1 00:00:04,517 --> 00:00:07,655 The Boeing 737 is one of the most popular 2 00:00:07,758 --> 00:00:09,310 passenger jets in the world. 3 00:00:12,000 --> 00:00:13,034 Around the globe, 4 00:00:13,137 --> 00:00:15,827 the plane has carried more than 12-billion passengers. 5 00:00:17,344 --> 00:00:19,586 It's the backbone of the aviation industry. 6 00:00:25,000 --> 00:00:29,379 But in 1991, something happened onboard a 737 that sent 7 00:00:29,482 --> 00:00:31,379 shudders through the world of aviation. 8 00:00:31,482 --> 00:00:35,724 Oh my lord. 9 00:00:35,827 --> 00:00:41,862 A deadly crash has investigators scrambling. 10 00:00:41,965 --> 00:00:43,689 There was a time 11 00:00:43,793 --> 00:00:45,862 when I had doubts that we'd be able to solve it. 12 00:00:45,965 --> 00:00:48,482 It was like he was tracking a serial killer. 13 00:00:48,586 --> 00:00:52,931 The hunt for answers 14 00:00:53,034 --> 00:00:56,241 will take ten long and grueling years. 15 00:00:56,344 --> 00:00:59,241 The fate of the airline industry hangs in the balance. 16 00:01:00,413 --> 00:01:02,068 And the mystery isn't solved, 17 00:01:02,172 --> 00:01:05,034 until more than 1-hundred and 50 people are dead. 18 00:01:33,827 --> 00:01:36,379 9:40 AM, March the 3rd 1991. 19 00:01:42,482 --> 00:01:45,344 After a short 17-minute trip from Denver, 20 00:01:45,448 --> 00:01:48,724 United Airlines Flight 585 is on final approach 21 00:01:48,827 --> 00:01:50,137 into Colorado Springs. 22 00:01:52,931 --> 00:01:55,931 It looks like a perfect day for flying. 23 00:01:56,034 --> 00:02:02,965 But there's trouble in the air. 24 00:02:03,068 --> 00:02:03,896 Nice looking day. 25 00:02:04,000 --> 00:02:05,551 Hard to believe the skies are unfriendly. 26 00:02:05,655 --> 00:02:10,448 There's been heavy turbulence during the flight, 27 00:02:10,551 --> 00:02:14,344 and violent gusts of wind are forecast over Colorado Springs. 28 00:02:14,448 --> 00:02:20,448 Never driven to Colorado Springs and not gotten sick. 29 00:02:20,551 --> 00:02:26,793 At the controls is 52-year-old 30 00:02:26,896 --> 00:02:28,586 Captain Harold Green, 31 00:02:28,689 --> 00:02:30,758 a pilot with 20 years' experience 32 00:02:30,862 --> 00:02:33,310 and a sterling reputation. 33 00:02:33,413 --> 00:02:36,275 Green's co-pilot is Patricia Eidson. 34 00:02:36,379 --> 00:02:39,586 At 42, she is one of the first female flight officers 35 00:02:39,689 --> 00:02:40,689 in United's history. 36 00:02:40,793 --> 00:02:44,241 Flight attendants prepare for landing. 37 00:02:55,551 --> 00:02:57,965 At Colorado Springs Municipal Airport, 38 00:02:58,068 --> 00:03:00,137 air traffic controller James Rayfield 39 00:03:00,241 --> 00:03:02,586 is ready to bring Flight 585 in. 40 00:03:02,689 --> 00:03:06,758 United 585 report the airport in sight. 41 00:03:06,862 --> 00:03:11,448 Got it? Yup. 42 00:03:11,551 --> 00:03:14,137 Airport in sight United 585. 43 00:03:14,241 --> 00:03:15,413 Lower landing gear. 44 00:03:15,517 --> 00:03:21,137 United 585 is cleared for a visual approach to runway 35. 45 00:03:21,241 --> 00:03:27,689 Weather conditions, wind 320 degrees at 16, gusting at 29. 46 00:03:27,793 --> 00:03:29,379 As its speed decreases, 47 00:03:29,482 --> 00:03:33,482 flight 585 becomes more vulnerable to the turbulence. 48 00:03:33,586 --> 00:03:35,413 Eidson wants to know what other planes have 49 00:03:35,517 --> 00:03:36,862 experienced on landing. 50 00:03:36,965 --> 00:03:39,896 Any reports lately of any loss or gain of airspeed? 51 00:03:40,000 --> 00:03:45,413 Yes ma'am. Five hundred feet a fifty knot loss, 52 00:03:45,517 --> 00:03:48,551 at four hundred feet a fifteen knot gain 53 00:03:48,655 --> 00:03:51,862 and at a hundred and fifty feet a gain of twenty knots. 54 00:03:51,965 --> 00:03:55,793 Sounds adventurous. Thank you. 55 00:03:55,896 --> 00:03:57,137 Starting on down. 56 00:03:57,241 --> 00:04:05,068 Less than three kilometers from the airport, 57 00:04:05,172 --> 00:04:07,310 retired policeman Harold Darnell 58 00:04:07,413 --> 00:04:09,206 is on his way to a local flea market. 59 00:04:12,275 --> 00:04:14,724 A kilometer overhead, Green and Eidson 60 00:04:14,827 --> 00:04:17,689 focus on keeping their speed constant as they descend. 61 00:04:19,482 --> 00:04:20,689 We had a ten knot change here. 62 00:04:20,793 --> 00:04:24,379 Yeah I know. Awful lot of power to hold that airspeed. 63 00:04:24,482 --> 00:04:29,896 As United 585 approaches the runway, 64 00:04:30,000 --> 00:04:32,000 Darnell feels something strange. 65 00:04:32,103 --> 00:04:33,724 Whoa! What the heck was that? 66 00:04:33,827 --> 00:04:37,000 Out of nowhere, a powerful gust of wind 67 00:04:37,103 --> 00:04:39,793 strikes his vehicle, almost blowing him off the road. 68 00:04:39,896 --> 00:04:44,689 Another ten knot gain. Thirty flaps. 69 00:04:44,793 --> 00:04:50,620 From the control tower, 70 00:04:50,724 --> 00:04:54,517 James Rayfield can now see flight 585's final approach. 71 00:04:57,620 --> 00:04:59,965 As the aircraft closes in on the airport, 72 00:05:00,068 --> 00:05:01,793 the ride gets even bumpier. 73 00:05:04,758 --> 00:05:08,310 Wow. We're at a thousand feet. 74 00:05:12,517 --> 00:05:13,827 Then, without warning, 75 00:05:13,931 --> 00:05:16,793 the 737 starts to spin out of control. 76 00:05:16,896 --> 00:05:17,931 Oh god. Flip! 77 00:05:22,793 --> 00:05:24,448 Fifteen flaps. Fifteen. 78 00:05:25,551 --> 00:05:26,793 Oh no 79 00:05:26,896 --> 00:05:27,862 Oh my god! Oh my god! Oh my god! 80 00:05:47,689 --> 00:05:49,586 Crash! Crash! 81 00:05:49,689 --> 00:06:03,137 Rescue workers arrive within minutes - 82 00:06:03,241 --> 00:06:05,206 but there is almost no sign of the 737. 83 00:06:08,758 --> 00:06:11,482 The shattered remains of the 38-ton jet 84 00:06:11,586 --> 00:06:14,448 lie buried in a fire-blackened impact crater. 85 00:06:14,551 --> 00:06:17,931 The plane didn't, it didn't skate or bounce, 86 00:06:18,034 --> 00:06:20,724 you know like, like when a plane comes in normally and lands? 87 00:06:20,827 --> 00:06:24,482 It just nosed right in and where it hit is where it stayed. 88 00:06:24,586 --> 00:06:26,344 And I came down here and this is 89 00:06:26,448 --> 00:06:29,344 when I saw all of the huh it was horrible. 90 00:06:29,448 --> 00:06:33,310 There are no survivors. 91 00:06:33,413 --> 00:06:36,482 All 20 passengers and 5 crew members are killed 92 00:06:36,586 --> 00:06:40,000 instantly by the high-speed impact and exploding jet fuel. 93 00:06:44,551 --> 00:06:48,758 In 10 violent seconds, Colorado Springs has become the site 94 00:06:48,862 --> 00:06:52,413 of one of the most mysterious air crashes in aviation history. 95 00:07:17,517 --> 00:07:21,000 By nightfall, investigators from the National Transportation 96 00:07:21,103 --> 00:07:23,896 Safety Board descend on Colorado Springs. 97 00:07:28,034 --> 00:07:32,068 Known to insiders as tin kickers, NTSB investigators 98 00:07:32,172 --> 00:07:35,724 examine over 2-thousand aviation accidents a year, 99 00:07:35,827 --> 00:07:39,310 at times by picking through the metal debris of fallen aircraft. 100 00:07:43,586 --> 00:07:47,517 While coroners mark the location of human remains in red, 101 00:07:47,620 --> 00:07:51,689 NTSB investigators mark scraps of metal in yellow, 102 00:07:51,793 --> 00:07:55,275 looking for clues to help them solve the mystery of flight 585. 103 00:08:01,896 --> 00:08:04,103 Like investigating a mass murder, 104 00:08:04,206 --> 00:08:06,482 it's a tough job walking onto a crash site. 105 00:08:09,000 --> 00:08:11,241 Among the investigators assigned to the case is 106 00:08:11,344 --> 00:08:15,448 Malcolm Brenner, a specialist in human performance. 107 00:08:15,551 --> 00:08:16,931 His job will be to find out 108 00:08:17,034 --> 00:08:19,137 if the crash was caused by pilot error. 109 00:08:19,241 --> 00:08:22,000 The area was cordoned off by police 110 00:08:22,103 --> 00:08:25,275 and there were Salvation Army trucks. 111 00:08:25,379 --> 00:08:28,724 I got a cup of coffee, a cup of hot chocolate or something 112 00:08:28,827 --> 00:08:30,275 and I thanked them for it 113 00:08:30,379 --> 00:08:32,103 and they said no, no thank you and they had this 114 00:08:32,206 --> 00:08:34,724 look in their eyes like my god you have to go into this site. 115 00:08:34,827 --> 00:08:39,482 Clues to the fate of United 585 lie 116 00:08:39,586 --> 00:08:41,758 mangled in a deep, black hole. 117 00:08:43,689 --> 00:08:48,103 The fuselage is crushed like an accordion in the impact crater. 118 00:08:48,206 --> 00:08:50,827 The rest of the plane is in pieces spread over an area 119 00:08:50,931 --> 00:08:52,482 smaller than a football field. 120 00:08:52,586 --> 00:08:58,379 There was a lot of fire damage. 121 00:08:58,482 --> 00:09:00,137 There'd been a fire afterwards. 122 00:09:00,241 --> 00:09:03,620 And it was all contained in a relatively small area which, 123 00:09:03,724 --> 00:09:04,724 just initial impression, 124 00:09:04,827 --> 00:09:07,793 it can be a sign that the airplane was intact. 125 00:09:07,896 --> 00:09:09,724 If there was a midair explosion or something 126 00:09:09,827 --> 00:09:10,793 came off the airplane, 127 00:09:10,896 --> 00:09:13,931 you would expect that to be a much larger site. 128 00:09:14,034 --> 00:09:17,137 My first sense that it was going to take some time to 129 00:09:17,241 --> 00:09:21,103 investigate the accident was the damage that we saw to the parts. 130 00:09:21,206 --> 00:09:26,000 When they're burnt and broken, the process always takes longer. 131 00:09:26,103 --> 00:09:30,413 But with their work just beginning, members of 132 00:09:30,517 --> 00:09:35,344 the NTSB have no clue that the case of United 585 will become 133 00:09:35,448 --> 00:09:38,862 the longest crash investigation in aviation history. 134 00:09:42,793 --> 00:09:46,551 Fifteen flaps. Fifteen. 135 00:09:46,655 --> 00:09:49,206 A clear, late-winter day in 1991 136 00:09:49,310 --> 00:09:53,103 turned deadly in just ten short seconds. 137 00:09:53,206 --> 00:09:56,551 Moments from landing in Colorado Springs, United Airlines 138 00:09:56,655 --> 00:09:59,068 flight 585 fell out of the sky 139 00:09:59,172 --> 00:10:01,551 at 3-hundred and 70 kilometers per hour. 140 00:10:01,655 --> 00:10:06,034 Crash! Crash! 141 00:10:06,137 --> 00:10:09,068 All twenty passengers and five crew members died. 142 00:10:14,206 --> 00:10:16,448 The National Transportation Safety Board begins 143 00:10:16,551 --> 00:10:18,896 a painstaking investigation into the crash. 144 00:10:21,965 --> 00:10:24,931 Engine turbines, hydraulic pressure gauges, 145 00:10:25,034 --> 00:10:26,586 the cockpit voice recorder 146 00:10:26,689 --> 00:10:29,517 and in-flight data recorder are all carefully extracted 147 00:10:29,620 --> 00:10:33,172 from the site, photographed, and sent to the lab for analysis. 148 00:10:40,206 --> 00:10:42,689 An important first step in the investigation is 149 00:10:42,793 --> 00:10:44,931 the analysis of the cockpit voice recorder. 150 00:10:46,137 --> 00:10:48,896 With pilot error a factor in seventy percent of air 151 00:10:49,000 --> 00:10:53,000 disasters, Malcolm Brenner's job is to see what role pilots 152 00:10:53,103 --> 00:10:55,206 Green and Eidson played in the crash. 153 00:10:55,310 --> 00:10:59,275 This crew was, and I felt this at the time, 154 00:10:59,379 --> 00:11:02,551 was one of the more impressive crews I had ever dealt with. 155 00:11:02,655 --> 00:11:04,586 There was a little bit of tension release, 156 00:11:04,689 --> 00:11:05,758 a little bit of humour. 157 00:11:05,862 --> 00:11:07,068 The captain said... 158 00:11:07,172 --> 00:11:09,482 Never driven to Colorado Springs and not gotten sick. 159 00:11:09,586 --> 00:11:14,551 The first officer suggested that they add 160 00:11:14,655 --> 00:11:16,379 extra speed as a safety margin. 161 00:11:16,482 --> 00:11:18,517 The captain agreed with it. It was good interaction. 162 00:11:19,758 --> 00:11:21,724 Got it? Yup. 163 00:11:21,827 --> 00:11:23,241 Airport in sight United 585. 164 00:11:23,344 --> 00:11:25,172 Lower landing gear. 165 00:11:26,448 --> 00:11:29,931 This was a sense of an excellent crew 166 00:11:31,448 --> 00:11:32,862 caught randomly, if anything. 167 00:11:32,965 --> 00:11:36,241 So again that was my first impression is that this 168 00:11:36,344 --> 00:11:39,517 would be consistent more with a hardware situation. 169 00:11:39,620 --> 00:11:45,310 As more about flight 585 becomes known, 170 00:11:45,413 --> 00:11:48,172 mechanical failure becomes a serious suspect. 171 00:11:50,517 --> 00:11:52,413 Just seconds before it crashed, 172 00:11:52,517 --> 00:11:55,965 the plane rolled onto its back and spun wildly out of control. 173 00:11:58,034 --> 00:12:00,379 Investigators wonder if the sudden motion was 174 00:12:00,482 --> 00:12:03,000 caused by the plane losing an engine or a wing. 175 00:12:07,068 --> 00:12:09,172 From the state of the aircraft onsite, 176 00:12:09,275 --> 00:12:12,000 it's clear that it was intact at the time of the crash. 177 00:12:13,137 --> 00:12:15,068 What investigators don't know is 178 00:12:15,172 --> 00:12:17,310 if the engines were still working at impact. 179 00:12:24,655 --> 00:12:27,896 Technicians examine the engine turbines. 180 00:12:28,000 --> 00:12:31,310 They discover dirt has been drawn deeply into every crevice. 181 00:12:32,551 --> 00:12:34,068 These blades were clearly spinning 182 00:12:34,172 --> 00:12:36,310 and sucking in air at the time of impact. 183 00:12:39,172 --> 00:12:41,172 The engines may have been running 184 00:12:41,275 --> 00:12:43,896 but technicians aren't sure how well. 185 00:12:44,000 --> 00:12:46,793 The plane's hydraulic pressure dials are destroyed, 186 00:12:46,896 --> 00:12:49,241 their glass covers broken. 187 00:12:49,344 --> 00:12:51,517 The indicator needles have been snapped off 188 00:12:51,620 --> 00:12:53,275 by the force of the impact. 189 00:12:53,379 --> 00:12:55,965 But even these ravaged dials tell a tale. 190 00:12:56,068 --> 00:13:03,034 Fifteen flaps. Fifteen. 191 00:13:03,137 --> 00:13:04,586 On close inspection, 192 00:13:04,689 --> 00:13:07,517 investigators find a critical mark. 193 00:13:07,620 --> 00:13:08,862 At the moment of impact, 194 00:13:08,965 --> 00:13:12,172 a dent was made on the faceplate by the jarred indicator needle. 195 00:13:13,517 --> 00:13:16,482 It proves that when United 585 crashed, 196 00:13:16,586 --> 00:13:18,206 its engines were running normally. 197 00:13:29,103 --> 00:13:31,137 With engine failure ruled out, 198 00:13:31,241 --> 00:13:33,862 there seems to be only one other mechanical explanation 199 00:13:33,965 --> 00:13:38,172 for why 585 suddenly rolled over and then fell out of the sky. 200 00:13:41,275 --> 00:13:44,034 It appears increasingly likely that the plane had suffered 201 00:13:44,137 --> 00:13:47,379 a catastrophic problem with its flight controls. 202 00:13:47,482 --> 00:13:50,379 Investigators quickly become suspicious of the rudder 203 00:13:50,482 --> 00:13:51,517 at the back of the tail. 204 00:13:51,620 --> 00:13:55,344 We focused in after eliminating other flight 205 00:13:55,448 --> 00:13:59,344 control surfaces that we thought could contribute to the roll. 206 00:13:59,448 --> 00:14:00,724 We started looking at the rudder. 207 00:14:00,827 --> 00:14:04,689 Bring that up so I can take a look at it. 208 00:14:04,793 --> 00:14:06,724 Investigators begin their examination 209 00:14:06,827 --> 00:14:09,896 of the rudder on site but the violence of the crash makes 210 00:14:10,000 --> 00:14:11,413 the job extremely difficult. 211 00:14:11,517 --> 00:14:12,482 Almost nothing left. 212 00:14:12,586 --> 00:14:17,172 Most of the plane's parts are 213 00:14:17,275 --> 00:14:19,758 too crushed or burned for testing. 214 00:14:19,862 --> 00:14:22,655 But a vital component is still reasonably intact: 215 00:14:23,793 --> 00:14:26,310 the power control unit or PCU. 216 00:14:29,000 --> 00:14:32,758 Used constantly during flight, especially during landings, 217 00:14:32,862 --> 00:14:36,620 the PCU performs like a car's power steering. 218 00:14:36,724 --> 00:14:40,413 When the pilot pushes on a rudder pedal the PCU uses 219 00:14:40,517 --> 00:14:43,517 hydraulic fluid to convert gentle movements of a pilot's 220 00:14:43,620 --> 00:14:47,931 foot into the pressure needed to move the 737's enormous rudder. 221 00:14:50,931 --> 00:14:52,068 The heart of the PCU 222 00:14:52,172 --> 00:14:54,206 is something called the dual servo valve. 223 00:14:57,137 --> 00:14:59,724 Shaped like a soda can, it has two slides, 224 00:14:59,827 --> 00:15:02,517 which glide past one another, directing the flow 225 00:15:02,620 --> 00:15:05,137 of pressurized hydraulic fluid that moves the rudder. 226 00:15:05,241 --> 00:15:10,827 The servo valve is, is very unique. 227 00:15:10,931 --> 00:15:16,068 That it is in effect two valves in one 228 00:15:16,172 --> 00:15:20,241 and that that creates a whole range of interactions that 229 00:15:20,344 --> 00:15:24,413 don't occur in a, in a more conventional hydraulic valve. 230 00:15:24,517 --> 00:15:30,413 When a technician opens the power control unit, 231 00:15:30,517 --> 00:15:33,586 chips of metal are found floating in the hydraulic fluid. 232 00:15:35,034 --> 00:15:37,068 It's a disturbing find. 233 00:15:37,172 --> 00:15:40,275 These particles could cause the servo-valve to jam, 234 00:15:40,379 --> 00:15:42,551 making it impossible to work the plane's rudder. 235 00:15:45,586 --> 00:15:47,551 It's a chilling prospect. 236 00:15:47,655 --> 00:15:52,482 Could a microscopic fault bring down a 38-ton jet? 237 00:15:52,586 --> 00:15:55,172 It's difficult for Phillips to tell. 238 00:15:55,275 --> 00:15:57,137 While more intact than much of the wreck, 239 00:15:57,241 --> 00:16:00,379 the PCU and dual servo valve are both damaged. 240 00:16:00,482 --> 00:16:02,241 The airplane crashed 241 00:16:02,344 --> 00:16:04,758 and burnt in a pretty confined area and there was a lot 242 00:16:04,862 --> 00:16:08,103 of damage to the flight control components and the things 243 00:16:08,206 --> 00:16:11,000 we were testing and needed to test and look, look at. 244 00:16:11,103 --> 00:16:13,344 And the more damaged the components are, 245 00:16:13,448 --> 00:16:16,379 the harder it is to take measurements 246 00:16:16,482 --> 00:16:17,896 and do functional testing. 247 00:16:18,000 --> 00:16:23,206 To test what he does have, 248 00:16:23,310 --> 00:16:26,689 Phillips travels to California to the labs 249 00:16:26,793 --> 00:16:29,793 of Parker Hannifin where the rudder control unit is made. 250 00:16:36,448 --> 00:16:39,034 The curious metal chips floating in the PCU's 251 00:16:39,137 --> 00:16:41,689 chambers are dismissed. 252 00:16:41,793 --> 00:16:44,551 Phillips is told that filters keep them out of the delicate 253 00:16:44,655 --> 00:16:47,586 servo valve that directs fluid and moves the rudder. 254 00:16:51,482 --> 00:16:53,896 Nothing else is found that could explain any sudden 255 00:16:54,000 --> 00:16:55,827 movement of the rudder on flight 585. 256 00:16:55,931 --> 00:17:01,413 We didn't have any absolute indication or 257 00:17:01,517 --> 00:17:04,241 information that we could point to that said the rudder 258 00:17:04,344 --> 00:17:06,689 valve control unit, the servo valve or any, 259 00:17:06,793 --> 00:17:09,931 any part of that flight control system caused that accident. 260 00:17:10,034 --> 00:17:15,241 Phillips still suspects a mechanical problem, 261 00:17:15,344 --> 00:17:18,896 but with no conclusive evidence that the PCU or servo valve 262 00:17:19,000 --> 00:17:22,655 caused the crash, he is forced to sign off on the tests. 263 00:17:22,758 --> 00:17:23,793 It's a pass. 264 00:17:23,896 --> 00:17:31,689 With Phillips at a dead end, 265 00:17:31,793 --> 00:17:35,034 only bad mountain weather remains as a primary suspect. 266 00:17:37,344 --> 00:17:40,551 An expert on weather-related aviation accidents, 267 00:17:40,655 --> 00:17:42,862 Greg Salotollo is trying to determine 268 00:17:42,965 --> 00:17:45,793 if heavy winds on the day of the crash were a factor. 269 00:17:45,896 --> 00:17:49,275 There is a history of events where there've been 270 00:17:49,379 --> 00:17:52,620 airplane accidents, attributed to mountain waves and rotors. 271 00:17:52,724 --> 00:17:58,448 In 1966, a BOAC 707 near Mount Fuji 272 00:18:00,034 --> 00:18:02,000 disintegrated in a mountain wave and rotor. 273 00:18:02,103 --> 00:18:06,034 High winds crashing over mountain peaks leave 274 00:18:06,137 --> 00:18:09,068 so-called wind rotors in the lee side. 275 00:18:09,172 --> 00:18:12,000 Invisible, highly turbulent downdrafts that come 276 00:18:12,103 --> 00:18:14,517 plunging down with devastating power 277 00:18:14,620 --> 00:18:16,482 and are extremely dangerous to aircraft. 278 00:18:16,586 --> 00:18:19,758 We found a great deal of evidence, 279 00:18:21,241 --> 00:18:24,068 looking at the surface and upper air data and talking 280 00:18:24,172 --> 00:18:27,758 to witnesses in the area that rotors were a possibility. 281 00:18:27,862 --> 00:18:31,448 Salotollo hears several eyewitness 282 00:18:31,551 --> 00:18:35,137 reports of bizarre mountain weather on the day of the crash. 283 00:18:35,241 --> 00:18:37,689 One of the most intriguing is from Harold Darnell... 284 00:18:37,793 --> 00:18:40,586 Oh, what the heck was that? 285 00:18:40,689 --> 00:18:43,586 ...whose truck was struck by a powerful 286 00:18:43,689 --> 00:18:47,068 gust of wind just moments before 585 crashed. 287 00:18:48,827 --> 00:18:51,862 But as Greg Salottolo combs through his evidence, 288 00:18:51,965 --> 00:18:53,793 the theory that a wind rotor knocked 289 00:18:53,896 --> 00:18:57,000 the plane from the sky is getting less and less likely. 290 00:18:57,103 --> 00:19:04,931 Nice looking day. 291 00:19:05,034 --> 00:19:06,620 Hard to believe the skies are unfriendly. 292 00:19:06,724 --> 00:19:10,931 Wind rotors are areas of extremely low barometric 293 00:19:11,034 --> 00:19:15,689 pressure, so if flight 585 did pass through one, 294 00:19:15,793 --> 00:19:17,931 its altimeter reading would have spiked 295 00:19:18,034 --> 00:19:19,965 as the plane was blown suddenly upwards. 296 00:19:20,068 --> 00:19:27,241 There was no evidence that we saw 297 00:19:27,344 --> 00:19:30,310 that on the flight data recorder of 585. 298 00:19:30,413 --> 00:19:34,896 What the flight recorder did show was a fast 299 00:19:35,000 --> 00:19:52,689 and deadly drop in altitude as the plane fell to earth. 300 00:19:52,793 --> 00:19:55,689 It's been 21 months since the investigation 301 00:19:55,793 --> 00:19:59,689 into the crash of United Flight 585 began. 302 00:19:59,793 --> 00:20:04,586 Almost two years, in which the NTSB has studied the crew, 303 00:20:04,689 --> 00:20:06,724 the weather, the rudder, 304 00:20:06,827 --> 00:20:09,482 and thousands of other pieces of evidence. 305 00:20:09,586 --> 00:20:11,448 They've come up empty handed. 306 00:20:12,724 --> 00:20:15,000 For only the fourth time in its history, 307 00:20:15,103 --> 00:20:19,620 the NTSB releases a report which doesn't reach a conclusion. 308 00:20:19,724 --> 00:20:23,310 The cause of the crash of flight 585 is undetermined. 309 00:20:23,413 --> 00:20:27,896 We had put a lot of time and effort in into the 310 00:20:28,000 --> 00:20:30,931 investigation and we just weren't sure what had happened. 311 00:20:31,034 --> 00:20:33,862 It was like he was tracking a serial killer. 312 00:20:33,965 --> 00:20:37,068 He was frustrated that they had not solved 585. 313 00:20:38,344 --> 00:20:40,482 He did not want that to happen again. 314 00:20:40,586 --> 00:20:46,068 But, almost 2 years after the report 315 00:20:46,172 --> 00:20:50,034 on 585 is released, the killer strikes again. 316 00:20:53,551 --> 00:20:56,379 At 7 pm on a clear, windless day, 317 00:20:56,482 --> 00:21:00,551 US Air Flight 427 is nearing Pittsburg. 318 00:21:00,655 --> 00:21:04,344 Captain Peter Germano and First Officer Chuck Emmett 319 00:21:04,448 --> 00:21:06,241 are getting ready for their final approach. 320 00:21:06,344 --> 00:21:09,689 Folks, from the flight deck, 321 00:21:09,793 --> 00:21:12,482 we should be on the ground in 'bout ten more minutes. 322 00:21:12,586 --> 00:21:13,620 Sunny skies, little hazy. 323 00:21:13,724 --> 00:21:16,310 Flight attendants please prepare for landing. 324 00:21:16,413 --> 00:21:20,068 I ask you to check the security of your seatbelts. Thank you. 325 00:21:20,172 --> 00:21:23,034 US Air 309, descend and maintain 6000. 326 00:21:23,137 --> 00:21:27,000 As they close in on the airport, 327 00:21:27,103 --> 00:21:28,965 the pilots are on the lookout for another 328 00:21:29,068 --> 00:21:31,137 flight about 10 kilometers ahead of them. 329 00:21:31,241 --> 00:21:35,068 Looking for the traffic. 330 00:21:36,931 --> 00:21:43,034 Turning one zero zero US Air four twenty-seven. 331 00:21:43,137 --> 00:21:46,896 I see zuh jet stream. 332 00:21:47,000 --> 00:21:52,068 As they pass through the turbulence 333 00:21:52,172 --> 00:21:55,172 left behind by the other flight, their jet suddenly 334 00:21:55,275 --> 00:21:56,931 and alarmingly rolls left. 335 00:21:57,034 --> 00:22:02,655 Hold on, hold on. Shoot! 336 00:22:02,758 --> 00:22:06,379 Nothing the pilots do seems to have any effect. 337 00:22:13,034 --> 00:22:20,655 What the hell is this? What the hell? 338 00:22:27,482 --> 00:22:29,586 Shoot! 427 emergency! 339 00:22:35,275 --> 00:22:38,275 Oh shoot! Pull! Pull! 340 00:22:40,827 --> 00:22:42,896 Oh god no! No! 341 00:22:58,689 --> 00:23:00,965 Rescue crews arrive quickly, 342 00:23:01,068 --> 00:23:04,103 but the fate of flight 427 is tragically clear. 343 00:23:05,551 --> 00:23:09,758 There is no hope for the 132 passengers and crew. 344 00:23:09,862 --> 00:23:12,034 The human carnage is so bad 345 00:23:12,137 --> 00:23:15,103 authorities declare the crash site a biohazard. 346 00:23:15,206 --> 00:23:19,103 US Air 427 accident was the first US accident where 347 00:23:19,206 --> 00:23:24,137 biohazard suits were used and it made it more difficult. 348 00:23:24,241 --> 00:23:27,103 They were uncomfortable, they were hot and to this day 349 00:23:27,206 --> 00:23:30,172 when I put on a pair of rubber gloves for any reason I'm 350 00:23:30,275 --> 00:23:32,620 instantly transformed back to the site in Pittsburgh. 351 00:23:32,724 --> 00:23:39,103 Captain John Cox, a 737 pilot and flight systems 352 00:23:39,206 --> 00:23:42,413 specialist with the Airline Pilots Association, is asked 353 00:23:42,517 --> 00:23:45,103 to join the team investigating the crash of Flight 427. 354 00:23:48,206 --> 00:23:50,793 As coroners attempt to collect human remains, 355 00:23:53,068 --> 00:23:56,206 NTSB lead investigator Tom Haueter already 356 00:23:56,310 --> 00:23:59,517 knows his hunt for clues will be long and painstaking. 357 00:23:59,620 --> 00:24:04,068 When we first arrived to the crash site, uh, well, 358 00:24:04,172 --> 00:24:06,034 first of all, there was no aircraft there. 359 00:24:06,137 --> 00:24:08,275 There were only bits and pieces of the airplane. 360 00:24:08,379 --> 00:24:11,310 It wasn't really recognizable as an airplane. 361 00:24:11,413 --> 00:24:13,827 With the help of eyewitnesses, 362 00:24:13,931 --> 00:24:17,172 information from the flight data recorder and the cockpit voice 363 00:24:17,275 --> 00:24:20,862 recorder, investigators begin to quickly see some striking 364 00:24:20,965 --> 00:24:25,689 similarities between 427 and the unsolved case of United 585. 365 00:24:29,517 --> 00:24:32,310 In fact, they seem to be mirror images of each other. 366 00:24:33,862 --> 00:24:37,517 On final approach, United 585 rolls right, 367 00:24:37,620 --> 00:24:40,172 while US Air 427 rolls to the left. 368 00:24:43,275 --> 00:24:45,586 Both crews are caught by surprise. 369 00:24:45,689 --> 00:24:47,965 And after just a few terrifying seconds, 370 00:24:48,068 --> 00:24:50,482 both aircraft plummet straight into the ground. 371 00:24:50,586 --> 00:24:53,379 Certainly, the whole team was aware of the previous 372 00:24:53,482 --> 00:24:56,793 accident with United 585 in Colorado Springs. 373 00:24:56,896 --> 00:24:58,551 We tried to keep that in the back of our minds 374 00:24:58,655 --> 00:25:01,137 and take a look at this one as to what it presents to us. 375 00:25:01,241 --> 00:25:05,344 As the investigation continues, 376 00:25:05,448 --> 00:25:10,000 the list of similarities grows: 427's engines were also 377 00:25:10,103 --> 00:25:12,586 attached and functioning at the time of impact. 378 00:25:14,758 --> 00:25:16,620 But for all the similarities, 379 00:25:16,724 --> 00:25:18,172 there is one important difference. 380 00:25:19,413 --> 00:25:24,896 Unlike United 585, as US Air 427 approached Pittsburg 381 00:25:25,000 --> 00:25:26,655 weather conditions were dead calm. 382 00:25:26,758 --> 00:25:30,517 Folks, from the flight deck 383 00:25:30,620 --> 00:25:33,344 we should be on the ground in 'bout ten more minutes. 384 00:25:33,448 --> 00:25:34,827 Sunny skies, a little hazy. 385 00:25:34,931 --> 00:25:37,896 Taking a look at the flight data recorder information, 386 00:25:38,000 --> 00:25:39,655 the aircraft's approaching Pittsburgh. 387 00:25:39,758 --> 00:25:41,724 It's an extremely smooth night. 388 00:25:41,827 --> 00:25:46,137 Uh there's just no turbulence at all. Uh the pilots are relaxed. 389 00:25:46,241 --> 00:25:47,379 They're talking about the landing. 390 00:25:47,482 --> 00:25:49,620 Flight attendants please prepare for landing. 391 00:25:49,724 --> 00:25:51,793 Ask you to check the security of your seatbelts. Thank you. 392 00:25:51,896 --> 00:25:56,241 As he did in the case of United 585, 393 00:25:57,689 --> 00:25:59,344 Greg Phillips will once again lead 394 00:25:59,448 --> 00:26:02,379 the investigation into the mechanical aspects of the crash. 395 00:26:03,862 --> 00:26:06,724 Almost immediately, he makes a promising discovery. 396 00:26:08,931 --> 00:26:12,344 Miraculously, much of US Air 427's tail 397 00:26:12,448 --> 00:26:14,241 and rudder appear intact. 398 00:26:20,413 --> 00:26:22,896 The hydraulic devices inside the tail 399 00:26:23,000 --> 00:26:25,103 have also sustained very little damage. 400 00:26:26,620 --> 00:26:29,137 Phillips and Haueter prepare to send the parts to the 401 00:26:29,241 --> 00:26:33,000 manufacturer Parker Hannifin for testing as soon as possible. 402 00:26:34,137 --> 00:26:35,965 They need answers. 403 00:26:36,068 --> 00:26:39,620 Pressure on the NTSB to solve the accident is growing quickly. 404 00:26:42,965 --> 00:26:46,448 Not only are the crashes of flights 585 and 427 405 00:26:46,551 --> 00:26:49,000 disturbingly similar, both of them 406 00:26:49,103 --> 00:26:52,034 involve the same kind of airplane-- a Boeing 737. 407 00:26:56,379 --> 00:26:58,448 But with serious questions being raised 408 00:26:58,551 --> 00:27:01,758 about the plane's safety, billions of dollars 409 00:27:01,862 --> 00:27:05,034 and perhaps the airline industry itself, are at risk. 410 00:27:05,137 --> 00:27:08,896 We couldn't live with the fact as investigators 411 00:27:09,000 --> 00:27:12,137 of having two unsolved 737 accidents. 412 00:27:12,241 --> 00:27:15,344 The airplane is in too much use, too wide a use around the world. 413 00:27:15,448 --> 00:27:17,379 It carries too many people every day. 414 00:27:17,482 --> 00:27:20,448 Unsolved was not an acceptable answer. 415 00:27:20,551 --> 00:27:23,275 If 427 was an undetermined accident, 416 00:27:23,379 --> 00:27:26,586 we could not find the cause of this accident, 417 00:27:26,689 --> 00:27:28,379 there was a great chance that there was a, 418 00:27:28,482 --> 00:27:32,517 if there was a third accident with a 737 fleet under similar 419 00:27:32,620 --> 00:27:36,655 circumstances that the 737 fleet would have been grounded. 420 00:27:36,758 --> 00:27:41,034 Careful with that. 421 00:27:41,137 --> 00:27:46,758 The investigation into the crash of flight 427 422 00:27:46,862 --> 00:27:51,034 may be the most important in the history of the NTSB. 423 00:27:51,137 --> 00:27:55,137 But it won't be easy. Answers are still years away. 424 00:27:55,241 --> 00:28:00,896 In just three years, two Boeing 737s 425 00:28:01,000 --> 00:28:03,689 have crashed in the United States with no survivors. 426 00:28:03,793 --> 00:28:06,517 Airport in sight United 585. 427 00:28:06,620 --> 00:28:07,448 In both cases, 428 00:28:07,551 --> 00:28:09,172 the planes were moments from landing. 429 00:28:09,275 --> 00:28:10,448 Flight attendants, please prepare for landing. 430 00:28:10,551 --> 00:28:13,896 And in both cases, the planes were under full power, 431 00:28:14,000 --> 00:28:16,379 but the pilots were unable to control their jets. 432 00:28:16,482 --> 00:28:22,862 Pull! Pull! 433 00:28:22,965 --> 00:28:25,655 In the crash of United flight 585, 434 00:28:25,758 --> 00:28:28,793 NTSB investigators were unable to find a cause. 435 00:28:30,551 --> 00:28:33,448 Now, they're searching for clues into the second crash - 436 00:28:33,551 --> 00:28:34,793 US Air flight 427. 437 00:28:34,896 --> 00:28:38,586 As the investigator in charge, I never allowed myself 438 00:28:38,689 --> 00:28:41,413 to think this investigation could go undetermined. 439 00:28:41,517 --> 00:28:43,793 Just we kept on pushing and kept on researching. 440 00:28:43,896 --> 00:28:46,344 As long as we had things to research we kept on going. 441 00:28:46,448 --> 00:28:49,655 To find their killer, 442 00:28:49,758 --> 00:28:53,103 the NTSB can't afford to rule anything out. 443 00:28:53,206 --> 00:28:55,448 From the possibility that a collision with birds 444 00:28:55,551 --> 00:28:59,931 brought 427 down to strange, even bizarre theories. 445 00:29:00,034 --> 00:29:02,620 They looked at electromagnetic interference. 446 00:29:02,724 --> 00:29:03,965 They got calls from people 447 00:29:04,068 --> 00:29:06,620 saying it might be Russian death rays. 448 00:29:06,724 --> 00:29:07,758 They considered everything. 449 00:29:07,862 --> 00:29:10,310 There were a couple of witnesses who gave reports of 450 00:29:10,413 --> 00:29:13,448 the aircraft suddenly descending and hovering before it blew up. 451 00:29:13,551 --> 00:29:14,793 We discounted those. 452 00:29:14,896 --> 00:29:17,965 But the investigation's primary 453 00:29:18,068 --> 00:29:21,000 suspect is the dual servo valve, 454 00:29:21,103 --> 00:29:24,931 part of the power control unit that moves the 737's rudder 455 00:29:25,034 --> 00:29:27,344 and a suspect in the crash of United 585. 456 00:29:30,068 --> 00:29:32,206 Parker Hannifin made the valve. 457 00:29:32,310 --> 00:29:34,655 At it's lab in California, investigators 458 00:29:34,758 --> 00:29:38,586 look inside the main cavity of the US Air power control unit. 459 00:29:39,931 --> 00:29:41,517 Just like in the earlier crash, 460 00:29:41,620 --> 00:29:44,965 they find tiny chips of metal floating in the hydraulic fluid. 461 00:29:47,344 --> 00:29:51,206 But once again, Parker and Boeing repeat their claim. 462 00:29:51,310 --> 00:29:54,137 Filters designed to stop any debris from interfering 463 00:29:54,241 --> 00:29:56,827 with the delicate metal slides have done their job. 464 00:30:00,344 --> 00:30:04,344 Investigator Greg Phillips wants to be absolutely sure. 465 00:30:04,448 --> 00:30:07,379 If the chips were blocking the slides, they would have left 466 00:30:07,482 --> 00:30:10,482 tiny scratch marks behind where they rubbed against the metal. 467 00:30:13,241 --> 00:30:18,724 But Phillips can't find any. Another pass. Okay. 468 00:30:18,827 --> 00:30:23,448 Phillips has technicians put the servo 469 00:30:23,551 --> 00:30:25,482 valve from flight 427 through - 470 00:30:25,586 --> 00:30:29,000 as many tests as he can think of trying to find a weakness. 471 00:30:30,206 --> 00:30:31,586 If he can find one, 472 00:30:31,689 --> 00:30:34,793 it could explain why two planes were ripped from the sky. 473 00:30:36,620 --> 00:30:37,862 But he comes up empty. 474 00:30:37,965 --> 00:30:42,241 That, that unit passed all its operational tests. 475 00:30:42,344 --> 00:30:45,620 There wasn't any indication that it had failed and it, 476 00:30:45,724 --> 00:30:49,310 it operated within the parameters we expected it to. 477 00:30:49,413 --> 00:30:53,965 Once again, the investigators are forced 478 00:30:54,068 --> 00:30:56,137 to shift their focus back to the pilots. 479 00:31:00,965 --> 00:31:03,655 By studying the plane's flight data recorder, 480 00:31:03,758 --> 00:31:06,310 investigators know that the jet's rudder was deployed 481 00:31:06,413 --> 00:31:09,655 fully to one side, what's called rudder hard-over. 482 00:31:09,758 --> 00:31:15,000 We were definitely focused on a rudder, 483 00:31:15,103 --> 00:31:22,448 on hard over rudder, full rudder input for about 20 seconds. 484 00:31:22,551 --> 00:31:24,000 It can be caused either by hardware, 485 00:31:24,103 --> 00:31:25,137 something unknown in the hardware 486 00:31:25,241 --> 00:31:26,827 or it can be caused by pilot input. 487 00:31:26,931 --> 00:31:32,344 First Officer Chuck Emmett, who was 488 00:31:32,448 --> 00:31:37,068 flying 427 did indeed step down hard on his rudder and then 489 00:31:37,172 --> 00:31:39,827 held it there while the plane plummeted toward the earth. 490 00:31:41,103 --> 00:31:42,931 It raised a grizzly question, 491 00:31:43,034 --> 00:31:45,379 was he trying to fly the plane into the ground? 492 00:31:45,482 --> 00:31:50,689 In looking at this and, being a pilot myself, 493 00:31:50,793 --> 00:31:53,172 it's like this doesn't seem like rational behaviour. 494 00:31:53,275 --> 00:31:57,931 What the hell is this? 495 00:31:58,034 --> 00:32:00,241 Human performance specialist Malcolm Brenner 496 00:32:00,344 --> 00:32:04,034 listens closely for evidence on the cockpit voice recorder. 497 00:32:04,137 --> 00:32:06,827 What the...? No. Shoot. 498 00:32:06,931 --> 00:32:08,758 In this case, they had microphones right by their 499 00:32:08,862 --> 00:32:11,655 mouths and you can hear as well as in real life, or better. 500 00:32:11,758 --> 00:32:13,620 You can hear breathing sounds. 501 00:32:15,000 --> 00:32:16,965 Ooh ya. I see zuh jet stream. 502 00:32:17,068 --> 00:32:20,655 The cockpit recordings indicate that flight 427's 503 00:32:20,758 --> 00:32:23,758 troubles began at the moment it flew through the jet wake 504 00:32:23,862 --> 00:32:27,655 of a Delta Airlines 727 that had just passed in front of them. 505 00:32:27,758 --> 00:32:31,103 Both pilots are startled by the wake. 506 00:32:31,206 --> 00:32:33,034 I see zuh jet stream. 507 00:32:33,137 --> 00:32:34,931 The first officer breaks off 508 00:32:35,034 --> 00:32:35,965 at the end of a sentence. 509 00:32:36,068 --> 00:32:38,482 I see the jet stream. Zuh. 510 00:32:38,586 --> 00:32:39,655 And there's no more discussion 511 00:32:39,758 --> 00:32:40,413 of the jet stream or anything else. 512 00:32:40,517 --> 00:32:42,137 They both focus. Something happened here. 513 00:32:42,241 --> 00:32:44,965 Captain says sheez. Sheez. 514 00:32:45,068 --> 00:32:48,793 It was such a smooth flight that it was a momentary 515 00:32:48,896 --> 00:32:51,586 jolt that they just hadn't anticipated. 516 00:32:51,689 --> 00:32:54,724 And, with that, the, the pilots got on the controls 517 00:32:54,827 --> 00:32:56,758 and immediately, you know, put in a rudder input. 518 00:32:56,862 --> 00:33:02,586 Sheez. 519 00:33:02,689 --> 00:33:05,551 The cockpit recorder even records the thumping sound 520 00:33:05,655 --> 00:33:08,827 of the jet stream turbulence as 427 flies through it. 521 00:33:10,000 --> 00:33:12,655 As flight 427 encounters the turbulence, 522 00:33:12,758 --> 00:33:14,344 Brenner hears something unusual. 523 00:33:16,482 --> 00:33:18,689 First Officer Emmett begins to grunt. 524 00:33:18,793 --> 00:33:27,034 The grunting is unusual. 525 00:33:27,137 --> 00:33:29,931 The controls are designed so that pilots don't need to grunt. 526 00:33:30,034 --> 00:33:32,724 They're specially designed around human capabilities, 527 00:33:32,827 --> 00:33:34,586 so to have someone grunting is typically 528 00:33:34,689 --> 00:33:36,103 a sign of an emergency. 529 00:33:36,206 --> 00:33:38,655 By matching data from the flight 530 00:33:38,758 --> 00:33:40,689 recorder with the crew's voices, 531 00:33:40,793 --> 00:33:43,344 Brenner is able to confirm that Emmett's grunts begin 532 00:33:43,448 --> 00:33:46,793 a split second after he pushed down on the rudder pedal and 533 00:33:46,896 --> 00:33:50,103 3 to 4 seconds after the wake turbulence affected flight 427. 534 00:33:50,206 --> 00:33:53,206 What the...? Help! 535 00:33:53,310 --> 00:33:57,586 On their own, 536 00:33:57,689 --> 00:34:00,655 the cockpit voice recordings prove very little. 537 00:34:00,758 --> 00:34:02,137 But it seems clear that the crew 538 00:34:02,241 --> 00:34:04,448 weren't trying to crash their plane. 539 00:34:04,551 --> 00:34:07,586 Something happened which took them by surprise. 540 00:34:07,689 --> 00:34:09,655 They reacted as quickly as they could, 541 00:34:09,758 --> 00:34:11,482 but nothing they did seemed to help. 542 00:34:12,827 --> 00:34:16,689 What the hell is this? 543 00:34:16,793 --> 00:34:19,551 It's been almost two years since the crash of flight 427, 544 00:34:20,620 --> 00:34:23,344 and the investigation has stalled. 545 00:34:23,448 --> 00:34:27,724 Now, two 737s have gone down in startlingly similar ways 546 00:34:27,827 --> 00:34:30,137 and investigators still don't know why. 547 00:34:30,241 --> 00:34:34,586 We were all frustrated as months wore into years. 548 00:34:36,310 --> 00:34:37,379 What were we missing? 549 00:34:37,482 --> 00:34:39,827 It definitely took a toll in their personal lives. 550 00:34:39,931 --> 00:34:42,379 They worked incredibly long hours. 551 00:34:42,482 --> 00:34:43,965 They never stopped thinking about it. 552 00:34:44,068 --> 00:34:46,137 We were going up against an aircraft 553 00:34:46,241 --> 00:34:48,620 that had an incredible safety history. 554 00:34:48,724 --> 00:34:52,310 It was really everything you could see for 30 years 555 00:34:52,413 --> 00:34:53,482 this had been a great airplane. 556 00:34:53,586 --> 00:34:57,862 Um we were trying to prove that there was 557 00:34:57,965 --> 00:34:59,655 something wrong with the straight A student. 558 00:34:59,758 --> 00:35:03,275 It clearly was on his mind. 559 00:35:03,379 --> 00:35:06,620 He at one point had a nightmare about it, where he dreamed 560 00:35:06,724 --> 00:35:10,206 that he was in front of a congressional committee that 561 00:35:10,310 --> 00:35:15,965 was grilling him on, now there had been a third 737 crash. 562 00:35:16,068 --> 00:35:20,172 And, in Tom's dream, all the cameras were pointing to him 563 00:35:20,275 --> 00:35:23,586 and a congressman asked, why didn't you ground the fleet? 564 00:35:23,689 --> 00:35:32,137 Unsure of where to look next, 565 00:35:32,241 --> 00:35:34,793 and with the trail of evidence getting colder, 566 00:35:34,896 --> 00:35:38,068 investigators need a break in the case, and fast. 567 00:35:41,000 --> 00:35:43,000 Eastwind 517, you're clear for landing. 568 00:35:48,068 --> 00:35:50,344 On June 9th 1996, 569 00:35:50,448 --> 00:35:52,931 they finally get the break they've been looking for. 570 00:35:54,344 --> 00:35:58,103 Captain Brian Bishop is on final approach to Richmond Virginia 571 00:35:58,206 --> 00:35:59,448 when, without warning, 572 00:35:59,551 --> 00:36:02,103 his Eastwind jet rolls sharply to the right. 573 00:36:02,206 --> 00:36:10,689 We didn't know to what extent, 574 00:36:10,793 --> 00:36:13,275 but we knew we had a problem with the rudder. 575 00:36:13,379 --> 00:36:15,379 I turned the yoke the opposite direction 576 00:36:15,482 --> 00:36:16,896 and stood on the opposite rudder pedal. 577 00:36:17,000 --> 00:36:21,103 The pedal didn't move for me. 578 00:36:21,206 --> 00:36:25,275 For over 30 seconds, the 737 flies in a precarious 579 00:36:25,379 --> 00:36:28,551 right bank as Bishop fights to keep it from rolling over. 580 00:36:32,000 --> 00:36:35,448 Then suddenly, the unknown forces holding the jet let go, 581 00:36:39,206 --> 00:36:41,275 snapping the wings back to horizontal. 582 00:36:41,379 --> 00:36:48,793 In a matter of seconds, it released itself 583 00:36:48,896 --> 00:36:49,896 and went back to normal. 584 00:36:51,103 --> 00:36:52,448 We had started the checklist. 585 00:36:54,034 --> 00:36:56,000 Almost before I could finish the sentence, 586 00:36:56,103 --> 00:36:58,206 all of a sudden there was just a wham. 587 00:36:58,310 --> 00:37:07,931 For a second time, the 737 is pushed on its side. 588 00:37:09,310 --> 00:37:13,379 For 30 harrowing seconds, the 737 takes on a life of its own. 589 00:37:16,275 --> 00:37:20,551 Then, once again, as quickly as it began, the rollover stops. 590 00:37:20,655 --> 00:37:26,034 After the second time, I looked at the first officer 591 00:37:26,137 --> 00:37:27,586 and I said, declare an emergency. 592 00:37:27,689 --> 00:37:30,310 Tell the controller we have flight control problems. 593 00:37:30,413 --> 00:37:41,241 As they slow down to land, the risks increase. 594 00:37:45,931 --> 00:37:47,551 If a third rollover occurs, 595 00:37:47,655 --> 00:37:49,724 they won't have enough airspeed to recover. 596 00:37:49,827 --> 00:37:52,413 I did, at some point, tell my first officer 597 00:37:52,517 --> 00:37:56,000 to look out the window and find a dark spot. 598 00:37:56,103 --> 00:37:58,034 It was nighttime and we were looking to avoid 599 00:37:58,137 --> 00:38:02,448 a neighbourhood or a populated area and he very calmly 600 00:38:02,551 --> 00:38:04,379 responded that hey here's a spot over here. 601 00:38:04,482 --> 00:38:15,689 But there is no third rollover. 602 00:38:15,793 --> 00:38:20,034 Bishop brings Flight 517 in high and fast, and lands safely. 603 00:38:20,137 --> 00:38:26,448 Taxiing in is when I realized my legs were shaking. 604 00:38:28,068 --> 00:38:30,034 We got the aircraft to the gate 605 00:38:30,137 --> 00:38:32,724 and I did pick up the PA to make an announcement to try 606 00:38:32,827 --> 00:38:35,482 to explain what had just happened to these people. 607 00:38:35,586 --> 00:38:39,965 And on picking up the microphone I realized there was 608 00:38:40,068 --> 00:38:42,724 nothing I could say to make this any better. 609 00:38:42,827 --> 00:38:46,689 And probably for the first time in a long time 610 00:38:46,793 --> 00:38:48,655 I was at a loss of words. 611 00:38:48,758 --> 00:38:54,620 So I simply put the microphone down and let it go at that. 612 00:38:54,724 --> 00:38:57,758 But Bishop won't remain speechless for long. 613 00:38:57,862 --> 00:38:58,793 By the next day, 614 00:38:58,896 --> 00:39:01,448 the investigation team has arrived in Richmond. 615 00:39:01,551 --> 00:39:07,413 Flight data recorder was undamaged, 616 00:39:07,517 --> 00:39:08,655 the airplane undamaged. 617 00:39:08,758 --> 00:39:10,655 We launched to the scene. 618 00:39:10,758 --> 00:39:13,517 The airplane literally didn't move, 619 00:39:13,620 --> 00:39:15,965 stayed at its location at the airport 'til we got down there. 620 00:39:16,068 --> 00:39:19,103 There were a lot of FAA, a lot of NTSB 621 00:39:19,206 --> 00:39:21,551 and they all wanted to talk to us very badly. 622 00:39:21,655 --> 00:39:25,275 It gave the NTSB a tremendous break 623 00:39:25,379 --> 00:39:27,620 because suddenly they had a 737 624 00:39:27,724 --> 00:39:29,517 that had had a rudder incident, 625 00:39:29,620 --> 00:39:33,000 that was intact, and they had a pilot who was alive 626 00:39:33,103 --> 00:39:34,482 and who could talk about it. 627 00:39:34,586 --> 00:39:35,310 I think they were much happier 628 00:39:35,413 --> 00:39:36,413 to have the airplane than me. 629 00:39:37,724 --> 00:39:41,137 I think the airplane probably gave them 630 00:39:41,241 --> 00:39:44,034 more to research than I ever could. 631 00:39:44,137 --> 00:39:48,931 NTSB investigators quickly determine that what 632 00:39:49,034 --> 00:39:52,689 happened onboard Eastwind flight 517 is alarmingly 633 00:39:52,793 --> 00:39:55,724 similar to events on flights 427 and 585. 634 00:39:56,965 --> 00:40:00,655 If they can discover why Bishop's 737 rolled over, 635 00:40:00,758 --> 00:40:04,965 they may be able to crack two mysterious and fatal accidents. 636 00:40:05,068 --> 00:40:06,379 And when we said what happened? 637 00:40:06,482 --> 00:40:09,068 They said there was something wrong with the rudder pedal. 638 00:40:09,172 --> 00:40:10,793 The pedal wouldn't go down. 639 00:40:10,896 --> 00:40:12,724 I was standing on the rudder pedal 640 00:40:12,827 --> 00:40:14,344 and I couldn't get it to go down. 641 00:40:17,275 --> 00:40:18,448 My god! 642 00:40:18,551 --> 00:40:23,965 With Bishop's first person testimony, investigators 643 00:40:24,068 --> 00:40:27,000 immediately zero in on Eastwind's rudder controls. 644 00:40:31,241 --> 00:40:34,137 The power control unit is removed, inspected 645 00:40:34,241 --> 00:40:36,241 and then tested again and again. 646 00:40:39,310 --> 00:40:43,137 To the frustration of everyone, the unit performs perfectly. 647 00:40:43,241 --> 00:40:46,103 We tested that aircraft as is. It was intact. 648 00:40:46,206 --> 00:40:49,379 We went through it completely, did flight tests with it. 649 00:40:49,482 --> 00:40:52,103 And it passed all tests. 650 00:40:52,206 --> 00:40:58,034 After a five-year hunt for clues, a third mysterious 651 00:40:58,137 --> 00:41:03,379 rudder event on a 737 and a live pilot as a witness, Tom Haueter 652 00:41:03,482 --> 00:41:06,206 still lacks the evidence he needs to crack his case. 653 00:41:08,172 --> 00:41:10,482 He decides to push his chief suspect, 654 00:41:10,586 --> 00:41:13,655 Flight 427's rudder controls, a little harder. 655 00:41:13,758 --> 00:41:20,793 One fellow mentioned a test 656 00:41:20,896 --> 00:41:26,413 they had done in the military of a thermal shock where 657 00:41:26,517 --> 00:41:30,068 if you had the actuator being very cold and put in very hot 658 00:41:30,172 --> 00:41:33,586 hydraulic fluid, it would cause it to react in strange ways. 659 00:41:37,034 --> 00:41:39,551 So we put together the thermal shock test. 660 00:41:39,655 --> 00:41:41,724 And this test was extreme, to say the least. 661 00:41:41,827 --> 00:41:46,103 On August 26th 1996, 662 00:41:48,034 --> 00:41:51,482 in Valencia California, NTSB investigators 663 00:41:51,586 --> 00:41:54,655 gather to watch the torture test of US Air 427's PCU. 664 00:41:58,551 --> 00:42:00,517 After soaking it in dry ice, 665 00:42:00,620 --> 00:42:03,827 the PCU is blasted with nitrogen gas to simulate 666 00:42:03,931 --> 00:42:07,068 the minus 40-degree temperatures at 10-thousand meters. 667 00:42:10,965 --> 00:42:14,758 Then, it's quickly injected with super-heated hydraulic fluid 668 00:42:14,862 --> 00:42:16,827 and given the command to start working. 669 00:42:16,931 --> 00:42:22,689 As we were standing there listening to the actuator 670 00:42:22,793 --> 00:42:29,137 move left and right, left and right it stopped, 671 00:42:30,448 --> 00:42:32,137 and it was not commanded to stop. 672 00:42:32,241 --> 00:42:37,000 It just jammed, stopped working completely. Take a look. 673 00:42:37,103 --> 00:42:44,482 Systems investigator Greg Phillips now 674 00:42:44,586 --> 00:42:48,068 asks that the valve be taken apart and scanned for scratches. 675 00:42:52,689 --> 00:42:53,758 They find none. 676 00:42:53,862 --> 00:42:57,724 Look at that. Doesn't leave a trace. 677 00:42:58,931 --> 00:43:00,241 It is a crucial breakthrough 678 00:43:00,344 --> 00:43:03,517 to solving an almost perfect crime. 679 00:43:03,620 --> 00:43:06,172 Not only have they proven that the valve which controls 680 00:43:06,275 --> 00:43:09,896 the rudders can jam, no evidence is left behind. 681 00:43:12,931 --> 00:43:15,896 Tom Haueter and his team have now found that a small 682 00:43:16,000 --> 00:43:18,896 hydraulic valve that controls the rudder of the world's most 683 00:43:19,000 --> 00:43:23,034 popular commercial jetliner can jam in the right circumstances. 684 00:43:25,448 --> 00:43:29,827 It's an ominous discovery but incredibly, there's another 685 00:43:29,931 --> 00:43:32,724 shocking surprise in store for the investigators. 686 00:43:37,000 --> 00:43:38,793 October the 15th, 1996. 687 00:43:40,137 --> 00:43:42,689 For the last five years the National Transportation 688 00:43:42,793 --> 00:43:45,931 Safety Board has been struggling to crack its toughest case-- 689 00:43:48,689 --> 00:43:52,103 two completely separate but seemingly linked accidents. 690 00:43:54,137 --> 00:43:58,379 The crash of United 585 killed 25 passengers and crew. 691 00:44:03,172 --> 00:44:06,862 Three years later, the US Air Flight 427 disaster took 692 00:44:06,965 --> 00:44:09,172 another 1-hundred and 32 lives. 693 00:44:15,758 --> 00:44:18,551 Now, after examining hundreds of clues, 694 00:44:18,655 --> 00:44:21,275 investigators have made a surprising discovery. 695 00:44:24,310 --> 00:44:27,620 A new test has revealed that under the right circumstances, 696 00:44:27,724 --> 00:44:31,620 the hydraulic valve that moves the 737's rudder can jam. 697 00:44:31,724 --> 00:44:34,103 It just jammed. 698 00:44:34,206 --> 00:44:37,068 But the surprises aren't over. 699 00:44:37,172 --> 00:44:41,275 The most important breakthrough came 700 00:44:41,379 --> 00:44:43,275 when a Boeing engineer, 701 00:44:43,379 --> 00:44:48,862 examining the data from that test, discovered some numbers 702 00:44:48,965 --> 00:44:54,034 that indicated the valve at that point had actually reversed. 703 00:44:54,137 --> 00:44:58,517 Whoa. Sheez. 704 00:44:58,620 --> 00:45:00,689 It is a stunning revelation. 705 00:45:00,793 --> 00:45:03,275 Not only can the servo-valve jam, 706 00:45:03,379 --> 00:45:05,965 but it can then function in reverse. 707 00:45:06,068 --> 00:45:08,482 It means that anytime a pilot tries to correct 708 00:45:08,586 --> 00:45:11,551 a rollover by pushing on the rudder, the rudder might 709 00:45:11,655 --> 00:45:15,379 turn in the opposite direction, causing a fatal accident. 710 00:45:15,482 --> 00:45:18,551 And the reversal is like driving your car. 711 00:45:18,655 --> 00:45:20,344 You turn to the right, it goes left. 712 00:45:21,482 --> 00:45:23,206 You're not gonna figure out this failure mode 713 00:45:23,310 --> 00:45:24,517 until you go off the road. 714 00:45:24,620 --> 00:45:27,965 And, in these cases, that's what the pilots were faced with, 715 00:45:28,068 --> 00:45:30,068 something so unusual 716 00:45:30,172 --> 00:45:31,793 that they didn't understand what was happening. 717 00:45:31,896 --> 00:45:35,896 What the hell is this? 718 00:45:36,000 --> 00:45:39,827 They had evidence now that the valve was unique, 719 00:45:39,931 --> 00:45:44,586 that the valve not only could jam, but would reverse. 720 00:45:44,689 --> 00:45:46,482 427 emergency. 721 00:45:46,586 --> 00:45:52,931 That would explain why the first officer, 722 00:45:53,034 --> 00:45:56,862 Chuck Emmett, would keep his foot on the rudder pedal, 723 00:45:56,965 --> 00:46:01,206 because he's thinking why isn't the plane going right? 724 00:46:01,310 --> 00:46:03,482 And he's feeling the plane go to the left. 725 00:46:03,586 --> 00:46:09,206 To the very end, Chuck Emmett pushes hard, 726 00:46:09,310 --> 00:46:12,517 hoping his rudder will help him pull out of his deadly spiral. 727 00:46:14,172 --> 00:46:16,413 Tragically, he has no way of knowing that he's 728 00:46:16,517 --> 00:46:18,862 steering his aircraft straight into the ground. 729 00:46:24,068 --> 00:46:26,344 Never driven to Colorado Springs and not gotten sick. 730 00:46:31,758 --> 00:46:33,310 Flight attendants prepare for landing. 731 00:46:33,413 --> 00:46:36,448 Satisfied that they've determined 732 00:46:36,551 --> 00:46:39,758 the cause of the crash of US Air 427, 733 00:46:39,862 --> 00:46:43,793 the NTSB turns its attention to the unsolved case of United 585. 734 00:46:43,896 --> 00:46:49,896 Another ten knot gain. 735 00:46:50,000 --> 00:46:51,482 Going back to Colorado Springs, 736 00:46:51,586 --> 00:46:54,000 you could follow a progression of what the captain was doing. 737 00:46:55,206 --> 00:46:57,793 He's close to the ground and suddenly under rudder 738 00:46:57,896 --> 00:46:59,724 reversal he puts in a little bit of pedal. 739 00:46:59,827 --> 00:47:02,965 The pedal violently pushes his leg back. 740 00:47:05,482 --> 00:47:05,965 Oh god, flip. Fifteen flaps. 741 00:47:06,068 --> 00:47:08,793 Fifteen. 742 00:47:08,896 --> 00:47:10,862 Rudder reversal certainly fits what 743 00:47:10,965 --> 00:47:12,551 I know about this crew and how it fits. 744 00:47:12,655 --> 00:47:15,379 We were able to show the failure mode. 745 00:47:15,482 --> 00:47:18,965 It matched the flight data recorder for each aircraft. 746 00:47:19,068 --> 00:47:19,793 It fit like a glove. 747 00:47:21,275 --> 00:47:23,172 So we now had a lot more information 748 00:47:23,275 --> 00:47:26,344 we could apply to United Flight 585 and, 749 00:47:26,448 --> 00:47:28,172 based on that, we redid the accident report. 750 00:47:28,275 --> 00:47:29,965 Oh my god, oh my god! 751 00:47:30,068 --> 00:47:32,310 From rudder reversal to impact took 752 00:47:32,413 --> 00:47:34,551 less than ten seconds. 753 00:47:34,655 --> 00:47:37,034 585's flight crew had no chance 754 00:47:37,137 --> 00:47:39,137 to save their plane or passengers. 755 00:47:42,000 --> 00:47:43,689 In the aftermath of the investigation, 756 00:47:43,793 --> 00:47:45,965 sweeping changes were made to improve 757 00:47:46,068 --> 00:47:49,724 the safety of the 737 and the entire aviation industry. 758 00:47:51,793 --> 00:47:54,448 New training protocols were designed to help pilots 759 00:47:54,551 --> 00:47:57,689 react to unusual in-flight events. 760 00:47:57,793 --> 00:48:01,655 In the 737 fleet, pilots are now trained on how to react 761 00:48:01,758 --> 00:48:04,172 to both rudder hard-overs and reversals. 762 00:48:04,275 --> 00:48:09,344 The scenario of the US Air 427 accident, 763 00:48:09,448 --> 00:48:13,448 if the crew had the information that we have today I believe 764 00:48:13,551 --> 00:48:15,034 they would have landed safely in Pittsburgh that evening. 765 00:48:15,137 --> 00:48:22,517 The FAA also directed Boeing to redesign the rudder's 766 00:48:22,620 --> 00:48:26,000 dual servo valve to eliminate the potential for reversal. 767 00:48:27,517 --> 00:48:29,931 Boeing spent hundreds of millions of dollars to 768 00:48:30,034 --> 00:48:33,551 replace the valves on thousands of 737s around the world. 769 00:48:33,655 --> 00:48:36,758 One thing we don't like at the Safety Board 770 00:48:36,862 --> 00:48:38,827 is to have an undetermined accident, 771 00:48:38,931 --> 00:48:42,275 because then we can't make a change to improve safety. 772 00:48:42,379 --> 00:48:45,000 So out of US Air 427, United 585, 773 00:48:46,241 --> 00:48:48,724 we have a much safer 737 fleet. 774 00:48:48,827 --> 00:48:59,620 It took NTSB tin kickers ten years to solve 775 00:48:59,724 --> 00:49:03,000 the mysterious crashes of Flights 585 and 427, 776 00:49:04,172 --> 00:49:06,862 the longest investigation in aviation history. 777 00:49:06,965 --> 00:49:11,344 There are still some people in aviation who 778 00:49:11,448 --> 00:49:13,620 don't think the NTSB got it right. 779 00:49:13,724 --> 00:49:16,689 But I became convinced after talking to many, many, 780 00:49:16,793 --> 00:49:21,275 many people, pilots, engineers, people at Boeing uh 781 00:49:21,379 --> 00:49:22,620 and spending a lot of time 782 00:49:22,724 --> 00:49:25,241 with the investigators that they did get it right. 783 00:49:25,344 --> 00:49:33,620 Since the replacement of the 737 servo valves, 784 00:49:33,724 --> 00:49:36,586 there hasn't been a similar crash of the most popular, 785 00:49:36,689 --> 00:49:38,965 most profitable plane in the world.