WEBVTT 1 00:00:00.040 --> 00:00:02.000 So I want you to picture a pitch black night 2 00:00:02.160 --> 00:00:07.559 in October. The year is nineteen ninety six. You're standing 3 00:00:07.639 --> 00:00:11.640 right on the tarmac at Jorge Hwavez International Airport in Lima, Peru. 4 00:00:12.160 --> 00:00:15.160 The air is really heavy, and there's just this dark 5 00:00:15.439 --> 00:00:18.320 expanse of the Pacific Ocean waiting just beyond the end 6 00:00:18.320 --> 00:00:18.879 of the runway. 7 00:00:18.960 --> 00:00:20.559 Right. It's a very atmospheric scene. 8 00:00:20.640 --> 00:00:23.559 Yeah, And roaring down that tarmac is Aero Peru flight 9 00:00:23.800 --> 00:00:26.359 six oh three. It's a state of the art, seventy 10 00:00:26.399 --> 00:00:29.640 five million dollars Boeing seven five seven, and it's bound 11 00:00:29.679 --> 00:00:33.679 for Santiago, Chili. Inside the cabin, you know, you've got 12 00:00:33.840 --> 00:00:37.759 sixty one passengers and nine crew members just settling into 13 00:00:37.759 --> 00:00:40.719 their seats, listening to that familiar hum of the jet engines. 14 00:00:40.799 --> 00:00:42.200 Just a totally normal flight. 15 00:00:42.000 --> 00:00:45.640 For them, exactly. But they are completely unaware that before 16 00:00:45.679 --> 00:00:49.240 the wheels even lifted off the pavement, a catastrophic, literal 17 00:00:49.240 --> 00:00:51.640 two cent mistake had already doomed their. 18 00:00:51.479 --> 00:00:53.840 Flight, which is just a chilling thing to visualize, because 19 00:00:53.840 --> 00:00:55.520 you know, what we're about to look at here isn't 20 00:00:55.520 --> 00:00:57.960 a mechanical failure in the traditional sense of the word. 21 00:00:58.119 --> 00:01:01.280 It's really the beginning of this agonizing thirty minute battle 22 00:01:01.320 --> 00:01:04.799 between man and machine. We're looking at a scenario where 23 00:01:04.840 --> 00:01:08.319 a highly advanced computer system, which was designed explicitly to 24 00:01:08.400 --> 00:01:11.560 keep humans safe, suddenly just turns against its crew in 25 00:01:11.599 --> 00:01:12.959 the total darkness of night. 26 00:01:13.159 --> 00:01:16.519 Yeah, and in this deep dive, we are stepping directly 27 00:01:16.560 --> 00:01:19.760 into the shoes of aviation accident investigators. We're going to 28 00:01:19.799 --> 00:01:25.280 meticulously reconstruct those horrific thirty minutes, decode the cockpit voice recorders, 29 00:01:25.599 --> 00:01:28.760 and unravel the whole chain of human errors that caused 30 00:01:28.799 --> 00:01:33.480 a perfectly fliable, entirely physically intact aircraft to plunge into 31 00:01:33.480 --> 00:01:35.280 the ocean. So, okay, let's unpack this. 32 00:01:35.439 --> 00:01:38.359 To really understand how things deteriorated so quickly, we have 33 00:01:38.439 --> 00:01:40.959 to look at who was actually at the controls that night. Okay, 34 00:01:41.319 --> 00:01:43.400 Aero PERU six oh three was in the hands of 35 00:01:43.439 --> 00:01:47.120 two of the airline's absolute best pilots. You had Captain 36 00:01:47.239 --> 00:01:49.799 Eric Schreiber, who was fifty eight years old, and first 37 00:01:49.799 --> 00:01:53.120 Officer David Fernandez, who was forty two. These were heavily 38 00:01:53.200 --> 00:01:56.239 seasoned veterans, right, they knew what they were doing absolutely, 39 00:01:56.280 --> 00:01:59.599 and they were flying a relatively new four year old 40 00:01:59.599 --> 00:02:02.799 Boeing seven fifty seven. I mean, this was the dawn 41 00:02:02.959 --> 00:02:07.519 of the new generation of computer controlled glass cockpit aircraft. 42 00:02:07.879 --> 00:02:11.120 Pilots were specifically trained to rely heavily on this central 43 00:02:11.199 --> 00:02:14.680 data system to reduce both mechanical and human errors. 44 00:02:14.800 --> 00:02:16.560 Yeah, and you can see that confidence. I mean, they 45 00:02:16.560 --> 00:02:19.240 go through their pre flight checklists and the captain even 46 00:02:19.240 --> 00:02:22.120 makes a joke on the voice recorder about their precision. 47 00:02:22.159 --> 00:02:24.879 He says something like not even Swiss, you know, joking 48 00:02:24.879 --> 00:02:27.560 about how on time they are. And the takeoff roll 49 00:02:27.680 --> 00:02:31.080 is just absolutely flawless. They hit their speeds, they rotate, 50 00:02:31.199 --> 00:02:34.800 lift off, the landing gear comes up smoothly. But then 51 00:02:35.120 --> 00:02:39.199 almost immediately the nightmare begins. The ltimeters, which are the 52 00:02:39.240 --> 00:02:43.280 primary altitude instruments on their screens, they are inexplicably stuck 53 00:02:43.319 --> 00:02:45.960 at zero like they are climbing up, but the plane 54 00:02:45.960 --> 00:02:46.919 says they are still. 55 00:02:46.680 --> 00:02:48.199 On the ground, which is terrifying. 56 00:02:48.319 --> 00:02:50.680 It is, so, before we get into the ensuing panic, 57 00:02:50.719 --> 00:02:52.960 can you just explain the mechanics here, like, how does 58 00:02:52.960 --> 00:02:55.479 a modern jet actually know how high up it is? 59 00:02:55.759 --> 00:02:58.400 Well, it's a great question, and it's completely fundamental to 60 00:02:58.439 --> 00:03:03.560 this entire tragedy. Aircraft determine altitude and speed using something 61 00:03:03.639 --> 00:03:08.159 called the pittastatic system. Okaystatic, Yeah, simply put, these are 62 00:03:08.280 --> 00:03:12.520 small external sensors located on the outside of the fuselage. 63 00:03:12.599 --> 00:03:16.159 You have static ports, which are basically just small flush 64 00:03:16.199 --> 00:03:18.719 holes on the side of the plane that measure ambient 65 00:03:18.840 --> 00:03:19.960 outside air pressure. 66 00:03:20.039 --> 00:03:20.400 Got it. 67 00:03:20.960 --> 00:03:23.800 As a plane climbs higher into the atmosphere, obviously, the 68 00:03:23.840 --> 00:03:27.319 air gets thinner and the pressure drops. The altimeter measures 69 00:03:27.360 --> 00:03:30.759 that drop in pressure and basically translates it into altitude 70 00:03:30.800 --> 00:03:31.360 on the screen. 71 00:03:31.560 --> 00:03:34.039 So if the altimeters are stuck in zero, that means 72 00:03:34.120 --> 00:03:36.719 those static chords aren't sensing any change in outside air 73 00:03:36.719 --> 00:03:39.520 pressure at all. Yeah, the computer basically thinks they're still 74 00:03:39.520 --> 00:03:41.639 just sitting on the runway at sea level exactly. 75 00:03:41.919 --> 00:03:44.879 But it doesn't stop with the altitude. The air speed 76 00:03:44.879 --> 00:03:48.039 indicators also start to fail on them. Yeah, because air 77 00:03:48.080 --> 00:03:50.919 speed is measured by the pit to tubes. These are 78 00:03:51.000 --> 00:03:54.280 little forward facing probes that stick out and catch the 79 00:03:54.400 --> 00:03:57.159 ram air as we call it. As the plane flies forward, 80 00:03:57.719 --> 00:04:00.479 the computer compares that high pressure ram air entering the 81 00:04:00.479 --> 00:04:03.319 front of the pit to tube with the ambient still 82 00:04:03.360 --> 00:04:04.639 air from the static port. 83 00:04:04.879 --> 00:04:07.240 So it's using the difference between the two to figure. 84 00:04:06.919 --> 00:04:10.400 Out the speed right exactly. The difference between those two 85 00:04:10.439 --> 00:04:13.280 pressures tells the plane exactly how fast it's moving through 86 00:04:13.280 --> 00:04:16.439 the air. But at the static port is compromised, your 87 00:04:16.519 --> 00:04:20.079 air speed calculations are completely corrupted to wow. 88 00:04:20.519 --> 00:04:23.279 So they are climbing out over the dark Pacific Ocean. 89 00:04:23.560 --> 00:04:26.279 There are no city lights reflecting below them, there is 90 00:04:26.319 --> 00:04:29.319 no visible horizon ahead of them, and they have zero 91 00:04:29.519 --> 00:04:32.040 accurate data on how high they are or how fast 92 00:04:32.079 --> 00:04:34.639 they're going. I mean, they are flying entirely blind. 93 00:04:34.839 --> 00:04:37.759 They are. And that's when the plane's central flight computers, 94 00:04:37.839 --> 00:04:40.519 sensing that the aerodyamic physics aren't making any sense anymore, 95 00:04:40.879 --> 00:04:44.319 begin to flood the pitch black cockpit with alarm, just 96 00:04:44.360 --> 00:04:47.759 a wall of noise, a literal wall of noise. First, 97 00:04:47.800 --> 00:04:50.680 they get a rudder ratio warning, which triggers an amber 98 00:04:50.759 --> 00:04:53.680 light and a really loud horn. The rudder steers the 99 00:04:53.680 --> 00:04:57.040 plane left and right, and normally the system restricts how 100 00:04:57.120 --> 00:05:00.199 much the rudder can physically move as the plane goes faster, 101 00:05:00.639 --> 00:05:03.240 just so a sudden pilot input doesn't snap the tail 102 00:05:03.279 --> 00:05:03.879 off right. 103 00:05:03.920 --> 00:05:04.720 That makes sense, but. 104 00:05:04.680 --> 00:05:06.839 Because the computer has no idea how fast the plane 105 00:05:06.839 --> 00:05:09.519 is flying, it just throws a fault warning, and next 106 00:05:09.560 --> 00:05:12.399 the autopilot simply gives up and disconnects entirely. 107 00:05:12.759 --> 00:05:15.600 I actually noticed in the accident reports that right after 108 00:05:15.639 --> 00:05:19.240 the autopilot disconnects they get something called a mock trim warning. 109 00:05:19.519 --> 00:05:21.439 What on earth is mock trim? 110 00:05:21.480 --> 00:05:24.360 So when a heavy jet flies at very high speeds, 111 00:05:24.399 --> 00:05:27.600 like approaching the speed of sound, the aerodynamic center of 112 00:05:27.720 --> 00:05:31.839 lift on the wing physically moves backward. This causes the 113 00:05:31.879 --> 00:05:34.519 nose of the aircraft to pitch down heavily, which is 114 00:05:34.560 --> 00:05:38.279 something called mock tuck. The mock trim system automatically adjusts 115 00:05:38.319 --> 00:05:40.959 the elevators on the tail to keep the nose level 116 00:05:40.959 --> 00:05:41.879 at those high speeds. 117 00:05:42.000 --> 00:05:44.240 But I'm guessing it needs the speed data to do that. 118 00:05:44.600 --> 00:05:47.560 Exactly, to do that, the computer needs to know your speed. 119 00:05:48.120 --> 00:05:52.000 Without speed data, the system fails, triggering a master caution 120 00:05:52.199 --> 00:05:55.439 and a master warning. So now they have blaring red 121 00:05:55.480 --> 00:05:58.199 lights and another loud oral alarm. 122 00:05:58.439 --> 00:06:01.160 It's just a relentless cask of noise. Like, let's put 123 00:06:01.160 --> 00:06:03.079 ourselves in that cockpit for a second and think about 124 00:06:03.079 --> 00:06:06.680 the psychological terror of this. Imagine you are driving down 125 00:06:06.720 --> 00:06:10.680 a pitch black, winding Mountain Highway at night, you can't 126 00:06:10.680 --> 00:06:14.480 see out the windows. Suddenly your speometer starts violently fluctuating 127 00:06:14.480 --> 00:06:16.519 from zero to one hundred and twenty miles per hour. 128 00:06:16.839 --> 00:06:19.879 Your GPS map just starts spinning in rapid circles, and 129 00:06:19.920 --> 00:06:23.480 your car's central computers starts screaming in audio alarm that 130 00:06:23.560 --> 00:06:27.160 you are somehow simultaneously driving in reverse and accelerating into 131 00:06:27.199 --> 00:06:27.560 a wall. 132 00:06:27.759 --> 00:06:29.160 That is a perfect analogy. 133 00:06:29.279 --> 00:06:33.040 It's just entirely disorienting, Like without visual references outside, your 134 00:06:33.079 --> 00:06:35.480 brain just cannot process what the machine is telling you. 135 00:06:35.920 --> 00:06:40.519 That analogy perfectly captures the psychological overload they were experiencing. 136 00:06:41.160 --> 00:06:44.439 The plane's computer was generating all these cryptic advisories which 137 00:06:44.480 --> 00:06:47.439 were designed to help, but because the foundational data that 138 00:06:47.480 --> 00:06:50.439 static air pressure was corrupt, the warnings just created a 139 00:06:50.560 --> 00:06:52.040 terrifying maze of confusion. 140 00:06:52.399 --> 00:06:52.560 Yea. 141 00:06:52.720 --> 00:06:55.279 And what's truly tragic here is that despite all of 142 00:06:55.279 --> 00:06:59.639 this electronic screaming, the physical aircraft was perfectly fine. Captain 143 00:06:59.639 --> 00:07:02.959 Schreiber could have kept that plane aloft for hours, but 144 00:07:03.240 --> 00:07:06.240 very sensibly he decided to turn back to Lima first. 145 00:07:06.279 --> 00:07:10.079 After Fernandez gets on the radio and immediately declares an emergency. 146 00:07:09.839 --> 00:07:12.319 Right, They tell the air traffic controller in Lima they 147 00:07:12.319 --> 00:07:15.879 have no basic instruments. They desperately ask for help. They 148 00:07:15.959 --> 00:07:18.360 essentially ask the tower to tell them their speed and 149 00:07:18.360 --> 00:07:21.439 their altitude from the ground radar. And here's where a 150 00:07:21.480 --> 00:07:24.040 momentary sense of relief kind of washes over the cockpit 151 00:07:24.240 --> 00:07:27.480 because the tower comes back and confidently reports that the 152 00:07:27.480 --> 00:07:28.319 plane is climbing. 153 00:07:28.399 --> 00:07:30.079 Yeah, a huge sigh of relief for them. 154 00:07:30.279 --> 00:07:33.120 Exactly. The controller says they are at four thousand feet, 155 00:07:33.399 --> 00:07:36.399 then six thousand, and eventually the tower confirms they are 156 00:07:36.439 --> 00:07:39.600 maintaining a safe altitude of nine thousand, seven hundred feet. 157 00:07:40.079 --> 00:07:42.680 So the pilots are reassured. They think, okay, our screens 158 00:07:42.680 --> 00:07:44.959 are broken, but the tower has eyes on us. 159 00:07:45.040 --> 00:07:47.399 But this is where the technical reality of the situation 160 00:07:47.560 --> 00:07:51.040 turns a crisis into a fatal trap. The air traffic 161 00:07:51.079 --> 00:07:54.160 controller genuinely believe he was helping them, but you have 162 00:07:54.199 --> 00:07:57.439 to really understand how air traffic control radar actually works. 163 00:07:57.720 --> 00:07:59.000 Okay, break that down for us. 164 00:07:59.360 --> 00:08:02.839 His radar screen was not calculating the plane's true altitude 165 00:08:02.879 --> 00:08:07.160 independently by say, bouncing a radio wave off the metal 166 00:08:07.199 --> 00:08:09.839 hull of the Boeing. That would be called primary radar. 167 00:08:10.279 --> 00:08:14.439 In commercial aviation, controllers rely heavily on secondary surveillance radar, 168 00:08:14.560 --> 00:08:17.360 which basically interrogates the aircraft's transponder. 169 00:08:17.480 --> 00:08:20.279 Wait, man, are you saying the transponder gets its data 170 00:08:20.279 --> 00:08:21.439 from the plane's own computer. 171 00:08:21.759 --> 00:08:22.600 I am. 172 00:08:23.040 --> 00:08:25.959 So the broken aircraft was lying to the pilots, lying 173 00:08:25.959 --> 00:08:28.680 to the transponder, beaming that lied down to the tower, 174 00:08:28.959 --> 00:08:31.120 and then the tower was just echoing that exact same 175 00:08:31.199 --> 00:08:33.360 lie back up to the cockpit as if it were 176 00:08:33.360 --> 00:08:34.360 a confirmed fact. 177 00:08:34.600 --> 00:08:38.039 That is precisely what happened. The plane's erratic air data 178 00:08:38.039 --> 00:08:41.080 computer was sending junk altitude readings down to the radar 179 00:08:41.200 --> 00:08:44.240 unit in LIMA, and the controller was just reading those 180 00:08:44.240 --> 00:08:46.039 exact same junk numbers back to the crew. 181 00:08:46.720 --> 00:08:50.399 Wow. That is an absolutely devastating design flaw. I mean, 182 00:08:50.799 --> 00:08:54.519 it's like a doctor asking a delirious, hallucinating patient what 183 00:08:54.559 --> 00:08:57.879 their heart rate is, writing it down, and then reassuring 184 00:08:57.919 --> 00:09:00.720 the patient that their vitals are perfectly fine because the 185 00:09:00.799 --> 00:09:04.480 chart says so, all without ever actually checking a real monitor. 186 00:09:04.600 --> 00:09:06.720 That is a brilliant way to put it. Honestly, it 187 00:09:06.799 --> 00:09:10.240 highlights a really critical mental model we use in systems engineering, 188 00:09:10.279 --> 00:09:11.840 which is false redundancy. 189 00:09:11.960 --> 00:09:12.840 False redundancy. 190 00:09:12.919 --> 00:09:15.600 Yeah, a redundant safety system is only as strong as 191 00:09:15.600 --> 00:09:18.519 its independent data sources. If two systems are relying on 192 00:09:18.559 --> 00:09:21.919 the exact same corrupted data stream, you don't have redundancy 193 00:09:21.960 --> 00:09:24.720 at all. You just have an echo chamber. The pilots 194 00:09:24.720 --> 00:09:27.000 thought they had an independent lifeline, but they were actually 195 00:09:27.000 --> 00:09:29.240 just being poisoned by their own corrupted. 196 00:09:28.879 --> 00:09:32.360 Data and that false sense of security really sets the 197 00:09:32.399 --> 00:09:36.320 stage for the most contradictory, totally impossible moments of the 198 00:09:36.480 --> 00:09:39.360 entire flight, because while the tower is telling them they 199 00:09:39.360 --> 00:09:42.559 are safe at nearly ten thousand feet, the plane's computer 200 00:09:42.720 --> 00:09:44.440 just completely loses its mind. 201 00:09:44.679 --> 00:09:47.000 Right, we reach a point where the pilots are trying 202 00:09:47.000 --> 00:09:50.120 to manage their descent back to Lima, but the airspeed 203 00:09:50.120 --> 00:09:54.120 indicator on the captain's screen suddenly plummets to zero, and 204 00:09:54.159 --> 00:09:56.159 then it races all the way up to over three 205 00:09:56.279 --> 00:10:00.720 hundred and fifty knots. They get a really loud over speed. 206 00:10:00.440 --> 00:10:03.320 Warning, and overspeed means what exactly it means? 207 00:10:03.360 --> 00:10:06.360 The computer thinks the plane is flying so incredibly fast 208 00:10:06.759 --> 00:10:10.080 that the aerodynamic forces will literally rip the wings off 209 00:10:10.080 --> 00:10:11.240 the aircraft in midair. 210 00:10:11.399 --> 00:10:13.480 Okay, so their natural reaction is to throw on the 211 00:10:13.519 --> 00:10:16.720 speed brakes, trying to slow this massive jet down. But 212 00:10:16.879 --> 00:10:20.600 almost immediately, while that overspeed alarm is still blaring in 213 00:10:20.600 --> 00:10:23.960 their ears, they get a stall warning. The computers now 214 00:10:24.000 --> 00:10:25.600 saying they're falling out of the. 215 00:10:25.600 --> 00:10:27.879 Sky, completely conflicting information. 216 00:10:28.279 --> 00:10:30.879 Yeah, before we get to the pilot's reaction, I just 217 00:10:30.960 --> 00:10:33.600 want to clarify something for our listeners who might just 218 00:10:33.639 --> 00:10:36.200 think of a stall as like, you know, a car 219 00:10:36.240 --> 00:10:39.879 engine dying. Can you explain the actual aerodynamics of an 220 00:10:39.919 --> 00:10:43.080 aviation stall, like what is mechanically happening to the wing? 221 00:10:43.240 --> 00:10:45.879 Absolutely, an aerodynamic stall has absolutely nothing to do with 222 00:10:45.919 --> 00:10:48.200 the jet engines. It's all about the angle of attack, 223 00:10:48.240 --> 00:10:50.639 which is the angle at which the wing meets the 224 00:10:50.679 --> 00:10:53.320 oncoming air. Okay, So, for a wing to generate lift, 225 00:10:53.960 --> 00:10:57.679 air has to flow smoothly over the curved top surface. 226 00:10:58.000 --> 00:10:59.919 If the plane flies too slow or if the no 227 00:11:00.279 --> 00:11:03.279 is pitched up way too high, that smooth airflow basically 228 00:11:03.320 --> 00:11:06.679 detaches from the wing. It becomes turbulent. When that boundary 229 00:11:06.720 --> 00:11:10.200 layer of air separates, the wing instantly loses its lift 230 00:11:10.240 --> 00:11:13.799 and gravity just takes over. The plane literally drops out 231 00:11:13.799 --> 00:11:16.720 of the sky. When this happens, it triggers a stick shaker. 232 00:11:17.440 --> 00:11:21.600 The pilot's control column begins vibrating violently, just aggressively shaking 233 00:11:21.600 --> 00:11:24.399 their hands to physically warn them that the wings are failing. 234 00:11:24.679 --> 00:11:27.480 So we have an overspeed warning screaming that they are 235 00:11:27.519 --> 00:11:31.039 flying too fast, and a violent stick shaker vibrating their 236 00:11:31.159 --> 00:11:33.440 arms to the bone saying they are flying too slow 237 00:11:33.759 --> 00:11:37.759 at the exact same second. Yes, how is that even 238 00:11:37.799 --> 00:11:40.720 physically possible? I know you said the sensors are broken, 239 00:11:40.759 --> 00:11:44.080 but how does the computer calculate two extreme opposites at once. 240 00:11:44.279 --> 00:11:46.360 This goes back to the physics of that trapped air 241 00:11:46.399 --> 00:11:50.559 we discussed earlier. Remember, the static port was somehow sealed 242 00:11:50.559 --> 00:11:54.519 at sea level, so it trapped thick, dense, high pressure 243 00:11:54.559 --> 00:11:57.879 air inside the system. Okay, as the plane climbed up 244 00:11:57.919 --> 00:12:00.799 to what it thought was ten thousand feet, the outside 245 00:12:00.879 --> 00:12:04.200 air actually became very thin and low pressure, but the 246 00:12:04.240 --> 00:12:07.600 static port couldn't sense it. So the airspeed computer is 247 00:12:07.639 --> 00:12:10.639 looking at the dynamic PTO tube which is bringing in 248 00:12:10.960 --> 00:12:14.000 real thin air from the sky and comparing it against 249 00:12:14.039 --> 00:12:16.600 that trapped, thick sea level air in the static port. 250 00:12:16.679 --> 00:12:20.440 Oh easy, because of that massive artificial pressure differential, the 251 00:12:20.480 --> 00:12:23.799 computer miscalculates and decides that the plane must be flying 252 00:12:23.799 --> 00:12:27.320 at supersonic speeds, hence the overspeed alarm. 253 00:12:27.480 --> 00:12:29.440 But the plan wasn't actually flying that fast. 254 00:12:29.759 --> 00:12:32.559 No, it wasn't at all. In fact, because the pilots 255 00:12:32.559 --> 00:12:35.320 were terrified of tearing the plane apart from the overspeed warning, 256 00:12:35.600 --> 00:12:38.440 they pulled back the throttles and deployed the speed brakes. 257 00:12:39.080 --> 00:12:41.360 They slowed the plane down so much that the wings 258 00:12:41.480 --> 00:12:45.799 genuinely did lose lift. Wow, the actual physical wings began 259 00:12:45.840 --> 00:12:49.200 to stall. So the air speed computer, totally blind by 260 00:12:49.240 --> 00:12:53.639 the trapped air, was screaming overspeed, while the aerodynamic sensors 261 00:12:53.679 --> 00:12:56.639 on the wings, which were working perfectly fine, felt the 262 00:12:56.679 --> 00:12:59.039 loss of lift and triggered the stick shaker. 263 00:12:59.440 --> 00:13:02.159 It is an im possible paradox, like, if you speed 264 00:13:02.240 --> 00:13:03.720 up to fix the stall, you think you'll tear the 265 00:13:03.720 --> 00:13:06.200 plane apart. If you slow down to fix the overspeed, 266 00:13:06.200 --> 00:13:10.080 you drop into the ocean. And amid this absolute coffeity, 267 00:13:10.120 --> 00:13:12.159 I mean the amber lights, the red lights, the horns, 268 00:13:12.200 --> 00:13:15.159 the stick shaker, another voice suddenly cuts through the cockpit, 269 00:13:15.879 --> 00:13:18.840 the ground proximity warning system, A very calm, automated voice 270 00:13:18.840 --> 00:13:22.120 just says too low terrain and This. 271 00:13:22.000 --> 00:13:25.200 Is the great heartbreaking irony of Flight six oh three. 272 00:13:25.399 --> 00:13:27.559 Out of all the bells and whistles going off that night, 273 00:13:27.679 --> 00:13:30.600 the ground proximity warning was the only accurate alarm in 274 00:13:30.639 --> 00:13:31.440 the entire. 275 00:13:31.200 --> 00:13:33.120 Cockpit, which is just awful to think about. 276 00:13:33.360 --> 00:13:37.639 It is because it uses an independent radio altimeter that 277 00:13:37.679 --> 00:13:40.799 bounces a beam directly down at the ground. It was 278 00:13:40.879 --> 00:13:43.679 sensing their actual physical rate of descent. 279 00:13:43.519 --> 00:13:45.480 Toward the water, but they didn't believe it. 280 00:13:45.679 --> 00:13:48.159 How could they? I mean, they had been battered by 281 00:13:48.240 --> 00:13:51.519 false data and severe alarm fatigue for twenty five minutes, 282 00:13:52.000 --> 00:13:55.399 and tragically the air traffic controller had just reassured them 283 00:13:55.440 --> 00:13:59.080 again when the ground proximity alarm goes off. Captain Schreiber 284 00:13:59.080 --> 00:14:01.159 even asks the tower where you know? Are you sure 285 00:14:01.159 --> 00:14:04.159 you have us on radar? And the tower replies, yes, 286 00:14:04.279 --> 00:14:07.720 we have you. You are maintaining nine seven hundred feet. 287 00:14:07.840 --> 00:14:10.480 So they ignore the one machine telling them the truth. 288 00:14:10.720 --> 00:14:13.000 They just keep trying to fly the plane, trying to 289 00:14:13.039 --> 00:14:16.000 intercept an instrument landing signal, just trying to make sense 290 00:14:16.039 --> 00:14:19.080 of the absolute madness. The chilling climax comes when they 291 00:14:19.080 --> 00:14:21.480 ask the tower, what do we do with the landing gear? 292 00:14:21.759 --> 00:14:24.440 And in that split second the realization hits them. You 293 00:14:24.480 --> 00:14:26.759 could hear the impact on the voice recorder. The left 294 00:14:26.759 --> 00:14:30.600 wing violently clips the water. The aircraft flips, it cartwheels 295 00:14:30.639 --> 00:14:33.600 and sinks into the dark Pacific, taking all seventy lives 296 00:14:33.600 --> 00:14:34.120 with it. 297 00:14:34.120 --> 00:14:37.320 It is a truly devastating end to a very heroic struggle. 298 00:14:37.960 --> 00:14:40.240 They fought that plane all the way down to the water. 299 00:14:40.639 --> 00:14:42.600 But you know, when a plane crash is intact into 300 00:14:42.639 --> 00:14:45.639 the ocean, it becomes a ghost ship. For the investigators, 301 00:14:45.679 --> 00:14:48.679 the task is incredibly daunting. You basically have to reverse 302 00:14:48.679 --> 00:14:51.360 engineer the physical city of the aircraft solely from the 303 00:14:51.440 --> 00:14:53.559 digital screams left on the black boxes. 304 00:14:53.759 --> 00:14:57.360 Right, which brings us to Guido Fernandez. He had just 305 00:14:57.399 --> 00:15:01.240 been appointed Peru's lead accident investment instigator, and the very 306 00:15:01.279 --> 00:15:03.200 first call he gets at four point thirty in the 307 00:15:03.240 --> 00:15:06.919 morning is about aero PERU six ZH three. But this 308 00:15:07.080 --> 00:15:10.600 wasn't just his first case. The co pilot, David Fernandez, 309 00:15:10.960 --> 00:15:11.919 was his own nephew. 310 00:15:12.440 --> 00:15:15.519 You really have to admire his stoicism. Here he flies 311 00:15:15.559 --> 00:15:17.679 out to the crash site in a Navy helicopter. He 312 00:15:17.720 --> 00:15:19.799 meets with the air traffic controller whose account of the 313 00:15:19.799 --> 00:15:23.279 plane's altitude is just baffling to him. Recognizing the massive 314 00:15:23.279 --> 00:15:26.799 conflict of interest and the sheer technical complexity, Fernandez calls 315 00:15:26.799 --> 00:15:29.600 in the National Transportation Safety Board from the United States, 316 00:15:29.840 --> 00:15:32.480 bringing in an investigator named Richard Rodriguez. 317 00:15:32.799 --> 00:15:36.320 Yeah, and Rodriguez actually suggested that Fernandez step down because 318 00:15:36.320 --> 00:15:40.480 of the emotional conflict, but Fernandez refused. He stayed completely 319 00:15:40.519 --> 00:15:43.799 objective through the whole thing. So together they start looking 320 00:15:43.799 --> 00:15:47.480 at the evidence. The Peruvia Navy finds the wreckage and 321 00:15:47.519 --> 00:15:51.399 the debris field is very tight. Why is that specific 322 00:15:51.440 --> 00:15:52.600 detail so important? 323 00:15:52.799 --> 00:15:55.720 A tight debris field is a crucial piece of forensic evidence. 324 00:15:56.159 --> 00:15:58.559 If a plane breaks up in mid air, say from 325 00:15:58.600 --> 00:16:01.240 an explosion or from an act will overspeed that tears 326 00:16:01.240 --> 00:16:04.799 the wings off, the debris is scattered over miles of ocean. 327 00:16:05.480 --> 00:16:08.440 A tight concentrated debris field proves the seven to fifty 328 00:16:08.440 --> 00:16:11.759 seven hit the water entirely intact at a high speed. 329 00:16:12.440 --> 00:16:15.519 They were flying a perfectly healthy airplane right into the ocean. 330 00:16:15.840 --> 00:16:18.279 So the US Navy brings in these remote operated underwater 331 00:16:18.360 --> 00:16:20.799 vehicles to find the black boxes. They pulled the flight 332 00:16:20.879 --> 00:16:23.320 data and cockpit voice recorders from the ocean floor, and 333 00:16:23.360 --> 00:16:25.840 they immediately dropped them into coolers full of fresh water 334 00:16:26.320 --> 00:16:29.279 just to stop the corrosive salt water from destroying magnetic tapes. 335 00:16:29.399 --> 00:16:30.320 A very smart move. 336 00:16:30.600 --> 00:16:34.799 Yeah. Back in Washington, the NTSB digitizes the faint audio 337 00:16:35.480 --> 00:16:39.399 revealing the sheer, overwhelming chaos of the alarms, but the 338 00:16:39.480 --> 00:16:42.080 voice recorder really only tells them how the pilots reacted. 339 00:16:42.440 --> 00:16:44.559 The flight data recorder is what actually solves the. 340 00:16:44.519 --> 00:16:47.600 Mystery, precisely because when the NTSB looked at the data 341 00:16:47.639 --> 00:16:50.039 points on the graph for the flight, everything was chaotic, 342 00:16:50.200 --> 00:16:53.360 the air speed wildly swinging the pitch and roll all 343 00:16:53.360 --> 00:16:56.600 over the place, but the data line for static air 344 00:16:56.639 --> 00:17:01.000 pressure was perfectly flat, perfectly flat, from the moment the 345 00:17:01.039 --> 00:17:03.600 plane sat at the gate and lima to the moment 346 00:17:03.679 --> 00:17:06.640 it hit the water. The static pressure never changed a 347 00:17:06.720 --> 00:17:10.240 single millibar. It was just a straight horizontal line. The 348 00:17:10.279 --> 00:17:13.599 investigators knew immediately the static ports were sealed. 349 00:17:13.680 --> 00:17:16.440 Here's where it gets really interesting, because of that flatline 350 00:17:16.480 --> 00:17:18.519 on the graph, they know exactly what to look for, 351 00:17:18.559 --> 00:17:21.279 so they send the underwater robots back down scanning this 352 00:17:21.319 --> 00:17:25.400 submerged wreckage specifically for those static ports, and they find it. 353 00:17:25.920 --> 00:17:29.000 Captain Schreiber's static port was completely sealed over with a 354 00:17:29.039 --> 00:17:30.799 piece of standards silver duct tape. 355 00:17:30.839 --> 00:17:33.119 A single piece of tape on a seventy five million 356 00:17:33.160 --> 00:17:33.920 dollar machine. 357 00:17:34.000 --> 00:17:36.880 It's unbelievable, like, how does that even happen? As you 358 00:17:36.920 --> 00:17:39.880 dig into the NTSP reports, you see it's a textbook 359 00:17:39.920 --> 00:17:42.839 example of the Swiss cheese model of failure, where the 360 00:17:42.880 --> 00:17:47.559 holes in multiple layers of defense just perfectly align. Right 361 00:17:48.359 --> 00:17:51.200 before the flight, a maintenance worker was cleaning the outside 362 00:17:51.200 --> 00:17:54.759 of the plane. Standard procedures to cover the static ports 363 00:17:54.880 --> 00:17:57.200 so you don't get high pressure water or cleaning fluid 364 00:17:57.519 --> 00:18:02.000 inside those sensitive tubes, taped them over, but he forgot 365 00:18:02.000 --> 00:18:03.480 to take the tape off when he was done. 366 00:18:03.599 --> 00:18:06.559 That's the first hole in the cheese. Then the quality 367 00:18:06.559 --> 00:18:08.599 inspector who was supposed to sign off on his work 368 00:18:08.640 --> 00:18:12.559 simply didn't check it. Hole number two. The maintenance supervisor 369 00:18:12.599 --> 00:18:15.680 for that shift actually called in sick, and his replacement 370 00:18:15.720 --> 00:18:17.960 didn't notice the tape either. So there's hole number three. 371 00:18:17.839 --> 00:18:22.599 And finally whole number four. Captain Schreiber himself. Before every 372 00:18:22.640 --> 00:18:25.640 single flight, the pilot does a mandatory walk around to 373 00:18:25.720 --> 00:18:29.599 the aircraft to visually inspect it. But remember the context here. 374 00:18:29.599 --> 00:18:31.759 It was late at night. The static port on a 375 00:18:31.759 --> 00:18:34.680 Boeing seven fifty seven is fifteen to seventeen feet up 376 00:18:34.680 --> 00:18:34.960 in the air. 377 00:18:35.039 --> 00:18:35.559 That's high up. 378 00:18:35.640 --> 00:18:37.839 Yeah, and the worker had used standard silver duct tape 379 00:18:37.839 --> 00:18:41.240 which blended perfectly with the silver metallic fuselage of the 380 00:18:41.279 --> 00:18:44.880 aero Peru jet. Schreiber stood on the dark tarmac with 381 00:18:44.920 --> 00:18:47.640 a flashlight, looked up and he simply missed it. 382 00:18:47.799 --> 00:18:50.279 And when the plane took off, it carried that trapped 383 00:18:50.519 --> 00:18:53.839 sea level air pressure inside those taped overports, setting off 384 00:18:53.839 --> 00:18:56.400 the entire deadly chain reaction. We just discussed. 385 00:18:56.519 --> 00:18:59.680 It's staggering, but as we look at the source material, 386 00:18:59.720 --> 00:19:03.640 there's a detail that is just incredibly frustrating. This exact 387 00:19:03.640 --> 00:19:07.440 scenario had happened before. Just eight months prior, in February 388 00:19:07.519 --> 00:19:11.839 nineteen ninety six, a German charter flight called Burgeonaire crashed 389 00:19:11.880 --> 00:19:16.480 in the Dominican Republic. One hundred and eighty nine people died. Wow, 390 00:19:16.799 --> 00:19:18.519 it was a Boeing seven to fifty seven, It was 391 00:19:18.559 --> 00:19:21.039 at night, and it was caused by a block Pittow 392 00:19:21.079 --> 00:19:24.400 tube that triggered the exact same contradictory the rhetor ratio 393 00:19:24.400 --> 00:19:26.519 of the max trim, the overspeed, the stall warning. 394 00:19:26.640 --> 00:19:28.720 It was essentially a dress rehearsal for the Ara Peru 395 00:19:28.799 --> 00:19:30.279 disaster exactly. 396 00:19:30.559 --> 00:19:32.799 So if you were sitting there listening to this, you're 397 00:19:32.839 --> 00:19:36.079 probably screaming the same question I am. If this exact 398 00:19:36.119 --> 00:19:39.680 scenario just killed one hundred and eighty nine people, how 399 00:19:39.720 --> 00:19:43.079 on earth did the Aero Peru crew not know about it? 400 00:19:43.559 --> 00:19:47.200 How were they not trained to recognize this specific pattern 401 00:19:47.240 --> 00:19:47.839