WEBVTT 1 00:00:00.120 --> 00:00:04.879 Picture a massive ninety one ton Bowing seven twenty seven 2 00:00:05.040 --> 00:00:08.119 just roaring through the sky at three hundred kilometers per. 3 00:00:08.000 --> 00:00:10.199 Hour rereck and it is packed with people. 4 00:00:10.039 --> 00:00:12.560 Right, packed with people. And now I want you to 5 00:00:12.599 --> 00:00:16.519 picture a tiny, single engine training plane just kind of 6 00:00:16.559 --> 00:00:18.640 floating in that exact same airspace. 7 00:00:18.879 --> 00:00:20.480 It's quite the contrast, isn't it. 8 00:00:20.480 --> 00:00:24.079 It really is. In September nineteen seventy eight, these two 9 00:00:24.239 --> 00:00:29.160 drastically different aircraft collided and perfectly clear sunny skies over 10 00:00:29.239 --> 00:00:29.879 San Diego. 11 00:00:30.120 --> 00:00:32.159 And you know the crazy part is they didn't crash 12 00:00:32.200 --> 00:00:35.799 it because of an engine exploding or like a wing snapping. 13 00:00:35.479 --> 00:00:39.600 Off, no catastrophic mechanical failure at all. This devastating collision 14 00:00:39.719 --> 00:00:43.920 happened because of microscopic human blind spots, the psychology of 15 00:00:43.960 --> 00:00:48.200 alarm fatigue, and literally a single fatal misheard syllable on 16 00:00:48.240 --> 00:00:49.280 a radio transmission. 17 00:00:49.320 --> 00:00:51.399 It's chilling when you break it down. So really grasp 18 00:00:51.439 --> 00:00:53.240 how this happens. You have to place yourself in the 19 00:00:53.320 --> 00:00:55.560 environment of San Diego's Lindbergh Field. 20 00:00:55.399 --> 00:00:57.320 Which is kind of a crazy airport, right. 21 00:00:57.320 --> 00:01:00.640 Oh, it's a notoriously intense piece of aviation. Real it's 22 00:01:00.640 --> 00:01:03.679 the busiest single runway airport in North America. Yeah, but 23 00:01:03.759 --> 00:01:07.359 it sits directly next to this dense downtown city scape. 24 00:01:07.519 --> 00:01:10.640 You have high rise obstructions and then a very drastic 25 00:01:10.719 --> 00:01:13.319 terrain drop right before the runway, so. 26 00:01:13.280 --> 00:01:16.159 You're skimming over as skyscrapers basically essentially. 27 00:01:16.239 --> 00:01:20.959 Yeah, it's this steep, dramatic approach that demands total concentration. 28 00:01:21.439 --> 00:01:24.280 You don't just casually glide into San Diego. You are 29 00:01:24.359 --> 00:01:26.400 threading a massive needle. 30 00:01:26.239 --> 00:01:29.680 And threading that needle on this particular like beautiful cloudless 31 00:01:29.719 --> 00:01:34.239 morning is Pacific Southwest Airlines PSA flight one eight two. 32 00:01:34.239 --> 00:01:36.959 A massive Boeing seven to twenty seven. 33 00:01:36.920 --> 00:01:40.719 Exactly carrying one hundred and twenty eight passengers, and thirty 34 00:01:40.760 --> 00:01:43.519 of those passengers are actually PSA employees heading back to 35 00:01:43.519 --> 00:01:44.159 their home base. 36 00:01:44.359 --> 00:01:49.519 PSA was famous back then for this very fun, laid 37 00:01:49.519 --> 00:01:50.719 back corporate culture. 38 00:01:50.799 --> 00:01:53.519 Yeah. Their literal motto was catch our smile. They painted 39 00:01:53.560 --> 00:01:55.040 it right onto the nose of their planes. 40 00:01:55.120 --> 00:01:56.959 That's right. And up in the cockpit you have an 41 00:01:57.000 --> 00:01:59.159 incredibly seasoned crew super experience. 42 00:01:59.200 --> 00:02:01.760 There's a nine year veteran first officer at the controls 43 00:02:01.920 --> 00:02:04.959 and a seventeen year veteran captain sitting next to him. 44 00:02:04.840 --> 00:02:07.159 A guy who is widely regarded by his peers, is 45 00:02:07.239 --> 00:02:08.479 just you know, a born pilot. 46 00:02:08.639 --> 00:02:11.240 So in this deep dive you are going to piece 47 00:02:11.280 --> 00:02:14.400 together the puzzle of what was at the time the 48 00:02:14.479 --> 00:02:17.199 deadliest aviation disaster in US history. 49 00:02:17.719 --> 00:02:20.879 We're going to explore the cascading series of invisible eras 50 00:02:20.919 --> 00:02:24.840 that brought these two planes together because sharing that exact 51 00:02:24.879 --> 00:02:28.479 same busy airspace floating out there in the sprawling San 52 00:02:28.560 --> 00:02:32.599 Diego morning is a tiny Cessna one SEV two insider. 53 00:02:32.759 --> 00:02:35.960 Just two people, right, just a flight instructor and his student. 54 00:02:36.960 --> 00:02:38.560 The contrast is staggering. 55 00:02:38.680 --> 00:02:41.000 I mean, you have this absolute beast of a commercial 56 00:02:41.080 --> 00:02:44.360 jetliner descending rapidly and this little mosquito of a. 57 00:02:44.319 --> 00:02:50.280 Training plane, completely dwarfed in size, speed, and technological capability. 58 00:02:50.319 --> 00:02:52.360 So let's walk through the timeline leading up to nine 59 00:02:52.439 --> 00:02:55.240 zero zero am, because it reveals how quickly a routine 60 00:02:55.280 --> 00:02:57.159 morning just completely unravels. 61 00:02:57.240 --> 00:02:59.520 Right, Flight one eighty two is descending down the coast 62 00:02:59.520 --> 00:03:01.960 from Sacra. Down on the ground, you have the approach 63 00:03:02.000 --> 00:03:03.919 controller sitting in a darkened room in front of a 64 00:03:04.000 --> 00:03:06.879 radar screen roughly fifteen kilometers away. 65 00:03:06.759 --> 00:03:08.560 And he spots both of them he does. 66 00:03:08.759 --> 00:03:11.159 He spots the radar return of the little cessna flying 67 00:03:11.159 --> 00:03:12.159 ahead of the mass of seven to. 68 00:03:12.159 --> 00:03:14.919 Twenty seven, so he does his job. He executes his 69 00:03:14.960 --> 00:03:19.120 training flawlessly and radio's PSA one to eighty two, issuing 70 00:03:19.199 --> 00:03:22.240 a really clear warning. He says traffic at twelve o'clock 71 00:03:22.360 --> 00:03:23.719 three miles out, and. 72 00:03:23.680 --> 00:03:26.479 The veteran crew of the seven twenty seven acknowledges the 73 00:03:26.520 --> 00:03:32.479 warning immediately, but they radio back the phrase that ultimately seals. 74 00:03:32.120 --> 00:03:35.080 Their fate, right They say, got it, traffic in sight. 75 00:03:35.479 --> 00:03:38.919 That radio call changes everything, how so well, the moment 76 00:03:38.960 --> 00:03:42.240 the pilot says traffic in sight, the controller essentially hands 77 00:03:42.240 --> 00:03:45.400 over the responsibility for visual separation to the flight crew. 78 00:03:45.599 --> 00:03:47.639 So the controller is no longer in charge of keeping 79 00:03:47.639 --> 00:03:48.439 them apart. 80 00:03:48.400 --> 00:03:52.080 Exactly under the rules visual flight. The pilot has acknowledged 81 00:03:52.080 --> 00:03:55.439 the other aircraft and is now legally responsible for maintaining 82 00:03:55.439 --> 00:03:56.280 a safe distance. 83 00:03:56.599 --> 00:03:59.120 Okay, so it's kind of like two boats passing on 84 00:03:59.159 --> 00:04:03.039 an open lake. The overtaking boat is entirely responsible for 85 00:04:03.159 --> 00:04:04.759 watching out for the slower one. 86 00:04:04.840 --> 00:04:07.719 That's a perfect analogy. So the controller clears the seven 87 00:04:07.719 --> 00:04:10.800 to twenty seven for a visual approach inside the cockpit, 88 00:04:10.840 --> 00:04:13.280 the crews going through their final checklists. 89 00:04:12.759 --> 00:04:15.719 The cabin is secured, the heavy landing gear is coming down. 90 00:04:16.160 --> 00:04:18.800 By all accounts, it is a wonderfully routine. 91 00:04:18.439 --> 00:04:21.839 Descent until it suddenly violently isn't. 92 00:04:22.240 --> 00:04:25.079 Just before nine point zero am, the seven twenty seven 93 00:04:25.160 --> 00:04:27.480 essentially rear ends the Cessna mid air. 94 00:04:27.800 --> 00:04:30.879 The massive jet, moving with all that inertia at nearly 95 00:04:30.879 --> 00:04:34.199 three hundred kilometers per hour, just tears right through the 96 00:04:34.800 --> 00:04:36.480 much lighter, slower training plane. 97 00:04:36.639 --> 00:04:39.600 The physical physics of the impact are just devastating. 98 00:04:39.720 --> 00:04:42.240 Yeah. On the cockpit voice recorder, the suddenness of the 99 00:04:42.240 --> 00:04:45.360 catastrophe is chilling. There's the sound of the impact, a 100 00:04:45.399 --> 00:04:48.439 sharp intake of breath, and then alarms instantly blaring. 101 00:04:48.639 --> 00:04:52.000 The kinetic energy of the collision just destroys the seven 102 00:04:52.000 --> 00:04:55.160 to twenty seven's right wing right and its hydraulic lines. 103 00:04:55.279 --> 00:04:57.839 Yeah, it completely cripples it. The massive aircraft goes into 104 00:04:57.879 --> 00:04:59.680 an uncontrollable steep dive. 105 00:04:59.639 --> 00:05:02.759 And the the final heartbreaking words captured on the recording 106 00:05:02.839 --> 00:05:05.560 before the jet plunges to the earth are simply, mah, 107 00:05:05.800 --> 00:05:07.040 I love you God. 108 00:05:07.079 --> 00:05:09.279 It's just awful. And this wreckage doesn't fall into an 109 00:05:09.279 --> 00:05:10.920 empty desert or a body of water. 110 00:05:11.120 --> 00:05:15.519 No, Both planes plummet directly into the quiet, densely populated 111 00:05:15.560 --> 00:05:17.959 San Diego residential neighborhood of North Park. 112 00:05:18.199 --> 00:05:20.639 The seven twenty seven crashes at the intersection of Dwight 113 00:05:20.720 --> 00:05:21.800 and Nile Streets. 114 00:05:21.680 --> 00:05:24.160 And the pieces of the Cessana land about six walks 115 00:05:24.199 --> 00:05:25.680 away at thirty second in pulk. 116 00:05:25.839 --> 00:05:30.000 The apocalyptic kinetic energy of a ninety one ton jet 117 00:05:30.439 --> 00:05:33.279 hitting a neighborhood at that angle is I mean, it's 118 00:05:33.319 --> 00:05:34.800 almost impossible to comprehend. 119 00:05:34.920 --> 00:05:37.079 Twenty two homes are instantly pulverized. 120 00:05:37.199 --> 00:05:40.160 For the first responders and police officers rushing to the scene, 121 00:05:40.399 --> 00:05:43.920 that devastation is surreal. It looks less like a plane 122 00:05:43.959 --> 00:05:47.360 crash and more like a large military bomb had got off. 123 00:05:47.480 --> 00:05:51.800 Witnesses talked about a massive, towering mushroom cloud of black 124 00:05:51.839 --> 00:05:55.360 smoke and fire right visible to thousands of people across 125 00:05:55.399 --> 00:05:56.240 the entire city. 126 00:05:56.360 --> 00:05:59.279 Yeah, passenger seats and landing gear are embedded in the 127 00:05:59.319 --> 00:06:02.399 sides of romain houses. The smell of jet fuel and 128 00:06:02.439 --> 00:06:05.279 destruction is literally everywhere. 129 00:06:04.800 --> 00:06:08.160 And everyone on board both planes is dead, plus seven 130 00:06:08.199 --> 00:06:09.959 residents on the ground who just happened to be in 131 00:06:10.000 --> 00:06:12.480 their homes. That morning, one hundred and forty four people 132 00:06:12.519 --> 00:06:12.920 in total. 133 00:06:13.000 --> 00:06:14.360 It's a staggering loss of life. 134 00:06:14.519 --> 00:06:17.879 I can only imagine the sheer helplessness of those first responders. 135 00:06:18.240 --> 00:06:21.480 You know, they arrive with sirens blaring, adrenaline pumping, ready 136 00:06:21.480 --> 00:06:23.199 to pull people from the wreckage, and they just have 137 00:06:23.240 --> 00:06:24.000 to stand there. 138 00:06:24.120 --> 00:06:25.160 There is no one to save. 139 00:06:25.399 --> 00:06:28.480 They are reduced to covering bodies in a burning neighborhood. 140 00:06:28.839 --> 00:06:33.000 It is a profoundly grim task. When the National Transportation 141 00:06:33.120 --> 00:06:36.680 Safety Board gets the call, they deploy a lead investigator 142 00:06:37.120 --> 00:06:38.040 named Wally. 143 00:06:37.800 --> 00:06:41.639 Funk, and he arrives from Los Angeles to a scene 144 00:06:41.680 --> 00:06:46.000 that is just a sprawling, mangled mess of charred metal. 145 00:06:46.240 --> 00:06:50.959 As a seasoned investigator, his immediate overwhelming challenge is figuring 146 00:06:50.959 --> 00:06:53.759 out how to even begin putting this puzzle together. 147 00:06:53.600 --> 00:06:56.079 Because the wreckage only tells the final half second of 148 00:06:56.079 --> 00:06:57.319 the story right exactly. 149 00:06:57.399 --> 00:07:00.480 To figure out how a veteran flight crew over a 150 00:07:00.480 --> 00:07:02.959 plane right in front of them, he has to rewind 151 00:07:03.000 --> 00:07:03.439 the clock. 152 00:07:03.800 --> 00:07:06.279 Well, let's rewind that clock then, because honestly, I have 153 00:07:06.360 --> 00:07:08.680 to push back on the very premise of this airspace setup. 154 00:07:08.720 --> 00:07:09.360 Okay, go ahead. 155 00:07:09.519 --> 00:07:11.959 You have a massive commercial jet packed with one hundred 156 00:07:11.959 --> 00:07:15.800 and twenty eight people on an assigned high speed glide 157 00:07:15.839 --> 00:07:19.279 path to a major international airport, right, and you have 158 00:07:19.319 --> 00:07:23.279 a tiny student plane practicing maneuvers in the exact same spot. 159 00:07:23.800 --> 00:07:26.120 It seems insane to me that the sky doesn't have 160 00:07:26.199 --> 00:07:28.319 a right of way rule. How do you mean, like, 161 00:07:28.439 --> 00:07:31.439 if an ambulance has its sirens on, you pull your 162 00:07:31.480 --> 00:07:33.839 Honda Civic over to the shoulder. It feels like the 163 00:07:33.839 --> 00:07:36.399 Cessena shouldn't even be allowed in the way of a jetliner. 164 00:07:36.680 --> 00:07:39.639 You know, that is the single most common bias people 165 00:07:39.720 --> 00:07:41.800 have when looking at aviation crashes. 166 00:07:42.000 --> 00:07:42.360 Really. 167 00:07:42.519 --> 00:07:45.879 Oh yeah, The media and the general public immediately assumed 168 00:07:45.879 --> 00:07:48.360 it had to be the Cessena's fault. They figured it 169 00:07:48.399 --> 00:07:51.680 was just an inexperienced student pilot who wandered into the 170 00:07:51.720 --> 00:07:53.120 path of a real airliner. 171 00:07:53.399 --> 00:07:55.120 I mean, it's an easy assumption. 172 00:07:54.759 --> 00:07:58.600 To make, it is, but an investigator has to dismantle 173 00:07:58.680 --> 00:08:02.439 that assumption entirely. The sky in nineteen seventy eight did 174 00:08:02.480 --> 00:08:04.560 not work like a highway with emergency lanes. 175 00:08:04.639 --> 00:08:05.600 So how did it work. 176 00:08:05.879 --> 00:08:09.279 It was strictly a first come, first serve system. The 177 00:08:09.319 --> 00:08:12.519 Sessna had every legal right to be occupying that specific 178 00:08:12.519 --> 00:08:13.800 piece of airspace. 179 00:08:13.360 --> 00:08:16.399 Which means the airliner has to navigate around the tiny plane, 180 00:08:16.439 --> 00:08:18.120 no matter how inconvenient it. 181 00:08:18.079 --> 00:08:22.600 Is, precisely that. So to physically visualize this impossible scenario, 182 00:08:23.240 --> 00:08:26.680 investigator Wally Funk actually brought the recovered wreckage of the 183 00:08:26.720 --> 00:08:29.439 Sesta over to a hangar and laid it out next 184 00:08:29.480 --> 00:08:31.360 to the main seven twenty seven wreckage. 185 00:08:31.439 --> 00:08:33.600 Wow. Literally piecing it together physically. 186 00:08:33.759 --> 00:08:36.200 Yeah, he need to understand the spatial relationship. He had 187 00:08:36.240 --> 00:08:38.320 to look at the radar tracks to see the geometry 188 00:08:38.320 --> 00:08:39.360 of the collision, and. 189 00:08:39.279 --> 00:08:42.320 The radar tracks add a whole new layer of mystery 190 00:08:42.360 --> 00:08:44.200 to this, don't they They really do. 191 00:08:44.639 --> 00:08:47.480 The data shows that the Sessna actually drifted to the right, 192 00:08:47.919 --> 00:08:50.559 directly into the seven twenty sevens descending path. 193 00:08:50.759 --> 00:08:53.360 So if the Sessna had just flown perfectly straight, they 194 00:08:53.480 --> 00:08:54.919 likely wouldn't have collided. 195 00:08:55.080 --> 00:08:58.600 Most likely. Yes. The immediate question for Funk is why 196 00:08:58.639 --> 00:09:01.879 the Sessna drifted, and the answer lies in the cockpit 197 00:09:01.919 --> 00:09:05.480 of that small plane, specifically in what the student pilot 198 00:09:05.559 --> 00:09:05.960 was wearing. 199 00:09:06.120 --> 00:09:08.799 He had on something called a training hood, right, which 200 00:09:08.879 --> 00:09:11.600 is essentially a visor that restricts your vision. 201 00:09:11.840 --> 00:09:14.960 It's a black plastic shield that extends out from the 202 00:09:15.000 --> 00:09:18.360 forehead to block the pilot's view of the natural horizon 203 00:09:18.440 --> 00:09:19.480 outside the windows. 204 00:09:19.720 --> 00:09:21.960 Why would you want to block your view of the horizon. 205 00:09:22.080 --> 00:09:23.240 That sounds dangerous. 206 00:09:23.360 --> 00:09:25.720 Well, the whole point of the HOOD is sensory deprivation. 207 00:09:26.639 --> 00:09:29.919 It forces the student to ignore their outside environment and 208 00:09:30.080 --> 00:09:33.799 fly exclusively by referencing their glowing instrument panel. 209 00:09:33.919 --> 00:09:36.080 Oh, I see for training exactly. 210 00:09:36.159 --> 00:09:39.240 It's standard mandatory practice for getting an instrument rating. 211 00:09:39.480 --> 00:09:43.600 But human error happens, right like sometimes a student's gaze 212 00:09:43.639 --> 00:09:47.039 isn't scanning the altimeter and heading indicator fast enough. 213 00:09:47.320 --> 00:09:50.759 Yeah, and without the horizon for reference, the plane's heading 214 00:09:50.799 --> 00:09:51.879 will subtly drift. 215 00:09:52.120 --> 00:09:54.559 But wait, if we look at the timeline, even if 216 00:09:54.600 --> 00:09:57.799 the Sessana drifted slightly off course because of that training hood, 217 00:09:58.320 --> 00:10:00.759 PSA one eighty two had already told Air Traffic Control 218 00:10:00.799 --> 00:10:03.960 they had the Sessena insight. They did, and the NTSB 219 00:10:04.159 --> 00:10:07.960 did a massive visibility study during this investigation. Right, they 220 00:10:08.000 --> 00:10:10.200 mapped out the radar tracks, they mapped out the camera 221 00:10:10.279 --> 00:10:12.399 angles from the cockpit, and they found. 222 00:10:12.200 --> 00:10:15.159 That the PSA crew had one hundred and seventy seconds 223 00:10:15.159 --> 00:10:18.879 of completely unobstructed view of the Sessna through. 224 00:10:18.720 --> 00:10:22.399 Their windscreen nearly three full minutes of clear visibility. 225 00:10:22.480 --> 00:10:26.480 Almost three minutes. That is an absolute eternity in an airplane. 226 00:10:26.919 --> 00:10:29.639 So how do you miss a plane that is theoretically 227 00:10:29.679 --> 00:10:32.240 staring you in the face for one hundred and seventy seconds. 228 00:10:32.320 --> 00:10:33.159 That's a great question. 229 00:10:33.399 --> 00:10:35.720 It feels exactly like when someone gets into a car 230 00:10:36.240 --> 00:10:38.799 and to look cool or stretch out, they reclaim their 231 00:10:38.840 --> 00:10:40.679 car seats so far back and so low that they 232 00:10:40.679 --> 00:10:43.600 can barely see over the steering wheel. If they lower 233 00:10:43.639 --> 00:10:46.559 their seat, they are changing the geometry of their entire 234 00:10:46.639 --> 00:10:51.559 field division they accidentally create a massive blind spot right 235 00:10:51.600 --> 00:10:53.039 beneath the hood of their car. 236 00:10:53.519 --> 00:10:56.960 As shocking as it sounds, that is fundamentally what happened 237 00:10:56.960 --> 00:11:00.120 in the cockpit of that seven twenty seven. Wait really, yes, 238 00:11:00.600 --> 00:11:03.840 The engineers who designed the Boeing seven twenty seven built 239 00:11:03.879 --> 00:11:07.039 a very specific tool into the cockpit called the design 240 00:11:07.120 --> 00:11:08.200 eye reference point. 241 00:11:08.679 --> 00:11:09.720 What is that? 242 00:11:09.759 --> 00:11:13.080 These are literally little white balls aligned on the centerpost 243 00:11:13.159 --> 00:11:17.240 of the windscreen. The instruction is simple. You adjust the 244 00:11:17.240 --> 00:11:20.000 height of your pilot's seat until those balls line up 245 00:11:20.000 --> 00:11:22.039 in your vision and your eyes are now in the 246 00:11:22.080 --> 00:11:25.799 perfect mathematically optimal position to see out of the aircraft's 247 00:11:25.960 --> 00:11:27.399 complex window structure. 248 00:11:27.559 --> 00:11:29.600 But I'm guessing it wasn't a strict rule that you 249 00:11:29.679 --> 00:11:30.399 had to use them. 250 00:11:30.480 --> 00:11:33.600 It wasn't strictly enforced. Pilots come in all shapes and sizes, 251 00:11:33.720 --> 00:11:36.679 and over a long, tiring career, they tend to adjust 252 00:11:36.720 --> 00:11:39.039 the seat's lower for their own personal comfort. 253 00:11:38.799 --> 00:11:41.240 Or maybe to get a much better closer view of 254 00:11:41.279 --> 00:11:43.480 their instrument panel down below them. 255 00:11:43.679 --> 00:11:47.360 Exactly, And when the NTSB investigators recalculated that visibility study 256 00:11:47.600 --> 00:11:51.720 from this lower customized seat position, the mass changes completely. 257 00:11:51.879 --> 00:11:55.000 Oh wow, So that one hundred and seventy seconds of 258 00:11:55.120 --> 00:11:57.279 clearer visibility vanishes. 259 00:11:56.919 --> 00:12:01.200 Completely vanishes from that lower reclined seat angle. The Cessna 260 00:12:01.360 --> 00:12:03.720 was only visible in the seven to twenty seven's windscreen 261 00:12:03.799 --> 00:12:07.240 for about five to ten seconds. You're kidding, No, For 262 00:12:07.320 --> 00:12:09.960 the entire rest of the descent, the tiny plane was 263 00:12:10.000 --> 00:12:13.159 completely hidden in the massive blind spot below the nose 264 00:12:13.200 --> 00:12:13.639 of the jet. 265 00:12:13.799 --> 00:12:16.200 Five to ten seconds to spot a target before it 266 00:12:16.240 --> 00:12:18.559 disappears under your nose, and we have to factor in 267 00:12:18.559 --> 00:12:20.679 the visual environment too, right, It's not. 268 00:12:20.639 --> 00:12:23.000 Like the Cessna was painted neon orange against a pitch 269 00:12:23.039 --> 00:12:23.559 black sky. 270 00:12:23.759 --> 00:12:28.159 It was perfectly accidentally camouflaged. They are descending over the 271 00:12:28.200 --> 00:12:30.600 sprawling urban clutter of San Diego. 272 00:12:30.960 --> 00:12:35.399 You have a chaotic backdrop of white roofs, dark asphalt roads, 273 00:12:35.759 --> 00:12:39.480 sparkling lakes, and green trees. The background is constantly shifting 274 00:12:39.519 --> 00:12:40.879 and highly textured. 275 00:12:40.559 --> 00:12:43.000 And the Cessna is flying at roughly the same altitude 276 00:12:43.000 --> 00:12:45.679 and heading in the exact same direction as the jet. 277 00:12:45.440 --> 00:12:48.039 Which means it isn't creating much relative movement in the 278 00:12:48.039 --> 00:12:49.159 pilot's field of vision. 279 00:12:49.440 --> 00:12:53.320 And the human eye is evolutionarily wired to detect movement 280 00:12:53.440 --> 00:12:55.120 across a background exactly. 281 00:12:55.799 --> 00:13:00.120 A slow moving plane against a heavily cluttered, static looking 282 00:13:00.159 --> 00:13:03.840 city backdrop is almost impossible for the brain to pick 283 00:13:03.879 --> 00:13:07.600 out unless you were staring directly at its exact coordinates. 284 00:13:07.879 --> 00:13:10.200 Okay, that answers how they lost it in the background, 285 00:13:10.399 --> 00:13:13.080 but it raises a much more terrifying question for me. 286 00:13:13.279 --> 00:13:16.000 What's that If they couldn't see the Sessena because their 287 00:13:16.000 --> 00:13:18.919 seats were too low and the plane was camouflaged against 288 00:13:18.960 --> 00:13:22.039 the roofs of San Diego, then why on earth did 289 00:13:22.039 --> 00:13:24.799 the PSA crew tell the tower they had the traffic in. 290 00:13:24.799 --> 00:13:28.159 Sight To unravel that, the investigators had to listen obsessively 291 00:13:28.240 --> 00:13:31.799 to the cockpit voice recorder the CVR about thirty five 292 00:13:31.879 --> 00:13:33.080 seconds before the impact. 293 00:13:33.159 --> 00:13:33.919 What were they saying? 294 00:13:34.080 --> 00:13:37.360 The crew is recorded talking among themselves. They state that 295 00:13:37.399 --> 00:13:40.799 they see the plane at their one o'clock position, slightly 296 00:13:40.840 --> 00:13:43.799 to their right, and they specifically note that it is 297 00:13:43.799 --> 00:13:46.919 flying inbound, meaning it is flying toward them in the 298 00:13:46.960 --> 00:13:47.720 opposite direction. 299 00:13:48.000 --> 00:13:50.600 But the radar tracks proved the Cessna was actually at 300 00:13:50.639 --> 00:13:53.320 their eleven o'clock position, slightly to their left, and it 301 00:13:53.360 --> 00:13:55.120 was flying away from them in the same. 302 00:13:54.960 --> 00:13:58.559 Direction right, So the PSA pilots were describing a completely 303 00:13:58.559 --> 00:13:59.440 different aircraft. 304 00:13:59.559 --> 00:14:01.519 They weren't looking at the Cessna at all. 305 00:14:01.639 --> 00:14:02.320 No, they weren't. 306 00:14:02.519 --> 00:14:06.919 They safely cleared what was essentially a ghost plane. Basically, yeah, 307 00:14:06.960 --> 00:14:10.240 they genuinely believed they had identified the traffic the tower 308 00:14:10.279 --> 00:14:13.559 warned them about. They watched it pass, and they mentally 309 00:14:13.679 --> 00:14:16.840 checked the box and stopped looking. But how could there 310 00:14:16.960 --> 00:14:19.320 just be a ghost plane up there that air traffic 311 00:14:19.360 --> 00:14:20.879 control didn't know about. 312 00:14:21.559 --> 00:14:25.159 This requires understanding how radar worked in the nineteen seventies. 313 00:14:26.000 --> 00:14:29.960 During the investigation, sixteen different witnesses on the ground reported 314 00:14:30.039 --> 00:14:34.559 seeing other small aircraft in that exact airspace at that time. Okay, 315 00:14:34.759 --> 00:14:37.879 the problem is the difference between primary and secondary radar. 316 00:14:38.159 --> 00:14:41.639 Primary radar just bounces radio waves off metals, very basic, 317 00:14:41.720 --> 00:14:45.320 and secondary radar, secondary radar actively interrogates a device in 318 00:14:45.360 --> 00:14:49.120 the plane called a transponder, which pings back altitude and identity. 319 00:14:49.559 --> 00:14:53.200 Many small private planes back then simply didn't carry transponders. 320 00:14:53.279 --> 00:14:53.960 H I see. 321 00:14:54.039 --> 00:14:57.639 Yeah, Without a transponder pinging data, a small aircraft could 322 00:14:57.639 --> 00:15:01.159 be completely invisible to the approach controllers secondary radar screen. 323 00:15:01.480 --> 00:15:04.919 So the PSA pilots visually spotted one of these undocumented 324 00:15:04.960 --> 00:15:08.279 small planes, assumed it was their target and just moved on. 325 00:15:08.639 --> 00:15:09.159 Exactly. 326 00:15:09.799 --> 00:15:12.559 This brings us to the air traffic controllers, and we 327 00:15:12.639 --> 00:15:14.960 really need to look at the systems in that dark 328 00:15:15.039 --> 00:15:15.639 radar room. 329 00:15:15.840 --> 00:15:17.559 Yeah, it's a crucial part of the puzzle. 330 00:15:17.720 --> 00:15:20.240 Even if the pilots were confused by a ghost plane, 331 00:15:20.759 --> 00:15:23.000 the controllers have the Cessna and the seven to twenty 332 00:15:23.039 --> 00:15:27.519 seven on their screens, two glowing dots merging into one. 333 00:15:28.480 --> 00:15:30.600 Surely they had some kind of alarm system for this. 334 00:15:30.759 --> 00:15:33.600 We did, and this reveals the tragic irony of the 335 00:15:33.639 --> 00:15:36.279 new technology that had just been installed in the San 336 00:15:36.279 --> 00:15:39.080 Diego approach facility. They had a new system, they had 337 00:15:39.080 --> 00:15:42.679 a state of the art collision alert system programs specifically 338 00:15:42.679 --> 00:15:46.039 by computers to predict if two transponder equipped planes were 339 00:15:46.039 --> 00:15:46.480 going to hit. 340 00:15:46.639 --> 00:15:49.120 Well, it seems obvious that the alarm must have gone off. 341 00:15:49.240 --> 00:15:52.559 It did. The visual and auditory alarms triggered perfectly in 342 00:15:52.600 --> 00:15:53.600 the control room, but. 343 00:15:53.559 --> 00:15:55.720 They didn't radio the seven to twenty seven to pull 344 00:15:55.840 --> 00:15:57.679 up because of alarm fatigue, as. 345 00:15:57.519 --> 00:16:02.279 A deeply ingrained human psychological flaw. The controller heard the alarm, 346 00:16:02.759 --> 00:16:05.960 mentioned it to a supervisor, and then they wilfully ignored 347 00:16:06.000 --> 00:16:10.240 it because that brand new, highly sensitive system was horribly 348 00:16:10.320 --> 00:16:14.080 calibrated for the crowded San Diego airspace. It was giving 349 00:16:14.080 --> 00:16:17.480 them an average of thirteen false alarms every single day. 350 00:16:17.639 --> 00:16:21.399 Thirteen false alarms day means it just becomes background noise exactly. 351 00:16:21.559 --> 00:16:23.679 It's exactly like a car alarm going off on a 352 00:16:23.720 --> 00:16:26.840 busy city street. You don't think, oh, no, a grand 353 00:16:26.879 --> 00:16:29.279 theft auto is in progress. Your brain just filters it 354 00:16:29.320 --> 00:16:31.840 out and you think, wow, someone bumped a bumper. That's annoying. 355 00:16:32.360 --> 00:16:34.000 That is the perfect way to look at it. The 356 00:16:34.039 --> 00:16:36.600 controllers assumed it was just the system crying wolf. 357 00:16:36.399 --> 00:16:38.840 Again, and I suppose they felt that since the PSA 358 00:16:39.000 --> 00:16:43.039 jet had already confirmed visual contact over the radio. The 359 00:16:43.120 --> 00:16:46.240 pilots were actively handling the visual separation. 360 00:16:46.240 --> 00:16:50.360 Precisely under the operational guidelines of the time. The radar 361 00:16:50.399 --> 00:16:53.639 controller was not expected to intervene if visual rules were 362 00:16:53.679 --> 00:16:56.639 in effect, so they disregarded the flashing alert. 363 00:16:56.720 --> 00:16:59.080 But the radar controller hands the planes off to the 364 00:16:59.120 --> 00:17:01.960 local tower controller. Right, the guy looking out the window 365 00:17:02.080 --> 00:17:05.319 handling the final seconds before landing, and he didn't have 366 00:17:05.400 --> 00:17:07.880 that fancy new alarm system. He just had a regular 367 00:17:08.000 --> 00:17:10.640 radar display in his eyes, and he could see those 368 00:17:10.720 --> 00:17:14.279 two dots getting dangerously close. Yes, he could, so, about 369 00:17:14.319 --> 00:17:17.359 seventy seconds before the collision, he radios the seven to 370 00:17:17.400 --> 00:17:18.400 twenty seven to check in. 371 00:17:18.640 --> 00:17:21.440 And this is the moment the entire tragedy hinges on 372 00:17:22.000 --> 00:17:24.759 the final nail in the coffin comes down to how 373 00:17:24.759 --> 00:17:28.160 a single word is processed through the technology of the era. 374 00:17:28.680 --> 00:17:31.440 Because the PSA captain is now clearly unsure if he 375 00:17:31.519 --> 00:17:34.319 still sees the plane he thought was the Cessenet. 376 00:17:33.920 --> 00:17:35.240 Right, he's second guessing himself. 377 00:17:35.279 --> 00:17:37.480 He keys his microphone and says to the tower, I 378 00:17:37.480 --> 00:17:38.680 think he's passed off to. 379 00:17:38.680 --> 00:17:41.400 Our right, but that is not what the tower controller 380 00:17:41.440 --> 00:17:42.359 hears in his headset. 381 00:17:42.480 --> 00:17:46.559 Because of the reality of nineteen seventies VHF aviation radios, 382 00:17:47.119 --> 00:17:51.359 they are prone to static clipping and overlapping transmissions, very 383 00:17:51.400 --> 00:17:54.200 prone because of a burst of radio static At that 384 00:17:54.319 --> 00:17:57.880 exact millisecond the tower controller hears, I think he's passing 385 00:17:57.960 --> 00:17:58.599 off to our right. 386 00:17:58.920 --> 00:18:02.079 We really need to isolate the deadly psychological difference between 387 00:18:02.119 --> 00:18:05.519 those two words passed with an ed versus passing with 388 00:18:05.599 --> 00:18:06.160 an ing. 389 00:18:06.640 --> 00:18:09.079 If the pilot says he's passed off to our right, 390 00:18:09.480 --> 00:18:11.759 he is describing a historical event. 391 00:18:11.720 --> 00:18:13.960 Right, something he thinks has already concluded. 392 00:18:14.079 --> 00:18:16.799 It strongly implies he is no longer looking at the 393 00:18:16.839 --> 00:18:18.720 plane because it's behind him, and. 394 00:18:18.640 --> 00:18:22.599 More importantly, it implies a critical level of confusion. If 395 00:18:22.640 --> 00:18:25.680 the controller had clearly heard the word passed, he could 396 00:18:25.720 --> 00:18:28.359 have looked down at his radar screen, seeing that the 397 00:18:28.400 --> 00:18:31.640 seven twenty seven was actually still entirely behind the Cessna, 398 00:18:32.240 --> 00:18:37.000 and realized instantly that the pilot was completely dangerously mistaken. 399 00:18:36.599 --> 00:18:39.519 Because the physical threat was still directly in front of them. 400 00:18:39.640 --> 00:18:43.160 Exactly hearing the word passed would have triggered an immediate 401 00:18:43.160 --> 00:18:46.519