Flying Too High: AI and Air France Flight 447
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When the trouble started, in the middle of the Atlantic, Captain Marc Dubois was in the flight rest compartment, right next to the flight deck. He was in charge of Air France Flight 447, en route overnight from Rio de Janeiro to Paris. But he was tired. He'd been seeing the sights of Rio with his girlfriend, Copacabana Beach, a helicopter tour, and he hadn't had a lot of sleep.

The airliner was in the hands of flight officers David Robert and Pierre-Cedric Bonin. And when the trouble started, First Officer David Robert pressed the call button to summon Captain Dubois. When you're asleep and the alarm goes off, how quickly do you wake up? Captain Dubois took 98 seconds to get out of bed and into the flight deck. Not exactly slow, but not quick enough.

By the time Dubois arrived on the flight deck of his own airplane, he was confronted with a scene of confusion. The plane was shaking so violently that it was hard to read the instruments. An alarm was alternating between a chirping trill and an automated voice. "Stall, stall, stall." His junior co-pilots were at the controls. In a calm tone, Captain Dubois asked, "What's happening?"

Co-pilot David Robert's answer was less calm. "We completely lost control of the airplane and we don't understand anything. We tried everything." Two of those statements were wrong. The crew were in control of the airplane. It was doing exactly what they told it to do. And they hadn't tried everything. In fact, one very simple course of action would soon have solved their problem. But David Robert was certainly right on one count.

They didn't understand what was happening. I'm Tim Harford, and you're listening to Cautionary Tales. The disappearance of Air France Flight 447 in the early hours of the 1st of June 2009 was, at first, an utter mystery.

The plane was an Airbus A330, a modern airplane with an excellent safety record. In the 15 years since being introduced in the early 1990s, not a single passenger A330 had crashed anywhere in the world. This one was just four years old and fully serviced. The crew were highly trained, the captain experienced, and there seemed to be nothing too challenging about the conditions. And yet...

Somehow, Flight 447 had simply fallen out of the sky. Search teams found traces of wreckage on the surface of the waves a few hours later, confirming that the plane had been destroyed and all 228 people on board were dead. But the black box flight recorder, containing possibly vital clues to the cause of the disaster,

It was somewhere on the bottom of the Atlantic Ocean. It wasn't until nearly two years later that the black box was discovered and the mystery could start to be solved. This, dear listener, is not just a story about a plane crash. It's a warning to all of us about what's coming.

Air France Flight 447 had begun with an on-time take-off from Rio de Janeiro at 7.29pm on May 31st 2009, bound for Paris. With hindsight, the three pilots had their weaknesses. Captain Marc Dubois, 58, had plenty of experience flying both light airplanes and large passenger aircraft, but he'd had very little sleep.

Pierre-Cedric Bonin, 32, was young and didn't have many flying hours under his belt. David Robert, 37, had recently become an Air France manager and no longer flew full time. He was flying this route to keep active his credentials as a pilot.

Fortunately, given these potential fragilities, the crew were in charge of one of the most advanced planes in the world, an Airbus 330, legendarily smooth and easy to fly. Like any other modern aircraft, the A330 has an autopilot to keep the plane flying on a programmed route. But it also has a much more sophisticated automation system called Assistive Fly-by-Wire,

A traditional airplane gives the pilot direct control of the flaps on the plane, its rudder, elevators and ailerons. This means the pilot has plenty of latitude to make mistakes.

Fly-by-wire is much smoother and potentially safer too. It inserts itself between the pilot with all his or her faults and the plane's physical mechanisms. A tactful translator between human and machine, it observes the pilot tugging on the controls, figures out how the pilot wanted the plane to move, and executes that maneuver perfectly.

It will turn a clumsy movement into a graceful one. This makes it very hard to crash an A330. Very hard, but it turns out not impossible. As the plane approached the equator, the junior pilot, Pierre-Cedric Bonin, was flying or, more precisely, was letting the autopilot fly. Captain Dubois was with him.

Ahead, on the weather radar, they could see tropical thunderstorms gathering, which, at that time of year and in that location, was common enough. We're not bothered by storm clouds, eh? said the old hand Dubois. Young Bonin didn't respond. He was, it would turn out, very much bothered by the thunderstorms, and many captains would have chosen to divert around them, for the comfort of the passengers as much as anything.

That wasn't a possibility that was discussed. Instead, Dubois noted, we'll wait a little and see if that goes away. And if not, then what? Not Captain Dubois' problem. A few minutes later, at 11pm Rio time, he pressed the buzzer to summon David Robert so that Dubois could take a nap. This wasn't particularly unusual.

Everyone needs a rest after all and the junior pilots need to get some experience making decisions about the plane. Still, with the plane on course to fly straight into thunderstorms, Dubois' decision to leave the flight deck raises questions. The chief investigator of the crash, Alain Bouillard, spoke to the writer and pilot William Longavicia about that. His leaving was not against the rules. Still, it is surprising.

If you're responsible for the outcome, you do not go on vacation during the main event. With Dubois gone, Pierre-Cédric Bonin's nerves about the storms became more apparent. Putain la vache! Putain! He yelled at one point. The outburst, the French equivalent of fucking hell, fuck, seemed to be provoked by nothing in particular. He talked with David Robert about how it was a shame that they couldn't fly high enough to clear the storms.

But they couldn't. There's a limit to how high a plane can go. The higher you fly, the further you are from dangers on the ground. But the thinner the atmosphere becomes. And the atmosphere, of course, is what the wings are using to support the aircraft. Too high and the margins for error become tight.

That's OK though, because on an A330, the assistive fly-by-wire system always keeps the pilots within those margins. As the plane approached the storm, ice crystals rattled unnervingly against the windscreen and ice began to form on the wings. Bonin and Robert switched on the anti-icing system to prevent too much ice building up and slowing the plane down.

Robert nudged Bonin a couple of times to pull left, avoiding the worst of the weather. Bonin seemed slightly distracted, perhaps put on edge by the fact that they hadn't plotted a route around the storms much earlier. A faint odour of electrical burning filled the cockpit and the temperature rose. Robert assured Bonin that all this was the result of the electrical storm, not an equipment failure.

But the ice wasn't just forming on the wings. It had also blocked the plane's airspeed sensors, meaning that the autopilot could no longer fly the plane by itself. A defrosting system activated to melt the ice and unblock the sensors. But in the meantime, the pilots needed to take control. An alarm sounded in the cockpit, notifying Bonin and Robert that the autopilot had disconnected.

And a message popped up adding that at the same time and for the same reason, the assistive fly-by-wire system had stopped assisting. No longer would it be the smooth-tongued interpreter between pilot and plane. Instead, the system was a literal-minded translator that would relay any instruction, no matter how foolish.

Pierre-Cedric Bonin was in direct, unmediated control of the airplane, a situation with which he had almost no experience. Still, all he needed to do was to keep the plane flying straight and level for a couple of minutes until the airspeed indicators defrosted. How hard could that be? Cautionary Tales will return after the break.

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Not long ago, Fabrizio Dell'Acqua, a researcher at Harvard Business School, ran an experiment to see how people performed when they were assisted by an algorithm.

The experiment was designed to be practical and realistic. It involved professional recruiters being paid to evaluate real resumes, equipped with commercially available software to use the sophisticated pattern recognition we call machine learning to assess and grade those resumes. Some of the recruiters were given software that was designed to operate at a very high standard. For simplicity, Dell Aqua calls that good AI.

Other recruiters, chosen at random, were given an algorithm which didn't work quite as well, or bad AI. They were told that the algorithm was patchy. It would give good advice, but it would also make mistakes. Then there was a third group, also chosen at random, who got no AI support at all.

Delacroix found that the computer assistant was very helpful. Whether recruiters were given good AI or bad AI, they made more accurate recruitment choices than the recruiters with no AI at all. But here's the surprise. The recruiters with good AI did worse than those with bad AI. Why? Because they switched off.

The group who had the good AI spent less time analysing each application. They more or less left the decision to the computer. The group who knew they had a less reliable AI tool spent more effort and paid closer attention to the applications. They used the AI, but they also used their own judgement. And despite having a worse tool, they made more accurate decisions.

With the rise of powerful new AI systems, we tend to ask who's better: humans or computers? The Delacqua experiment reminds us that that might be the wrong question. Often decisions are made by humans and computers working together. And just using the best computer doesn't necessarily get the best results out of the humans.

Pierre-Cedric Bonin was flying at high altitude in thin, unforgiving air into a thunderstorm. It was dark with an unnerving burning smell in the cabin because of the electrical charge in the air and the clatter of hailstones on the windshield. Then there was the sound of the alarm disconnecting the autopilot.

Bonin needed all the help he could get and just at that moment, the assistive fly-by-wire system disconnected. Bonin had no real experience flying without it. When the autopilot disengaged, Bonin grabbed the control stick and immediately the trouble began. The plane rocked right and left and right and left and each time Bonin overcorrected.

He was used to flying in the thick air of take-off and landing, whereas at high altitude, plane behaved differently. And more importantly, Von Ahn was used to flying with the assistive fly-by-wire, gracefully interpreting his every move. And suddenly, he was having to fly the plane without it. Right and left and right and left at rock, ten times in 30 seconds.

The side-to-side rocking of the plane must have been unsettling, but it wasn't particularly dangerous. What was dangerous was that Bernan also pulled back on the control stick, sending the plane into a climb. In the thin air, a climbing plane could easily stall. Stalling is what happens when the wings don't generate enough lift. A stalling plane is pointed upwards, trying to climb,

but it's losing forward speed and losing height, scrabbling for altitude as it slides down through the air. So why did Bonin point the plane up and risk a stall? It was an instinctive reaction from a pilot used to taking control of the plane at take-off and landing. When a stall is unlikely, then the main danger comes from not having enough height and slamming into the ground.

If there's a problem as you're landing, you gun the engines and point the nose of the plane upwards. That's what Bonin was doing. In an article in Popular Mechanics, the aviation journalist Jeff Wise explained, Intense psychological stress tends to shut down the part of the brain responsible for innovative creative thought. Instead, we tend to revert to the familiar and the well-rehearsed.

at more than 37,000 feet. The familiar and well-rehearsed action of pointing the nose of the plane up wasn't going to make Bonin safer. It was bringing the entire plane closer to catastrophe.

In 1942, two psychologists, Abraham and Edith Lutyens, who were married, published the results of a famous experiment. In this experiment, subjects were given three different sized water jugs and asked to figure out how to measure out a certain amount. For example, one jug might have a capacity of 20 ounces, the second 100 ounces, and the third 4 ounces.

Then the question is: how would you measure 72 ounces using these jugs? The answer: fill the 100 ounce jug, then pour off 20 ounces into the medium sized jug. Then you fill the small 4 ounce jug twice from the big jug. With a pencil and paper it's not too tricky to figure this out. 100 minus 20 minus 4 minus 4 gives you 72 ounces.

The Lutyens gave their experimental subjects several of these problems, each with different sized jars and a different target volume of water. But each time the solution followed the same pattern: fill the big jar, then use it to fill the medium jar once, and the small jar twice. Now comes the trick. The Lutyens would give people a problem like this:

The big jar holds 39 ounces. The medium jar holds 15. The small jar holds 3. How do you get 18 ounces? Well, you can repeat the same process as before. Fill the big jar and use it to fill the medium jar once and the small jar twice. It works. But if you do it that way, you're overcomplicating things.

Because you could simply fill the medium and the small jar. 15 plus 3 is 18. That's much easier. But a lot of people missed that obvious solution because they'd already solved a bunch of previous problems that required the more elaborate method. Abraham and Edith Luchin also had a control group. They hadn't been given any practice problems. Instead...

They started with the 18-ounce problem and of course most of them found the simple solution. Not having practiced was actually an advantage. They saw the problem with fresh eyes and solved it quickly and simply. The people who had practiced tended to get stuck with a clumsy solution. The Lutyens called this the "Einstellung effect". Einstellung is perhaps best translated here as "state of mind".

The practiced participants found a simple rule of thumb that seemed to work and so they began applying it unthinkingly. As the Lutschins put it, the problem-solving act had been mechanized. Bonnard's instinctive attempt to climb by pulling back on the stick demonstrated an Einstellung effect in two ways.

First, as Jeff Wise explained, he was reverting to his instinct that when you're in trouble, safety is to be found by pulling the plane up and seeking height. Second...

Bonin had almost always flown the A330 plane with the assistive fly-by-wire. And with the assistive fly-by-wire operating, you literally cannot stall the plane. The computer won't let you. Bonin had been trained by his own airplane never to worry about stalls.

never to even think about stalls, because stalls simply can't happen. As flight 447 began to lose airspeed and altitude, an automated voice announced, stall. Qu'est-ce que c'est, ça? said David Robert. What was that? Stall. Stall. Over the next four minutes, the word stall would be repeated more than 70 times.

But Bonin and Robert, it seems, couldn't grasp that a stall was possible. Their einstellung, their state of mind, made that risk inconceivable.

I first heard the story of Flight 447 told on the 99% Invisible podcast back in 2015. By the way, 99% Invisible is amazing, and if by some miracle you're not already a listener, go and subscribe. You can thank me later. Now, in 2015, this seemed like a warning about self-driving cars.

Here's a pilot who grew so reliant on his assistive technology that he forgot how to fly a plane at high altitude. So what happens when the self-driving cars take over and we all become Pierre Cédric Bonin? Unable to remember what to do, and the computer needs us to take over. I see the story differently now. It's not just the self-driving cars.

It's the appearance of artificial intelligence everywhere. Consider those decision-making algorithms that Fabrizio Dell'Acqua gave to professional recruiters, which made them switch off and let the algorithm handle the problem. He called that study "falling asleep at the wheel". I think you can see why. Or generative AI, which we use to paint pictures, create videos, write essays.

Like the assistive fly-by-wire on an A330, it's a technological miracle. But like the assistive fly-by-wire, the question is not how well the computer works, it's how well the computers and the humans work together.

Consider the hapless lawyers who turned to ChatGPT for help in formulating a case, only to find it had simply invented new cases. Not only did this actually happen, it's happened more than once. In a New York case, the lawyers were fined $5,000 and ordered to write letters of apology to the judges whose names had been taken in vain by ChatGPT.

In Canada, another lawyer was let off with a warning. The Supreme Court of British Columbia believed her when she said she didn't really understand how chatGTP worked, which I can believe too. By now, surely even the lawyers have figured out that you can't ask chatGPT to prepare a legal submission for you without checking.

But problems with generative AI can occur in more surprising places. Cautionary Tales will return in a moment.

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Jeremy Utley, Kian Gohar and Henrik Verdelin are experts in ideation, or to use its more everyday label, brainstorming, creative problem solving as a group. Naturally, when they heard about the launch of ChatGPT, they asked themselves what this new tool might bring to the ideation process. After all, ChatGPT was a sudden sensation. Powerful, flexible, easy to use,

And the problem that the lawyers had, that ChatGPT just makes stuff up, isn't a problem for ideation. Because the aim isn't accuracy, but to generate a huge range of solutions as quickly as possible before you work out the details later. So the three researchers decided to conduct a simple experiment in which they compared ideation sessions using ChatGPT with ideation sessions without it.

Jeremy Utley, who teaches innovation at Stanford University, thought that ChatGPT would help teams produce vastly more ideas, maybe twice as many, five times as many, a hundred times as many. He told the podcast You Are Not So Smart that he thought the question their study would answer was how many multiples more ideas are AI-assisted teams generating? And then he

He saw the results. He told, you are not so smart. My first thought was, oh no, oh no. For many of the teams using ChatGPT, the entire collaborative back and forth of the ideation process stopped. Instead, the room would be silent, except for the pecking at keyboards. Each person would be staring into their screen, displaying what the researchers came to describe as

resting AI face. And the ideas they produced? Utterly mediocre. Equipped with the latest, greatest, most sophisticated tool in the history of brainstorming, these teams produced totally predictable stuff. Nothing brilliant, nothing particularly varied, nothing that didn't need a lot of development work, and above all, just not many ideas.

Which is insane, because ideation is all about creating a huge variety of ideas and sorting through them later, and ChatGPT is absolutely a machine for producing a huge variety of ideas. It was the Einstellung problem again.

What people really needed to do was to engage with each other and engage with the AI, prompting it, discussing the prompts, going back to the machine, mixing things up, varying their queries, asking for more. But what ChatGPT gave them looked a lot like a Google search bar. You type in your question, you get an answer, and then you stop.

You feel like you've seen this situation before and so you do what you always do. And if it doesn't work, often, you just do it again. You get stuck. Pierre-Cédric Bonin was certainly stuck.

His instinct was to pull back on the control stick, which was stalling the plane, which was sinking, sinking, sinking towards the Atlantic Ocean. All around him and David Robert, alarms were sounding, including the alarm, stall, stall, stall. But they just didn't seem to be able to diagnose their self-inflicted problem.

By this time, even the airspeed indicators had defrosted. There was literally nothing wrong with the plane. If they'd gently pointed the nose of the plane downwards, it would have regained speed and lift and pulled out of the storm. They had plenty of altitude to do that, but they didn't. Robert had pressed the button to summon Captain Dubois from the rest cabin.

Fuck, where is he? In a panic, he mashed it again and again. Fuck, is he coming or not? Remember, Captain Dubois took only 98 seconds to reach the flight deck. What's happening? Dubois seemed calm, given the circumstances. David Robert and Pierre-Cedric Bonin were not. Bonin had stalled the plane, which was plummeting out of the sky, nose way up in the air at 150 feet per second.

David Robert had noted that the airspeed indicators had failed, and although the other readings were accurate, including the stall, stall, stall, he didn't believe them. The Air France pilots were "hideously incompetent", says William Longavisha.

Longavisha argued that the pilots simply weren't used to flying their own airplane at altitude without the help of the computer. Even Captain Dubois had spent only four hours in the last six months actually flying the plane rather than supervising the autopilot. And he'd had the help of the full assistive fly-by-wire system. If the plane flies itself...

When do the pilots get to practice? So far, we haven't seen that problem with modern AI systems. But it's obvious that trouble is coming. Think of the recruiters who fell asleep at the wheel, the lawyers who didn't understand chat GTP, and the brainstorming groups who stared slack-jawed at their screens rather than talking to each other.

In each case we can see an all too human willingness to abandon our own judgement and let the computer do the thinking. And the more we do that, the less practice we will get. Better AIs are coming of course, and that will only make the problem worse. The psychologist James Reason, the author of Human Error, explains why.

Skills need to be practiced continuously in order to maintain them. Yet an automatic control system that fails only rarely denies operators the opportunity for practicing these basic control skills. When manual takeover is necessary, something has usually gone wrong. This means that operators need to be more rather than less skilled in order to cope with these atypical conditions.

This is called the paradox of automation. Unreliable automation keeps the operators sharp and well-practiced. But the better the automated system gets, the less experience the operators will have in doing things for themselves. And cruelly, the weirder the situations will be when the computer gives up. You might say, well, then we shouldn't use these automated systems.

Pilots should practice their skills rather than using assistive fly-by-wire. We should memorize phone numbers instead of relying on our smartphones. Kids should learn long division rather than using calculators. Heck, books are a disaster. In the good old days before books, people used to just remember 15-hour epic poems such as the Iliad. And that's not going to happen. Anyway...

These tools don't just make life easier, they improve our performance. You can do more sophisticated calculations with a pocket calculator than without one. A library can contain vastly more information than any human could memorize. And modern planes with autopilots and assistive fly-by-wire are much, much safer than the old-fashioned kind.

But there is a price to be paid. Sometimes we'll find we can't remember a phone number, or how to do long division. Or perhaps we'll find we've asked an AI system to help us brainstorm, or to help us decide who to hire, or write new laws, or help us control weapon systems, or plan military strategy. Maybe we stop paying attention.

or become so helplessly out of practice that when the computer lets us down, we don't even notice. By the time Captain Marc Dubois returned to the flight deck, it was still possible to rescue the plane. Point the nose downward, regain forward airspeed and dive out of the stall.

The plane still had enough altitude to make that possible, but Dubois would have had to take in a lot of information in a very short space of time to diagnose the stall. And neither he nor Robert could directly see that Bonin was still yanking back on the control stick, instinctively trying to climb.

The plane was falling so quickly that some of the indicators had stopped giving readouts. And the ones that were working might have seemed unbelievable because of the extreme speed of the fall. And then there's a fundamental ambiguity. In a stall, you're pointing up, but you're falling down. To stop descending, you first have to dive. That can make it difficult both to diagnose the problem and to talk about it.

Less than a minute after Captain Dubois entered the flight deck, there's an exchange. Robert says, "You're climbing." Then he says, "You're going down, down, down, down." Is that an instruction to point the nose down? Or a description of the plane which is falling fast? Captain Dubois echoes, "Going down."

Bonin asks, "Am I going down now?" Robert and Dubois both disagree. Robert answers, "Go down." Dubois says, "No, you climb here." That's a description, not an order. Robert adds, "Go down." Bonin says, "I'm climbing, okay, so we're going down." It's a mess. Are they climbing or going down? Both. The nose is pointed up, Bonin's stick is back, and they're falling at more than 10,000 feet a minute.

Maybe Captain Dubois has realised they're stalling. Maybe not. He doesn't say so directly. And he's not at the controls, Bonanit. All the while, the computer voice is adding, stall, stall. It takes another minute before there's some kind of clarity. The plane has fallen through the 10,000 feet mark. There's now less than a minute left.

Robert says, "Climb, climb, climb, climb!" Of course he does. The plane is plummeting. Bonin replies, "But I've been at maxi nose-up for a while." At last, Captain Dubois seems to understand what Bonin has done. "No, no, don't climb!" At this point, David Robert pushes a button to switch control to his seat, pushes the nose of the plane down.

Bonin, presumably panicking, pushes his button and silently takes back control of the aircraft and sticks the nose back up. It doesn't matter. It's too late anyway. They only have seconds left. Pierre-Cedric Bonin's wife is back in the passenger cabin. Their two young sons are back in Paris. Does Bonin realise they're about to be orphaned? Probably. "We're going to crash," he says. "This can't be true."

Fuck, we're dead, says David Robert. In less than three seconds, the plane will belly flop into the Atlantic Ocean, instantly killing all 228 people on board. Robert, Bonin, Captain Dubois, Bonin's wife, Dubois' girlfriend, everyone. Pierre-Cédric Bonin's last words, but what's happening?

For a full list of our sources, see the show notes at timharford.com. Cautionary Tales is written by me, Tim Harford, with Andrew Wright. It's produced by Alice Fiennes, with support from Marilyn Rust. The sound design and original music is the work of Pascal Wise. Sarah Nix edited the scripts. It features the voice talents of Ben Crow, Melanie Guttridge, Stella Harford, Gemma Saunders and Rufus Wright.

The show also wouldn't have been possible without the work of Jacob Weisberg, Ryan Dilley, Greta Cohen, Eric Sandler, Carrie Brody and Christina Sullivan.

Cautionary Tales is a production of Pushkin Industries. It's recorded at Wardour Studios in London by Tom Berry. If you like the show, please remember to share, rate and review. Tell your friends. And if you want to hear the show ad-free, sign up for Pushkin Plus on the show page in Apple Podcasts or at pushkin.fm.com.

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