Original subtitles

Helios 522, do you read?

Over.

All radio contact is lost for the plane

All radio contact is lost for the plane

carrying 115 passengers.

Everybody's mind was going to a hijack or to terrorists.

Everybody's mind was going to a hijack or to terrorists.

High above the Taiwan Strait, a 747 jumbo jet

goes mysteriously silent.

goes mysteriously silent.

Dynasty 611, Taipei.

So the first thing you think about is a bomb.

So the first thing you think about is a bomb.

And when controllers lose

contact with a private jet, fighter pilots

contact with a private jet, fighter pilots

scramble to intercept.

No movement.

Everybody knew that there was a major problem.

Everybody knew that there was a major problem.

Three perplexing cases of radio silence

send investigators hunting for answers.

send investigators hunting for answers.

Do you read?

Over.

Radio silence can mean a long and dark mystery unfolding

Radio silence can mean a long and dark mystery unfolding

as the world watches, or it can mean

that your plane has just devastatingly

that your plane has just devastatingly

been blown from the sky.

Ladies and gentlemen,

we are starting our approach.

We lost both engines.

We lost both engines.

Mayday.

Mayday.

Brace for impact!

He's gonna crash!

It's early morning on the island of Cyprus,

It's early morning on the island of Cyprus,

as the crew of Helios Airways Flight 522

prepares for today's flight.

prepares for today's flight.

Sure is a beautiful day.

Maybe I shouldn't have come in.

Maybe I shouldn't have come in.

Andreas Prodromou wasn't scheduled

for the flight, but he's offered to work in order

for the flight, but he's offered to work in order

to spend some time with his girlfriend,

another flight attendant.

Temperature's still up there.

Temperature's still up there.

In the cockpit, the flight crew

is occupied with a daily routine of preparing

their jet for takeoff.

their jet for takeoff.

Bright today.

Captain Hans Merten is a contract pilot hired by Helios

for the busy holiday season.

for the busy holiday season.

Are you almost through?

Nearly.

Nearly.

First officer Pampos Charalambous has been flying

with Helios for five years.

There are switches.

There are switches.

Sorry.

Could you store trays?

Move your seat back and turn off electronics, please.

The Boeing 737 is carrying

The Boeing 737 is carrying

a total of 115 passengers and six crew members.

PAMPOS CHARALAMBOUS (ON INTERCOM): Flight attendants,

please take your seats.

Prepare for takeoff.

Safe flight.

Just after 9:00 in the morning,

Helios Airways Flight 522 lifts off.

Nicosia Air control, this is Helios 522.

Nicosia Air control, this is Helios 522.

Request cruising at 340.

Request cruising at 340.

Helios 522, you are cleared to climb to 340.

Have a good day.

Have a good day.

Set 340.

340.

340.

Flight 522 is an hour and a half flight from Larnaca,

Cyprus, to Athens, Greece.

Cyprus, to Athens, Greece.

The plane is still climbing towards its cruising altitude,

when suddenly...

when suddenly...

What is it?

The takeoff config warning.

The takeoff config warning.

The takeoff configuration

alarm warns pilots that their jet isn't ready for takeoff.

alarm warns pilots that their jet isn't ready for takeoff.

But why is it sounding now, during flight?

The captain radios the Helios Operations Center back

in Cyprus.

in Cyprus.

Operations, this is Flight 522.

Over.

Flight 522, what can I do for you?

Flight 522, what can I do for you?

We have a takeoff config warning on.

Then the situation becomes even more confusing.

Then the situation becomes even more confusing.

We now have a Master Caution.

We now have a Master Caution.

I'll get you an engineer, 522, in just a minute.

I'll get you an engineer, 522, in just a minute.

In the cabin, the passengers are hardly

aware there's a problem until...

aware there's a problem until...

Everyone stay calm, and please do remain seated.

Everyone stay calm, and please do remain seated.

Everyone, please put the oxygen masks on completely

Everyone, please put the oxygen masks on completely

over your mouth and nose.

In the cockpit, the pilots still don't know

In the cockpit, the pilots still don't know

why both alarms are sounding.

Can you confirm that the pressurization

Can you confirm that the pressurization

panel is set to Auto?

Where are my equipment cooling circuit breakers?

Where are my equipment cooling circuit breakers?

Behind the captain's seat.

Can you see them?

As the plane continues to climb,

passengers and crew are growing concerned.

Helios 522, can you see the circuit breakers?

Helios 522, can you see the circuit breakers?

But the Helios crew doesn't respond.

But the Helios crew doesn't respond.

Helios 522, can you hear me?

Helios 522, can you hear me?

Athens air traffic controllers

Athens air traffic controllers

can see the plane is still on course high

over the Mediterranean Sea.

over the Mediterranean Sea.

Helios 522, do you read?

Over.

But all they're getting is radio silence.

But all they're getting is radio silence.

We heard that there was an airplane

which was flying into the Greek territory

which was flying into the Greek territory

and had no communication.

Everybody's mind was going to a hijack or to terrorists.

Everybody's mind was going to a hijack or to terrorists.

The passenger jet has been in the air

for over two hours.

for over two hours.

They were scheduled to land 30 minutes ago.

The plane is now circling in a holding

The plane is now circling in a holding

pattern over Athens, a city of over 3 million people.

The Greek Air Force scrambles two

fighter jets to investigate.

fighter jets to investigate.

Helios 522, do you read?

Over.

Helios 522, do you read?

Helios 522, do you read?

Over.

One of the Jets flies closer.

One of the Jets flies closer.

Someone is in the first officer's seat,

slumped over the controls.

But there's no sign of the captain at all.

But there's no sign of the captain at all.

Athinai ACC, Athinai ACC, checking the cabin.

Athinai ACC, Athinai ACC, checking the cabin.

He can see passengers in their seats,

He can see passengers in their seats,

but none of them react to the presence of the jet.

Then the pilot sees someone moving into the cockpit.

Athiniai Control, there is one person moving

Athiniai Control, there is one person moving

in the cockpit of Helios 522.

Repeat... there is one person inside the cockpit.

Repeat... there is one person inside the cockpit.

Helios 522, do you read?

Over.

Flight HCY522, this is radar control.

Suddenly the 737 turns left

Suddenly the 737 turns left

and begins to quickly descend.

Athiniai ACC, Helios 522 turning sharply.

Athiniai ACC, Helios 522 turning sharply.

Following down.

The aircraft is dropping

from more than 32,000 feet.

from more than 32,000 feet.

HCY522, this is Athinai Radar Control.

Just after 12 o'clock...

Just after 12 o'clock...

...Flight 522 slams into the ground just north of Athens.

Helios 522 is down on Grammatiko Hill.

Helios 522 is down on Grammatiko Hill.

Over.

It's an eerie disaster.

For over an hour, air traffic controllers

For over an hour, air traffic controllers

watched the passenger jet fly in radio silence, closer

and closer to Athens, with no idea what

and closer to Athens, with no idea what

was happening inside the jet.

Investigators and first responders

rushed to the burning crash site.

There we were, facing the situation which

There we were, facing the situation which

was beyond any description.

It was black, burning, people spread, pieces of...

It was black, burning, people spread, pieces of...

of the airplane.

There are no survivors.

There are no survivors.

It's the worst air crash in Greek history.

In the Helios event, there was really

nothing they could do from the ground to help the aircraft.

nothing they could do from the ground to help the aircraft.

There wasn't any warning.

There wasn't any idea from air traffic control

that there was sort of any issue until there was no contact.

that there was sort of any issue until there was no contact.

Chief Investigator Tsolakis and his team

get to work immediately, combing through what

get to work immediately, combing through what

remains of the passenger jet.

Recovered bodies start to arrive at the morgue in Athens.

It is a truly nightmarish sight.

I hope that I never experience it again.

I hope that I never experience it again.

It was terrible, just terrible.

When investigators find tissue samples

in the remains of the cockpit, they make a stunning discovery.

in the remains of the cockpit, they make a stunning discovery.

The person at the controls of the plane when it crashed

The person at the controls of the plane when it crashed

was flight attendant Andreas Prodromou.

But why was he in the cockpit?

But why was he in the cockpit?

Was he trying to save the plane or did he deliberately

fly it into the ground?

fly it into the ground?

Investigators have recovered

the cockpit voice recorder from Helios Flight 522.

the cockpit voice recorder from Helios Flight 522.

When Chief Investigator Tsolakis listens

to the final moments of the flight,

to the final moments of the flight,

it answers a vital question.

Mayday.

Mayday.

Mayday.

Mayday.

This was no terrorist act.

Helios Airways Flight 522.

Flight attendant Prodromou was calling for help.

Flight attendant Prodromou was calling for help.

Tsolakis hears five separate maydays on the tape,

but they were never heard by air traffic controllers.

but they were never heard by air traffic controllers.

Investigators suspect the radio was still tuned to Cyprus,

Investigators suspect the radio was still tuned to Cyprus,

their departure point.

He wasn't a coward.

He wasn't a coward.

He knew something about planes, and he had

He knew something about planes, and he had

the capacity to do something.

Sure is a beautiful day.

In fact, Prodromou had his commercial pilot's license.

In fact, Prodromou had his commercial pilot's license.

But all of his training wouldn't have saved the jet.

But all of his training wouldn't have saved the jet.

When the team reviews the flight data recorder,

they discover that the Helios plane sharply descended

they discover that the Helios plane sharply descended

because it was out of fuel.

The FDR and CVR gave us absolute proof

The FDR and CVR gave us absolute proof

that the plane ran out of fuel.

that the plane ran out of fuel.

And this was the cause of the crash.

But one mystery still remains.

But one mystery still remains.

Why was Prodromou flying the aircraft?

What happened to the flight crew?

What happened to the flight crew?

Back at the crash site, investigators

Back at the crash site, investigators

catch a break when a key control panel is recovered.

The panel, which is responsible for pressurization,

The panel, which is responsible for pressurization,

is set in an unusual position.

Are you sure this is the way it was found?

Are you sure this is the way it was found?

It hasn't been moved at all?

We were lucky finding this funnel, which had the switch

We were lucky finding this funnel, which had the switch

on the manual position.

It was a major one.

It was a major one.

Normally, pressurization

happens automatically.

But when the switch is set to manual,

But when the switch is set to manual,

the flight crew is responsible for controlling

the cabin pressure.

But why would the crew set the system to manual?

But why would the crew set the system to manual?

When Tsolakis interviews the Helios engineer,

When Tsolakis interviews the Helios engineer,

he learns the accident aircraft had a history

of pressurization problems.

of pressurization problems.

Coincidentally, on the day of the fatal flight,

engineers inspected the aircraft for air leaks

engineers inspected the aircraft for air leaks

that could cause depressurization.

Switching digital pressure control unit from auto

Switching digital pressure control unit from auto

to manual.

Using the aircraft's power systems,

the engineer pressurized the cabin for several minutes

the engineer pressurized the cabin for several minutes

while another engineer checked for leaks.

But there was no sign of any air escaping.

But there was no sign of any air escaping.

There was a push to return the selector to the auto position.

There was a push to return the selector to the auto position.

But at the end of the test,

the engineer left the switch in the manual position.

the engineer left the switch in the manual position.

It is bright today.

Are you almost through?

Nearly.

Nearly.

Investigators theorize neither the pilot

or first officer noticed the manual setting

or first officer noticed the manual setting

during pre-flight preparations.

Pressurization mode selector.

As a result the cabin would not

As a result the cabin would not

have pressurized properly, causing the incapacitation

of everyone on board.

of everyone on board.

To prove their theory, they perform

To prove their theory, they perform

a test flight using the same conditions

as the Helios flight.

as the Helios flight.

Make sure the P5 is set to manual.

Tsolakis has the crew turn the pressurization switch

Tsolakis has the crew turn the pressurization switch

to manual.

It's hard to see.

As the test flight climbs,

oxygen thins quickly in the aircraft.

oxygen thins quickly in the aircraft.

The same thing happened on the Helios flight,

triggering an alarm.

What is it?

The takeoff config warning?

But when the alarm goes off on the test flight,

Tsolakis makes a shocking discovery.

Tsolakis makes a shocking discovery.

It's not the takeoff configuration

alarm that sounds, but rather the depressurization alarm.

alarm that sounds, but rather the depressurization alarm.

The two alarms sound virtually identical.

OK.

Take it down.

Take it down.

The alarm sounded, and that alarm

was misinterpreted.

Most of the flight crew, they will never

Most of the flight crew, they will never

face an alarm with no pressurization

face an alarm with no pressurization

because it's a rare event.

Even if the flight crew did misinterpret

Even if the flight crew did misinterpret

the first alarm, Tsolakis learns they

had another chance to determine what the problem was.

had another chance to determine what the problem was.

When he revisits the cockpit recording,

Tsolakis hears the plane's Master Caution alarm

Tsolakis hears the plane's Master Caution alarm

sounding for almost a minute.

We now have a Master Caution.

We now have a Master Caution.

The Master Caution alarm

can indicate that the plane's systems are overheating.

can indicate that the plane's systems are overheating.

But it can also tell pilots the oxygen masks are down.

But it can also tell pilots the oxygen masks are down.

The lack of oxygen probably caused the pilots

to confuse the alarms.

Instead of pressurization, they thought

Instead of pressurization, they thought

the plane was overheating and needed to be cooled.

Where are my equipment cooling circuit breakers?

Where are my equipment cooling circuit breakers?

Behind the captain's seat.

They began to lose the ability to think coherently.

They began to lose the ability to think coherently.

Investigators believe the captain may have been

checking on the circuit breakers behind his seat

when he and the first officer ran out of air.

The autopilot system maintained the flight path to Athens,

and then put the plane in a holding pattern

and then put the plane in a holding pattern

as it flew over the airport.

In the cabin, as the emergency oxygen supply runs out,

In the cabin, as the emergency oxygen supply runs out,

everyone takes their last breaths.

Well, the problem with the passenger masks is

Well, the problem with the passenger masks is

they're designed to give you enough oxygen so that you can

survive until you can... the pilots get the airplane

survive until you can... the pilots get the airplane

down to a low altitude.

Passenger masks are supplied

by a chemical generator above their seats.

by a chemical generator above their seats.

But the generators only produce enough oxygen

to last about 12 minutes.

to last about 12 minutes.

Most of the people,

once the hypoxia begins to cause them to lose consciousness,

once the hypoxia begins to cause them to lose consciousness,

they're just gonna go to sleep.

Mayday.

So how did Andreas Prodromou remain conscious?

Helios Airways Flight 5...

Helios Airways Flight 5...

When investigators interview Helios

instructors and crew, they begin to understand

instructors and crew, they begin to understand

what may have happened.

After the passenger oxygen system stopped working,

Prodromou most likely used some of the 737's portable oxygen

Prodromou most likely used some of the 737's portable oxygen

to survive.

to survive.

Probably was a little bit disoriented.

He's reacting a lot slower than he normally would.

He's reacting a lot slower than he normally would.

Mayday.

The young flight attendant calls for help,

The young flight attendant calls for help,

but no one could hear him.

And there was nothing he could have done.

The official report shows that a fatal combination

The official report shows that a fatal combination

of small mechanical problems and human error

led to the worst air disaster in Greek history.

led to the worst air disaster in Greek history.

It was the flipping of one switch

that was the difference between life and death.

that was the difference between life and death.

And what came out of this investigation

was basically a re-emphasis to flight crews.

was basically a re-emphasis to flight crews.

You have to do checklists.

You have to have that checklist discipline.

You have to have that checklist discipline.

But not all cases of radio silence

unfold over many hours.

Sometimes they happen in the blink of an eye.

Sometimes they happen in the blink of an eye.

The third waypoint, change to low.

The third waypoint, change to low.

Dynasty 611, Taipei.

Dynasty 611, Taipei.

Dynasty 611, Taipei.

China Airlines Flight 611 lifts off

China Airlines Flight 611 lifts off

from Taiwan's capital, Taipei.

Gear is up.

Dynasty 611, airborne passing 1,600.

Dynasty 611, airborne passing 1,600.

Dynasty 611, Taipei, approach radar.

Contact climb and maintain flight level 260.

Contact climb and maintain flight level 260.

260, Dynasty 611.

260, Dynasty 611.

Autopilot B engaged.

There are 225 people on board the Boeing 747.

There are 225 people on board the Boeing 747.

FLIGHT ATTENDANT (ON INTERCOM): Ladies

and gentlemen, the Fasten Seatbelt

and gentlemen, the Fasten Seatbelt

sign has been turned off.

For your safety, we do recommend that you

keep your seatbelt fastened at all times while seated.

keep your seatbelt fastened at all times while seated.

Flight 611 is an hour and 40 minute trip across

the Taiwan Strait to Hong Kong.

the Taiwan Strait to Hong Kong.

The aircraft continues to climb steadily

to its cruising altitude.

But then, 20 minutes after taking off,

at an altitude of almost 35,000 feet...

at an altitude of almost 35,000 feet...

The third waypoint, change to low.

The third waypoint, change to low.

...the flight vanishes from radar.

Dynasty 611, Taipei.

Dynasty 611, Taipei.

Air traffic control gets no response.

Air traffic control gets no response.

I've got a plane off radar, China Airlines 611.

Its last known return was East 119.67, North 23.98.

Its last known return was East 119.67, North 23.98.

Its last known return was East 119.67, North 23.98.

Taiwanese authorities quickly

Taiwanese authorities quickly

launched one of the largest rescue missions in

the country's aviation history.

the country's aviation history.

Flight 611 was 34 miles from the Taiwanese shore,

just north of the Penghu Islands when it disappeared.

just north of the Penghu Islands when it disappeared.

Within hours, rescuers find debris

floating in the Taiwan Strait.

floating in the Taiwan Strait.

There are no survivors.

Airplanes don't fall out of the sky.

Airplanes don't fall out of the sky.

We have had so many aircraft accidents

over the past 50 years that have ended up in water.

over the past 50 years that have ended up in water.

It's always a challenge.

Because the first thing is to find the wreckage.

The second thing is to pull enough of it

The second thing is to pull enough of it

up to be useful to the accident investigation.

Taiwan's Aviation Safety Council, or ASC,

Taiwan's Aviation Safety Council, or ASC,

begins its investigation into the mysterious crash

of the 747.

of the 747.

August 2, 1979.

Kay Yong is the managing director of the AFC.

Kay Yong is the managing director of the AFC.

He'll be leading the investigation.

We're setting up a command post in Penghu Island.

We're setting up a command post in Penghu Island.

This particular investigation was,

by far, the most difficult one.

by far, the most difficult one.

And one of the reasons why was it's... it's in the ocean floor.

And one of the reasons why was it's... it's in the ocean floor.

While recovery teams gather the floating wreckage...

Good morning.

I'm anxious to see what you have.

I'm anxious to see what you have.

...Kay Yong reviews the radar

recording of the doomed flight.

Minutes into the recording, he makes a critical discovery.

Shortly after reaching 35,000 feet,

Shortly after reaching 35,000 feet,

Flight 611's signal suddenly splits apart.

Flight 611's signal suddenly splits apart.

The breakup is quite graphic.

There were four sizable pieces of wreckage that were getting

There were four sizable pieces of wreckage that were getting

radar returns that then began to drift and scatter

radar returns that then began to drift and scatter

as they fell to the Earth.

So that told us that the airplane broke up in flight.

So that told us that the airplane broke up in flight.

But why would one of the world's

most dependable passenger kept calm apart in midair?

most dependable passenger kept calm apart in midair?

Since the accident involved an American-made plane,

a team from the National Transportation Safety Board

a team from the National Transportation Safety Board

is dispatched to Taiwan.

Good morning.

Good morning.

I'm Clint Crookshanks from the NTSB.

Hello.

Three weeks after the crash, the Jan

Three weeks after the crash, the Jan

Steen, a sophisticated salvage vessel,

arrives in the Taiwan Strait.

arrives in the Taiwan Strait.

Using the vessel's sonar technology,

investigators locate the remaining wreckage

of Flight 611 deep under water.

of Flight 611 deep under water.

It was really quite a shock when I first saw pieces

on the floor of the ocean.

on the floor of the ocean.

Remarkably, 25 days after the crash of Flight 611,

Remarkably, 25 days after the crash of Flight 611,

the plane's two black boxes are found.

Investigators hope the data will help explain why

Investigators hope the data will help explain why

the 747 exploded in mid-air.

They begin with the plane's cockpit voice recorder.

Clear for takeoff, Dynasty 611.

Clear for takeoff, Dynasty 611.

CO-PILOT (ON RECORDING): Takeoff.

80.

CO-PILOT (ON RECORDING): Check.

CO-PILOT (ON RECORDING): Check.

Gear 1.

Rotate.

In the moments before the disaster,

In the moments before the disaster,

nothing seems wrong.

Now descend and maintain 250.

Now descend and maintain 250.

The captain calls out the distance

to their cruising altitude.

2,000.

2,000.

That's followed by the sound of a chime...

...alerting the crew that they are nearing 35,000 feet.

...alerting the crew that they are nearing 35,000 feet.

But then...

...the recording stops.

The recorders told us that something happened,

The recorders told us that something happened,

but we didn't have the real piece

of evidence that told us what initiated

the breakup of the 747.

the breakup of the 747.

The flight recorders are a dead end.

The fate of the investigation lies in what can be uncovered

The fate of the investigation lies in what can be uncovered

in the wreckage of Flight 611.

in the wreckage of Flight 611.

I've been reading about the trajectory analysis.

I'd like to try it.

Computerized ballistic trajectory analysis

Computerized ballistic trajectory analysis

is based on a simple fact.

The pieces that came off the plane first

The pieces that came off the plane first

are the first to hit the water.

If investigators can figure out which pieces those were,

If investigators can figure out which pieces those were,

they'll know where the trouble began.

327.

327.

Kay Yong selects 18 pieces of wreckage

from all over the plane for the computer analysis.

from all over the plane for the computer analysis.

199.

Can we see when each one of those items

separated from the aircraft?

separated from the aircraft?

His team uses GPS coordinates of the wreckage,

His team uses GPS coordinates of the wreckage,

as well as precise details in ocean currents and wind speed,

to calculate which pieces were the first to come off

to calculate which pieces were the first to come off

the plane.

The tail came off first.

The tail came off first.

It's a huge discovery for investigators.

It's a huge discovery for investigators.

That pretty much indicating that something happened

in the back of the aircraft.

in the back of the aircraft.

Now the team needs to track down

pieces from the tail section.

But wreckage is still being recovered from the ocean floor.

But wreckage is still being recovered from the ocean floor.

Will they be able to find the source of the breakup that led

Will they be able to find the source of the breakup that led

to the deaths of 225 people?

While searching through newly

recovered wreckage from China Airlines Flight 611,

NTSB investigator Frank Zakar spots something unusual.

NTSB investigator Frank Zakar spots something unusual.

When I walked up to item 640, I

When I walked up to item 640, I

noticed that there were some peculiar areas of interest

that I wanted to look at a little bit further.

that I wanted to look at a little bit further.

Zakar needs to get a closer

look at the mysterious piece.

look at the mysterious piece.

It's from the back of the plane, precisely where the analysis

told them the breakup began.

told them the breakup began.

Let's get as many pictures as we can, especially the edges

Let's get as many pictures as we can, especially the edges

there and there.

But then the team notices a concerning detail.

But then the team notices a concerning detail.

The wreckage has a metal patch on it called a doubler plate.

The wreckage has a metal patch on it called a doubler plate.

If there were to be a tear or a crack identified,

If there were to be a tear or a crack identified,

you'd want to repair the fuselage

back to its original strength.

And one way to do that is to put a doubler plate right

And one way to do that is to put a doubler plate right

over the existing structure.

At some point this section of the 747

At some point this section of the 747

had been repaired.

Investigators need to know why and how it was done.

Investigators need to know why and how it was done.

Let's cut it from here to here,

Let's cut it from here to here,

and send this piece to Zhongshan.

A large piece of the wreckage

A large piece of the wreckage

is sent to a military research center for expert analysis.

is sent to a military research center for expert analysis.

When the repair patch is removed,

damage on the aluminum skin underneath

intrigues investigators.

intrigues investigators.

We noticed that there were some fairly long gouge marks.

This is beyond the kind of damage

This is beyond the kind of damage

a doubler is meant to patch.

That was an a-ha moment that we might have something here.

That was an a-ha moment that we might have something here.

Investigators wonder what

caused the gouges on the aircraft's aluminum exterior.

caused the gouges on the aircraft's aluminum exterior.

When they search the plane's extensive maintenance records,

they uncover a very short reference

they uncover a very short reference

to a mishap 22 years earlier.

Beat is low, sir.

Watch it.

Tail strike, sir.

I better log that.

I better log that.

The tail section of the 747

scraped the runway on landing.

But when investigators search for details on how

China Airlines repaired the plane,

China Airlines repaired the plane,

they make a shocking discovery.

The maintenance records indicated

The maintenance records indicated

that the permanent repair was done in accordance

with Boeing recommendations.

Evidence that we uncovered indicate

Evidence that we uncovered indicate

that the repair was not done per the Boeing repairman.

According to the manual,

According to the manual,

the entire damaged area should have been cut out and replaced.

But the repair was never done.

But the repair was never done.

Workers simply attached a doubler

plate over the damaged area.

plate over the damaged area.

What was so insidious

about this improper repair was that the doubler

plate hid all of the damage.

plate hid all of the damage.

Workers recorded the repair was completed,

making their mistake impossible to detect.

making their mistake impossible to detect.

So if you weren't there watching

them do this repair improperly, you wouldn't know

them do this repair improperly, you wouldn't know

that it was done improperly.

Every time the plane took off

Every time the plane took off

over the next 22 years, the cracks in the plane's skin

grew and spread.

grew and spread.

It just spread like a spiderweb.

It went in all directions, and it probably looped all the way

It went in all directions, and it probably looped all the way

around the fuselage to the point where the entire aft section

of the airplane just broke off from the rest of the structure.

of the airplane just broke off from the rest of the structure.

Investigators recommend

that aviation agencies around the world

that aviation agencies around the world

immediately inspect repairs that were

patched using doubler plates.

patched using doubler plates.

We were requiring operators to take doubler

plates off and do a visual inspection

plates off and do a visual inspection

of the structure underneath.

The NTSB issues its own recommendation,

The NTSB issues its own recommendation,

that mechanics be warned of hiding damage that could lead

to the failure of an airplane.

to the failure of an airplane.

The airline literally had 22

years or so to get this right.

So this is a wake up call.

So this is a wake up call.

Any airline that has this kind of issue

has to be keenly aware that the responsibility never goes away.

has to be keenly aware that the responsibility never goes away.

And when a private jet with a celebrity passenger

falls into radio silence over Florida...

This is Jacksonville Center.

This is Jacksonville Center.

I'm declaring an emergency.

...fighter Jets scramble to find out why.

...fighter Jets scramble to find out why.

We don't know where this aircraft is gonna go,

but it's starting to move.

It's 8:30 AM at Orlando International Airport.

It's 8:30 AM at Orlando International Airport.

The crew of a private Learjet is preparing for today's flight.

Nav light?

Nav light?

On.

Radios.

Are set.

Morning.

American pro golfer Payne Stewart is on his way

to Dallas with some close business associates.

to Dallas with some close business associates.

Known for his flamboyant attire and remarkable swing,

Known for his flamboyant attire and remarkable swing,

Stewart is one of the most popular golfers on the tour.

He's just won the US Open, his third major championship win.

He's just won the US Open, his third major championship win.

Stewart flies regularly on a Learjet,

Stewart flies regularly on a Learjet,

a luxury aircraft that was modeled

after a Swiss military plane.

after a Swiss military plane.

47 Bravo Alpha, you are cleared for takeoff.

You ready?

You ready?

OK.

Here we go.

And take off thrust.

Captain Michael Kling is a former Air Force

pilot and flight instructor.

pilot and flight instructor.

Gear 1.

First Officer Stephanie

Bellegarrigue has less than 100 hours in the Lear.

Bellegarrigue has less than 100 hours in the Lear.

She's keen to log more flight time.

Rotate.

Rotate.

At 9:19 AM, the Learjet lifts off.

Good morning, Jacksonville.

This is Learjet 47 Bravo Alpha climbing to flight level 260.

This is Learjet 47 Bravo Alpha climbing to flight level 260.

Good morning, 47 Bravo Alpha.

Climb and maintain flight level 390.

Climb and maintain flight level 390.

The controller clears the jet to keep

climbing up to 39,000 feet.

climbing up to 39,000 feet.

The flight plan calls for the airplane

to fly northwest towards Cross City, Florida, then turn west

to fly northwest towards Cross City, Florida, then turn west

and fly direct to Dallas.

The Learjet has traveled 80 miles.

It's time to pass control of the plane

It's time to pass control of the plane

over to a new air traffic controller.

47 Bravo Alpha, contact Jack Center at 135 decimal 65.

47 Bravo Alpha, contact Jack Center at 135 decimal 65.

The controller gives the crew the new frequency.

The controller gives the crew the new frequency.

Air traffic control is a series

of what we call handoffs.

And that means that it's time for him to cross

And that means that it's time for him to cross

to somebody else's sector.

47 Bravo Alpha, please acknowledge.

I didn't get an acknowledgment for that frequency change.

So you give her a moment.

So you give her a moment.

47 Bravo Alpha, contact Jack Center on 135 decimal 65.

47 Bravo Alpha, contact Jack Center on 135 decimal 65.

There's only radio silence from the Learjet.

There's only radio silence from the Learjet.

What's up?

Is that Learjet.

It's not answering.

Maybe he's off frequency.

Maybe he's off frequency.

Let's see if it levels off when it's supposed to.

Let's see if it levels off when it's supposed to.

But when the aircraft reaches its cruising altitude

of 39,000 feet...

of 39,000 feet...

They're still climbing.

Let me see their flight plan.

Let me see their flight plan.

They've got a turn coming at Cross City.

Let's hope they make that turn.

Let's hope they make that turn.

The tension level was so high you could hear a pin drop.

Damn it.

Damn it.

It's not making the course correction.

There was something terribly wrong.

There was something terribly wrong.

This is Jacksonville Center.

This is Jacksonville Center.

I'm declaring an emergency.

Benzon here.

Benzon here.

Experts at the National

Transportation Safety Board are notified

of the escalating emergency.

of the escalating emergency.

Once the aircraft had gone rogue, so to speak,

the next step is to try to figure out why.

the next step is to try to figure out why.

To track down the wayward Learjet,

To track down the wayward Learjet,

controllers call in F-16 fighters,

including pilot Kent Olsen.

including pilot Kent Olsen.

Is the crew incapacitated?

Is there something wrong with the aircraft?

There's some reason why that crew is not communicating

There's some reason why that crew is not communicating

with air traffic control.

So our job is to go up and find out why.

Meanwhile, the NTSB recruits Learjet investigator

Meanwhile, the NTSB recruits Learjet investigator

Jim Tidball to the team.

Where is it right now?

Where is it right now?

His first task is to determine

how far the plane can get with the amount of fuel on board.

how far the plane can get with the amount of fuel on board.

When the airplane didn't make its turn,

it continued on towards Memphis.

it continued on towards Memphis.

And after Memphis it was headed towards Saint Louis.

If it went down in those areas there'd be mass casualties.

If it went down in those areas there'd be mass casualties.

If it doesn't change course soon,

If it doesn't change course soon,

the fighter Jets may be forced to take drastic measures.

ATC kept giving the team real time data

ATC kept giving the team real time data

as to where the airplane was.

And calculating the fuel burn at those altitudes,

And calculating the fuel burn at those altitudes,

we could figure how far it was going to go.

My best guess is South Dakota, possibly North Dakota.

My best guess is South Dakota, possibly North Dakota.

In the air, the F-16 pilots

catch up with the rogue plane.

Can he see anything in the cockpit?

The windows of the aircraft

provide an ominous clue.

No movement, and the window

No movement, and the window

is covered in frost.

If the people are conscious,

they'd be trying to scrape away that condensation

they'd be trying to scrape away that condensation

so they could see.

So if you see no attempt to get rid of that condensation,

then your mind goes, what's the condition

then your mind goes, what's the condition

of the crew and the passengers that are on board the aircraft.

The frosted over windscreen and the darkened cockpit

The frosted over windscreen and the darkened cockpit

and cabin indicated that the crew

was probably no longer with us.

was probably no longer with us.

After nearly four hours in the air,

After nearly four hours in the air,

the Learjet approaches Aberdeen, South Dakota.

According to calculations, the jet is almost out of fuel.

They're going down.

They're going down.

They're going down.

The plane is spiraling toward the ground.

Investigators have no idea where it will crash.

Investigators have no idea where it will crash.

All they can do is wait.

They're going down.

They're going down.

A Learjet carrying pro golfer

Payne Stewart and five other people

Payne Stewart and five other people

is falling from the sky over South Dakota.

Center, I've got a crash site.

The jet has slammed into a hayfield

near Aberdeen, South Dakota.

near Aberdeen, South Dakota.

There are no survivors.

When NTSB investigators arrive at the crash site,

they discover the aircraft has completely disintegrated.

they discover the aircraft has completely disintegrated.

When you've had a vertical impact at high speed

and everything is compressed and in pieces,

and everything is compressed and in pieces,

you've got to dig all that out.

You've got to identify what's where.

You've got nothing but shards and scraps.

You've got nothing but shards and scraps.

Remarkably, the Learjet's

only black box, the cockpit voice recorder, is recovered.

only black box, the cockpit voice recorder, is recovered.

I only hope we hear something that tells us what went wrong.

I only hope we hear something that tells us what went wrong.

It was sent back immediately to the NTSB lab.

It was sent back immediately to the NTSB lab.

And they did a fantastic job of piecing this thing together and

getting data out of the CVR.

getting data out of the CVR.

OK.

Let's hear it.

As they listen, investigators

As they listen, investigators

make a disturbing discovery.

It was eerie.

It was eerie.

Because the airplane is flying, and there

is no voice whatsoever.

But one sound provides a vital clue.

That's the cabin altitude warning.

We are definitely looking at a loss of pressure accident.

The cabin altitude alarm sounds when

The cabin altitude alarm sounds when

the aircraft's cabin hasn't been properly pressurized, meaning

the aircraft's cabin hasn't been properly pressurized, meaning

the passengers and crew aren't receiving enough oxygen.

The mystery now is why did the Learjet

The mystery now is why did the Learjet

lose vital cabin pressure.

Unfortunately, investigators have

limited evidence to work with.

limited evidence to work with.

The disintegrated wreckage is a dead end,

and the Learjet is not equipped with a flight data recorder.

and the Learjet is not equipped with a flight data recorder.

Because of the chaotic nature

of airplane accidents, you don't have a lot of clues sometimes.

of airplane accidents, you don't have a lot of clues sometimes.

But that doesn't mean that we stop investigating.

Set us to climb, please.

The team hopes a flight simulation will

The team hopes a flight simulation will

help determine what happened on board

after the cabin lost pressure.

after the cabin lost pressure.

There goes the cabin altitude warning.

Start the clock.

Emergency checklist.

Emergency checklist.

Got it?

I think all of us

sort of had in our heads the checklist

we'll have once you hear the altitude warning horn.

we'll have once you hear the altitude warning horn.

That you're going to put your oxygen mask on

is the first and immediate action item.

is the first and immediate action item.

Benzon scans the same emergency checklist that

was used by the Learjet pilots.

was used by the Learjet pilots.

At 10,000 plus or minus 500 feet,

cabin altitude control pressure to the outflow valve

is trapped.

is trapped.

It leads him to an astonishing discovery.

We were surprised.

Because it implied pretty strongly

Because it implied pretty strongly

that you need to troubleshoot a pressurization problem.

First step should have been don oxygen masks.

First step should have been don oxygen masks.

The oxygen mask instruction

is much further down the list.

is much further down the list.

You've got maybe four or five seconds worth of actual oxygen

You've got maybe four or five seconds worth of actual oxygen

in your brain, and then another 12 to 15 seconds

in your circulation.

Once all that is gone, things are

Once all that is gone, things are

going to go very horribly awry for you very, very quickly.

Investigators finally have

a theory about what may have happened on board the Learjet.

a theory about what may have happened on board the Learjet.

Everything is fine, then something causes

the plane to lose pressure.

the plane to lose pressure.

We've got a cabin altitude warning.

Emergency checklist.

Emergency checklist.

Uh...

They reach for their checklist and start to troubleshoot.

They reach for their checklist and start to troubleshoot.

What does the checklist say?

At 10,000 plus or minus 500 feet,

At 10,000 plus or minus 500 feet,

cabin altitude control pressure to the outflow valve

is trapped.

They picked up a checklist, read it, were confused by it,

They picked up a checklist, read it, were confused by it,

and the oxygen mask were sitting there unused.

After 15 seconds without oxygen,

the crew would be confused and disoriented.

the crew would be confused and disoriented.

Uh, read that again.

Before they can solve the problem,

Before they can solve the problem,

the crew loses consciousness.

The Lear checklist, in a sense,

The Lear checklist, in a sense,

could lead a crew astray.

Without those masks on, they wouldn't stand a chance.

Investigators are never

able to determine conclusively what caused

the plane to lose pressure.

The decompression could have been caused

by a leaky seal on a door, a small leak about the size

by a leaky seal on a door, a small leak about the size

of a pencil in the side of the aircraft,

a malfunction within the system.

a malfunction within the system.

So we don't know.

But whatever the reason,

the crew would likely have recovered

the crew would likely have recovered

if they had put their masks on.

The NTSB, in its report, ultimately concluded that had

The NTSB, in its report, ultimately concluded that had

they received oxygen in a timely manner it's likely

that we would not be talking about this particular accident

that we would not be talking about this particular accident

today.

We've got a cabin altitude warning.

Emergency checklist.

Emergency checklist.

Following the investigation,

the NTSB recommends important changes to aviation checklists.

the NTSB recommends important changes to aviation checklists.

We asked very strongly that that checklist that we

suspected got the crew in trouble

suspected got the crew in trouble

be changed to make it clearer and more

useful in an emergency.

useful in an emergency.

The Federal Aviation Administration

is quick to respond.

Don oxygen masks is now the first item on the checklist,

Don oxygen masks is now the first item on the checklist,

not just for Learjets, but for every similar plane in the sky.

not just for Learjets, but for every similar plane in the sky.

When we look at the accidents involving

no radio communication, there's a lot of questions to be asked.

no radio communication, there's a lot of questions to be asked.

Radio silence between pilots and air traffic controllers

can mean many different things.

can mean many different things.

But only the physical evidence can tell the real story.