1 00:00:05,448 --> 00:00:08,758 Halloween, 1994. 2 00:00:08,862 --> 00:00:10,896 You haven't heard anymore from this controller chick, huh? 3 00:00:11,000 --> 00:00:12,103 No, not a word. 4 00:00:14,413 --> 00:00:18,551 A commuter plane circles outside Chicago, waiting for clearance to land. 5 00:00:19,827 --> 00:00:23,965 Eagle Flight 184, descend and maintain 8000. 6 00:00:24,068 --> 00:00:26,000 Maintain 8000. Eagle 184. 7 00:00:31,344 --> 00:00:33,620 Without warning, the controls snap to the right. 8 00:00:39,103 --> 00:00:40,896 The plane plunges straight for the ground. 9 00:00:50,137 --> 00:00:54,206 The behavior of the crew and the air traffic controllers would be examined. 10 00:00:56,965 --> 00:01:00,000 Pilots would question the safety of an airplane. 11 00:01:00,103 --> 00:01:03,413 The airplane will have a nasty tendency to go out of control. 12 00:01:03,517 --> 00:01:06,241 Investigators travel the world for answers. 13 00:01:09,448 --> 00:01:13,344 The crash makes 'Roselawn' one of aviation's darkest words. 14 00:01:17,655 --> 00:01:19,310 Mayday! Mayday! 15 00:01:47,448 --> 00:01:51,310 It's mid afternoon on October the 31st, 1994. 16 00:01:53,344 --> 00:01:58,310 American Eagle Flight 4184 left Indianapolis, Indiana, 15 minutes ago. 17 00:01:59,586 --> 00:02:00,724 It's heading to Chicago. 18 00:02:03,448 --> 00:02:05,689 There are 68 passengers and crew on board. 19 00:02:15,000 --> 00:02:17,068 - Happy Halloween Cowboy. - Thank you. 20 00:02:23,689 --> 00:02:27,482 Flying through the clouds, the aircraft begins to experience some turbulence. 21 00:02:32,137 --> 00:02:34,137 I'm going to keep them in their seats in this chop. 22 00:02:34,241 --> 00:02:35,586 No sense in taking chances. 23 00:02:38,103 --> 00:02:41,344 Captain Orlando Aguiar is in command of today's flight. 24 00:02:43,896 --> 00:02:45,310 It's supposed to be his day off. 25 00:02:47,448 --> 00:02:50,482 He volunteered for this flight to make extra money. 26 00:02:50,586 --> 00:02:52,620 His wife is expecting their second child. 27 00:02:54,448 --> 00:02:56,931 Let's see if we can get above this. 28 00:02:57,034 --> 00:03:01,413 Center any chance Flight 184 can climb to 16,000? 29 00:03:01,517 --> 00:03:03,655 Eagle Flight 184 maintain 16,000. 30 00:03:05,896 --> 00:03:08,931 First Officer Jeff Gagliano is handling the flying duties 31 00:03:09,034 --> 00:03:11,034 on this leg of the flight. 32 00:03:11,137 --> 00:03:14,689 He programs the autopilot to climb to a less turbulent altitude. 33 00:03:16,068 --> 00:03:20,379 Jeff actually was working on his dad's ranch in Wisconsin 34 00:03:20,482 --> 00:03:24,965 uh, just before he came in for that trip on, uh, Halloween that day. 35 00:03:25,068 --> 00:03:26,827 Getting on a horse or getting in an airplane, 36 00:03:26,931 --> 00:03:28,655 those were two of the things that Jeff loved most. 37 00:03:35,896 --> 00:03:40,137 Flight 4184 is an ATR-72. 38 00:03:40,241 --> 00:03:42,862 A groundbreaking new aircraft built in France. 39 00:03:45,137 --> 00:03:49,482 Cost efficient and comfortable, the plane has become popular on short runs. 40 00:03:52,034 --> 00:03:55,862 This flight is just one of five short hops the crew will be making today. 41 00:03:59,310 --> 00:04:01,724 It's Amanda Holberg's first day on the job 42 00:04:01,827 --> 00:04:03,620 as a flight attendant with American Eagle. 43 00:04:05,310 --> 00:04:08,000 She's paired with Sandi Modaff, a seasoned veteran. 44 00:04:17,827 --> 00:04:22,103 Aguiar and Gagliano have flown this route countless times and know it by heart. 45 00:04:24,000 --> 00:04:26,103 When you're flying from Indianapolis to Chicago, 46 00:04:26,206 --> 00:04:29,344 you're flying through some of the busiest, uh, airspace in the world. 47 00:04:31,103 --> 00:04:35,000 As Flight 4184 approaches Chicago O'Hare, 48 00:04:35,103 --> 00:04:37,551 the pilots begin the descent to 10,000 feet. 49 00:04:40,034 --> 00:04:44,551 Chicago center. We have discretion down to uh, 10,000. 50 00:04:45,344 --> 00:04:46,758 We're on our way down now. 51 00:04:46,862 --> 00:04:47,965 Eagle 184, roger. 52 00:04:54,206 --> 00:04:56,862 In Chicago, Controller Michelle Willman is returning from a break 53 00:04:59,000 --> 00:05:02,344 The trainee controller is still working under the supervision of a monitor. 54 00:05:05,344 --> 00:05:07,241 She's told that traffic into O'Hare 55 00:05:07,344 --> 00:05:09,448 is facing potential delays because of weather. 56 00:05:10,862 --> 00:05:14,448 She will have to be prepared to put some flights on hold. 57 00:05:14,551 --> 00:05:18,344 Operations into and out of O'Hare are handled on a priority basis. 58 00:05:18,448 --> 00:05:21,172 It's not necessarily a first-come, first-serve basis. 59 00:05:21,275 --> 00:05:23,931 Um, international flights arriving to O'Hare 60 00:05:24,034 --> 00:05:25,896 because of their fuel status get priority. 61 00:05:26,000 --> 00:05:28,965 And then the turbo props come in at the end. 62 00:05:29,068 --> 00:05:33,379 Eagle 184, hold southeast on Victor seven. 63 00:05:33,482 --> 00:05:37,241 Chicago Center, roger hold southeast on Victor seven. Eagle 184. 64 00:05:40,310 --> 00:05:44,689 Flight 4184 must now fly a racetrack shaped holding pattern 65 00:05:44,793 --> 00:05:46,034 over northwestern Indiana. 66 00:05:49,586 --> 00:05:52,137 Chicago Center, Eagle 184 entering the hold. 67 00:05:52,689 --> 00:05:54,275 Eagle 184, roger. 68 00:05:57,448 --> 00:06:01,724 Aguiar programs the Autopilot to keep the planes circling at 10, 000 feet. 69 00:06:09,034 --> 00:06:10,758 I'll go up front to see if they want anything. 70 00:06:16,620 --> 00:06:19,827 The crew has little to do as they wait for Air Traffic Controllers 71 00:06:19,931 --> 00:06:21,344 to give them permission to land. 72 00:06:24,344 --> 00:06:27,103 - Can I get you boys anything? - I'm good. 73 00:06:27,206 --> 00:06:29,965 Stereo, you don't have a hard job. 74 00:06:30,068 --> 00:06:30,931 We do have it pretty easy. 75 00:06:35,689 --> 00:06:38,103 Man, this thing gets a real high deck angle in these turns. 76 00:06:38,206 --> 00:06:41,137 - Yeah. - We're just wallowing in the air right now. 77 00:06:41,241 --> 00:06:42,620 You want flaps 15? 78 00:06:42,724 --> 00:06:43,896 - I'll bring the nose down. - Sure. 79 00:06:50,827 --> 00:06:52,655 I guess Sandi's going ooh now. 80 00:06:59,137 --> 00:07:00,862 - See y'all. - All right. 81 00:07:08,862 --> 00:07:12,137 The crew needs to let the airline know about their delay. 82 00:07:12,241 --> 00:07:13,965 It could affect the rest of the day's schedule. 83 00:07:15,551 --> 00:07:18,896 Crews use text messages to communicate with dispatchers 84 00:07:19,000 --> 00:07:21,310 so they don't tie up radio frequencies. 85 00:07:21,413 --> 00:07:22,793 Should I let 'em know how much fuel we got? 86 00:07:23,275 --> 00:07:24,689 Sure. 87 00:07:24,793 --> 00:07:28,241 Space, F U E L, is that... 88 00:07:28,344 --> 00:07:30,689 We've got uh, 3600 pounds. 89 00:07:37,275 --> 00:07:39,068 Well, folks, once again, this is the captain. 90 00:07:40,206 --> 00:07:42,517 I do regret to inform you that Air Traffic Control 91 00:07:42,620 --> 00:07:45,034 has put us into a holding pattern up here. 92 00:07:45,137 --> 00:07:48,448 We're holding for approximately 20 minutes out of Chicago at this time. 93 00:07:49,448 --> 00:07:50,793 I do apologize for all the delays. 94 00:07:52,896 --> 00:07:53,758 That's much nicer, 95 00:07:54,344 --> 00:07:55,620 flaps 15. 96 00:07:55,724 --> 00:07:57,793 I'm sure once they let us out of the hold and forget they're down, 97 00:07:57,896 --> 00:07:59,103 we'll get the overspeed warning. 98 00:08:02,068 --> 00:08:04,068 I can't hold anymore, man. 99 00:08:14,241 --> 00:08:15,896 I'm doing circles up here, yeah. 100 00:08:17,655 --> 00:08:20,000 We got plenty of gas. We could be up here for a long while. 101 00:08:22,862 --> 00:08:24,586 - Hey, bro. - Yeah. 102 00:08:24,689 --> 00:08:26,206 I'm getting busy with the ladies back here. 103 00:08:26,586 --> 00:08:28,034 Ooh. 104 00:08:28,137 --> 00:08:30,793 Yeah, so if I don't make it up there in the next say, 15 or 20 minutes, 105 00:08:30,896 --> 00:08:32,310 you know why. 106 00:08:32,413 --> 00:08:35,482 Ok, I'll uh, when we get close to touchdown, I'll give you a ring. 107 00:08:35,586 --> 00:08:36,931 Oh, nah, I'll be up right now. 108 00:08:48,896 --> 00:08:52,517 You uh, you haven't heard any more from this controller chick, huh? 109 00:08:52,620 --> 00:08:53,551 No, not a word. 110 00:08:57,965 --> 00:09:03,172 Eagle Flight 184 descend and maintain 8000. 111 00:09:03,275 --> 00:09:05,103 Down to 8000. Eagle Flight 184. 112 00:09:07,137 --> 00:09:11,344 Eagle Flight 184 uh, should be about 10 minutes 113 00:09:11,448 --> 00:09:12,862 uh, till you're cleared in. 114 00:09:12,965 --> 00:09:13,827 Thank you. 115 00:09:15,172 --> 00:09:16,517 The flight is allowed to descend. 116 00:09:18,413 --> 00:09:19,517 Are we out of the hold? 117 00:09:19,620 --> 00:09:21,482 No, we're just going down to 8000. 118 00:09:24,827 --> 00:09:26,275 Then a warning. 119 00:09:26,379 --> 00:09:28,275 I knew we'd do that. 120 00:09:28,379 --> 00:09:32,068 The plane is going too fast to fly with its flaps extended. 121 00:09:32,172 --> 00:09:34,517 Well, I was trying to keep it at 180. 122 00:09:34,620 --> 00:09:38,655 Galliano retracts the flaps. 123 00:09:38,758 --> 00:09:41,137 There's a strange sound coming through the fuselage. 124 00:09:47,482 --> 00:09:50,137 Suddenly, the control column turns sharply to the right. 125 00:10:00,344 --> 00:10:01,482 The controls won't budge. 126 00:10:07,965 --> 00:10:09,586 The plane is falling from the sky. 127 00:10:13,655 --> 00:10:15,310 The pilots begin to recover control. 128 00:10:20,551 --> 00:10:21,551 But then it happens again. 129 00:10:30,068 --> 00:10:31,137 Mellow it out, mellow it out! 130 00:10:33,931 --> 00:10:35,896 Terrain. Pull Up. 131 00:10:39,586 --> 00:10:41,275 - Terrain. Doesn't pull. 132 00:10:46,517 --> 00:10:51,068 Terrain. Pull Up. Terrain. Pull Up. 133 00:11:05,896 --> 00:11:09,793 It was coming down too steep to even try to land. 134 00:11:09,896 --> 00:11:15,724 It was coming down at a, I mean, a sharp angle, a real sharp angle. 135 00:11:15,827 --> 00:11:18,827 Flight 4184 has crashed into a field 136 00:11:18,931 --> 00:11:20,931 just outside Roselawn, Indiana. 137 00:11:23,000 --> 00:11:25,827 Oh my God they're dead, they have to be 138 00:11:25,931 --> 00:11:30,241 for the speed that it was coming down. 139 00:11:30,344 --> 00:11:34,000 Hundreds of volunteers arrive at the crash site to offer help. 140 00:11:34,103 --> 00:11:35,620 But there's nothing they can do. 141 00:11:37,413 --> 00:11:41,172 There was not much to see of any airplane, you, you couldn't see no, 142 00:11:41,275 --> 00:11:42,965 no cabin or anything of the airplane, 143 00:11:43,965 --> 00:11:45,206 there just wasn't anything left of it. 144 00:11:47,448 --> 00:11:52,241 Both pilots, the two flight attendants and all 64 passengers are dead. 145 00:11:57,379 --> 00:11:59,172 The Roselawn crash would soon become 146 00:11:59,275 --> 00:12:02,000 one of the most important accidents in aviation history. 147 00:12:04,655 --> 00:12:09,310 It will lead investigators to new conclusions about a string of older crashes. 148 00:12:18,344 --> 00:12:22,586 The morning after the crash of American Eagle Flight 4184, 149 00:12:22,689 --> 00:12:25,068 a team from the National Transportation Safety Board 150 00:12:25,172 --> 00:12:27,620 is on the scene just outside Roselawn, Indiana. 151 00:12:30,862 --> 00:12:33,931 Greg Feith is the lead investigator. 152 00:12:34,034 --> 00:12:36,344 The morning that we arrived at the accident site 153 00:12:36,448 --> 00:12:40,896 it was cold, it was overcast, It was one of those drizzly, dank days. 154 00:12:41,000 --> 00:12:44,379 All you could smell was the Jet-A or the kerosene fuel 155 00:12:44,482 --> 00:12:49,517 and because it was muddy and wet, you had that odor or that aroma of dirt 156 00:12:49,620 --> 00:12:53,965 and so with all of those smells, that I mean, that really evokes some emotion there. 157 00:12:54,068 --> 00:12:58,241 And now you have to walk through that field and actually start to do your job. 158 00:13:00,931 --> 00:13:04,724 The crash site is soaked in jet fuel and hydraulic fluid. 159 00:13:04,827 --> 00:13:07,241 Human remains are scattered everywhere. 160 00:13:07,344 --> 00:13:09,379 The site is declared a bio hazard. 161 00:13:11,448 --> 00:13:14,793 With 4184, it was one of those types of accidents 162 00:13:14,896 --> 00:13:16,724 where there was very little left of the airplane. 163 00:13:19,586 --> 00:13:22,310 Investigators know that the way the wreckage is spread out 164 00:13:22,413 --> 00:13:24,275 can tell them how the plane hit the ground. 165 00:13:27,758 --> 00:13:30,034 Because there was a fan shaped debris pattern 166 00:13:30,137 --> 00:13:32,448 and it was spread out over a very large area, 167 00:13:32,551 --> 00:13:35,586 we knew that the impact was very shallow, but at a very high speed. 168 00:13:40,931 --> 00:13:44,275 The airplane's two flight recorders are found intact in the tail. 169 00:13:45,827 --> 00:13:48,379 They're taken to the NTSB labs for analysis. 170 00:13:51,034 --> 00:13:53,413 The data on the recorders could provide the clues 171 00:13:53,517 --> 00:13:55,482 investigators need to solve the mystery. 172 00:13:57,344 --> 00:13:59,310 But extracting the data takes time. 173 00:14:01,965 --> 00:14:05,655 In the meantime, investigators look for the location of key pieces of wreckage. 174 00:14:07,689 --> 00:14:09,689 The first things we typically look for 175 00:14:09,793 --> 00:14:12,379 are the four corners of the airplane. 176 00:14:12,482 --> 00:14:16,172 The NTSB's Bob Swaim leads that search. 177 00:14:16,275 --> 00:14:18,551 You're looking for the nose and the tail and the two wing tips, 178 00:14:18,655 --> 00:14:21,862 because if you can tell where the four corners of the airplane are, 179 00:14:21,965 --> 00:14:26,137 you get an initial idea of whether the pilot was in control or not. 180 00:14:29,137 --> 00:14:32,482 The plane's four corners are far from each other. 181 00:14:32,586 --> 00:14:34,689 The nose and cockpit are completely destroyed. 182 00:14:39,482 --> 00:14:42,827 This tells investigators that the plane hit the ground nose first, 183 00:14:42,931 --> 00:14:44,586 in a shallow but rapid descent. 184 00:14:48,034 --> 00:14:50,931 Mellow it out, mellow it out! 185 00:14:51,034 --> 00:14:54,241 The fact that the plane wasn't in a steep descent on impact 186 00:14:54,344 --> 00:14:56,517 indicates that the pilots had some control 187 00:14:56,620 --> 00:14:58,275 in the final seconds before the crash. 188 00:15:02,344 --> 00:15:03,827 They just ran out of room to pull up. 189 00:15:15,655 --> 00:15:19,758 Investigator Bob Swaim meanwhile, has recovered some of the plane's instruments 190 00:15:19,862 --> 00:15:22,068 including its Attitude Director Indicator. 191 00:15:23,137 --> 00:15:25,000 Also known as the artificial horizon. 192 00:15:27,068 --> 00:15:30,137 It's a key instrument that tells pilots if they're flying level. 193 00:15:31,413 --> 00:15:32,931 If it malfunctioned, 194 00:15:33,034 --> 00:15:37,034 it could have misled the crew and caused them to make mistakes. 195 00:15:37,137 --> 00:15:40,758 We had a pretty good idea of the attitude of the airplane at impact, 196 00:15:40,862 --> 00:15:45,034 so it would really help at that point to see if the pilots 197 00:15:45,137 --> 00:15:48,965 had the same view of the flight that we found as they hit the ground. 198 00:15:49,068 --> 00:15:49,965 Can you get the lights for me please? 199 00:15:52,000 --> 00:15:56,413 A lot of the cockpit pieces use a fluorescent paint, or something similar, 200 00:15:56,517 --> 00:16:01,068 and when they contact each other little, little bits of the paint transfer. 201 00:16:02,379 --> 00:16:04,310 If we look at those with a black light 202 00:16:04,413 --> 00:16:07,275 we can see things that the naked eye cannot see. 203 00:16:08,172 --> 00:16:09,068 There's a good imprint here. 204 00:16:11,551 --> 00:16:14,068 The force of the impact has left tiny scratches 205 00:16:14,172 --> 00:16:15,206 on the shattered instrument. 206 00:16:18,448 --> 00:16:22,862 Swaim discovers that the attitude indicator seems to have been working. 207 00:16:22,965 --> 00:16:25,620 Its final readings show the plane was leveling off. 208 00:16:27,965 --> 00:16:30,758 The instrument coincides with the plane's actual position on impact. 209 00:16:34,551 --> 00:16:37,655 It indicated that at least the flight instruments 210 00:16:37,758 --> 00:16:40,379 that the pilots would have been looking at were appropriate, 211 00:16:40,482 --> 00:16:43,758 they were proper, that the pilots had something to fly by. 212 00:16:46,655 --> 00:16:52,137 The discovery means that the pilots knew their plane was diving towards the ground. 213 00:16:52,241 --> 00:16:56,413 Investigator Greg Feith is getting a clearer picture of the flight's final seconds. 214 00:16:58,724 --> 00:17:02,689 Now he wants to know about the history of this flight before it fell from the sky. 215 00:17:06,413 --> 00:17:08,482 One of the elements of the investigation, of course, 216 00:17:08,586 --> 00:17:10,000 was to look at Air Traffic Control. 217 00:17:12,448 --> 00:17:14,517 Eagle 184 hold southeast... 218 00:17:14,620 --> 00:17:18,275 Feith learns that Flight 4184 had been in a holding pattern 219 00:17:18,379 --> 00:17:22,068 southeast of Chicago for 39 minutes before the crash. 220 00:17:24,862 --> 00:17:26,448 When we looked at the Air Traffic Control records, 221 00:17:26,551 --> 00:17:28,448 we found that the flow rate, 222 00:17:28,551 --> 00:17:32,241 that is the number of airplanes that were going into Chicago O'Hare at the time, 223 00:17:32,344 --> 00:17:35,275 had to be reduced because of the weather moving through the area. 224 00:17:35,379 --> 00:17:38,344 Well, folks, I do regret to inform you that Air Traffic Control 225 00:17:38,448 --> 00:17:40,724 has put us into a holding pattern up here. 226 00:17:40,827 --> 00:17:43,655 And because of the reduced rate into Chicago, 227 00:17:43,758 --> 00:17:47,275 we knew that 4184 was going to have to hold for a very long period of time. 228 00:17:48,586 --> 00:17:49,965 I do apologize for all the delays. 229 00:17:52,241 --> 00:17:54,862 One of the aspects that we found was that one of the controllers 230 00:17:54,965 --> 00:17:58,413 in the facility was relatively new, they were considered a trainee. 231 00:18:01,275 --> 00:18:05,517 Had an inexperienced controller put Flight 4184 in peril? 232 00:18:09,931 --> 00:18:14,034 Chief investigator Greg Feith wants to know more about the weather conditions 233 00:18:14,137 --> 00:18:15,172 along the holding pattern. 234 00:18:18,862 --> 00:18:20,206 I want weather data, 235 00:18:20,310 --> 00:18:22,862 pilot reports, atmospheric conditions, 236 00:18:22,965 --> 00:18:24,413 Doppler radar or anything you can find. 237 00:18:34,896 --> 00:18:38,965 Flight 4184 wasn't the only plane circling O'Hare that day. 238 00:18:40,241 --> 00:18:42,275 Several other planes were also on hold. 239 00:18:44,517 --> 00:18:45,620 They all landed safely. 240 00:18:50,379 --> 00:18:52,689 Interviews with the pilots of some of those planes 241 00:18:52,793 --> 00:18:54,586 give investigators an important clue. 242 00:18:56,068 --> 00:18:57,586 One after another, 243 00:18:57,689 --> 00:19:01,034 they all experienced icing, some as much as three quarters of an inch. 244 00:19:02,655 --> 00:19:04,655 Many of the pilots report the same thing. 245 00:19:05,724 --> 00:19:06,689 Ice. 246 00:19:09,965 --> 00:19:14,000 Dr. Marcia Politovich works at the National Center for Atmospheric Research. 247 00:19:16,344 --> 00:19:21,793 She's one of the leading experts on icing, and the danger it poses to aircraft 248 00:19:21,896 --> 00:19:24,862 It essentially changes the shape of the wing while you're in flight. 249 00:19:26,137 --> 00:19:29,103 It creates drag, it reduces lift, 250 00:19:29,206 --> 00:19:32,034 it causes performance and handling problems 251 00:19:32,137 --> 00:19:33,551 and it's just not a good thing to have. 252 00:19:37,379 --> 00:19:41,482 Investigators examine weather records from the day of the crash. 253 00:19:41,586 --> 00:19:46,620 They find a disturbing pattern of reports of icing all along a cold front near Chicago. 254 00:19:48,965 --> 00:19:51,758 But the reports describe the icing as light to moderate. 255 00:19:53,931 --> 00:19:57,068 Perhaps the size of the commuter plane was a factor in this crash. 256 00:19:59,379 --> 00:20:02,068 Different planes respond to icing differently. 257 00:20:02,172 --> 00:20:05,482 A large plane will respond differently than a small plane. 258 00:20:05,586 --> 00:20:10,379 Uh, reasons for that are both environmental and having to do with the airframe itself. 259 00:20:12,620 --> 00:20:16,517 Large jets generally fly above the dangerous conditions inside a cloud. 260 00:20:18,517 --> 00:20:20,689 But the ATR-72 can't do that. 261 00:20:22,689 --> 00:20:24,862 A smaller plane can't fly as high. 262 00:20:24,965 --> 00:20:27,689 They're stuck in the icing environment for longer. 263 00:20:27,793 --> 00:20:29,724 They may not have de-icing equipment. 264 00:20:29,827 --> 00:20:31,482 And if they get in trouble, 265 00:20:31,586 --> 00:20:34,827 they may not have enough excess power to get out of it. 266 00:20:34,931 --> 00:20:38,482 Investigators discover that Flight 4184's holding pattern 267 00:20:38,586 --> 00:20:40,655 took it through layers of cloud repeatedly. 268 00:20:42,172 --> 00:20:44,965 Each time it would have been exposed to icing conditions. 269 00:20:46,344 --> 00:20:49,896 4184 we knew had been holding in an icing event, 270 00:20:50,000 --> 00:20:54,137 there were layers of clouds that they have been flying in and out of. 271 00:20:54,241 --> 00:20:58,655 Steve Frederick was flying out of Chicago on the morning of the crash. 272 00:20:58,758 --> 00:21:01,620 He flew through the same treacherous weather. 273 00:21:01,724 --> 00:21:03,655 Each time that I went through that cold front 274 00:21:03,758 --> 00:21:06,344 during that day, the weather was intensifying, 275 00:21:06,448 --> 00:21:10,000 the ice was getting worse and I was getting more and more concerned. 276 00:21:12,310 --> 00:21:15,586 Frederick asked his captain to pass on a warning about the weather, 277 00:21:15,689 --> 00:21:17,965 so that other pilots would be alerted to the danger. 278 00:21:19,862 --> 00:21:23,931 I found out a little bit later that my captain had never warned dispatch 279 00:21:24,034 --> 00:21:28,034 and these pilots never got the warning about the ice that was out there that day. 280 00:21:28,137 --> 00:21:31,689 And there's no feeling in the world that can compare 281 00:21:31,793 --> 00:21:33,896 to how badly I felt at that moment. 282 00:21:41,482 --> 00:21:44,620 Greg Feith knows that controllers had put several other planes 283 00:21:44,724 --> 00:21:46,379 into a holding pattern near Chicago. 284 00:21:48,172 --> 00:21:52,137 But they all landed safely after coming out of the hold. 285 00:21:52,241 --> 00:21:57,517 This means the controller had not put Flight 4184 in jeopardy. 286 00:21:57,620 --> 00:22:00,862 She acted correctly, given the information she had about the weather. 287 00:22:02,206 --> 00:22:04,103 One of the issues about Air Traffic Control 288 00:22:04,206 --> 00:22:06,379 is that the controllers can't just look at their radar screen 289 00:22:06,482 --> 00:22:09,620 and identify areas of, of precipitation 290 00:22:09,724 --> 00:22:11,862 or icing conditions readily. 291 00:22:11,965 --> 00:22:15,000 The controllers don't know that an airplane is sitting in icing conditions 292 00:22:15,103 --> 00:22:17,724 unless the pilot provides them 293 00:22:17,827 --> 00:22:20,241 with what they call a Pirep or a Pilot Report. 294 00:22:20,344 --> 00:22:25,275 So if, if the crew in this case, 4184, doesn't provide that information 295 00:22:25,379 --> 00:22:27,344 to the controller, then the controller doesn't know 296 00:22:27,448 --> 00:22:31,275 that an icing event actually is occurring out there. 297 00:22:31,379 --> 00:22:34,827 Feith and his team wonder if the flight crew simply didn't realize 298 00:22:34,931 --> 00:22:36,517 they were flying into icy conditions. 299 00:22:43,275 --> 00:22:45,793 The plane's cockpit voice recorder provides the answer. 300 00:22:46,896 --> 00:22:49,965 Can I get you boys anything? 301 00:22:50,068 --> 00:22:52,965 Stereo, you don't have a hard job. 302 00:22:53,068 --> 00:22:54,206 We have it pretty easy. 303 00:22:55,482 --> 00:22:56,379 Hey, bro. 304 00:22:57,586 --> 00:22:59,000 I'm getting busy with the ladies back here. 305 00:22:59,448 --> 00:23:01,206 Ooh. 306 00:23:01,310 --> 00:23:04,448 At first glance, the crew's behavior seems unprofessional 307 00:23:04,551 --> 00:23:05,448 and undisciplined. 308 00:23:07,275 --> 00:23:09,586 The first officer was listening to some music. 309 00:23:09,689 --> 00:23:13,448 We knew that there were a lot of non-aviation things going on. 310 00:23:13,551 --> 00:23:17,620 One of the most contentious elements was how did that affect the crew's performance 311 00:23:17,724 --> 00:23:20,827 and their awareness to the situation that was starting to develop. 312 00:23:21,586 --> 00:23:22,517 That's much nicer now, 313 00:23:22,620 --> 00:23:23,517 flaps 15. 314 00:23:26,689 --> 00:23:28,965 Showing some ice now. 315 00:23:29,068 --> 00:23:30,896 I'm sure once they let us out of the hold and forget... 316 00:23:31,000 --> 00:23:32,586 But nine minutes before the crash 317 00:23:32,689 --> 00:23:36,724 the crew had noticed their plane was picking up ice. 318 00:23:36,827 --> 00:23:41,689 The pilots must have been aware they were flying through an area of aircraft icing. 319 00:23:41,793 --> 00:23:43,793 You haven't heard any more from this controller chick, huh? 320 00:23:43,896 --> 00:23:44,896 No, not a word. 321 00:23:46,793 --> 00:23:48,965 Then, two minutes before the accident, 322 00:23:49,068 --> 00:23:51,620 another remark draws the attention of investigators. 323 00:23:52,448 --> 00:23:53,310 We still got ice. 324 00:23:55,655 --> 00:23:56,517 I see what you mean. 325 00:23:59,793 --> 00:24:02,034 The crew knew about the ice. 326 00:24:02,137 --> 00:24:04,448 Now investigators need to know what they did about it. 327 00:24:19,275 --> 00:24:24,172 The ATR-72 is equipped with sophisticated de-icing devices. 328 00:24:24,275 --> 00:24:27,758 It's crucial to know what the crew did about the ice buildup on their wings. 329 00:24:30,758 --> 00:24:33,379 This time, the flight's data recorder provides the answers. 330 00:24:38,172 --> 00:24:40,517 Almost 17 minutes before the crash 331 00:24:40,620 --> 00:24:42,793 something sets off the master caution warning. 332 00:24:44,724 --> 00:24:47,034 It could signal a problem in one of the plane's systems. 333 00:24:48,586 --> 00:24:50,862 It could also mean the electronic ice detector 334 00:24:50,965 --> 00:24:52,586 is picking up the presence of ice. 335 00:24:56,413 --> 00:25:00,275 The flight data recorder shows investigators that in response to the alert, 336 00:25:00,379 --> 00:25:04,827 Captain Aguiar turned the plane's de-icing system to its maximum setting. 337 00:25:10,862 --> 00:25:15,586 The NTSB's Charley Pereira looks into the performance of the ATR-72. 338 00:25:17,724 --> 00:25:22,344 The icing, uh, alert system had sounded aurally and they heard it, 339 00:25:22,448 --> 00:25:24,862 and they activated protection systems on the airplane, 340 00:25:24,965 --> 00:25:27,448 and at the time of the accident, uh, the de-ice systems were on. 341 00:25:30,793 --> 00:25:34,793 The complete ice protection system on the ATR-72 airplane 342 00:25:34,896 --> 00:25:38,586 consists of a combination of what we call anti-icing 343 00:25:38,689 --> 00:25:42,517 which are hot surfaces that don't allow the ice to form. 344 00:25:42,620 --> 00:25:47,137 The windshields and the propellers are also heated on this airplane 345 00:25:47,241 --> 00:25:49,517 and then they have de-ice systems which are on the leading edge 346 00:25:49,620 --> 00:25:52,620 of the wings, what you call pneumatic boots. 347 00:25:52,724 --> 00:25:56,172 Uh, they're like rubber inflatable chambers that you blow air into 348 00:25:56,275 --> 00:25:59,379 and they expand kind of like a balloon and that cracks the ice 349 00:25:59,482 --> 00:26:00,793 and the ice flies off the airplane. 350 00:26:05,689 --> 00:26:07,103 The flight data recorder shows 351 00:26:07,206 --> 00:26:11,206 that after he activated his de-icing system, Captain Aguiar, 352 00:26:11,310 --> 00:26:13,000 also pushed the throttle forward slightly, 353 00:26:14,000 --> 00:26:16,931 increasing the plane's speed. 354 00:26:17,034 --> 00:26:19,758 This increased the speed of the air moving over the plane's wings, 355 00:26:21,103 --> 00:26:24,517 making it harder for ice to settle there. 356 00:26:24,620 --> 00:26:28,172 The pilots had done everything they could to deal with ice buildup on the plane. 357 00:26:30,620 --> 00:26:32,965 But were the anti-icing systems actually working? 358 00:26:38,931 --> 00:26:41,689 The shattered remains of that de-icing system 359 00:26:41,793 --> 00:26:43,965 are now the main focus of the investigation. 360 00:26:47,724 --> 00:26:50,344 The airplane was designed in France 361 00:26:50,448 --> 00:26:53,655 by a group of French and Italian companies. 362 00:26:53,758 --> 00:26:56,310 The de-icing system was part of that design. 363 00:26:58,793 --> 00:27:03,413 So the components were made by small French vendors. 364 00:27:03,517 --> 00:27:05,896 who were located around the countryside, 365 00:27:06,000 --> 00:27:09,482 and then they were assembled there in Toulouse into the final airplane. 366 00:27:15,620 --> 00:27:19,310 Bob Swaim arrives in France with pieces of the de-icing system. 367 00:27:23,758 --> 00:27:26,931 I brought some pieces from Flight 4184 to look at. 368 00:27:27,034 --> 00:27:29,896 The key component to the de-icing system is probably not 369 00:27:30,000 --> 00:27:33,689 the black rubber boot that you see on the airplane, 370 00:27:33,793 --> 00:27:37,206 but the timer that's inside the airplane, or the timers 371 00:27:37,310 --> 00:27:38,965 in the valves that control those boots. 372 00:27:43,482 --> 00:27:47,379 The force of the crash has left telltale markings called index marks. 373 00:27:49,000 --> 00:27:51,724 They show the position of the valves at the time of impact. 374 00:27:53,310 --> 00:27:55,689 Swain compares them to the original blueprints. 375 00:27:57,655 --> 00:27:59,344 Does anything seem out of the ordinary? 376 00:28:03,206 --> 00:28:06,000 The trip to France has led to yet another dead end. 377 00:28:07,896 --> 00:28:10,965 There was nothing wrong with the plane's de-icing system. 378 00:28:11,068 --> 00:28:12,931 Thanks a lot. I appreciate it. Thank you. 379 00:28:13,034 --> 00:28:14,275 Investigators are puzzled. 380 00:28:18,034 --> 00:28:20,137 Showing some ice now. 381 00:28:20,241 --> 00:28:22,896 If the crew knew they had ice on their wings 382 00:28:23,000 --> 00:28:25,413 and their de-icing system was working, 383 00:28:25,517 --> 00:28:26,689 why did the plane crash? 384 00:28:30,172 --> 00:28:33,862 Other pilots think they know the answer and decide to speak out. 385 00:28:33,965 --> 00:28:37,310 Their decision will dramatically change the course of this investigation. 386 00:28:49,344 --> 00:28:52,689 Three weeks after the crash near Roselawn, Indiana, 387 00:28:52,793 --> 00:28:57,344 American Eagle pilot Steve Frederick distributes a warning. 388 00:28:57,448 --> 00:29:01,793 It says the ATR-72 fleet operated by American Eagle, 389 00:29:01,896 --> 00:29:04,965 is dangerous in icing conditions. 390 00:29:05,068 --> 00:29:08,103 It claims American Eagle pilots have pleaded with the airline 391 00:29:08,206 --> 00:29:12,793 and regulators to do something about it, but to no effect. 392 00:29:12,896 --> 00:29:15,724 I drafted and, and distributed a brochure 393 00:29:15,827 --> 00:29:17,689 in Chicago O'Hare Airport, 394 00:29:17,793 --> 00:29:19,448 which essentially warned people 395 00:29:19,551 --> 00:29:23,965 about the problems with the ATR aircraft and made an outreach to the public 396 00:29:24,068 --> 00:29:27,000 in order to try and get something done because nothing was happening. 397 00:29:28,655 --> 00:29:31,275 Steve Frederick has more than a professional interest 398 00:29:31,379 --> 00:29:33,551 in the crash of Flight 4184. 399 00:29:35,172 --> 00:29:38,758 Co-pilot Jeff Gagliano was his close friend. 400 00:29:38,862 --> 00:29:40,724 They graduated from flight school together. 401 00:29:42,413 --> 00:29:45,068 Galliano's death has hit him hard. 402 00:29:45,172 --> 00:29:46,931 He made the comment one time 403 00:29:47,034 --> 00:29:50,000 that he would probably wind up dying because of ice in an ATR. 404 00:29:51,068 --> 00:29:53,620 And it was eerily prophetic. 405 00:29:57,000 --> 00:29:58,724 A month after the crash. 406 00:29:58,827 --> 00:30:02,896 Pilot frustration over the ATR's airworthiness boils over. 407 00:30:03,000 --> 00:30:07,103 A group of a dozen pilots refused to fly, citing risky weather. 408 00:30:08,620 --> 00:30:11,655 The airline is forced to cancel flights 409 00:30:11,758 --> 00:30:15,103 and then Steve Frederick goes one step further. 410 00:30:15,206 --> 00:30:18,344 He voices his concerns on a US Network morning show. 411 00:30:20,724 --> 00:30:24,344 We were told this airplane will try and kill you if you get too slow 412 00:30:24,448 --> 00:30:29,620 in ice the the airplane will have a nasty tendency to go out of control. 413 00:30:29,724 --> 00:30:33,068 When I came back to flying after my appearance on Good Morning America 414 00:30:33,172 --> 00:30:35,275 I was summarily suspended without pay. 415 00:30:45,965 --> 00:30:48,758 The public protest leads investigators to wonder 416 00:30:48,862 --> 00:30:52,310 if the ATR-72 has a deadly vulnerability to ice. 417 00:30:55,034 --> 00:30:56,000 Merci. 418 00:30:57,896 --> 00:30:59,862 Investigator Charley Pereira 419 00:30:59,965 --> 00:31:03,620 visits the ATR's French manufacturer Aerospatiale 420 00:31:03,724 --> 00:31:05,379 to learn more about the plane's history. 421 00:31:06,689 --> 00:31:11,137 We embarked on a research effort to try to identify 422 00:31:11,241 --> 00:31:16,896 all previous ATR-42 and 72 uh, roll control uh, incidents. 423 00:31:18,448 --> 00:31:20,137 He finds a disturbing pattern. 424 00:31:22,034 --> 00:31:26,862 And, and about 5, 5 of those were found to be similar, 425 00:31:26,965 --> 00:31:30,965 uh, after the fact in our review to the Roselawn case. 426 00:31:32,586 --> 00:31:35,862 One such incident took place in December 1988 427 00:31:36,793 --> 00:31:38,000 in Mosinee, Wisconsin. 428 00:31:40,275 --> 00:31:43,068 An American Eagle ATR-42 had been preparing 429 00:31:43,172 --> 00:31:46,655 to land in icy conditions at Central Wisconsin airport. 430 00:31:46,758 --> 00:31:48,344 The airplane was on approach 431 00:31:48,448 --> 00:31:50,379 uh, in severe icing conditions 432 00:31:50,482 --> 00:31:53,344 um, described as freezing drizzle and freezing rain. 433 00:31:54,862 --> 00:31:57,344 Captain Mike Bodak was the pilot that day. 434 00:31:58,517 --> 00:32:01,655 We were just on the last two legs of our trip 435 00:32:01,758 --> 00:32:03,482 before we'd be done with work. 436 00:32:03,586 --> 00:32:06,172 And uh, we were doing our descent. 437 00:32:06,275 --> 00:32:09,379 um, everything was proceeding normally. 438 00:32:10,413 --> 00:32:12,827 Negative ice, just wet. 439 00:32:12,931 --> 00:32:14,551 I'll call the flight Center to let them know we're turning inbound. 440 00:32:16,655 --> 00:32:20,689 I hear in the tail a sound like that. 441 00:32:20,793 --> 00:32:22,103 It just got louder and louder. 442 00:32:26,241 --> 00:32:28,965 We have no idea what is occurring. 443 00:32:29,068 --> 00:32:31,965 I thought initially a propeller blade may have come off. 444 00:32:34,206 --> 00:32:36,758 It was as if the steering wheel wasn't connected to anything. 445 00:32:37,827 --> 00:32:39,758 The plane stalls. 446 00:32:39,862 --> 00:32:42,724 Its wings can't generate enough lift to keep it in the air. 447 00:32:46,379 --> 00:32:48,655 As I see I'm not getting any of the airplane back, 448 00:32:48,758 --> 00:32:51,931 I come up on the power levers all the way. 449 00:32:52,034 --> 00:32:54,620 The engines are really trying to fly. 450 00:32:54,724 --> 00:32:56,931 And at this point I'm getting some of the airplane back. 451 00:32:57,034 --> 00:33:00,482 So I make a forward motion to try and break the stall 452 00:33:00,586 --> 00:33:03,413 and it's still going, "terrain, terrain" 453 00:33:03,517 --> 00:33:05,724 and I don't have the airplane back yet 454 00:33:05,827 --> 00:33:07,551 and my first officer says... 455 00:33:07,655 --> 00:33:08,793 Props. 456 00:33:08,896 --> 00:33:10,482 And I say, "max rpm." 457 00:33:10,586 --> 00:33:11,827 Terrain. Terrain. 458 00:33:11,931 --> 00:33:15,172 And he throws the props from 86 to 100 percent. 459 00:33:17,827 --> 00:33:20,206 And instantaneously boom, we fly out of the stall. 460 00:33:20,689 --> 00:33:22,241 Whoo! 461 00:33:22,344 --> 00:33:25,000 The plane is less than 1200 feet above the ground. 462 00:33:27,000 --> 00:33:30,310 Captain Bodak has learned a sobering lesson about the ATR. 463 00:33:31,965 --> 00:33:33,000 There was no warning. 464 00:33:33,103 --> 00:33:36,000 The plane stalled without any warning. 465 00:33:36,103 --> 00:33:38,379 Planes do have warnings for stalls. 466 00:33:38,482 --> 00:33:40,344 But in this case there was no warning. 467 00:33:40,448 --> 00:33:43,931 I got the first warning that I was in a stall was, I was in a stall. 468 00:33:47,689 --> 00:33:49,310 But other pilots weren't as lucky. 469 00:33:51,655 --> 00:33:54,758 An ATR-42 operated by an Italian airline 470 00:33:54,862 --> 00:33:58,862 was flying over the Alps enroute to Germany in October 1987. 471 00:34:00,724 --> 00:34:03,758 The plane lost control and crashed in the mountains, 472 00:34:03,862 --> 00:34:05,689 killing all 37 people onboard. 473 00:34:07,103 --> 00:34:09,068 Ice was the main factor. 474 00:34:09,172 --> 00:34:11,620 But the final report blamed pilot procedures. 475 00:34:13,068 --> 00:34:16,034 For investigators it's really important to look back 476 00:34:16,137 --> 00:34:18,896 at historical information about any airplane. 477 00:34:19,000 --> 00:34:20,034 You want to look for trends. 478 00:34:26,586 --> 00:34:29,965 What they would find is a troubling detail with this plane's history. 479 00:34:31,379 --> 00:34:34,103 Did any of your studies uncover a wing design flaw? 480 00:34:36,413 --> 00:34:39,758 Charley Pereira wants to know if the engineers who built the plane 481 00:34:39,862 --> 00:34:43,931 could explain why an ATR-72 would go so badly out of control. 482 00:34:45,896 --> 00:34:49,896 To his surprise, he learns they knew that it had a susceptibility to icing. 483 00:34:51,206 --> 00:34:54,137 You've seen the flight data from the accident flight. 484 00:34:54,241 --> 00:34:57,275 Where would the ice have formed to cause that? 485 00:34:57,379 --> 00:35:00,758 When I asked one of their oldest most senior aerodynamicists 486 00:35:00,862 --> 00:35:02,724 who couldn't speak any English at all, 487 00:35:02,827 --> 00:35:06,517 what he thought would be the shape and location 488 00:35:06,620 --> 00:35:09,586 of an ice accretion that could cause uh, the behavior that we saw 489 00:35:09,689 --> 00:35:11,379 on the flight recorder for the Roselawn airplane. 490 00:35:13,862 --> 00:35:17,172 He drew up the airfoil section and a little shape 491 00:35:17,275 --> 00:35:21,068 just behind the de-ice boots and said this was it, 492 00:35:21,172 --> 00:35:23,931 and the translation was that this is what will cause the problem. 493 00:35:25,172 --> 00:35:26,655 Aft of the de-icing boot. 494 00:35:28,862 --> 00:35:33,103 Investigator Charley Pereira's beginning to understand how ice can affect 495 00:35:33,206 --> 00:35:34,724 the wings of the French-built plane. 496 00:35:36,896 --> 00:35:39,241 If the ice built up behind the boot 497 00:35:39,344 --> 00:35:41,068 the crew would have no way to clear it. 498 00:35:42,103 --> 00:35:43,620 We still got ice. 499 00:35:43,724 --> 00:35:45,137 And even a small amount of ice 500 00:35:45,241 --> 00:35:47,344 can have a devastating effect on an airplane. 501 00:35:50,931 --> 00:35:54,034 Ice can disrupt the smooth movement of air over the wing. 502 00:35:56,241 --> 00:35:59,103 But how could so much ice buildup behind the boot? 503 00:36:02,068 --> 00:36:05,448 Investigators contact Dr Marcia Politovich for assistance. 504 00:36:06,689 --> 00:36:09,241 The NTSB called us uh, to help them analyze 505 00:36:09,344 --> 00:36:11,137 weather conditions in this case. 506 00:36:13,137 --> 00:36:16,379 Her research shows that the pilots of Flight 4184 507 00:36:16,482 --> 00:36:19,068 likely flew into something they've never even heard of. 508 00:36:21,310 --> 00:36:23,965 Something even more dangerous than ordinary ice. 509 00:36:25,793 --> 00:36:28,241 Now based on the weather analysis, it looked to us 510 00:36:28,344 --> 00:36:30,448 like the kind of icing that plane encountered 511 00:36:30,551 --> 00:36:32,275 was from super-cooled large drops. 512 00:36:33,620 --> 00:36:35,068 Now large is relative, 513 00:36:35,172 --> 00:36:37,931 what we're talking about large here is about the size of a human hair. 514 00:36:39,137 --> 00:36:40,862 Super-cooled large droplets 515 00:36:40,965 --> 00:36:44,620 are about 100 times smaller than a raindrop. 516 00:36:44,724 --> 00:36:47,827 They form inside storm clouds when the temperature is near freezing. 517 00:36:50,000 --> 00:36:52,413 But the drops don't freeze until they come into contact 518 00:36:52,517 --> 00:36:55,000 with something solid, like the wing of an airplane. 519 00:36:58,931 --> 00:37:04,413 Conditions that day were ideal for the formation of these tiny freezing droplets. 520 00:37:04,517 --> 00:37:06,586 We had all the clues that we needed. 521 00:37:06,689 --> 00:37:10,344 A warm cloud top, minus eight to minus 12 degree Celsius. 522 00:37:10,448 --> 00:37:15,310 We had drizzle formation near the top that was probably encouraged by some wind shear 523 00:37:15,413 --> 00:37:17,034 near the cloud top. 524 00:37:17,137 --> 00:37:18,827 And very little ice in the cloud 525 00:37:18,931 --> 00:37:19,896 from what we could tell. 526 00:37:21,896 --> 00:37:24,034 On every lap of its holding pattern 527 00:37:24,137 --> 00:37:30,137 Flight 4184 flew through layers of clouds that hid a small but lethal element. 528 00:37:30,241 --> 00:37:32,827 They just put that poor guy in the wrong place at the wrong time. 529 00:37:39,206 --> 00:37:42,034 Investigators learn that super-cooled large droplets 530 00:37:42,137 --> 00:37:45,000 have a distinctive way of accumulating on an aircraft wing. 531 00:37:48,413 --> 00:37:51,413 Ordinary ice accumulates on the leading edge of the wing, 532 00:37:51,517 --> 00:37:53,551 where de-icing boots can get rid of it easily. 533 00:37:55,620 --> 00:37:58,206 But SLD act differently. 534 00:37:58,310 --> 00:38:02,379 These super-cooled drops hit the wing and slide back over it before freezing. 535 00:38:04,793 --> 00:38:08,931 This forms a ridge behind the boots, out of reach of the de-icing system. 536 00:38:11,241 --> 00:38:14,965 So, as 4184 was flying in that type of environment, 537 00:38:15,068 --> 00:38:17,931 rather than the water droplet freezing on the protected surface 538 00:38:18,034 --> 00:38:21,689 of the de-ice boot, it actually ran behind the de-ice boot 539 00:38:21,793 --> 00:38:23,137 and froze on the metal surface. 540 00:38:26,068 --> 00:38:29,793 The pilots can't get a good view of their wings from the cockpit. 541 00:38:29,896 --> 00:38:33,000 They would have been utterly unaware of the danger taking shape. 542 00:38:34,931 --> 00:38:37,000 For the pilots, when they looked out their side window, 543 00:38:37,103 --> 00:38:38,655 they would see the outer portion of the wing. 544 00:38:40,586 --> 00:38:43,000 They definitely could not see the top of the wing, 545 00:38:43,103 --> 00:38:44,655 where this ice ridge was starting to form. 546 00:38:50,724 --> 00:38:53,482 For Greg Feith, the investigation is coming to a head. 547 00:38:55,517 --> 00:38:59,724 His investigators think they know why Flight 4184 crashed, 548 00:38:59,827 --> 00:39:00,896 but they can't prove it. 549 00:39:04,068 --> 00:39:06,689 To make matters worse, the plane's manufacturer 550 00:39:06,793 --> 00:39:10,724 suggests that the Roselawn crash wasn't caused by an ice buildup 551 00:39:10,827 --> 00:39:12,000 but by poor piloting. 552 00:39:13,448 --> 00:39:16,413 The NTSB thought it was an aircraft problem. 553 00:39:16,517 --> 00:39:18,413 And the French aircraft manufacturer 554 00:39:18,517 --> 00:39:21,551 thought it was a pilot problem and not their particular product. 555 00:39:28,344 --> 00:39:29,655 Feith wants to know if there had been 556 00:39:29,758 --> 00:39:32,413 problems with ice on ATR-built planes in the past. 557 00:39:35,965 --> 00:39:37,655 He finds troubling similarities 558 00:39:37,758 --> 00:39:40,000 between some incidents dating back decades. 559 00:39:42,586 --> 00:39:45,275 Using data from flight data recorders, 560 00:39:45,379 --> 00:39:49,413 investigators look at aileron movements from Flight 4184 561 00:39:49,517 --> 00:39:51,137 and compare them to the other incidents. 562 00:39:54,586 --> 00:39:56,620 They discover that on all those flights 563 00:39:56,724 --> 00:39:59,448 the aileron deflected in exactly the same way. 564 00:40:01,758 --> 00:40:03,655 There's no input at all from the pilots. 565 00:40:05,275 --> 00:40:08,620 We knew that all of these ailerons were being commanded 566 00:40:08,724 --> 00:40:12,620 to move not by the pilot but in fact the disrupted airflow 567 00:40:12,724 --> 00:40:15,586 created by the icing event that the airplane had encountered. 568 00:40:18,172 --> 00:40:20,241 The physics of ice buildup explains 569 00:40:20,344 --> 00:40:24,000 why the control column on Flight 4184 snapped to the right 570 00:40:26,310 --> 00:40:29,137 Air turbulence on the wing was so powerful 571 00:40:29,241 --> 00:40:31,862 that it lifted the aileron, which caused the plane to roll. 572 00:40:34,275 --> 00:40:37,827 Since the aileron is attached to the control column by a cable, 573 00:40:37,931 --> 00:40:39,862 it jerked the control yoke to the right. 574 00:40:43,344 --> 00:40:46,379 The force of the turbulence pulling on the aileron was so great, 575 00:40:47,620 --> 00:40:50,000 that even two pilots trying to counter steer 576 00:40:50,103 --> 00:40:52,000 weren't able to bring the aileron back down. 577 00:40:54,000 --> 00:40:57,448 The forces were determined to be about 250 pounds. 578 00:40:57,551 --> 00:40:59,620 So for the pilot, it would have been trying 579 00:40:59,724 --> 00:41:03,103 to roll against 250 pounds of aerodynamic force. 580 00:41:05,758 --> 00:41:09,827 Worse, the ATR's control yoke doesn't have power steering, 581 00:41:09,931 --> 00:41:12,896 so those forces are transmitted directly to the pilots. 582 00:41:15,896 --> 00:41:19,103 The pilots could not fight back against the air pulling on their aileron 583 00:41:25,448 --> 00:41:27,965 For chief investigator Greg Feith, 584 00:41:28,068 --> 00:41:30,620 super-cooled water droplets that left a ridge of ice 585 00:41:30,724 --> 00:41:32,793 on the wings are now the prime suspect. 586 00:41:34,965 --> 00:41:36,551 But how to prove it? 587 00:41:36,655 --> 00:41:39,413 Now, the real analysis began because we had to understand 588 00:41:39,517 --> 00:41:42,379 what was going on in-flight with the airplane. 589 00:41:42,482 --> 00:41:44,862 We had good flight, data recorder information. 590 00:41:44,965 --> 00:41:46,344 It only told us what happened, 591 00:41:46,448 --> 00:41:48,344 it didn't tell us why it happened. 592 00:41:48,448 --> 00:41:51,517 We had to try and model this icing event some way. 593 00:41:54,620 --> 00:41:57,689 At the time of the crash, NASA was just beginning 594 00:41:57,793 --> 00:42:01,000 to study the effect of super-cooled large droplets on airplanes. 595 00:42:03,827 --> 00:42:07,793 Back in 1994 pilots didn't know what SLD 596 00:42:07,896 --> 00:42:10,241 or super-cooled large droplets were. 597 00:42:10,344 --> 00:42:12,827 There was very little information in the pilot community 598 00:42:12,931 --> 00:42:14,896 and there was actually very little information 599 00:42:15,000 --> 00:42:17,068 in the aviation industry about SLD. 600 00:42:22,413 --> 00:42:24,862 Investigators first turn to NASA for help. 601 00:42:27,137 --> 00:42:29,172 Together they launch a daring experiment. 602 00:42:31,965 --> 00:42:34,241 They use a US Air Force tanker plane 603 00:42:34,344 --> 00:42:37,000 to create a cloud of super-cooled water droplets. 604 00:42:39,551 --> 00:42:42,000 An ATR-72 flies behind the tanker. 605 00:42:44,034 --> 00:42:46,413 Yellow dye in the water shows investigators 606 00:42:46,517 --> 00:42:47,931 how the droplets cover the plane. 607 00:42:49,620 --> 00:42:51,896 The test should solve the final mystery. 608 00:42:53,275 --> 00:42:57,551 How had ice caused Flight 4184 to go so badly out of control? 609 00:42:59,379 --> 00:43:01,931 One of the primary purpose this is applying the ATR-72 610 00:43:02,034 --> 00:43:04,034 in behind the tanker was to understand 611 00:43:04,137 --> 00:43:06,103 how the ice accumulated on the airplane. 612 00:43:06,206 --> 00:43:08,517 But more importantly, the effect of that ice 613 00:43:08,620 --> 00:43:10,896 in varying configurations of the airplane, 614 00:43:11,000 --> 00:43:13,517 on the flight control surfaces, that is the ailerons. 615 00:43:16,206 --> 00:43:18,896 Investigators make a startling discovery. 616 00:43:19,000 --> 00:43:22,896 A seemingly harmless action meant to increase comfort on the plane 617 00:43:23,000 --> 00:43:24,206 may have led to disaster. 618 00:43:32,137 --> 00:43:34,379 - Can I get you boys anything? - I'm good. 619 00:43:34,482 --> 00:43:36,827 While American Eagle Flight 4184 620 00:43:36,931 --> 00:43:40,068 was holding, Captain Orlando Aguiar notices 621 00:43:40,172 --> 00:43:41,896 that the nose is tipped quite high. 622 00:43:43,620 --> 00:43:45,827 Man, this thing gets a real high deck angle in these turns. 623 00:43:45,931 --> 00:43:47,137 Yeah. 624 00:43:47,241 --> 00:43:49,931 Captain Aguiar knows that the plane's high nose angle 625 00:43:50,034 --> 00:43:53,000 was producing an uncomfortable tilt in the passenger cabin. 626 00:43:53,103 --> 00:43:54,620 You want flaps 15? 627 00:43:54,724 --> 00:43:57,241 - It'll bring the nose down. - Sure. 628 00:43:57,344 --> 00:44:01,275 Extending the flaps would have the effect of lowering the plane's nose, 629 00:44:01,379 --> 00:44:02,689 making the ride more comfortable. 630 00:44:05,068 --> 00:44:06,896 I guess Sandi's going ooh now. 631 00:44:10,724 --> 00:44:13,517 When investigators duplicated this maneuver, 632 00:44:13,620 --> 00:44:15,413 they found that it had a dramatic effect 633 00:44:15,517 --> 00:44:17,965 on where the ice reach formed on the plane's wing. 634 00:44:20,103 --> 00:44:22,655 the flaps made the icing problem even worse. 635 00:44:24,275 --> 00:44:26,517 by exposing more of the upper surface of the wing 636 00:44:26,620 --> 00:44:28,724 to the oncoming water droplets 637 00:44:28,827 --> 00:44:32,344 and that's one of the reasons why we got um, the ridge of ice 638 00:44:32,448 --> 00:44:34,793 where we got it was because of the flaps 15 configuration. 639 00:44:35,620 --> 00:44:36,586 That's much nicer now, 640 00:44:36,689 --> 00:44:37,586 flaps 15. 641 00:44:40,137 --> 00:44:42,310 The crew of Flight 4184 642 00:44:42,413 --> 00:44:46,241 is unaware that a ridge of ice more than a centimeter high 643 00:44:46,344 --> 00:44:48,310 has built up on the surface of their wings. 644 00:44:53,517 --> 00:44:58,655 Eagle Flight 184 descend and maintain 8000. 645 00:44:58,758 --> 00:45:01,206 Down to 8000. Eagle Flight 184. 646 00:45:01,310 --> 00:45:03,517 The ice buildup has no effect on the flight 647 00:45:03,620 --> 00:45:07,862 until First Officer Gagliano begins his descent to 8000 feet. 648 00:45:09,068 --> 00:45:10,758 I knew we'd do that. 649 00:45:10,862 --> 00:45:12,862 The descent increases the plane's airspeed. 650 00:45:14,206 --> 00:45:16,379 This triggers a warning from the flight computer, 651 00:45:16,482 --> 00:45:19,931 telling the crew they're flying too fast with the flaps extended. 652 00:45:20,034 --> 00:45:22,724 Well, I was trying to keep it at 180. 653 00:45:22,827 --> 00:45:24,724 Gagliano now retracts the flaps. 654 00:45:26,758 --> 00:45:30,206 But the routine gesture has a dramatic effect on the plane's aerodynamics. 655 00:45:32,413 --> 00:45:36,551 When they retracted the flaps as they started their descent down to 8000 feet, 656 00:45:36,655 --> 00:45:39,689 the airplane pitched back up into a very nose-high attitude. 657 00:45:41,172 --> 00:45:44,241 Airflow over the ice-laden wing was disrupted 658 00:45:44,344 --> 00:45:45,655 when those lifted back up. 659 00:45:51,379 --> 00:45:54,344 That created the turbulence that pulled up the ailerons, 660 00:45:54,448 --> 00:45:55,724 sending the plane into a roll. 661 00:45:59,689 --> 00:46:02,000 The plane stalled, and tumbled from the sky. 662 00:46:03,379 --> 00:46:05,551 Damn. 663 00:46:07,724 --> 00:46:11,344 Had this crew had about two to 3000 more feet of altitude, 664 00:46:11,448 --> 00:46:13,551 there's a high probability that they would have been able 665 00:46:13,655 --> 00:46:16,793 to salvage or recover the airplane before it struck the ground. 666 00:46:27,413 --> 00:46:31,379 The NTSB has uncovered a deadly flaw in a popular airplane. 667 00:46:33,517 --> 00:46:36,551 There's a growing concern that unless something is done, 668 00:46:36,655 --> 00:46:38,758 this kind of accident would soon happen again. 669 00:46:41,310 --> 00:46:44,620 Investigators conclude that problems with the ATR's wind design 670 00:46:44,724 --> 00:46:46,379 make it vulnerable to this menace. 671 00:46:49,137 --> 00:46:53,206 The agency that regulates US aviation takes drastic action. 672 00:46:53,310 --> 00:46:57,586 We are going to issue an Air Worthiness Directive this afternoon, 673 00:46:57,689 --> 00:47:01,137 that will preclude the operation of these aircraft 674 00:47:01,241 --> 00:47:03,206 into known icing conditions. 675 00:47:05,103 --> 00:47:07,000 The FAA takes swift action 676 00:47:07,103 --> 00:47:11,241 banning all models of the aircraft from flying in icy conditions. 677 00:47:11,344 --> 00:47:14,655 This throws regional airlines like American Eagle into chaos. 678 00:47:16,379 --> 00:47:19,517 Public concern over the safety of ATR airplanes grows 679 00:47:19,620 --> 00:47:21,517 in the aftermath of the Roselawn crash. 680 00:47:23,241 --> 00:47:25,620 The most controversial charge, 681 00:47:25,724 --> 00:47:28,344 that the FAA had relied on the French authorities 682 00:47:28,448 --> 00:47:32,310 to test and certify the aircraft then rubber-stamped the results. 683 00:47:34,793 --> 00:47:39,275 Therefore, the ATR-72 was never really tested by the FAA 684 00:47:39,379 --> 00:47:40,931 in any way, shape and form 685 00:47:41,034 --> 00:47:42,896 as though it was manufactured here. 686 00:47:45,034 --> 00:47:47,965 The plane's French builder proposes to fix the problem 687 00:47:48,068 --> 00:47:50,344 by making the de-icing boots wider, 688 00:47:50,448 --> 00:47:52,275 so they cover a larger part of the wing. 689 00:47:55,275 --> 00:47:56,793 The company also rewrites 690 00:47:56,896 --> 00:48:00,758 operating procedures, forbidding pilots from using the flaps 691 00:48:00,862 --> 00:48:04,724 or flying on autopilot in icing conditions. 692 00:48:04,827 --> 00:48:08,758 In response, the FAA issues an amendment to their earlier directive, 693 00:48:08,862 --> 00:48:11,206 loosening operating restrictions on the ATR's. 694 00:48:15,068 --> 00:48:17,482 Most airlines decide not to take any chances. 695 00:48:20,241 --> 00:48:23,275 They move their ATRs to the south, 696 00:48:23,379 --> 00:48:25,862 where a warmer climate would reduce the risk of ice. 697 00:48:31,827 --> 00:48:35,172 The crash at Roselawn set off a flurry of new research 698 00:48:35,275 --> 00:48:38,206 into aircraft icing and the conditions that produce it. 699 00:48:39,586 --> 00:48:41,379 There's a lot of weather data out there. 700 00:48:42,655 --> 00:48:44,793 Satellites, radars, surface ops, 701 00:48:44,896 --> 00:48:47,896 and it just keeps getting bigger and bigger 702 00:48:48,000 --> 00:48:49,000 the collection of data. 703 00:48:50,931 --> 00:48:53,482 New techniques in forecasting are being developed 704 00:48:53,586 --> 00:48:56,310 to show pilots where icing is likely to occur 705 00:48:56,413 --> 00:48:58,172 and help them avoid it. 706 00:48:58,275 --> 00:49:00,827 But we're working on ways to get it to the people who need it. 707 00:49:01,896 --> 00:49:03,827 Uh, dispatcher at airlines, 708 00:49:03,931 --> 00:49:06,931 um, meteorologists at airlines. 709 00:49:07,034 --> 00:49:09,068 And now even into the cockpit itself. 710 00:49:10,931 --> 00:49:15,206 Many of those changes will take time to come into effect. 711 00:49:15,310 --> 00:49:19,000 Pilots like Steve Frederick think that time will cost lives. 712 00:49:20,689 --> 00:49:25,241 The problem that exists is that there is no technology available today 713 00:49:25,344 --> 00:49:29,586 to the pilots or anyone on the ground to accurately forecast or predict 714 00:49:29,689 --> 00:49:33,896 where these situations of bad ice are going to occur. 715 00:49:34,000 --> 00:49:36,793 Once these airplanes have been exposed to the bad ice, 716 00:49:36,896 --> 00:49:40,000 it's too late because these are no longer airline pilots, 717 00:49:40,103 --> 00:49:41,448 they're test pilots. 718 00:49:41,551 --> 00:49:45,137 And that airplane can fall out from under them and their passengers 719 00:49:45,241 --> 00:49:47,344 without any warning and in the blink of an eye.