Original subtitles

639 pieces of wreckage are recovered from the sea,

639 pieces of wreckage are recovered from the sea,

639 pieces that only deepen the mystery

639 pieces that only deepen the mystery

of a deadly plane crash.

All right.

A little bit more to the right.

There.

But when investigators bring up

But when investigators bring up

the 640th piece of China Airlines Flight 611,

they get their answer.

they get their answer.

There was definitely a eureka moment on the dock.

It would be scrutinized more closely

It would be scrutinized more closely

than any other piece of debris.

On this single piece of wreckage,

investigators would find the one clue that would tell them why

investigators would find the one clue that would tell them why

a modern jetliner with 225 people on board

a modern jetliner with 225 people on board

shattered in mid-air.

Ladies and gentlemen, we are starting our approach.

We lost both engines.

Be advised, there will be an emergency descent.

Mayday, mayday.

Mayday, mayday.

Wait, what is that?

It's a plane.

30 feet.

Speed is low, sir.

Watch it.

Did you feel that?

TRAFFIC CONTROLLER 1 Traffic

control, descend and maintain echo foxtrot

control, descend and maintain echo foxtrot

126 In the air, 608.

126 In the air, 608.

May 25, 2002.

May 25, 2002.

Gears up.

A China Airlines 747 lifts off

A China Airlines 747 lifts off

from Taiwan's capital, Taipei.

IP approach dynasty 611, airborne passing 1,600.

IP approach dynasty 611, airborne passing 1,600.

TRAFFIC CONTROLLER 2 Dynasty 611,

Taipei approach radar.

Contact climb and maintain flight level 260.

Contact climb and maintain flight level 260.

260.

Dynasty 611.

Dynasty 611.

Autopilot be engaged.

China Airlines is Taiwan's national airline.

There are 225 people on board Flight 611.

There are 225 people on board Flight 611.

Today's flight is a short one, one hour

Today's flight is a short one, one hour

and 40 minutes across Taiwan Strait to Hong Kong.

This route is one of the most widely traveled on the planet.

It makes so much money, it's called the golden route.

It makes so much money, it's called the golden route.

Ladies and gentlemen, the fasten seatbelt sign

has been turned off.

has been turned off.

For your safety, we do recommend that you

keep your seatbelt fastened at all times while seated.

Minutes after taking off,

Flight 611 climbs steadily above the Taiwan Strait.

Flight 611 climbs steadily above the Taiwan Strait.

The plane's autopilot controls the ascent.

The third waypoint changed.

TRAFFIC CONTROLLER 1 (ON RADIO): Unit air 608.

TRAFFIC CONTROLLER 1 (ON RADIO): Unit air 608.

And then, 20 minutes after taking off,

And then, 20 minutes after taking off,

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

...at Taipei area control, the flight vanishes from radar.

...at Taipei area control, the flight vanishes from radar.

TRAFFIC CONTROLLER 1 (ON RADIO): Dynasty 611 Taipei.

TRAFFIC CONTROLLER 1 (ON RADIO): Dynasty 611 Taipei.

Dynasty 611 Taipei.

I've got a plane off radar.

China Airlines 611.

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 launch

one of the largest rescue missions in that country's

aviation history.

aviation history.

I gave a clear order that the priority would

I gave a clear order that the priority would

be searching for whoever was still alive, then bodies,

and then, only then, wreckage.

and then, only then, wreckage.

More than 1,000 people take part.

Fishing boats, the Coast Guard, and Taiwan's military race

Fishing boats, the Coast Guard, and Taiwan's military race

out to sea.

Flight 611 was 34 miles from the Taiwanese shore,

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.

Rescuers find debris floating in the Taiwan Strait.

Rescuers find debris floating in the Taiwan Strait.

The first thing we saw

The first thing we saw

was a great amount of wreckage, including landing gear wheels,

napkins, knives, and forks.

napkins, knives, and forks.

Wreckage from the plane is spread far and wide.

Wreckage from the plane is spread far and wide.

Some items are found on land more than 62

miles away in central Taiwan.

miles away in central Taiwan.

As the rescue effort continues, Taiwan's Aviation Safety

As the rescue effort continues, Taiwan's Aviation Safety

Council begins its investigation into the crash

of the 22-year-old plane.

of the 22-year-old plane.

747 200 delivered August 2, 1979.

Kay Yong is the managing director of the ASC.

Kay Yong is the managing director of the ASC.

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.

Let's go.

China Airlines have had very, very poor safety record.

China Airlines have had very, very poor safety record.

As a matter of fact, it was considered

one of the worst in the world.

one of the worst in the world.

Typically, it had like one major accident every four years.

Typically, it had like one major accident every four years.

This particular investigation was

This particular investigation was

by far the most difficult one.

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

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

The search for survivors

goes on around the clock.

goes on around the clock.

There were 225 people on the airplane.

No one is found alive.

No one is found alive.

The bodies are taken to the Penghu Islands

The bodies are taken to the Penghu Islands

to be identified and examined.

Since the accident involved an American-made plane,

Since the accident involved an American-made plane,

the NTSB joins the investigation.

A team of investigators is dispatched to Taiwan.

A team of investigators is dispatched to Taiwan.

They'll be led by John DeLisi in Washington.

We have a very good working relationship with the ASC,

We have a very good working relationship with the ASC,

the Aviation Safety Council of Taiwan,

the Aviation Safety Council of Taiwan,

so we knew that they would ask for and welcome our assistance

in the investigation.

in the investigation.

Wreckage that's found floating is also

brought to the Penghu Islands.

Investigators need to know how one of the world's most

Investigators need to know how one of the world's most

successful planes on one of the world's most traveled routes

simply fell out of the sky.

simply fell out of the sky.

Well, the Boeing 747 is the world's

most popular jumbo jet.

And it's flown millions of people

And it's flown millions of people

probably billions of miles so we were very concerned.

probably billions of miles so we were very concerned.

Good morning.

I'm anxious to see what you have.

Sophisticated, ground-based radar

tracked flight 611 throughout its short journey.

tracked flight 611 throughout its short journey.

It should provide investigators with a much

clearer picture of the flight than the radar at air

clearer picture of the flight than the radar at air

traffic control.

Kay Yong gets the first major clue in this case.

Kay Yong gets the first major clue in this case.

The radar tracked the plane as it climbed

on course to 35,000 feet.

Then, suddenly, flight 611's signal split apart.

Then, suddenly, flight 611's signal split apart.

The breakup is quite graphic.

The breakup is quite graphic.

Right when the event happened, it

appeared as if there were three or four sizable pieces

appeared as if there were three or four sizable pieces

of wreckage that were getting radar

returns that then began to drift and scatter

as they fell to the earth.

as they fell to the earth.

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

Investigators now must turn their attention to finding

out what caused that break up.

out what caused that break up.

There's all kinds of theories about what

seems to be happening of that particular aircraft.

seems to be happening of that particular aircraft.

It doesn't take long for the media

to consider a sinister possibility,

to consider a sinister possibility,

that flight 611 was shot down.

China and Taiwan have a combative relationship.

China has fired missiles toward Taiwan in the past.

China has fired missiles toward Taiwan in the past.

There's suspicion in the media that China

There's suspicion in the media that China

shot down Flight 611.

There were a lot of theories about,

you know, it was shooting down by enemy fire.

you know, it was shooting down by enemy fire.

On the day of the China Airlines crash,

China was conducting military exercises in the Taiwan Strait.

China was conducting military exercises in the Taiwan Strait.

But officials there insist no missile was

launched towards Flight 611.

launched towards Flight 611.

None of the wreckage recovered so far

None of the wreckage recovered so far

has any of the tell tale signs of being hit.

And there's no evidence on radar that there was ever a missile

And there's no evidence on radar that there was ever a missile

heading for flight 611.

Few things would cause a plane to break up in mid-air.

Few things would cause a plane to break up in mid-air.

One of the big ones is a bomb.

One of the big ones is a bomb.

Medical examiners check the bodies that have been recovered

for burn marks and shrapnel.

for burn marks and shrapnel.

They find none.

The plane's metal skin would be torn

and curled in a very particular way

and curled in a very particular way

if there had been a bomb on board.

Investigators find no such damage on any of the pieces.

Investigators find no such damage on any of the pieces.

But to rule out a bomb, they'll have to find more wreckage.

But to rule out a bomb, they'll have to find more wreckage.

I think that'll be it for floating wreckage.

The team from the NTSB arrives in Taiwan.

The team from the NTSB arrives in Taiwan.

Good morning.

I'm Clint Crookshanks from the NTSB.

Hello.

Good to see you, gentlemen.

Good to see you, gentlemen.

I'm afraid we still don't have much.

Clint Crookshanks is a structural engineer

who knows the 747 intimately.

who knows the 747 intimately.

I didn't have any preconceived notions.

This was my first major accident working for the NTSB.

This was my first major accident working for the NTSB.

We are not getting much from the floating debris.

We are not getting much from the floating debris.

In-flight breakup.

That's all we know.

Taiwan's civil aeronautics authority

doesn't take any chances.

They ground all of China Airlines' 747-200 series planes

They ground all of China Airlines' 747-200 series planes

until they can be inspected for mechanical flaws.

until they can be inspected for mechanical flaws.

This puts added pressure on investigators

This puts added pressure on investigators

to find out what happened.

Thank you for bringing these.

To the NTSB, this accident

To the NTSB, this accident

seems to have a lot in common with one of the world's most

studied plane crashes, that of TWA Flight

studied plane crashes, that of TWA Flight

800 six years earlier.

800 six years earlier.

Like the China Airlines Flight, it broke into pieces

Like the China Airlines Flight, it broke into pieces

while still climbing.

That plane crashed into the Atlantic

shortly after taking off from New York.

shortly after taking off from New York.

TWA Flight 800 was the biggest investigation

the NTSB has ever done.

the NTSB has ever done.

It lasted about four years.

The painstaking investigation uncovered

The painstaking investigation uncovered

a design flaw with the 747.

Wiring near one of the plane's fuel tanks

Wiring near one of the plane's fuel tanks

could spark and ignite the fuel in the tank.

Investigators conclude that's what likely caused the crash.

Investigators conclude that's what likely caused the crash.

Investigators are struck by similarities

between the two flights.

between the two flights.

Both were 747s.

Both disintegrated without warning while still climbing.

Both disintegrated without warning while still climbing.

Both flights took off in very hot weather.

Both flights took off in very hot weather.

The heat may have caused TWA Flight 800 to explode.

The heat may have caused TWA Flight 800 to explode.

That plane sat on the tarmac with its air

conditioning running.

Investigators believe hot air from the air conditioner

Investigators believe hot air from the air conditioner

overheated the plane's fuel.

overheated the plane's fuel.

The early evidence is pointing to a repeat of TWA Flight 800.

So it looks really very, very similar

So it looks really very, very similar

so therefore our immediate focus was essentially

so therefore our immediate focus was essentially

the central fuel tank.

Using a remote operating vehicle or ROV,

Using a remote operating vehicle or ROV,

investigators have located the wreckage of Flight 611

investigators have located the wreckage of Flight 611

deep underwater.

All right.

To the right a bit.

To the right a bit.

Clint Crookshanks knows

all the pieces that make up a 747 but he's

never seen them like this.

never seen them like this.

It was really quite

a shock when I first saw pieces on the floor of the ocean.

a shock when I first saw pieces on the floor of the ocean.

With only the lighting of the ROV to guide you,

you would notice something that looked like an airplane part.

you would notice something that looked like an airplane part.

The ROV would then circle around the part

looking at it from all angles.

looking at it from all angles.

Crookshanks' job is to help

the Taiwanese identify specific airplane

parts among the wreckage.

parts among the wreckage.

I think it takes a different kind of mind

to be able to look at a mangled part

to be able to look at a mangled part

and kind of straighten it out in your head

to really determine where it comes from on the airplane.

to really determine where it comes from on the airplane.

All right.

A little bit more to the right.

All right.

Go back.

There. OK.

That's definitely a piece of wing.

Let's mark it.

Once a piece is identified,

Once a piece is identified,

its GPS coordinates get recorded.

The GPS mapping tells investigators

The GPS mapping tells investigators

that the debris is spread out over 125 square miles.

It will be difficult to track down

specific pieces of the plane.

25 days after the crash of Flight 611,

25 days after the crash of Flight 611,

the plane's two black boxes have been found.

the plane's two black boxes have been found.

One contains voice recordings of conversations

in the cockpit, the other data from the plane's flight

in the cockpit, the other data from the plane's flight

computer.

Either could hold the clues that will

Either could hold the clues that will

reveal what happened during the final minutes of the flight.

If the answer is on the tape, investigators

If the answer is on the tape, investigators

may not have to bring up more wreckage to the surface.

may not have to bring up more wreckage to the surface.

The data is critical.

Everybody ready?

Everybody ready?

Investigators begin with the plane's cockpit voice

recorder.

They hope that the pilots will have

said something to each other about an emergency on board.

said something to each other about an emergency on board.

Welcome aboard China Airlines.

The recording begins about 10 minutes

before the plane took off.

before the plane took off.

20.

Preparations for the flight sound normal.

Preparations for the flight sound normal.

OK.

I have to start checklist.

After start, anti-ice.

After start, anti-ice.

The crew checks all their systems and runs

through standard checklists.

Off.

Off.

Off.

It was a very, very experienced Crew.

Both the captain and the first officers were quite seasoned.

Both the captain and the first officers were quite seasoned.

TRAFFIC CONTROLLER 2 Dynasty 611,

runway 06, wind 050 at 9er, cleared for takeoff.

runway 06, wind 050 at 9er, cleared for takeoff.

Cleared for takeoff, Dynasty 611.

Cleared for takeoff, Dynasty 611.

Takeoff.

Haiti.

Check.

V1.

V1.

Rotate.

Investigators listened to more than conversations.

Investigators listened to more than conversations.

Flap five

They also want to hear if the plane itself

was making any unusual sounds.

was making any unusual sounds.

Direct channel.

Resume own navigation.

TRAFFIC CONTROLLER 1 (ON RADIO): Traffic control.

If anything though, this cockpit

If anything though, this cockpit

is unusually quiet.

TRAFFIC CONTROLLER 1 (ON RADIO): Unit air 608,

reduce speed 210 knots.

reduce speed 210 knots.

The captain seems relaxed.

200 knots.

Roger.

In the moments before the disaster,

In the moments before the disaster,

nothing seems wrong.

There are no unusual sounds.

Now descend and maintain 250.

Now descend and maintain 250.

The final words spoken in the cockpit

are from captain Yi Ching-Fung.

are from captain Yi Ching-Fung.

2,000.

He calls out the distance

to their cruising altitude.

That's followed by the sound of a chime

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.

And then the cockpit microphone picks up the sound

And then the cockpit microphone picks up the sound

of the plane breaking apart.

Half a second later, the recording stops.

Half a second later, the recording stops.

After the disappointment of the voice recorder,

studying the wreckage becomes the only option

studying the wreckage becomes the only option

for investigators.

They focus their efforts on items

that can either prove or disprove

the link to TWA Flight 800.

the link to TWA Flight 800.

So we play a lot of focus on the wreckage

So we play a lot of focus on the wreckage

observation and examination of the central fuel tank.

On July 12, 48 days after the crash...

Whoa, whoa.

Little to the left, please.

Little to the left, please.

Success.

All right.

All right.

That's definitely the central fuel tank.

OK.

Let's mark that.

Let's bring that up.

The tank joins the sea of wreckage

piling up at the pier.

Investigators study it closely for any evidence

Investigators study it closely for any evidence

that it exploded.

If it did explode like the TWA tank,

If it did explode like the TWA tank,

it would be curled and twisted and the metal

it would be curled and twisted and the metal

would be bent outwards.

But this fuel tank is different.

And we found the central fuel tank was relatively intact.

And we found the central fuel tank was relatively intact.

And it's crumpled inwards.

Unlike the tank from the TWA flight, there's no soot.

Unlike the tank from the TWA flight, there's no soot.

There would be if the jet fuel inside had ignited.

There would be if the jet fuel inside had ignited.

So at that time, we pretty much rule out

it was the cause of the fuel tank.

The wreckage recovered so far

has also forced investigators to abandon another theory,

has also forced investigators to abandon another theory,

that a bomb brought down the plane.

None of the wreckage

showed any evidence of sooting, any kind of explosive damage.

The China Airlines crash of Flight 611

The China Airlines crash of Flight 611

was neither a repeat of TWA Flight 800

nor a deliberate bombing.

nor a deliberate bombing.

Investigators are running out of leads.

As more wreckage from China Airlines Flight 611

is identified and recovered, investigators

is identified and recovered, investigators

find an intriguing clue.

It's discovered when they examine a series of small vents

It's discovered when they examine a series of small vents

from the plane.

All commercial jetliners have dozens

All commercial jetliners have dozens

of these vents near the floor.

They're essentially pressure release valves.

They're essentially pressure release valves.

They're called dado panels.

And there's only one reason for them to open.

And there's only one reason for them to open.

If the cargo area underneath the passengers

were to suddenly decompress, the pressurized air above

were to suddenly decompress, the pressurized air above

would exert so much force on the floor

that it could collapse and damage vital flight controls.

that it could collapse and damage vital flight controls.

If there is decompression in the cargo area,

the dado panels open automatically and release

the dado panels open automatically and release

the pressure on the floor.

There are 65 dado panels on the China Airlines flight.

There are 65 dado panels on the China Airlines flight.

19 of them were recovered from the ocean.

19 of them were recovered from the ocean.

Four recovered panels were in the open position.

It tells investigators that there must have been

It tells investigators that there must have been

a sudden loss of pressure beneath the passenger cabin,

but it doesn't tell them what caused it.

but it doesn't tell them what caused it.

There are hundreds of pieces of wreckage

to be examined for clues.

to be examined for clues.

Kay Yong now wonders if a few of those pieces

might be able to tell him where the decompression originated.

might be able to tell him where the decompression originated.

I've been reading about the trajectory analysis

you did on Flight 800.

you did on Flight 800.

I'd like to try it.

Ballistic trajectory analysis is a technique

Ballistic trajectory analysis is a technique

that US investigators used to figure out how

TWA Flight 800 disintegrated.

TWA Flight 800 disintegrated.

It's impossible to do without specialized computers.

It's impossible to do without specialized computers.

The analysis is based on a simple fact.

The pieces that came off the plane first

The pieces that came off the plane first

would be the first to hit the water.

If investigators can figure out which pieces those were,

they'll know where the trouble began.

they'll know where the trouble began.

Radar that had been tracking the plane as it climbed also

Radar that had been tracking the plane as it climbed also

ended up tracking pieces of debris as they fell.

The salvage workers have recorded

The salvage workers have recorded

the precise location of those same pieces of wreckage.

Their logs could match a specific piece

Their logs could match a specific piece

to its radar track.

Investigators know the wind speed on the day of the crash.

Investigators know the wind speed on the day of the crash.

And they can obtain precise information

about ocean currents.

about ocean currents.

The last piece of the puzzle comes from the plane's flight

data recorder...

data recorder...

the plane's altitude, speed, and direction

at the time of the breakup.

As they're brought to the dock, every single piece of wreckage

As they're brought to the dock, every single piece of wreckage

has been logged and numbered for identification.

327.

Kay Yong selects 18 pieces of wreckage

for the computer analysis, some from the front,

for the computer analysis, some from the front,

some from the middle, and some from the back of the plane.

some from the middle, and some from the back of the plane.

199.

199.

Along with all the other data,

he'll feed information about each item's weight

and shape into the computer.

and shape into the computer.

526.

Based on where the pieces fell,

Based on where the pieces fell,

the computer should be able to calculate

which of those 18 pieces was the first to come off the plane.

which of those 18 pieces was the first to come off the plane.

Then we see when each one of those items

separated from the aircraft.

separated from the aircraft.

All of the data paints a telling picture of what

All of the data paints a telling picture of what

happened at 35,000 feet.

happened at 35,000 feet.

Kay Yong gets to see how Flight 611

broke up from beginning to end.

broke up from beginning to end.

The tail came off first.

Along with the dado panels,

it's a very important clue.

it's a very important clue.

We're now pretty much indicating that something

happened in the back of the aircraft,

happened in the back of the aircraft,

rather than something happened in the forward part.

Investigators are now keen to recover items

from the rear of the plane.

The NTSB sends metallurgist Frank Zakar to Taiwan

to examine the wreckage.

to examine the wreckage.

I was walking along the yard where the wreckage was placed.

I was walking along the yard where the wreckage was placed.

And at that time, I walked up to item 640

And at that time, I walked up to item 640

and 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.

With this battered piece of metal,

investigators have struck gold.

There was definitely a eureka moment on the dock.

And that was, hey, we might have something here.

And that was, hey, we might have something here.

Let's get as many pictures as we can.

Let's get as many pictures as we can.

The massive piece of fuselage

that has caught Frank Zakar's attention

that has caught Frank Zakar's attention

is exactly what investigators have been searching for.

It includes a piece of the belly, the side

It includes a piece of the belly, the side

wall, and the rear cargo door.

It's from the back of the plane, precisely

It's from the back of the plane, precisely

where the analysis told them the breakup had begun.

where the analysis told them the breakup had begun.

This piece of wreckage was highly unusual.

It wasn't what we were seeing on all the other pieces.

And it immediately drew our attention

and drew the focus of the investigation.

and drew the focus of the investigation.

The way most of the metal is torn

suggests it ripped apart violently in mid-air.

suggests it ripped apart violently in mid-air.

Aerodynamically, as an airplane is moving

through the air, if it were to break apart just the force

through the air, if it were to break apart just the force

of the incoming air at over 500 miles per hour

will just break up perfectly good structure.

will just break up perfectly good structure.

That's what we call an overload fracture.

So most of the pieces that came up early

So most of the pieces that came up early

were just indicative of that kind of overload.

When metal breaks due to overload or overstress,

When metal breaks due to overload or overstress,

it comes apart at an angle.

it comes apart at an angle.

But the fractured edges of piece number 640 aren't angled.

They're flat.

What do you think?

What do you think?

It's definitely not overstress.

It's metal fatigue.

Fatigue fractures happen

when metal is stressed repeatedly

over time until it breaks.

over time until it breaks.

It looks very different from a stress fracture.

Typically, a metal fatigue crack

Typically, a metal fatigue crack

will have a flat appearance.

It will be very smooth.

It will be very smooth.

That's exactly the kind of crack

that investigators observe on piece number 640.

that investigators observe on piece number 640.

That tells them it didn't break off the plane suddenly

as it fell from the sky.

This piece separated from the plane over time.

Had it caused the deaths of 225 people?

Had it caused the deaths of 225 people?

There was much more work that needed to be done.

A detailed analysis of the piece had to be done in order

A detailed analysis of the piece had to be done in order

to see if this, in fact, was the smoking gun.

There's something else about this piece

There's something else about this piece

that stands out.

It has a metal patch on it.

It's called a doubler plate.

It's called a doubler plate.

It's the equivalent of a patch on a punctured tire.

It's not unusual to find numerous doubler plates

on older planes like this one.

on older planes like this one.

A doubler plate is like a patch

that you put over fuselage skin.

that you put over fuselage skin.

If there were to be a tear, or a blemish,

If there were to be a tear, or a blemish,

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

And one way to do that is to put a doubler

plate or a patch right over the existing structure.

plate or a patch right over the existing structure.

At some point, this section of the 747

had been repaired.

Investigators need to know why it was fixed

Investigators need to know why it was fixed

and how that was done.

We're looking for repair to the aft lower lobe.

We're looking for repair to the aft lower lobe.

Whatever it was, it was big.

To find the answers to the crash of Flight 611,

To find the answers to the crash of Flight 611,

investigators sift through 22 years of documents

investigators sift through 22 years of documents

but the records are sketchy.

Finding details on one particular repair

Finding details on one particular repair

could take time.

There's something about this particular doubler that catches

Frank Zakar's attention.

Frank Zakar's attention.

Something is leaking from underneath the metal patch.

Was there a possibility that the skin had

broken, cracked, and was there any fuel

broken, cracked, and was there any fuel

or air coming out from between the doubler and the fuselage?

or air coming out from between the doubler and the fuselage?

And that warranted further examination.

Let us cut it from here to here and send

Let us cut it from here to here and send

this piece to Chung-Shan.

In order to see what's underneath the doubler,

In order to see what's underneath the doubler,

a large section of piece 640 is sent to a lab.

a large section of piece 640 is sent to a lab.

No evidence has been found of structural

or mechanical problems with Boeing 747-200 airplanes.

or mechanical problems with Boeing 747-200 airplanes.

Taiwanese aviation officials have no reason to keep

Taiwanese aviation officials have no reason to keep

the planes on the ground.

The Chung-Shan Institute of Science and Technology

The Chung-Shan Institute of Science and Technology

is a military research facility.

It's at the forefront of Taiwan's space program.

It's at the forefront of Taiwan's space program.

This is where investigators take a section of piece number 640

for a closer examination.

The NTSB's Frank Zakar finds a telling

clue on the crack itself.

When I looked at the fractured surface,

I found that this one specific area

I found that this one specific area

was covered with aluminum oxide, pretty

much similar to rust on a car.

much similar to rust on a car.

Years of exposure to oxygen

changes the color of metal.

The discoloration tells investigators

The discoloration tells investigators

that this particular crack at the rear of the airplane

has been there for a very long time.

has been there for a very long time.

Then, when the doubler is finally removed,

Then, when the doubler is finally removed,

investigators get a look at the aluminum skin underneath.

They are intrigued by what they see.

They are intrigued by what they see.

When we disassemble the doubler plate

from the skin, we noticed that there were

from the skin, 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 aha moment that we might have something here.

That was an aha moment that we might have something here.

The search of the plane's documents also

pays off.

pays off.

The records contain a very short reference to a mishap

22 years earlier when this plane was only six months old.

22 years earlier when this plane was only six months old.

Speed is low, sir.

Watch it.

Its tail scraped the runway while landing.

Its tail scraped the runway while landing.

Did you feel that?

It happens when a plane lands or takes

off at too steep an angle.

It's called a tailstrike.

It's called a tailstrike.

TRAFFIC CONTROLLER 3 Flight 009.

Hong Kong tower.

We observed smoke and sparks from your tail on landing.

We observed smoke and sparks from your tail on landing.

Roger, Hong Kong tower.

We'll have that looked at.

Tailstrike, sir.

I better log that.

I better log that.

Tailstrike damage is routinely repaired.

Investigators want to know how China Airlines

Investigators want to know how China Airlines

went about fixing the plane.

They can only find a brief mention

of the repairs that were done in the plane's logbook.

of the repairs that were done in the plane's logbook.

That's all there is?

That's all we could find.

There's not a lot of detail

in China Airlines' records.

in China Airlines' records.

The documents that do exist show that the day

after the tailstrike, China Airlines

after the tailstrike, China Airlines

did a temporary repair.

Workers attached a large aluminum

Workers attached a large aluminum

plate over the damaged area.

What do we know about the permanent repair?

What do we know about the permanent repair?

It doesn't get much better.

A more permanent repair was to be

carried out within four months.

carried out within four months.

This is what we got.

The maintenance records indicated

that the permanent repair was done in accordance

with Boeing recommendations in their structural repair manual.

with Boeing recommendations in their structural repair manual.

Evidence that we uncovered indicate

Evidence that we uncovered indicate

that the repair was not done per the Boeing repair manual.

According to the manual,

many of the scratches on the plane

were too deep to be repaired.

were too deep to be repaired.

The entire damaged section should

have been cut out and replaced.

have been cut out and replaced.

You have to follow certain procedures

in the Boeing structural repair manual

indicating very clearly what you should do step by step.

indicating very clearly what you should do step by step.

22 years later, investigators

can tell that, for some reason, the damaged piece was not

can tell that, for some reason, the damaged piece was not

replaced.

The scratches from the tailstrike are still there.

The scratches from the tailstrike are still there.

China Airlines engineers tell investigators

that the scratched area was too large to cut out so they sanded

that the scratched area was too large to cut out so they sanded

the scratches down instead.

In the event of scratching, it depends

In the event of scratching, it depends

on how deep the scratches are.

If they're not very deep, they can be blended out.

But if the scratches are too deep,

But if the scratches are too deep,

the repair technique that's called for

is to actually cut out all of the scratched material

is to actually cut out all of the scratched material

and then design a doubler patch that's

larger by a big percentage of the structure

larger by a big percentage of the structure

that was originally removed.

that was originally removed.

The scratches weren't sanded down or cut out.

They're still there.

Maintenance workers then made one final mistake.

Maintenance workers then made one final mistake.

They put the doubler plate right

over the scratched material.

The doubler plate that they put on

was not 30% larger than the affected area.

was not 30% larger than the affected area.

In fact, it was barely, maybe not even in certain locations,

In fact, it was barely, maybe not even in certain locations,

larger than the area that was scratched.

Even though the repair wasn't done according

to Boeing's instructions, the way it was logged

to Boeing's instructions, the way it was logged

made it seem like it was.

So for 22 years, anyone reading that entry would

So for 22 years, anyone reading that entry would

assume the damaged area had been cut out as it should have been.

assume the damaged area had been cut out as it should have been.

Pieces were really starting

to fall into place now.

to fall into place now.

Once we saw this piece of structure that

had the fatigue cracks in it and we realized that it came

had the fatigue cracks in it and we realized that it came

from a structural repair that was not done properly,

from a structural repair that was not done properly,

that was left to fly for 20 years...

Airborne passing 1,600.

Airborne passing 1,600.

...things began to make sense.

By covering an improper repair with a doubler

By covering an improper repair with a doubler

and then documenting the repair as meeting Boeing's standards,

the workers made their mistake impossible to detect.

the workers made their mistake impossible to detect.

And every time the plane took off over the next 22 years,

And every time the plane took off over the next 22 years,

the concealed problem got worse and worse.

the concealed problem got worse and worse.

The air inside a commercial airplane is pressurized.

As the plane climbs, air is forced into the cabin

As the plane climbs, air is forced into the cabin

to keep the pressure inside the plane greater

than the pressure outside.

It's like inflating a tire.

It's like inflating a tire.

The inside air pushes against the plane's skin.

The plane's skin expanded and contracted

The plane's skin expanded and contracted

a little bit every time.

Because they weren't properly repaired,

Because they weren't properly repaired,

the cracks grew and spread.

Eventually, the crack grew into a stunning 7 and 1/2 feet.

Eventually, the crack grew into a stunning 7 and 1/2 feet.

If you were charting the crack,

you would have seen very slow growth early.

But as time went on, the growth was getting bigger and bigger.

But as time went on, the growth was getting bigger and bigger.

A small scratch had grown into an enormous problem.

A small scratch had grown into an enormous problem.

Then, in May 2002, as Flight 611 climbed,

Then, in May 2002, as Flight 611 climbed,

that problem killed 225 people.

As the airplane climbed in altitude

As the airplane climbed in altitude

and the fuselage was pressured, that put enough strain

on this growing crack that it reached its critical length

on this growing crack that it reached its critical length

and from there it just spread like a spider web.

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.

When that piece tore off,

the plane went into a steep dive.

The force of the air on what was left of the plane

The force of the air on what was left of the plane

quickly ripped it to pieces.

Investigators know that an unseen crack caused

Flight 611 to break apart.

Flight 611 to break apart.

They now discover that China Airlines came

heartbreakingly close to finding that crack

heartbreakingly close to finding that crack

and saving 225 lives.

The China Airlines 747 that made its final flight as Flight 611

The China Airlines 747 that made its final flight as Flight 611

was in regular service for 22 years

was in regular service for 22 years

following the improper repair to its skin.

It took off and landed more than 20,000 times.

It took off and landed more than 20,000 times.

Over the years, mechanics would have scrutinized the plane.

Over the years, mechanics would have scrutinized the plane.

There's regular inspections per the Boeing

maintenance program that have to be performed on the airplane.

But the massive crack forming

at the rear of the plane was never detected.

at the rear of the plane was never detected.

Another accident in another country

Another accident in another country

almost led China Airlines to discover the hidden damage.

In 1988, the roof peeled off an aging Boeing

737 owned by Aloha Airlines.

737 owned by Aloha Airlines.

As a result of that incident, the Federal Aviation

As a result of that incident, the Federal Aviation

Administration laid out an inspection

procedure for older planes.

procedure for older planes.

Airlines around the world were forced

to inspect their planes much more diligently

for corrosion and cracks.

for corrosion and cracks.

The regulation called for airlines

to re-evaluate all existing repairs to a plane's structure.

to re-evaluate all existing repairs to a plane's structure.

Indications on this airplane were

that if they had looked at the maintenance records

that if they had looked at the maintenance records

and compared it to the repair, they would have had to remove

the repair and redo it.

China Airlines took the first steps

China Airlines took the first steps

of the new procedure in 2001, a year before the accident.

of the new procedure in 2001, a year before the accident.

The airline identified and photographed

31 different doublers on the 747,

31 different doublers on the 747,

including the one over the catastrophic crack.

including the one over the catastrophic crack.

Those pictures show investigators

that China Airlines overlooked a vital clue

that could have warned them of the looming danger.

that could have warned them of the looming danger.

We examined the photographs that China Airlines

We examined the photographs that China Airlines

took of the repair and noticed that there

was some issues that may have warranted

was some issues that may have warranted

further investigation.

Investigators see a dark brown stain

on the outside of the plane.

on the outside of the plane.

It's the same mysterious staining that led Frank Zakar

to suspect there was a hole behind the doubler when

to suspect there was a hole behind the doubler when

he first saw it on the pier.

So why hadn't this stain raised alarms before the crash?

So why hadn't this stain raised alarms before the crash?

For years, passengers on China Airlines' doomed 747

For years, passengers on China Airlines' doomed 747

were allowed to smoke.

They filled the pressurized air with nicotine.

They filled the pressurized air with nicotine.

The smoke was being forced out through the crack

The smoke was being forced out through the crack

at the rear of the plane.

Over time, that smoke left a nicotine stain

Over time, that smoke left a nicotine stain

on the outside of the plane.

It was very vivid.

Any experienced maintenance engineer would

Any experienced maintenance engineer would

be able to spot it immediately.

be able to spot it immediately.

Smoking hadn't been allowed

on China Airlines for seven years before the crash.

on China Airlines for seven years before the crash.

It tells investigators that the crack in the plane

had been there for at least that long.

But instead of investigating the source of the staining...

But instead of investigating the source of the staining...

We need to conduct the new inspection when

we do our next major check.

...China Airlines scheduled the second part

...China Airlines scheduled the second part

of the FAA's procedure, a detailed inspection

of the repaired areas.

of the repaired areas.

And that would be the seventh C-check, currently

scheduled for November 2, 2002.

scheduled for November 2, 2002.

But the 747 never made it to November 2, 2002.

But the 747 never made it to November 2, 2002.

It came apart over the Taiwan Strait

It came apart over the Taiwan Strait

five months before the inspection

that would have undoubtedly uncovered its hidden flaw.

Investigators want to prevent a similar accident

Investigators want to prevent a similar accident

from ever happening again.

They recommend that aviation agencies around the world

immediately inspect repairs for any possible hidden damage.

immediately inspect repairs for any possible hidden damage.

We were no longer going

We were no longer going

to accept just a quick write-up that the repair was

done properly.

If the repair didn't have all the necessary documentation

If the repair didn't have all the necessary documentation

to allow us to know it was done properly,

we were requiring operators to take doubler

we were requiring operators to take doubler

plates off and do a visual inspection

of the structure underneath.

of the structure underneath.

The National Transportation Safety Board

issues its own recommendations.

The board asks that maintenance personnel be warned

The board asks that maintenance personnel be warned

of the consequences of hiding the kind

of damage that could lead to the structural failure

of damage that could lead to the structural failure

of an airplane.

The moral of this story is that the repair

The moral of this story is that the repair

has to be done properly.

As a mechanic, when you're doing work on an airplane,

As a mechanic, when you're doing work on an airplane,

you're not thinking about the people who might be flying

on that fuselage 20 years from now,

on that fuselage 20 years from now,

but their safety depends on you doing the repair properly.

but their safety depends on you doing the repair properly.

China Airlines has revised the way its fleet

is inspected and maintained.

Its safety record has improved dramatically

Its safety record has improved dramatically

since the crash of Flight 611.

since the crash of Flight 611.

Investigators also proposed the development of new tools

that would allow mechanics to detect damage behind a doubler.

that would allow mechanics to detect damage behind a doubler.

Such tools are being used today.

Such tools are being used today.

Boeing developed a nondestructive procedure

that can find cracks in the fuselage underneath a doubler.

that can find cracks in the fuselage underneath a doubler.

That device uses ultrasound, sound waves

that travel through metal.

that travel through metal.

It can reveal damage underneath a doubler.

The problems that led to the China Airlines disaster

The problems that led to the China Airlines disaster

are not going away.

Planes the world over are getting older.

Planes the world over are getting older.

And older planes need to be more thoroughly

inspected for cracks.

inspected for cracks.

A proper program of maintenance and inspections can be costly.

A proper program of maintenance and inspections can be costly.

But as China Airlines showed, the price of not maintaining

aging planes is even costlier.

aging planes is even costlier.