RubyConf 2015 - How to Crash an Airplane by Nickolas Means

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Excellent presentation about a 1989 plane crash.

Little to no Ruby or software development related content but there's a bit at the end about how we should all try to work together on our projects. If you're interested in that topic, you're better off watching Sandi Metz' fantastic 'Keep Ruby Weird' Keynote which Nickolas himself recommends.

👍︎︎ 1 👤︎︎ u/Harmenian 📅︎︎ Dec 11 2015 🗫︎ replies
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(upbeat country music) - Good afternoon, everybody. I have been a student of plane crashes as long as I can remember. Now, I know that that is a weird thing to be fascinated by, but there's no faster way to get me into a Wikipedia safari then mentioning a plane crash that I don't know the particular details of. I am compelled to immediately go read about that crash and figure out what it is that I might have missed out on. Now, it sounds a little morbid to say you're fascinated with plane crashes, but it's not the morbidity that fascinates me. It's not the fear or the death. It's the human interaction in the cockpit, because the flight crew in these situations sometimes takes a tiny system fault and turns it into a gigantic catastrophe through a cascading series of events. At other times, the flight crew is able to take a catastrophic system failure and get some people back safely on the ground when they probably shouldn'tve been able to. The flight I want to tell you about today I think is one of the most fascinating flights in American aviation history. It's United Flight 232. July 19, 1989 was an absolutely beautiful day in Denver, Colorado. If you've been to Denver in the summer, you know exactly what kinda day I'm talkin' about: 80 degrees out, light scattered cloud cover, light breeze blowing in off the front range. It's the kinda day that just begs you to get outside and go do something. Go have fun. It was a beautiful day for flying as well, and flights were running on time at Denver's Stapleton Airport. A little before lunchtime, people started showing up for United Flight 232, scheduled service from Denver Stapleton to Chicago O'Hare. Scheduled for a push-back from the gate about 1:45 in the afternoon. If you'd been at the airport that day, looking through the window, getting ready to get on the plane, you would've seen something like this, and that's a bit of a foreign sight to modern travelers. You see that engine peeking up over the back of the plane, there. This is a McDonnell Douglas DC-10 series 10 aircraft. That picture is actually the aircraft that you would be getting on that day. Tail registration number November-1819-Uniform. It was delivered brand new to United Airlines in 1971, and it'd been flying as part of its fleet for 18 years since. Now, 18 years kinda sounds old, but it's not. Airplanes regularly fly much longer than that. In fact, United would fly most of their DC-10 fleet well into their 30s. A lot of these planes, you can still go out to the airport today and see them flying as cargo planes in FedEx livery. As you got on board the plane, you would have seen something like this, nice wide cabin, big seats. It's actually a little bit wider than a Boeing triple 7, if you've flown on one of those. Pilots loved the DC-10. They referred to it as the Cadillac Fleetwood of the skies. The big, roomy airplane, fun to fly and quiet. They especially loved taking off in a DC-10, because the three engines on this plane gave it way more power than it needed to get off the ground, so when they put their hand in the throttles, it would slam you back in your seats as you accelerated up to V-2 and rotated and took off. At around 2:10 this afternoon, that is exactly what happened. This plane took a very normal takeoff at about 2:10 p.m. Turned out east-northeast toward Chicago. If you'd been on the plane at this point, you would have smelled chicken strips, because that's what was cooking on the onboard ovens. United was running a special in the summer of 1989 that they called their picnic lunch, and they would give you, this was back in the days when airlines still served you food on every flight. They would give you a basket of chicken strips, oreos, and a little cup of cherries in a basket with red-and-white checked paper. About an hour into the flight, most passengers had finished their meal, and Jim McKay, the legendary host of ABC's "Wide World of Sports" was about 20 minutes into telling everybody on board about the history of horse racing in the "Jewels of the Triple Crown." At about this point, you would have heard an incredible explosion at the back of the plane. Most of the passengers on board thought that a bomb had gone off. The plane immediately, the back of the plane dropped out from under it. People were slammed back in their seats, and the plane climbed 300 feet almost immediately and then started rolling off to the right just a little bit. If you were looking around the cabin, you would've seen the flight attendants hit the deck. They all dove to the ground, grabbed the nearest armrest and held on, afraid that this might have been an explosive decompression and that they were about to be sucked out of the airplane. Well, it wasn't an explosive decompression, and it wasn't a bomb. What had actually happened is the fan disk in the number 2 engine in the tail of the airplane had exploded. Up in the cockpit, they didn't know what had happened either. They had just finished their lunches, and the flight attendants had just cleared them away and brought them second cups of coffee when they heard the explosion. Immediately after the explosion, First Officer Bill Records lunges forward, grab the yoke and yells, "I've got it!" And turns off the autopilot. Meanwhile, Flight Engineer Dudley Dvorak is looking at his instruments trying to figure out what in the world has happened to his beautiful ship. The gauges tell a clear story. The number 2 engine has failed. So, following procedure, Dvorak radios Minneapolis Center, the flight control center that's controlling them at that point, and doesn't declare an emergency because loss of an engine on a DC-10 is actually not a big deal. They would just descend to a lower altitude and go on to Chicago. So that's what he radios for. He asks for a lower altitude assignment. After that happens, Captain Al Haynes, who you see on your screen there, asks for the engine shutdown checklist. He asks for Dvorak to read that out loud to him. This is the first hint that there might be something more than just a failed engine wrong with this aircraft. The first step on the engine shutdown checklist is to reduce the throttle to idle. So Haynes tries to do that, and the throttle lever won't move. The second step is to cut off the fuel supply. Haynes tries that as well. It won't move. Now, the thing you need to know about the DC-10 is that these controls are all connected physically by steel cables to the engines. So the fact that these control levers won't move tells Captain Haynes that something serious has happened to that engine back there. It's more than just an engine flameout. It's more than just an engine shutdown. There's physical damage to the plane. Haynes and Dvorak are trying to figure out what to do next when Bill Records speaks up and says, "Al, I can't control the plane!" And Captain Haynes looks over and sees something terrifying to him in two ways. He sees Bill Records with the yoke all the way back, all the way to left. Now, to understand why that was such a surprising sight, think about driving down the highway in your car going 80 miles an hour and jerking the steering wheel to the side. It's the same kind of input. You would never do that to an airliner flying at cruise speed at 0.87 mach. But even more alarming to Haynes than that was the fact that even though First Officer Records was commanding the plane to go up and to the left, the plane was doing exactly the opposite. It was going down and to the right, and slowly rolling over. Haynes grabs the controls and says, "I've got it," and begins fighting the controls himself. No different outcome. Meanwhile, Dvorak is studying his gauges, still trying to figure out exactly what's happened to the plane when he glances up and notices that the horizon is very tilted. The plane has assumed a banking of about 38 degrees, which is way further over than any commercial airliner would ever go turning. And Dvorak immediately yells, "We're rolling!" Out of an instinct that... Sorry, I jumped ahead a little bit. Out of an instinct that he still doesn't understand to this day, Captain Haynes reaches down to the throttles, swats closed the number one, swats the number three up to full, and slowly but surely, their DC-10 goes from this angle, back to level flying. Later analysis would show that Captain Haynes saved the aircraft in that moment. If he had not changed the throttles when he did, the plane would have continued to roll and would eventually have gone into a descent straight to the ground. Now that they had the plane under a little bit of control, flying level again, Dudley Dvorak makes the first announcement to the passengers. Now, I have to tell you, this is not the exact words that Dudley Dvorak used because the cockpit voice recorder on this particular plane was on a 30-minute loop, and the sequence from when the rear engine explodes to when they get to the ground in Sioux City is actually 44 minutes. But passengers and flight attendants tell us it went something like this. "Ladies and gentlemen, we've lost our "tail engine, but this aircraft can fly fine "with the two remaining engines. "We're going to descend and "continue on to Chicago." Immediately after that, though, Flight Engineer Dvorak realizes that there is a bigger problem. He finally spots the thing that he's been staring so intently at his gauges trying to see. He sees that they have no hydraulic fluid and no hydraulic pressure in any of the three hydraulic systems on board. And that means that they can't control their aircraft. At this point, First Officer Records radios Minneapolis Center and declares the emergency and tells them that he needs a route to the closest suitable airport, and they send him to Sioux City. Shortly after that, Jan Brown, who is on the left there in the turquoise jacket, hears the overhead chimes in her section. She's the head flight attendant on this flight. She looks around the cabin and sees that nobody in the cabin is calling her. Nobody else has their air phone picked up, so she knows that it's someone from the flight deck. It would have been really unusual at this point in the flight for a flight attendant to hear from anybody on the flight deck. They're in cruise. There's nothing the flight deck would need to tell them about. The flight attendants are all busy taking care of the passengers. So it was really unusual, and she had a feeling in the pit of her stomach. She knew that it was something bad. She picks up the phone, and sure enough, Dudley Dvorak asks her to come up to the cockpit, and she does. And when she retells the story, she says that her whole world changed when that cockpit door opened. She said there was no panic, but that the sense of crisis on that flight deck was absolutely palpable. Haynes and Records both had their hands on the yoke, pulling as hard as they could on this plane trying to control it, sinews raised on their arms, and here's what Haynes told her, "We've lost all our hydraulics. "We're having trouble controlling the plane, "so we're gonna try an emergency landing "in Sioux City in about 30 minutes. "I need you to prepare the cabin and the passengers. "My signal over the P.A. will be brace, brace, brace. "and good luck." So Jan Brown mutters, "Good luck," and leaves the cockpit and goes to do exactly what the captain has asked her to do. Meanwhile, Captain Haynes asks Dudley Dvorak to get out the flight manual and to find a procedure to handle complete hydraulic loss. There's not one. (some quiet laughing) Now, the FAA mandates that air carriers and aircraft manufacturers design emergency procedures around every known failure modality that could occur on an airplane. But the odds of losing all three redundant hydraulic systems on board the DC-10 were so low that it was not even considered a reasonable enough possibility to design an emergency procedure around. So there wasn't one. At this point, Minneapolis-St. Paul hands off to Sioux City, and Captain Haynes makes this initial contact to the tower at Sioux City. - [Voiceover] Ok, so you know, we have almost no controllability. Ah, very little elevator, and almost no aileron. We're controlling the turns by power. We can only turn right. We can't turn left. - [Voiceover] United 232 heavy, uh, understand sir, ah, you can only make right turns? - [Voiceover] That's affirmative. You have to know a little bit about airplanes to understand exactly what Captain Haynes was talkin' about there. He says we have no elevator and you can infer from that that the elevator is what controls the airplane as it goes up and down. It's these parts right back here on the rear stabilizer that controls the ascent and descent of the aircraft. The ailerons are the flaps right here on the wing. They control the roll of the aircraft. That's how you turn an airplane is by rolling it to one side or the other. So in saying that we have no elevators and we have no ailerons, Captain Haynes is telling flight control we have no control of our aircraft other than what we can get from the engines. So about this point, Jan Murray, who's on the left there in the pink, has just been briefed by Jan Brown. Jan Murray is the first-class flight attendant aboard United 232, and she's walking back through the first-class section when Denny Fitch, who's there on the right, gets her attention. Now, Denny is also a United DC-10 captain. He happens to be commuting on this flight from Denver back to Chicago. He likes to say about himself that he has a radar for people in distress, and that Jan Murray was clearly in distress at this point. Go figure. And so, he pulls her aside, and he says, "Jan." They' been talking earlier on the flight, so they were already acquainted with each other, and he says, "Jan, don't worry about this. "This plane flies just fine on two engines. "We're just gonna descend a little bit, "and fly on to Chicago. "It's no big deal." So Jan, not wanting to alarm the other passengers, leans in to Denny Fitch and says, "Oh, Denny. "The captain has told us we've lost "all of our hydraulics. "Both the pilots are trying to fly "the airplane, but they have no control." Something else you need to know about Denny Fitch. He's not just a captain. He's a DC-10 check pilot for United Airlines. He spends most of his days in one of these, a full-motion flight simulator. His job is to prepare pilots for the impossible, to take them through emergency procedures, and check them out once a year to make sure that they handle situations that arise in flight and are able to get the aircraft back to the ground safely. Well, in all his preparation and all the flight crews he's taken through this simulator, he'd never taken anybody through a complete hydraulic loss. There was no reason to prepare for anybody for that. He knew Jan Murray must be misinformed. He knew there was no way that this plane had lost all of its hydraulics, and he asked her to go back up to the cockpit and tell the captain that he had a DC-10 check airman onboard, and if he would like assistance, he was happy to assist in any way he could. Well, Captain Haynes, of course, was welcoming to this concept. He hoped that a DC-10 check airman would have some magic incantation to restore control to his plane. (audience laughing) So he invited him on up to the cockpit. When Fitch got to the cockpit, he looked over the flight engineer's shoulder at the gauges, saw the same thing that Dudley Dvorak was seeing, no hydraulic quantity. Exactly what Jan Murray had told him. He looked at the breakers to make sure nothing was tripped that would explain a loss of flight instrumentation or something like that. There wasn't. He was convinced that the instruments were telling a true story, or showing the actual condition of the aircraft, and he knew within about five seconds that this was not like anything he had ever seen before. He says, "I knew in that first five seconds "that this was the day I was going to die. "The only question I had was how long "it was going to take Iowa to hit me." (scattered laughing) I've said several times, I've hinted around, that losing all hydraulics in a DC-10 is considered an impossibility. This is because there's three independent hydraulic systems in the DC-10, and each of the flight control surfaces is controllable by at least two of those systems. The systems are completely isolated from each other, there's no fluid connectivity, and hydraulic fluid is considered a precondition of flight on a DC-10. The DC-10, like the 747 and the Lockheed 1011 Tristar, was the first generation of airliners that had no manual reversion. If you're flying on say a 737, and you lose complete hydraulics, it's kind of like driving down the highway and losing your power steering. You can still wrestle the flight controls. You can still have some input and fly the plane. On a DC-10, not true. You lose your hydraulics, the flight control surfaces are so big and have so much force acting on them that there's no way you can move 'em without the hydraulics. Without hydraulics, one of two things was assumed to happen. It was assumed that the plane would either flutter to the ground like a leaf, completely outta control, or like this flight tried to do, roll over on its side and go into a dive and pick up airspeed so fast that it would break apart before it ever hit the ground. For some reason, this plane wasn't doing that. This plane was staying in the air. Since Denny Fitch didn't have any magic fixes, Haynes asked him to take over the throttles. Up 'til this point in the flight, he and First Officer Records had each been controlling one of the two throttle arms. Haynes had been controlling the arm on the left, and Fitch had been, er, Records had been controlling the one on the right, the number 1 and number 3 engine, and it was actually much more convenient for Denny to be able to squat right between 'em and control the two at the same time. As Fitch is getting settled into controlling the throttles, Haynes radios Sioux City again to ask 'em for somewhere else that they might land. - [Voiceover] We have no hydraulic fluid, which means we have no elevator control, ah, almost none and very little aileron control. I have serious doubts about making the airport. Have you got, ah, someplace near there, ah, that we might be able to ditch? Unless we get control of this airplane, we're gonna put it down wherever it happens to be. - Controller Kevin Bachman goes and looks at his charts for a few minutes and tries to figure somethin' out, but there's really nothing. There's not anyplace they can put it down. A few minutes later, he radios back with this. - [Voiceover] United 232 heavy. Roger. Can you pick up a road or something up there? - [Voiceover] We're tryin'. It's still, uh, anywhere from 2,000 feet up to 1,500 down now. In waves. - [Voiceover] Roger. - Now, in that radio communication, Captain Haynes is telling us about something else that's happening to this aircraft. It's call phugoid oscillation. This is one of the basic flight modes of any aircraft, any winged aircraft. What happens is, this plane is seeking equilibrium between lift on the wings and gravity. If you take a paper airplane and throw it off a high enough building, you'll see this exact same thing happen. It'll go up and down, up and down, trying to find that equilibrium. The plane goes down, builds airspeed, builds lift on the wings, and as the wings generate lift, it starts coming back up. And then it bleeds that lift back off and gets to the top and does a very light stall and starts going back down. But Haynes actually has his numbers reversed. He said that they were going 2,000 feet up, 1,500 feet down. It was actually backwards. Each one of these cycles, they were going about 1,500 feet up and 2,000 feet down, so instead of gaining altitude, they were losing altitude. This tells you exactly what Fitch is dealing with trying to manhandle the throttles on this airplane. He's trying to mitigate the phugoid oscillation, and he's also trying to prevent the plane from rolling over on its right, which it's been trying to do this whole time. This plane desperately wants to turn right. And he's starting to have some luck with it. - [Voiceover] Come spinning down here. - [Voiceover] United 232, ah, heavy, Sioux City airport's about 12 o'clock and three-six miles. - [Voiceover] Ok, we're tryin' to go straight but we're not havin' much luck. - At this point in the flight. Here's the radar track of the path that United 232 took. You can see the plane enters the radar track at the bottom, the triangle up top is where they lose their engine. They go into a wide, 30-mile right turn, and then somewhere where the path crosses the initial direction of flight is where Fitch takes over the throttle controls. And he has some luck pretty quick mitigating the phugoid oscillation, but you can see clearly he's made something else worse. They're now circling in right turns. That's why Haynes radios and says as we're coming spinning down here, where's the airport in relation to us? It turns out, though, that these turns were actually fortuitous. It was pretty lucky that this happened, because they were bleeding off altitude this whole time, and this series of turns is what let them bleed off enough altitude to get low enough that they could even attempt a landing in Sioux City. Jan Brown, the lead flight attendant, again, was walking from the back of the plane, when a passenger grabbed her attention and said, "Look out the window. "There's metal stickin' up out there." Brown goes over to the window, and she looks back at the horizontal stabilizer of the plane, and sure enough, there's metal stickin' up off the horizontal stabilizer. She lets the cockpit know. Dudley Dvorak comes out to look. Sure enough. I'll show you a picture that was taken as this airplane was coming in to Sioux City. If you look at the horizontal stabilizer, especially on the right, you can see daylight shining through a few places there where it shouldn't be. I'll show you a normal DC-10 tail next to it. That makes it a little more obvious what's goin' on. You can see that the plane has lost it's rear fuselage cone. There's several holes punched through the horizontal stabilizer, and it's lost the exhaust cone on the number 2 engine. Somewhere around three months later, they would find this in a corn field in Alta, Iowa. This is the main fan disk from the number 2 engine. If you look at it, you can see there's a gigantic crack running down the right side of it. They actually found this in a bunch of different pieces. None of those blades was attached. The disk had broken into two pieces. What you're actually lookin' at there is the very front of a turbo fan engine. If you look at the front of a jet airliner, the fan that you see in the engine they sell, that's what broke apart on this flight over Alta, Iowa. If you look at the position of that engine in the plane, you can see that it is perfectly positioned for maximum carnage. There is a containment ring around this engine, but it's designed to only contain the kinetic energy of one of those fan blades letting loose. Not the whole disk. To put enough armor around this engine to contain the entire fan disk as it exploded would make the plane too heavy to fly. There's no way you could do it. So they manufacture these disks with tolerances so they won't fail, but this one did. Here's what happened to the plane. This is the horizontal stabilizer. When the fan disk gave way, they lost hydraulic system number two because they lost the number 2 engine, which is what powered that hydraulic system. The shrapnel, 70 separate pieces of it that pierced the horizontal stabilizer, took out hydraulic system one and hydraulic system three. Now, the horizontal stabilizer is the one spot in the plane where all of these systems come together, and they have to, to get the desired redundancy. Because you have four separate elevator panels back there. Two endboard for use in high-speed cruise, and two outboard for use when you're closer to the ground and you need a little bit more force to move the airplane around. They've got all three hydraulic systems back there. Passengers right after the explosion described hearing something that sounded like a siren. What that actually was was the hydraulic pumps attached to engines 1 and 3 dutifully trying to bring the hydraulic systems back up to pressure, but actually pumping all of their hydraulic fluid overboard. While Dvorak is back at the back of the plane looking at the horizontal stabilizer damage, they enter into the one left turn that they were gonna make all day. They knew that if they were gonna get back to Sioux City, they were gonna have to turn left. There was no other suitable airport. They couldn't continue on forward. They had to turn left, and they get it done, and there's much rejoicing in the cockpit, 'cause they weren't sure they were gonna be able to pull this off. Immediately after they get done with this left-hand turn, they get this from air traffic control. - [Voiceover] United 232 heavy, you're gonna have to widen out just slightly to your left, sir, ah, to make the turn to final and also that'll take you away from the city. - [Voiceover] Whatever you do, keep us away from the city. - So that gives you a good picture of the gravity of the situation that they're facing. Haynes is still not very optimistic that if they go over Sioux City, Iowa that they're going to be able to avoid meeting Sioux City, Iowa, in a way that they don't want to. The crew is still fighting to suppress the phugoids and keep the plane lined up with the airport, and they manage to widen out just a little bit further left. They do it, and they get back on track to the airport. They finally see their destination, they finally see the airport in the windscreen of their airplane, and you can hear Captain Haynes' relief when they finally spot Sioux Gateway Airport. - [Voiceover] United 232 heavy, roger, and advise when you get the airport in sight. - [Voiceover] We have the runway in sight. We'll be with you very shortly. Thanks a lot for your help. - Shortly after this, Bachman calls back with their landing clearance, and this this particular piece is my favorite air traffic control exchange in this whole series. - [Voiceover] United 232 heavy, the wind's currently three-six-zero at one-one, three-sixty at eleven. You're cleared to land on any runway. - [Voiceover] Ha ha! You want to be particular and make it a runway, huh? (audience laughing) - And the remarkable thing about this to me is that in the midst of all this stress in the cockpit, Captain Haynes still has the wherewithal to crack a joke with air traffic control. Their fate is still very much in doubt at this point. They don't know if they're gonna be able to get this plane back on the ground or not, but he can still crack a joke. They actually do manage to get lined up with a runway, and here's the air traffic control exchange when they decide what they're gonna do, which runway they're gonna land on. - [Voiceover] There is a runway that's closed, sir, that could, ah, probably work, too. It runs, uh, northeast to southwest. - [Voiceover] Pretty well lined up on this one here. I think we will be. - [Voiceover] Alright. (audience laughing) United 232, heavy, uh, roger, sir. Okay, that's a closed runway. That'll work sir. We're gettin' the equipment off the runway, and they'll line up for that one. - [Voiceover] How long is it? - [Voiceover] Sixty-six hundred feet. Six thousand, six hundred, and the equipment's coming off. - So, they've lined up with the runway, but it's the runway that Sioux City Airport had decided to park all the emergency equipment on waiting for their arrival. (audience laughing) So, the tower has to clear this runway. It's an old World War II runway that actually hasn't been in service since World War II, concrete's in terrible shape, but it's a patch of concrete they can land on, and it's better than any of them thought they were gonna be able to accomplish. At this point, Captain Haynes makes his final announcement to the cabin. He says, "Brace, brace brace!" And the flight attendants all began shouting "brace" in unison. Passengers keep poking their heads up to look out the windows to see how close they are to the ground, and immediately the flight attendants yell at 'em to put their heads back down. Get back in brace position. As they're lined up and comin' in, Kevin Bachman the tower controller at Sioux City stands up and shouts, "They're gonna make it!" But then they notice how fast the plane's coming in. It wasn't floating like airliners normally appear to do when they're coming in for a landing. The reason for that is because they had, along with no ailerons and no elevators, they had no slats and no flaps. Slats are, if you've ever watched a passenger airline, if you've ever looked out the window as it comes in for landing, you've watched them reconfigure the wing as they get close to the airport. The slats are the surfaces on the front of the wing that they extend to bleed off speed as they get closer to the ground. The flaps are the surfaces on the back of the wing that they extend to give the wing more lift at slow speeds. If you didn't extend the flaps, the plane would stall before you ever got slow enough to land. So, part of keeping this plane in the air is making sure they don't bleed off enough speed that the wing can't keep 'em in the air without flaps. The DC-10 was traveling about 250 miles an hour. A normal DC-10 landing is about 125. Even worse than that, though, is the sink rate. They were descending at about 1,800 feet per minute. The structural limit for the landing gear on a DC-10 is 600 feet per minute, but that would be the hardest landing you'd ever experienced in your life. A normal landing in a DC-10 is about 200 feet per minute. In the last few seconds of the cockpit voice recorder audio, you can hear the ground proximity warning system telling them to pull up and get the airplane back in the air 'cause they're going too fast. (siren warning) - [Voiceover] Pull up! Pull up! - As Captain Haynes says, our luck ran out about 50 feet above the runway. As they're getting close to the ground, as they're getting close to the ground, the right wing dips and makes contact with the ground. The plane cartwheels. As they hit the runway, the damaged number 2 engine pops out of its mount, and because of that, because of that weight is missing, suddenly the lift on the horizontal stabilizer is enough to catapult the back end of the airplane up over the front end as they slide to a stop down the runway. I do have a video of the crash, and I'm gonna show it. I will warn you, if you're squeemish you might not wanna watch. There is a lot of fire and smoke. You can see here how fast that plane's comin' in. And you can also see that it's pitched nose down because they don't have controls, they can't flare up the way a plane normally would as it come in. About here is where the right wing makes contact with the ground. You can see 'em come sliding through. There's the cartwheel, and the back section of the fuselage ends up upside down and slides down the runway. They finally come to rest in a field of soybeans. As you look at this picture, the top, that slab of concrete at the top is runway 22, that was the closed runway that they were lined up with. They actually came down hard enough that they drug a trench in that concrete several feet long with their landing gear. Kevin Bachman, who'd spent the last 30 minutes talking to Captain Haynes trying to get this plane back on the ground had to leave the cab of the control tower to cry, 'cause he assumed everybody on board was dead. Everybody in the control tower thought everybody on board was dead. How would you live through something like that? But as the rescuers arrived at the plane, something strange started to happen. People started emerging from the wreckage. Some of 'em walked out without a scratch. There's a story of one man who walked out of the wreckage, got away from the plane, turned around and walked back to the plane, picked up his suitcase, and walked off. (audience laughing) Of 296 people on board, 185 survived. Still not a great day. A lotta people died. But there's some context that you need to know to understand that number. In the previous 25 years of aviation history, no one had ever survived the complete loss of flight controls on an airliner. There's a conclusive line in the NTSB report as well. "The Safety Board believes that under the circumstances "the United Airlines flight crew performance was highly "commendable and greatly exceeded reasonable expectations." As part of that report, as part of the NTSB report, they did a bunch of flight simulator studies. They put people in flight simulators configured very much the same way as the conditions that United 232 faced that day. Very few of the crews even got the plane close to Sioux City Airport. Nobody was as successful as this flight crew. Nobody had as good an outcome. So what made this crew different? Let me let Captain Haynes tell ya himself. - The preparation that paid off for the crew was something that United Airlines started in 1980 called Cockpit Resource Management. Up until 1980, we kinda worked on the concept that the captain was the authority of the aircraft. Whatever he said goes, and we've lost a few airplanes because of that. We had 103 years of flying experience up there in the cockpit trying to get that airplane on the ground, not one minute of which we had actually practiced, any one of us, so why would I know more about getting that airplane on the ground under those conditions than the other three. If I had not used CLR. If we had not let everyone put their input in, it's a cinch we wouldn't a made it. - If I had not used CLR, if I had not let everybody in the cockpit give their input, it's a cinch we wouldn'ta made it. That's the last thing he said there. What he refers to as CLR is referred to currently as Crew Resource Management. It's focused on the human dynamics of the cockpit. United 232 is considered to be one of the first big successes of Cockpit Resource Management. CRM is focused on interpersonal communication, leadership and decision making, and it's based on a bunch of research done by NASA Ames Research Center, the same place where Captain Haynes was giving this talk. The research was borne out of several flights where, exactly what Captain Haynes was talking about happened. A stubborn captain insisted that the crew follow his instructions, and the plane crashed because of it. CRM actually became mandated for American flight crews after the crash of United 173 in Portland. What happened in that case, as they were approaching Portland, they had an indicator that one of their landing gear wasn't down. Now it was actually down the whole time. It was a faulty switch in the wheel well that told them it wasn't down. But they spent so much time trying to troubleshoot that problem, flying around and around in a holding pattern, that they crashed 6 miles short of the airport. Despite the first officer and the flight engineer repeatedly encouraging the captain to turn back before they ran out of fuel. So what is it about Cockpit Resource Management that resulted in the success of United Flight 232? First, there's no heroes. Cockpit Resource Management emphasizes cooperation over heroics. One of the things that struck me as I was studying and doing research for this talk is that when he talks about this crash, Captain Haynes is very deliberate in using the word "we" to describe every action that was taken on that flight deck. He said things like, "We were at 38 degrees "of bank and increasing, so we closed "the number one throttle and firewalled "the number three." To be clear, Captain Haynes just used the word "we" to describe the moment when he saved that airplane. He lets Denny Fitch stay on the throttles long after it's obvious that that's the only thing controlling the aircraft. I woulda been really easy for Captain Haynes to say, alright, we don't have any aileron, we don't have any rudder, we have no hydraulics, let me have the throttles. But he doesn't, because Denny Fitch has spent a lot of time getting the rhythm of that airplane, understanding how the throttle works. So instead of insisting on being the hero and taking over at the last minute, he lets Fitch stay on the throttles all the way into the ground. There's an obvious parallel with our teams. We should avoid hero narratives in software. We should avoid working all night and on the weekends and making sure everybody in the company knows we did it. We should avoid building silos of expertise where we're the only ones that know what's going on. We should work together to find solutions to hard problems. And we should celebrate our successes as a team, not as individuals. Probably more importantly, we should learn from failure as a team instead of seeking to scapegoat individuals. The other thing that made this flight so successful is that everybody in the cockpit had a voice. You heard Captain Haynes say it in that video. If everyone hadn't had input, it's a cinch we wouldn'ta made it. In this, there's a very clear connection to software teams. It's a pattern, unfortunately, of software teams that there are one or two senior engineers that exert a dominant voice in the organization, and they insist in any conversation that their voices are heard above everybody else's. When you allow this to happen on your team, what it eventually does is shuts down other people. It keeps them from contributing, and you're not getting the full input that everybody on your team is capable of giving. This is especially true for new engineers, and it's especially important if you want to build a diverse team, because if you insist on your senior engineers asserting their voice above everybody else, you'll marginalize all the other voices on your team. Now the nuance to pick up about Cockpit Resource Management is that it doesn't eliminate the role of captain. It doesn't eliminate the hierarchy in the cockpit. It focuses instead on teaching the captain to communicate with everybody on the flight deck and to seek that input. That sounds very similar to what we oughtta be doing with senior engineers. You can't be a senior engineer if you don't spend your time coaching others on your team, seeking to bring them up to your level of expertise. There's a lot we can learn from aviation in this respect. Anytime you get on a plane, you might have a pilot in the left seat of your airplane that's been flying that particular model for 20 years, and someone in the right seat that may be flying their first revenue flight with passengers on board. But if there's a disaster, you want those two to be working together to solve the problem. You don't want them to be relying on just the captain's expertise. That's the same things we see on our teams. We might have someone who's been writing software for 20 years and someone who just graduated from a code school working together on code, and both of their voices are important. Both of them have expertise. If this is something that you wanna address on your team, Sandi Metz actually gave a fantastic keynote at Keep Ruby Weird a couple weeks ago about some of the psychological patterns that apply in this situation that keep people from speaking up and having a voice on teams. There's some very practical steps at the end of her talk that you can take to make your team more communicative and help elevate those voices. I highly recommend you watch it. Software is a team sport. Building software takes technical skill, but building the right software takes human interaction. A lot of our teams tend to look like those older flight crews that brought planes down. That's not how we want to operate. Let's work together to look more like the crew of Flight 232, so we can do great things together. Thanks. (audience clapping) I think I have a couple minutes for questions if anybody has any. So, I actually had that point in the talk, and I ran over on time. I'll make it real quick since you said it. One of the things that Captain Haynes attributes to their success that day is the fact that he was dealing with Kevin Bachman at Sioux City approach. He said the calm and measured voice that Kevin lent to the situation was a great reassurance to the crew. They happened to be landing at Sioux Gateway Airport on a Wednesday, and there is an Air National Guard detachment that's there on Wednesdays. That's the only day of the week that the Air National Guard is active. So there were 300 people at the airport ready to respond. They gave 30 minutes of notice, so first responders from all over the Sioux City area were at the airport ready for 'em to land. Every survivor was actually at the hospital in under 45 minutes, which is incredible. The moral of the story for me is that yet, exactly what you said, it's not just the pilots that have input to give, it's everybody on the team. You might have a formal QA team. You might have product managers. You might have account reps. You might have support people, and it's tempting for the engineering staff to kinda write them off because they're not developers, and it's easy for those relationships to get adversarial in a hurry. But Flight 232 wouldn't've had as many survivors as they did, if they hadn't utilized all the resources at their disposal. As far as specific advice, culture change takes a long time, and it's hard to know what specific levers to pull. The one thing I would say is try to find an ally on the software development team to help elevate your voice from within. You're probably gonna get the most traction the fastest by doing that. Anybody else? (question is asked but can't be heard) There was one flight attendant that didn't survive. Everybody on the flight deck did, so there was one flight attendant that was among the fatalities. Yes. - [Voiceover] Did they not need the hydraulics to get the landing gear down? No, they didn't actually. That was one thing that the designers of the DC-10 thought about, when the plane lost hydraulics, the landing gear would drop down onto the landing gear doors, and there was a lever they could pull in the cockpit to open those doors, and the landing gear would drop down from gravity into position. So there was one system on the aircraft that would work without hydraulics. (laughing) Alright. Thanks, everybody, I appreciate it. Thanks for comin'. (audience clapping) (upbeat country music)
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Channel: Confreaks
Views: 8,471
Rating: 4.9802957 out of 5
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Id: S2FUSr3WlPk
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Length: 42min 12sec (2532 seconds)
Published: Fri Nov 20 2015
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