,920 NARRATOR: Why has no debris been washed ashore in Australia 385 00:38:53,960 --> 00:38:59,040 Some of the ocean currents in the search area flow east towards the country. 386 00:38:59,080 --> 00:39:04,640 A plane crashing here should leave evidence on Australian beaches. 387 00:39:04,680 --> 00:39:09,240 DAVID: So this immediately tells us that all those potential parts 388 00:39:09,280 --> 00:39:13,760 of the seventh arc, where the flow is strongly towards Australia, 389 00:39:13,800 --> 00:39:15,080 they're essentially ruled out. 390 00:39:19,160 --> 00:39:23,760 NARRATOR: When David Griffin looks at the historic drifter data from the day MH370 391 00:39:23,800 --> 00:39:28,960 disappeared he finds three places on the seventh arc where the current would have pushed 392 00:39:29,000 --> 00:39:33,640 debris away from Australia towards Africa. 393 00:39:33,680 --> 00:39:39,760 DAVID: Here around 35, you have this area where everything is moving to the west. 394 00:39:39,800 --> 00:39:43,680 Again up at 31, everything's moving to the west. 395 00:39:43,720 --> 00:39:49,080 NARRATOR: If the plane crashed in one of these areas, it would explain why debris was not foun 396 00:39:49,120 --> 00:39:51,760 in Australia. 397 00:39:51,800 --> 00:39:57,240 And critically, only one of these locations matches his calculation of the flaperon's journey. 398 00:39:59,200 --> 00:40:03,720 DAVID: So that led us to propose that 35 south is the most likely area for the crash. 399 00:40:07,840 --> 00:40:15,720 NARRATOR: 35 south is an area that was not checked during the initial surface debris search. 400 00:40:15,760 --> 00:40:19,800 For investigators, it's an exciting new lead. 401 00:40:19,840 --> 00:40:21,880 But it comes too late. 402 00:40:21,920 --> 00:40:25,760 MINISTER: It is with some level of sadness, certainly with a great deal of frustration 403 00:40:25,800 --> 00:40:29,200 and disappointment that I stand here and acknowledge that the search, 404 00:40:29,240 --> 00:40:32,800 the underwater search area effort, has been suspended. 405 00:40:32,840 --> 00:40:39,880 NARRATOR: On January the 17th 2017, after almost three frustrating years, 406 00:40:39,920 --> 00:40:43,680 the search for MH 370 is called off. 407 00:40:43,720 --> 00:40:49,240 ANDY: Obviously I had strong feelings and am disappointed that we didn't find he aircraft 408 00:40:49,280 --> 00:40:55,520 but it's not for the technical abilities or the giving it full effort and feeling good about 409 00:40:55,560 --> 00:40:58,000 the job that we did at the time. 410 00:40:58,040 --> 00:41:02,960 PETER: It was record breaking in terms of the time it took and the area that was covered. 411 00:41:03,000 --> 00:41:07,480 There's never been a search as big by an order of magnitude. 412 00:41:11,760 --> 00:41:17,080 NARRATOR: But will David Griffin's flaperon experiment persuade authorities 413 00:41:17,120 --> 00:41:19,600 to search 35 degrees south? 414 00:41:21,880 --> 00:41:28,640 It takes almost a year to answer that question, and new evidence from the skies. 415 00:41:33,000 --> 00:41:40,880 [music] 416 00:41:40,920 --> 00:41:45,800 Oceanographer David Griffin has a new theory. 417 00:41:45,840 --> 00:41:52,120 He thinks MH370 is in an area called 35 south. 418 00:41:52,160 --> 00:41:57,240 And in 2017, he finds more evidence pointing to the same place. 419 00:41:58,560 --> 00:42:04,520 DAVID: I remember the day when I first saw those images in high resolution and I thought my God, 420 00:42:04,560 --> 00:42:06,640 this, this really helps. 421 00:42:09,120 --> 00:42:14,760 NARRATOR: Fifteen days after MH 370 disappeared, a French military satellite captured 422 00:42:14,800 --> 00:42:23,600 images of possible manmade debris in the vicinity of 35 south. 423 00:42:23,640 --> 00:42:30,560 At that time, the location wasn't considered a high priority area. 424 00:42:30,600 --> 00:42:35,520 But, four years later, it's a different story. 425 00:42:35,560 --> 00:42:37,800 DAVID: And I thought that this is really exciting. 426 00:42:37,840 --> 00:42:40,680 This could be used to restart the search. 427 00:42:45,560 --> 00:42:48,240 NARRATOR: A new year brings new hope. 428 00:42:48,280 --> 00:42:56,160 In January 2018, salvage compan Ocean Infinity sets out on a brand new, privately funded, mission. 429 00:42:58,960 --> 00:43:02,200 The seventh arc is still the focus. 430 00:43:02,240 --> 00:43:07,800 But they expand the width of th previous search zone and move towards the new area 431 00:43:07,840 --> 00:43:11,560 identified by David Griffin. 432 00:43:11,600 --> 00:43:20,840 Once again, Andy Sherrell is on board and this time he has eight autonomous underwater vehicles or AUVs. 433 00:43:22,720 --> 00:43:28,360 ANDY: One deep towed vessel would do a swing of about thirt days on site and over those 434 00:43:28,400 --> 00:43:33,080 thirty days on sight they would cover about 35 hundred square kilometres. 435 00:43:33,120 --> 00:43:38,560 Using eight AUVs simultaneously we can cover that in about three to four days. 436 00:43:40,760 --> 00:43:42,800 NARRATOR: It's a high stakes gamble. 437 00:43:42,840 --> 00:43:49,160 If they find nothing, they don't get paid. 438 00:43:49,200 --> 00:43:54,480 Ocean Infinity searches the new priority area at 35 south. 439 00:43:58,840 --> 00:44:06,480 In five months they cover an area almost equal in size to the original sea floor search. 440 00:44:09,400 --> 00:44:14,800 But frustratingly, they find no trace of MH370. 441 00:44:19,200 --> 00:44:25,640 The two search efforts have covered almost 92,000 square miles of sea floor 442 00:44:26,640 --> 00:44:32,520 fourteen times the size of the Air France 447 search zone. 443 00:44:32,560 --> 00:44:39,600 [music] 444 00:44:39,640 --> 00:44:47,600 In May 2018 the Malaysian government announces that it will not support any new searches. 445 00:44:47,640 --> 00:44:54,600 OFFICIAL: We cannot keep on searching for this 370 forever. 446 00:44:54,640 --> 00:44:59,200 NARRATOR: Is the wreckage of MH370 waiting to be discovered 447 00:44:59,240 --> 00:45:08,480 in the 386, 000 square miles of seventh arc search zone that remains unexplored? 448 00:45:08,520 --> 00:45:14,920 Do clues to the mystery lie a few feet outside the circle of light and knowledge already cas 449 00:45:14,960 --> 00:45:17,840 by the search teams? 450 00:45:17,880 --> 00:45:27,880 Only time, money and the continued desire for answers separate us from the moment of discovery. 451 00:45:27,920 --> 00:45:33,040 But the knowledge, hard won over two search efforts and four years, 452 00:45:33,080 --> 00:45:36,400 will be invaluable for any future hunt. 453 00:45:39,040 --> 00:45:43,400 Using the extraordinary data gathered by hundreds of investigators, 454 00:45:43,440 --> 00:45:50,760 we can drain the area around th seventh arc to reveal what MH37 might look like 455 00:45:50,800 --> 00:45:55,120 when it is found. 456 00:45:55,160 --> 00:46:00,160 The debris will stretch out over thousands of yards. 457 00:46:00,200 --> 00:46:04,360 The engines will be in one piece, the fuselage in thousands. 458 00:46:08,080 --> 00:46:13,160 The nearby black boxes will reveal if anyone was in the cockpit at the end. 459 00:46:16,080 --> 00:46:21,440 Emergency oxygen cylinders may show if the plane depressurized in flight, 460 00:46:21,480 --> 00:46:24,720 whether intentionally or the result of an accident. 461 00:46:26,360 --> 00:46:33,600 And personal electronic devices could reveal the experiences an fate of individual passengers and crew. 462 00:46:36,160 --> 00:46:42,600 It will be a profound moment, one that Andy Sherrell has experienced before. 463 00:46:42,640 --> 00:46:46,680 ANDY: It's a really surreal, kind of sombre moment because you realise all of a sudden 464 00:46:46,720 --> 00:46:53,240 that you have found this you, gravesite, this place where all these people perished. 465 00:46:53,280 --> 00:46:58,160 It's sad but it's also a bit of relief because you know that from that point forward 466 00:46:58,200 --> 00:47:00,760 some answers are going to come back. 467 00:47:00,800 --> 00:47:04,320 OLIVIER: I think you have to be to remain optimistic, and if you don't search, 468 00:47:04,360 --> 00:47:05,440 you don't find. 469 00:47:05,480 --> 00:47:08,280 So hopefully at the end you will find it.