RubyConf 2015

Lecciones que pueden aprender los programadores Ruby tras estrellarse un avión

Nickolas Means  · 


Extracto de la transcripción automática del vídeo realizada por YouTube.

- 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.

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