Original subtitles

ANNOUNCER: This program is rated PG, and contains

ANNOUNCER: This program is rated PG, and contains

mature subject matter.

Viewer discretion is advised.

(SIREN WAILING)

(MAN SPEAKING)

NARRATOR: It's one of the most shocking plane accidents in US history.

The plane literally spirals down the runway.

It is a complete disaster.

NARRATOR: But why did it crash?

Is it a mechanical problem, or is this a human factors problem?

How could this accident have happened?

NARRATOR: Now, engineers unlock the clues to the world's biggest disasters...

(PEOPLE SCREAMING)

...to find out what happens when Big Things Go Wrong.

MAN: Watch it! Watch it!

These are the ultimate fears

that keep structural engineers awake at night.

(THUDDING)

MAN: Oh, my God.

(AEROPLANE WHOOSHING)

NARRATOR: Incheon International.

One of Asia's busiest airports.

Check-in is underway for the 291 passengers on Asiana Flight 214.

A 10-and-a-half-hour trip across the Pacific, to San Francisco.

Among the travelers, the Jang family.

They're returning home from a month-long vacation.

Both my parents are from Korea, they were born there,

but they both moved to The States at a pretty young age.

My parents planned it so that we could see a bit of like where they grew up

and our culture, and stuff like that.

I think we were there, for about a month

and we did a lot of sight-seeing,

but I was really looking forward to going back home.

NARRATOR: They'll be flying on a Boeing 777.

One of the most high-tech passenger jets in the world.

(AEROPLANE WHIRRING)

The 777 was innovative from the start.

The way it was manufactured, designed, and built, was completely new.

NARRATOR: It's also among the safest.

A key selling point is its advanced autopilot system.

It draws information from multiple sensors all over the plane.

Then crunches the data and sends out commands.

It's a complex, state of the art airplane.

And with safety the number one priority in its design,

every flight should be routine.

(TICKING)

ESTHER: It was like any other typical flight.

They told us to bring our seats up,

put our trays up,

and just get ready for a landing.

(MAN SPEAKING KOREAN)

(AIR TRAFFIC CONTROLLER SPEAKING)

(PILOT SPEAKING)

NARRATOR: There's no obvious sign of anything wrong, but that's all about to change.

I don't know what it was, but I had like this weird gut feeling

that, like, something was a little off.

I remember thinking, "Oh, I see the seawall, is that normal?"

(TICKING)

NARRATOR: At the last moment, the pilots power up the engines.

The issue is it's too little, too late.

Instead of clearing the seawall, he clips it, and disaster.

(LOUD EXPLOSION)

It was a rollercoaster off its tracks, it was extremely rough.

I remember just bouncing up and down.

After all the movement stopped, I just remember being in total shock

(SIREN WAILING)

(MAN SPEAKING)

I remember looking over to my parents,

and that's when I really started to freak out.

(SIREN BLARING)

SARAH: They were on the ground, their seats half-fallen,

and they were super pale, with like, blood dripping down their faces.

NARRATOR: It's a horrific crash that shocks America.

MATT: What's going on here?

Is it a mechanical problem, or is this a human factors problem,

or a combination of both?

NARRATOR: With multiple safety systems built into the plane,

a disaster like this should never happen.

So what's really behind the Asiana tragedy?

NARRATOR: The answers begin at the airport itself.

San Francisco Airport is one of the busiest airports in the world.

However it's not one of the biggest,

and it does come with its own set of challenges.

The primary approach is over water. There's not much margin for error.

NARRATOR: Featureless terrain like water makes it harder for pilots to judge height.

I've flown into San Francisco Airport myself a number of times

and if you look out the window, all you see is water.

And you continue to see water essentially until you're on the runway.

And so you're just waiting to see the sea-wall flash underneath you,

and then hit the ground.

NARRATOR: But that's not the only challenge for pilots coming into San Francisco.

The airport has intersecting parallel runways unusually close together.

Planes can arrive simultaneously just 750 feet apart.

And six weeks before the crash, landing here gets even trickier.

Construction work forces the three-month shutdown

of a vital piece of safety equipment.

The airport's landing guidance system called a glide slope.

It transmits this radio signal out to aircraft,

and it tells them, "Hey, this is the angle you need to fly,

"in order to reach the runway."

If you go above it, you're probably going to overshoot the runway.

If you go below it you're in danger of colliding with terrain.

NARRATOR: It's an invaluable tool for pilots.

(SIGNAL BEEPING)

In 777 the autopilot detects this signal and follows the glide slope automatically.

And then from that point, it's just monitoring to make sure

you're on glide slope following that angle safely all the way down to touchdown.

NARRATOR: But with this failsafe system turned off,

the angle of approach is all down to the air crew.

It's not just planes that rely on safety systems.

Trains need them, too, as one driver finds out in Taiwan in 2018.

A high speed train races south from the capital, Taipei, carrying 370 passengers.

But as it approaches a bend at a local station,

its speed is twice what it should be.

It jumps the rails, and slams into the station pillars.

Four of its eight carriages overturn.

Eighteen die, and two hundred and ninety-one are injured.

So what causes the crash?

When the Puyuma express sets out from Taipei at 2:50 p.m.,

its driver immediately realizes he has a problem.

It keeps wanting to stop, and he can't figure out why.

So he turns off the automatic train protection system.

Now, this automatic train protection system is designed to keep

the train from going too fast, particularly when it's going into a curve.

NARRATOR: The driver must now carefully monitor his speed.

That's okay, because along the way there are signs,

there are visual cues that the driver can see,

alerting him that he has to slow down.

NARRATOR: But half a mile from Xinma Station, he misses a vital trackside sign.

And instead of going around a curve that had a maximum speed of 45 miles per hour,

he was actually going 93 miles per hour.

(LOUD CRASH)

LUKE: Humans can make errors, humans can get distracted,

humans can miss visual cues.

And and whilst we don't know why this driver necessarily went into this corner too quickly,

it's clear that if the automated system had been there to warn him,

it's very unlikely that that could have happened.

NARRATOR: In San Francisco, turning off the safety system

also adds pressure to human operators.

Yet for six weeks before the crash,

around three and a half thousand flights land without a problem.

So what else went wrong on Asiana Flight 214?

NARRATOR: Coming up...

More evidence uncovered.

If the wing isn't generating lift,

the airplane is basically just falling out of the sky.

NARRATOR: And could a Taiwan air crash hold a vital clue?

(PILOT SPEAKING)

(EXPLOSION)

(EXPLOSION)

NARRATOR: When Big Things Go Wrong...

engineers must find out why.

(GLASS SHATTERING)

In the terrifying crash at San Francisco,

the first issue, no landing guidance system.

But this didn't cause problems for any other planes landing here.

So what else goes wrong on flight 214?

A second clue lies in the plane's speed on final approach.

Crash investigators salvage the black box from the wreckage

and reveal a big surprise.

In the seconds before the disaster,

the aircraft's travelling 15% slower than it should be.

The reason why airspeed is so critical in airplanes

is because there requires a certain amount of flow over the wings to generate lift.

If the wing isn't generating lift,

the aeroplane is basically just falling out of the sky.

NARRATOR: Why is flight 214 going so slow at such a critical moment?

The black box data only adds to the mystery.

For just over a minute before impact, its engines are set to zero power.

Miraculously, the pilot survives the crash

and investigators are eager to interview him.

He admits that on final approach he wasn't monitoring his air-speed.

The reason, he believes his speed

is guaranteed by a 777 safety feature.

Low Speed Protection.

Every airplane has a minimum speed

at which it wants to land at. And for the 777,

if the plane starts to go too slow, it will boost the power of the plane.

And so it's one of those safety nets

that you just don't have to worry about going too slow.

They were anticipating that the system was,

the auto throttles were going to hold that airspeed for them.

NARRATOR: But for Asiania 214, that doesn't happen.

This massive plane has become a glider.

NARRATOR: And if an airplane loses power, it's game over.

As one pilot discovers in Taiwan, in 2015.

In the capital Taipei, TransAsia 235 prepares for take-off.

It's carrying 58 passengers and crew on a routine flight to China.

Then something goes wrong.

On take-off, the connection between the engine

and the sensor monitoring it breaks.

As a result, the computer no longer thinks that the engine's getting power.

NARRATOR: And human error makes a bad situation much worse.

The pilots inadvertently shut off the power in the actual functioning engine.

This causes the plane to stall and begin to crash.

(PILOT SPEAKING)

NARRATOR: Both engines are now completely unpowered,

and the airplane plummets towards a busy highway.

(THUDS)

Just three minutes after take-off, it crashes into Taipei's Keelung River.

As it's crashing down, it clips a taxi

that happens to be on the roadway right in front of it.

(THUDS)

NARRATOR: Miraculously, driver and passenger both survive.

But the airplane passengers aren't so lucky.

The plane strikes the water upside down, and tears apart.

It takes 35 minutes for rescue boats to reach the site.

Fifteen are seriously injured.

Forty-three die, including the pilots.

DAN: You have a small component

that malfunctions, but the consequence of that malfunction means

you lose all power to the aircraft. Well then, that's almost a knock-out blow.

NARRATOR: Coming up...

The 777 pilots rely on automation to keep them safe.

But does it let them down?

Automation is there to help you, but it can bite you.

And when it does bite you, it bites hard.

NARRATOR: And more Big Things Go Wrong...

(PEOPLE SCREAMING)

(ALL SCREAMING)

(OBJECTS CLATTERING)

NARRATOR: In San Francisco, investigators race

to explain the crash of a Boeing 777.

Immediately after the crash, there were some

burning questions that needed to be answered.

I mean, this was a clear sky day. Perfect flying day.

There was no warning from the pilot

that there was anything wrong with the plane.

How could this accident have happened?

NARRATOR: The survivors are also dazed.

The wind got knocked out of me. My ears were ringing.

There was a lot of yelling, a lot of moaning.

SARAH: I remember it just being chaos.

Everyone was screaming, crying, and just in complete shock.

NARRATOR: The pilot made a mistake with his approach angle,

and the jet's low speed also appears to be a factor.

But why doesn't its advanced safety system prevent disaster?

1995.

At press launches around the world, Boeing parades a brand new plane.

A high-tech passenger jet named the Triple Seven.

This airplane is in fact what we all know it to be.

It's more than safe and it's more than reliable.

The Boeing 777 is an amazing plane, because it's enormous.

It can hold upto 400 passengers. It can fly up to 10,000 miles.

It weighs 380 tons and it's a workhorse in the aviation field.

NARRATOR: The 777 is one of the most sophisticated passenger planes ever built.

And the first large commercial jet designed entirely by computer.

One key feature, its advanced autopilot.

Much more complex than previous generations.

It prevents the aircrew from getting the aircraft into a bad situation.

It automatically will prevent stalls.

It will prevent the aircrew from over stressing, over banking the aircraft.

NARRATOR: That's not the end of the 777's electronic revolution.

It has an incredible new flight control technology.

It was fly by wire. This is no longer cables and control rods

going directly from the cockpit to the control surfaces,

or to the hydraulic actuators. This was wires.

NARRATOR: The pilot's instructions

from cockpit controls are processed by computer.

Electronic signals are sent to motors throughout the plane.

And these motors activate the flaps, rudder and engines.

Fly by wire has been in widespread use in the military for decades.

However, in the 777 this was brand new

to the civil aviation, commercial aviation world.

NARRATOR: In this new electronic era,

pilot, machine and autopilot must work seamlessly together.

But automation can lead to over-reliance on the computer

to do the right thing in every situation.

Any time you relinquish control to an automated system,

you have the potential for that system to make a wrong,

or ill-advised, or ill-informed decisions.

NARRATOR: It's essential that 777 pilots constantly monitor what the autopilot is doing.

Because even the most advanced technology doesn't always cooperate.

Sometimes there is combinations that just come together

that can lead to unexpected outcomes.

Those unexpected outcomes can be dangerous, or even deadly.

NARRATOR: That's just what happened

to a cruise ship off the coast of Norway.

March, 2019.

The Viking Sky loses power in a violent storm.

(PEOPLE SCREAMING)

(PEOPLE SHOUTING)

And a computer program is the trigger.

(OBJECTS CLATTERING)

The danger of any automated system is,

the system doesn't have the contextual information

it needs to make a good decision in all cases.

If it does the wrong thing at the wrong time,

really bad stuff is possible.

NARRATOR: So what went wrong?

The Viking Sky is two days into a cruise along the rugged Norwegian coast.

The ship set out from Tromso, heading over 1200 miles south to Stavanger.

Then, the weather turns ugly.

She started heading into extremely rough seas with

thirty feet high waves coming at her every 12 seconds.

NARRATOR: An automatic trip-switch is about to put lives on the line.

Viking Sky begins to get a lot of low level lube oil alarms.

So lube oil is lubrication

for the diesel generators,

and as the ship is rolling back and forth

in these heavy sea states,

the ship is having trouble

pulling that fluid

into the diesel generator

to ensure lubrication for those components

to properly work.

NARRATOR: Without lube oil, the engines will overheat and sustain damage.

CAITLIN: The automation for this system is that

if those generators are not getting enough lube oil,

then they will shut down to not cause harm.

NARRATOR: Suddenly, all the ship's generators cut out,

plunging it into black-out.

(WIND BLOWING)

(CRACKING SOUND)

MAN: Whoa!

(METAL CLANGS)

And the Viking Sky starts drifting towards the rocky coastline.

All 1300 people on board are in serious danger.

You may have saved the engine, but you put the passengers

and the ship itself in great peril.

(WOMAN SCREAMS)

(METAL CLANGS)

(OBJECTS CLATTERING)

(INTENSE MUSIC PLAYING)

A helicopter evacuation begins.

(HELICOPTER WHIRRING)

The crew partially restart the engines.

But they take no chances.

Tugboats tow the troubled ship into port.

Finally, 26 hours after the black-out, the ordeal is over.

The Asiana 777 has the most advanced safety features of its day.

But could an unexpected computer glitch help explain its crash?

Coming up...

A chance to warn 777 pilots of danger is missed.

All it takes is one little thing to go wrong and catastrophe can happen.

(EXPLOSION)

NARRATOR: And an oil platform explosion shows just how deadly this can be.

NARRATOR: In San Francisco, the mysterious crash of a Boeing 777

demands urgent investigation.

And evidence is now emerging to explain what went wrong.

A dangerously low speed on approach...

The airplane is basically just falling out of the sky.

...and an overly complex new computerized flight control system.

There's always the chance that there are going to be

hidden interactions that we don't fully understand.

NARRATOR: But by 2013, 777 pilots have clocked up 38 million flight hours.

And with a zero crash fatality rate,

it's one of the safest planes in the sky.

So what else is behind the San Francisco tragedy?

NARRATOR: The next piece to the puzzle lies somewhere unexpected.

In 2010, a new Boeing model

rolls off the assembly line in Everett, Washington State.

It's the 787, follow-up to the successful 777.

Both planes have the same advanced autopilot.

Before the 787 can carry passengers, it must undergo testing.

MATT: Test pilots have quite the job.

They evaluate every aspect of this aircraft.

Not just how it maneuvers, how it performs,

but how they are able to interact with the systems

and how the systems interact with them.

NARRATOR: But during one flight, a test-pilot uncovers something alarming.

A test pilot is taking the plane in

for a descent with the autopilot engaged.

All of a sudden the collision alarm goes off.

(ALARM BEEPING)

NARRATOR: It's a warning there may be another aircraft below him.

So the test pilot turns off the autopilot,

adjusts the throttles so that the plane can level out.

NARRATOR: It's soon clear it was a false alarm.

But then the airplane does something totally unexpected.

SIAN: He realizes that

the plane has dropped below the minimum speed threshold.

NARRATOR: The pilot figures out his unusual actions

deactivate the low speed protection system.

And that's really the "aha" moment that this unique situation

and the unique combination led to the auto throttle not engaging.

NARRATOR: Speed protection should increase power to the engines when needed.

But if it's turned off unnoticed,

the plane could sink like a stone.

(ALARM BEEPING)

NARRATOR: Luckily, the test-pilot was high enough to react, this time.

But it revealed a dangerous flaw in the autopilot design.

One that could prove fatal for other pilots.

SIAN: This test pilot experiences this

in the 787, but realizes that the 777 has the same autopilot system.

So when he writes up his report, he flags it for both airplanes.

NARRATOR: Incredibly, these warnings don't reach 777 crews.

The FAA informed everybody that,

"Hey, if you're flying a 787 this has the potential to really bite you."

The sad part about this is that it never really got transferred

over to the 777 community and sent up from there.

NARRATOR: When dealing with complex engineering, things can go wrong.

But when warnings aren't shared, catastrophe becomes inevitable...

as workers on an oil-rig discover in 1988.

(THUNDER RUMBLING)

The Piper Alpha oil platform, 120 miles off Scotland.

On July 6th 1988,

failure to pass on crucial information triggers disaster.

(EXPLOSION)

MAN: There she goes...

NARRATOR: So what's behind this devastating blast?

SIAN: On this particular day, one of the pipes that is handling the gas,

the valve on it needs to be replaced.

So the worker takes the valve off and caps it.

NARRATOR: It's not enough to completely seal the pipe,

but before a new valve can be installed, the shift comes to an end.

There is a system on Piper Alpha to flag

and communicate works that are underway, but not yet finished.

But on this particular change of shift, that communication wasn't picked up.

NARRATOR: If any gas is fed down the pipeline,

it will escape from the temporary cap.

One spark and it could blow.

That evening, a pump fails in the other pipeline taking gas to the mainland.

(ALARMS BLARING)

Engineers can't get it restarted,

so switch the flow to the second pipeline.

They don't realize it's still under repair.

ROB: When the pump was switched on,

survivors report this loud screeching noise

that was coming from the temporary cap

that had been fitted instead of the safety valve.

Apparently, this lasted for about 30 seconds,

which would have released around 30 kilograms of highly explosive gas.

(EXPLOSION)

NARRATOR: Despite fire-fighters' best efforts, of 226 people on board, just 61 survive.

The lesson for the 777? Warnings not passed on can lead to disaster.

And with 1,100 Triple Sevens in the air, chances are,

a pilot will eventually fall into the autopilot trap.

However unlikely.

if you play a game a billion times,

a one in a billion chance is probably going to show up.

NARRATOR: Coming up...

What goes wrong in the final minutes of Asiana Flight 214?

NARRATOR: As machines get bigger, and more complex,

technology can be both a blessing and a curse.

NARRATOR: The B2 stealth bomber. One of the most advanced airplanes in the world.

It's so complex it can only fly with the help of its autopilot.

But in 2008, at the US airbase in Guam,

heavy rain causes vital speed sensors to malfunction.

Fed the wrong information on take-off, the autopilot triggers disaster.

(EXPLOSION)

The pilots eject milliseconds before impact.

It's the most expensive air crash in history,

a $1.4 billion airplane up in smoke.

An autopilot glitch brings down a sophisticated B2 bomber.

And as Asiana flight 214 approaches San Francisco,

nobody on board knows there's a trap in its autopilot

waiting to be triggered.

(TICKING)

Twenty minutes out, the 291 passengers prepare for landing.

So far the journey has been uneventful.

But nearly half of all plane crashes happen on final descent and landing.

The Jang family, returning from a month's vacation in Korea, sit in the back of the plane.

(TICKING)

The children are across the aisle from their parents.

We got really excited, we were just so ready to be home.

I always open the window right before I land, I like to see the landing.

(AIR TRAFFIC CONTROLLER SPEAKING)

(UNCLEAR RADIO CHATTER)

The weather conditions were almost ideal. It was day time, low wind.

NARRATOR: But just two minutes out from San Francisco,

the pilot finds himself in trouble.

He normally relies on the airport's glide slope system to line up his approach.

But today it's turned off, and he realizes he's coming in too high.

four hundred and fifty feet above the ideal line.

They needed to do something fairly drastic to get back down

to an altitude and a trajectory to the runway.

NARRATOR: The pilot is running out of time to get the angle right.

In a desperate attempt to get lower, the pilot selects an autopilot setting

he thinks will get him back on the right path,

"Flight level change speed."

But it only makes things worse.

(BEEPING)

Instead of bringing him down, it starts climbing the plane, making him too high.

NARRATOR: In response, the pilot puts his engines to idle.

He brings the throttle right down to zero on the engines.

So that the plane will lose speed and then lose height.

NARRATOR: Then he disconnects the autopilot to try and manually correct course.

But as he turns it off, this final action triggers the trap.

SIAN: The system automatically changes the throttle mode to "hold"

and the pilot has no idea that this has just occurred.

NARRATOR: The pilot doesn't realize it,

but the airplane's "low-speed protection" is now turned off.

The consequence is that the engines are not going to fire up

when the airspeed drops below that critical number that the pilot has set.

(TICKING)

(AIR TRAFFIC CONTROLLER SPEAKING)

(PILOT SPEAKING)

(AIR TRAFFIC CONTROLLER SPEAKING)

(TICKING)

NARRATOR: 30 seconds out. The airplane finally seems to be on the correct approach angle.

But instead of levelling out as the crew expects, it continues to drop.

JOSEPH: As we were approaching the runway,

I had like this weird, gut feeling that like, something was a little off.

(TICKING)

NARRATOR: 20 seconds out. The airplane is falling at 20 feet per second.

Now its speed drops below the minimum safe level.

But the engines fail to fire up.

Even now, the pilot doesn't realize.

It's almost like the pilot's waiting and waiting

and waiting for the system to do its thing, and it never shows up.

(TICKING)

NARRATOR: It's the co-pilot who finally reacts.

He realizes he's too low, and so what's going to happen

is that the plane is actually going to land short of the runway

and crash into the seawall.

DAN: He kicks in a large amount of throttle, to gain some air speed.

The airplane is too big, too low, and too slow.

(MUSIC INCREASES IN TEMPO)

(TICKING)

(LOUD EXPLOSION)

The tail is ripped off and the plane literally spirals and tumbles down the runway.

(EXPLOSION)

NARRATOR: It's a horrific crash.

SARAH: It all happened so quickly.

I remember bouncing up and down in my seat.

All of a sudden, we just stopped.

I checked to make sure that both my sisters were okay,

and I looked over to, I guess look for my mum and my dad.

(AIR TRAFFIC CONTROLLER SPEAKING)

My initial thought was that they died, because they... they weren't moving.

SARAH: They were on the ground,

their seats half-fallen, and they were super pale,

with, like, blood dripping down their faces.

NARRATOR: Asiana flight 214 has just crashed in San Francisco.

LUKE: Given the nature of the crash,

the fact that anyone survived, frankly I think is extraordinary.

(MAN SPEAKING)

NARRATOR: But soon, another threat looms.

I remember the flight attendant telling us,

"We need to get off the plane, we need to get off the plane."

NARRATOR: At any second, the plane's huge fuel tanks could explode.

The wings stay intact. And the thing about the wings staying intact

is that that's where the jet fuel is.

Jet fuel is extremely flammable and if the plane catches fire, everybody is going to be dead.

NARRATOR: Survivors attempt to flee the burning wreckage.

But only two of eight inflatable slides deploy,

leaving them scrambling for a way out.

My brother and I were able to just jump off the side of the plane, because

there was no slide at this exit.

Firefighters started panicking, and I remember one picked me up

and was running away from the plane.

-NARRATOR: Now begins a sickening wait. -(SIREN WAILING)

My brother and I were just sitting there, worried about my parents.

The engine was still going, the engine didn't stop,

and the fire was massive at the time.

NARRATOR: The Jang children are driven across the runway to join other survivors.

Just when hope is nearly gone, they see their parents in the crowd.

All I remember my mom saying was like, "Where are my kids? Where are my kids?"

and I remember just being like, "We're right here", like,

"We're all here together now. It's okay."

NARRATOR: The Jang parents are rushed to the hospital.

They're among 49 who suffer serious injuries.

Tragically, three passengers die.

All were seated at the rear of the plane.

We were sitting extremely close to the the passengers

that did pass away from the accident.

I just feel like it was a huge blessing,

that all of us made it out relatively unharmed.

NARRATOR: The crash came without warning, and left witnesses baffled.

To the general public, one would definitely ask,

"How could something like this happen on such a perfect day,

"with such a reliable, safe aircraft?"

NARRATOR: But to engineers, the answers to this puzzle seem clear.

No airport guidance system.

ROB: Without the glide slope system working,

the pilot ends up coming in too high.

NARRATOR: A vital missed warning.

In complex safety environments, it's the thing

that you don't know about that's often the most critical.

NARRATOR: And one unusual factor.

An autopilot with a deadly hidden trigger.

Automation is there to help you...

but you need to be careful,

because it can bite you.

And when it does bite you, it bites hard.

(EXPLOSION)

NARRATOR: In the aftermath, suspicion falls on the pilot.

But when National Transportation Safety Board crash investigators start looking into it,

they soon unearth deeper causes behind the pilot's error.

The investigation reveals that the confusing nature of the autopilot

was a big contributing factor to this crash,

and they actually recommend that all 777 pilots be trained on this hidden trap.

NARRATOR: Most of the latest planes have far more advanced autopilot systems.

ROB: Huge developments in the sophistication of aviation systems,

along with the processing power of the computers that run them,

mean that modern autopilot systems

are far more capable than they once were.

NARRATOR: And as Machines continue to get bigger and more complex...

Asiana Flight 214,

and other disasters around the world, offer a warning.

Automation can bring greater safety, but it also creates new risks.