All language subtitles for Air.Disasters.S20E09.Radio.Silence.1080p.SMIT.WEB-DL.AAC2.0.H.264-maldini_track3_[eng]

[suspenseful music]

CONTROLLER: Helios
522, do you read?

Over.

NARRATOR: All radio contact
is lost for the plane

carrying 115 passengers.

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

NARRATOR: High above the
Taiwan Strait, a 747 jumbo jet

goes mysteriously silent.

Dynasty 611, Taipei.

So the first thing you
think about is a bomb.

[screaming]

NARRATOR: And when
controllers lose

contact with a private
jet, fighter pilots

scramble to intercept.

No movement.

Everybody knew that
there was a major problem.

NARRATOR: Three perplexing
cases of radio silence

send investigators
hunting for answers.

CONTROLLER: Do you read?

Over.

WOMAN: Radio silence can mean a
long and dark mystery unfolding

as the world watches,
or it can mean

that your plane has
just devastatingly

been blown from the sky.

FLIGHT ATTENDANT (ON INTERCOM):
Ladies and gentlemen,

we are starting our approach.

PILOT: We lost both engines.

[radio chatter]

MAN: Mayday.

Mayday.

FLIGHT ATTENDANT:
Brace for impact!

[intense music]

MAN: He's gonna crash!

[somber music]

NARRATOR: It's early morning
on the island of Cyprus,

as the crew of Helios
Airways Flight 522

prepares for today's flight.

Sure is a beautiful day.

Maybe I shouldn't have come in.

NARRATOR: Andreas
Prodromou wasn't scheduled

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

to spend some time
with his girlfriend,

another flight attendant.

[radio chatter]

Temperature's still up there.

NARRATOR: In the
cockpit, the flight crew

is occupied with a daily
routine of preparing

their jet for takeoff.

Bright today.

Captain Hans Merten is a
contract pilot hired by Helios

for the busy holiday season.

[chatter]

Are you almost through?

Nearly.

First officer Pampos
Charalambous has been flying

with Helios for five years.

There are switches.

Sorry.

Could you store trays?

Move your seat back and turn
off electronics, please.

NARRATOR: 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.

NARRATOR: Just after
9:00 in the morning,

Helios Airways
Flight 522 lifts off.

Nicosia Air control,
this is Helios 522.

Request cruising at 340.

CONTROLLER: Helios 522, you
are cleared to climb to 340.

Have a good day.

Set 340.

340.

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

Cyprus, to Athens, Greece.

The plane is still climbing
towards its cruising altitude,

when suddenly--

[buzzer ringing]

What is it?

The takeoff config warning.

NARRATOR: The
takeoff configuration

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.

HANS MERTEN: Operations,
this is Flight 522.

Over.

Flight 522, what
can I do for you?

We have a takeoff
config warning on.

[buzzer ringing]

NARRATOR: Then the situation
becomes even more confusing.

[high-pitched beeping]

We now have a Master Caution.

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

NARRATOR: In the cabin,
the passengers are hardly

aware there's a problem until--

[screaming]

Everyone stay calm, and
please do remain seated.

Everyone, please put the
oxygen masks on completely

over your mouth and nose.

NARRATOR: In the cockpit,
the pilots still don't know

why both alarms are sounding.

Can you confirm that
the pressurization

panel is set to Auto?

[buzzer ringing]

Where are my equipment
cooling circuit breakers?

Behind the captain's seat.

Can you see them?

[buzzer ringing]

NARRATOR: As the plane
continues to climb,

passengers and crew
are growing concerned.

[suspenseful music]

Helios 522, can you
see the circuit breakers?

NARRATOR: But the Helios
crew doesn't respond.

Helios 522, can you hear me?

NARRATOR: Athens air
traffic controllers

can see the plane is
still on course high

over the Mediterranean Sea.

Helios 522, do you read?

Over.

NARRATOR: But all they're
getting is radio silence.

AKRIVOS TSOLAKIS: We heard
that there was an airplane

which was flying into
the Greek territory

and had no communication.

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

NARRATOR: The passenger
jet has been in the air

for over two hours.

They were scheduled to
land 30 minutes ago.

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.

CONTROLLER: Helios
522, do you read?

Over.

Helios 522, do you read?

Over.

NARRATOR: 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.

F-16 PILOT: Athinai ACC,
Athinai ACC, checking the cabin.

NARRATOR: 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

in the cockpit of Helios 522.

Repeat-- there is one
person inside the cockpit.

Helios 522, do you read?

Over.

[buzzer ringing]

Flight HCY522, this
is radar control.

NARRATOR: Suddenly
the 737 turns left

and begins to quickly descend.

Athiniai ACC, Helios
522 turning sharply.

Following down.

NARRATOR: The
aircraft is dropping

from more than 32,000 feet.

CONTROLLER: HCY522, this
is Athinai Radar Control.

NARRATOR: Just
after 12 o'clock--

[crash]

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

F-16 PILOT: Helios 522 is
down on Grammatiko Hill.

Over.

NARRATOR: It's an
eerie disaster.

For over an hour, air
traffic controllers

watched the passenger jet
fly in radio silence, closer

and closer to Athens,
with no idea what

was happening inside the jet.

Investigators and
first responders

rushed to the
burning crash site.

AKRIVOS TSOLAKIS: There we
were, facing the situation which

was beyond any description.

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

of the airplane.

NARRATOR: 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.

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.

NARRATOR: Chief Investigator
Tsolakis and his team

get to work immediately,
combing through what

remains of the passenger jet.

Recovered bodies start to
arrive at the morgue in Athens.

[chatter]

INTERPRETER: It is a
truly nightmarish sight.

I hope that I never
experience it again.

It was terrible, just terrible.

NARRATOR: When investigators
find tissue samples

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

The person at the controls
of the plane when it crashed

was flight attendant
Andreas Prodromou.

But why was he in the cockpit?

Was he trying to save the
plane or did he deliberately

fly it into the ground?

[crash]

[distant sirens]

NARRATOR: Investigators
have recovered

the cockpit voice recorder
from Helios Flight 522.

When Chief Investigator
Tsolakis listens

to the final moments
of the flight,

it answers a vital question.

(WEAKLY) Mayday.

Mayday.

[buzzer ringing]

Mayday.

NARRATOR: This was
no terrorist act.

Helios Airways Flight 522.

NARRATOR: Flight attendant
Prodromou was calling for help.

Tsolakis hears five separate
maydays on the tape,

but they were never heard
by air traffic controllers.

Investigators suspect the radio
was still tuned to Cyprus,

their departure point.

INTERPRETER: He wasn't a coward.

He knew something about
planes, and he had

the capacity to do something.

Sure is a beautiful day.

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

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

because it was out of fuel.

The FDR and CVR
gave us absolute proof

that the plane ran out of fuel.

And this was the
cause of the crash.

NARRATOR: But one
mystery still remains.

Why was Prodromou
flying the aircraft?

What happened to
the flight crew?

[ominous music]

Back at the crash
site, investigators

catch a break when a key
control panel is recovered.

The panel, which is
responsible for pressurization,

is set in an unusual position.

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

on the manual position.

It was a major one.

NARRATOR: Normally,
pressurization

happens automatically.

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?

When Tsolakis interviews
the Helios engineer,

he learns the accident
aircraft had a history

of pressurization problems.

Coincidentally, on the
day of the fatal flight,

engineers inspected the
aircraft for air leaks

that could cause
depressurization.

Switching digital pressure
control unit from auto

to manual.

NARRATOR: Using the
aircraft's power systems,

the engineer pressurized the
cabin for several minutes

while another engineer
checked for leaks.

But there was no sign
of any air escaping.

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

NARRATOR: But at
the end of the test,

the engineer left the switch
in the manual position.

It is bright today.

Are you almost through?

Nearly.

NARRATOR: Investigators
theorize neither the pilot

or first officer noticed
the manual setting

during pre-flight preparations.

Pressurization mode selector.

NARRATOR: As a result
the cabin would not

have pressurized properly,
causing the incapacitation

of everyone on board.

[screaming]

To prove their
theory, they perform

a test flight using
the same conditions

as the Helios flight.

Make sure the P5
is set to manual.

NARRATOR: Tsolakis has the crew
turn the pressurization switch

to manual.

It's hard to see.

NARRATOR: As the
test flight climbs,

oxygen thins quickly
in the aircraft.

The same thing happened
on the Helios flight,

triggering an alarm.

[buzzer ringing]

What is it?

The takeoff config warning?

[buzzer ringing]

NARRATOR: But when the alarm
goes off on the test flight,

Tsolakis makes a
shocking discovery.

It's not the takeoff
configuration

alarm that sounds, but rather
the depressurization alarm.

The two alarms sound
virtually identical.

OK.

Take it down.

FAITHON KARAIOSOFIDES: The
alarm sounded, and that alarm

was misinterpreted.

Most of the flight
crew, they will never

face an alarm with
no pressurization

because it's a rare event.

NARRATOR: Even if the
flight crew did misinterpret

the first alarm,
Tsolakis learns they

had another chance to
determine what the problem was.

When he revisits the
cockpit recording,

Tsolakis hears the plane's
Master Caution alarm

sounding for almost a minute.

[BUZZER RINGING, HIGH PITCHED
BEEPING]

We now have a Master Caution.

NARRATOR: The
Master Caution alarm

can indicate that the plane's
systems are overheating.

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

the plane was overheating
and needed to be cooled.

Where are my equipment
cooling circuit breakers?

Behind the captain's seat.

They began to lose the
ability to think coherently.

NARRATOR: 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

as it flew over the airport.

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

everyone takes
their last breaths.

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

down to a low altitude.

NARRATOR: Passenger
masks are supplied

by a chemical generator
above their seats.

But the generators only
produce enough oxygen

to last about 12 minutes.

BILL WALDOCK: Most
of the people,

once the hypoxia begins to cause
them to lose consciousness,

they're just gonna go to sleep.

(WEAKLY) Mayday.

[buzzer ringing]

NARRATOR: So how did Andreas
Prodromou remain conscious?

(WEAKLY) Helios
Airways Flight 5--

NARRATOR: When investigators
interview Helios

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

to survive.

BILL WALDOCK: Probably was
a little bit disoriented.

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

(WEAKLY) Mayday.

NARRATOR: The young flight
attendant calls for help,

but no one could hear him.

And there was nothing
he could have done.

[crash]

The official report shows
that a fatal combination

of small mechanical
problems and human error

led to the worst air
disaster in Greek history.

GREG FEITH: It was the
flipping of one switch

that was the difference
between life and death.

And what came out of
this investigation

was basically a re-emphasis
to flight crews.

You have to do checklists.

You have to have that
checklist discipline.

NARRATOR: But not all
cases of radio silence

unfold over many hours.

Sometimes they happen
in the blink of an eye.

The third waypoint,
change to low.

Dynasty 611, Taipei.

Dynasty 611, Taipei.

NARRATOR: China Airlines
Flight 611 lifts off

from Taiwan's capital, Taipei.

Gear is up.

Dynasty 611,
airborne passing 1,600.

CONTROLLER: Dynasty 611,
Taipei, approach radar.

Contact climb and
maintain flight level 260.

260, Dynasty 611.

Autopilot B engaged.

NARRATOR: There are 225 people
on board the Boeing 747.

FLIGHT ATTENDANT (ON
INTERCOM): Ladies

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.

NARRATOR: Flight 611 is an
hour and 40 minute trip across

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--

The third waypoint,
change to low.

NARRATOR: --the flight
vanishes from radar.

Dynasty 611, Taipei.

NARRATOR: 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.

[non-english speech]

NARRATOR: Taiwanese
authorities quickly

launched one of the
largest rescue missions in

the country's aviation history.

Flight 611 was 34 miles
from the Taiwanese shore,

just north of the Penghu
Islands when it disappeared.

Within hours,
rescuers find debris

floating in the Taiwan Strait.

[somber music]

There are no survivors.

JOHN NANCE: 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.

It's always a challenge.

Because the first thing
is to find the wreckage.

The second thing is
to pull enough of it

up to be useful to the
accident investigation.

NARRATOR: Taiwan's Aviation
Safety Council, or ASC,

begins its investigation
into the mysterious crash

of the 747.

August 2, 1979.

NARRATOR: 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.

KAY YONG: This particular
investigation was,

by far, the most difficult one.

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

NARRATOR: While recovery teams
gather the floating wreckage--

Good morning.

I'm anxious to
see what you have.

NARRATOR: --Kay Yong
reviews the radar

recording of the doomed flight.

[ominous music]

Minutes into the recording,
he makes a critical discovery.

Shortly after
reaching 35,000 feet,

Flight 611's signal
suddenly splits apart.

The breakup is quite graphic.

There were four sizable pieces
of wreckage that were getting

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.

NARRATOR: But why would
one of the world's

most dependable passenger
kept calm apart in midair?

[suspenseful music]

Since the accident involved
an American-made plane,

a team from the National
Transportation Safety Board

is dispatched to Taiwan.

Good morning.

I'm Clint Crookshanks
from the NTSB.

Hello.

NARRATOR: Three weeks
after the crash, the Jan

Steen, a sophisticated
salvage vessel,

arrives in the Taiwan Strait.

Using the vessel's
sonar technology,

investigators locate
the remaining wreckage

of Flight 611 deep under water.

It was really quite a
shock when I first saw pieces

on the floor of the ocean.

NARRATOR: 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

the 747 exploded in mid-air.

They begin with the plane's
cockpit voice recorder.

PILOT (ON RECORDING): Clear
for takeoff, Dynasty 611.

CO-PILOT (ON
RECORDING): Takeoff.

PILOT (ON RECORDING): 80.

CO-PILOT (ON RECORDING): Check.

PILOT (ON RECORDING): Gear 1.

Rotate.

NARRATOR: In the moments
before the disaster,

nothing seems wrong.

CONTROLLER (ON RECORDING):
Now descend and maintain 250.

NARRATOR: The captain
calls out the distance

to their cruising altitude.

2,000.

NARRATOR: That's followed
by the sound of a chime--

[ding]

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

But then--

[thud]

--the recording stops.

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.

NARRATOR: The flight
recorders are a dead end.

The fate of the investigation
lies in what can be uncovered

in the wreckage of Flight 611.

I've been reading about
the trajectory analysis.

I'd like to try it.

NARRATOR: Computerized
ballistic trajectory analysis

is based on a simple fact.

The pieces that came
off the plane first

are the first to hit the water.

If investigators can figure
out which pieces those were,

they'll know where
the trouble began.

327.

NARRATOR: Kay Yong selects
18 pieces of wreckage

from all over the plane
for the computer analysis.

ACTOR AS KAY YONG: 199.

Can we see when each
one of those items

separated from the aircraft?

NARRATOR: 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

the plane.

The tail came off first.

NARRATOR: It's a huge
discovery for investigators.

That pretty much indicating
that something happened

in the back of the aircraft.

NARRATOR: Now the team
needs to track down

pieces from the tail section.

But wreckage is still being
recovered from the ocean floor.

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

to the deaths of 225 people?

[suspenseful music]

[screaming]

NARRATOR: While
searching through newly

recovered wreckage from
China Airlines Flight 611,

NTSB investigator Frank Zakar
spots something unusual.

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.

NARRATOR: Zakar
needs to get a closer

look at the mysterious piece.

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

told them the breakup began.

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

there and there.

NARRATOR: But then the team
notices a concerning detail.

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

JOHN DELISI: 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

over the existing structure.

NARRATOR: At some point
this section of the 747

had been repaired.

Investigators need to know
why and how it was done.

Let's cut it
from here to here,

and send this
piece to Zhongshan.

NARRATOR: A large
piece of the wreckage

is sent to a military research
center for expert analysis.

When the repair
patch is removed,

damage on the aluminum
skin underneath

intrigues investigators.

We noticed that there were
some fairly long gouge marks.

NARRATOR: 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.

NARRATOR: Investigators
wonder what

caused the gouges on the
aircraft's aluminum exterior.

When they search the plane's
extensive maintenance records,

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.

NARRATOR: The tail
section of the 747

scraped the runway on landing.

But when investigators
search for details on how

China Airlines
repaired the plane,

they make a shocking discovery.

CLINT CROOKSHANKS: The
maintenance records indicated

that the permanent repair
was done in accordance

with Boeing recommendations.

Evidence that we
uncovered indicate

that the repair was not done
per the Boeing repairman.

NARRATOR: According
to the manual,

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

But the repair was never done.

Workers simply
attached a doubler

plate over the damaged area.

JOHN DELISI: What
was so insidious

about this improper repair
was that the doubler

plate hid all of the damage.

NARRATOR: Workers recorded
the repair was completed,

making their mistake
impossible to detect.

JOHN DELISI: So if you
weren't there watching

them do this repair
improperly, you wouldn't know

that it was done improperly.

NARRATOR: Every time
the plane took off

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

grew and spread.

JOHN DELISI: It just
spread like a spiderweb.

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.

[screaming]

[suspenseful music]

NARRATOR:
Investigators recommend

that aviation agencies
around the world

immediately inspect
repairs that were

patched using doubler plates.

We were requiring
operators to take doubler

plates off and do
a visual inspection

of the structure underneath.

NARRATOR: The NTSB issues
its own recommendation,

that mechanics be warned of
hiding damage that could lead

to the failure of an airplane.

TODD CURTIS: The
airline literally had 22

years or so to get this right.

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.

[suspenseful music]

NARRATOR: And when a private
jet with a celebrity passenger

falls into radio
silence over Florida--

This is Jacksonville Center.

I'm declaring an emergency.

NARRATOR: --fighter Jets
scramble to find out why.

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

but it's starting to move.

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

Nav light?

On.

Radios.

Are set.

[suspenseful music]

Morning.

NARRATOR: American pro golfer
Payne Stewart is on his way

to Dallas with some close
business associates.

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.

[bell dings]

Stewart flies
regularly on a Learjet,

a luxury aircraft
that was modeled

after a Swiss military plane.

CONTROLLER: 47 Bravo Alpha,
you are cleared for takeoff.

You ready?

OK.

Here we go.

And take off thrust.

[engine revs]

NARRATOR: Captain Michael
Kling is a former Air Force

pilot and flight instructor.

Gear 1.

NARRATOR: First
Officer Stephanie

Bellegarrigue has less
than 100 hours in the Lear.

She's keen to log
more flight time.

Rotate.

NARRATOR: At 9:19 AM,
the Learjet lifts off.

Good morning, Jacksonville.

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

Good morning, 47 Bravo Alpha.

Climb and maintain
flight level 390.

NARRATOR: The controller
clears the jet to keep

climbing up to 39,000 feet.

The flight plan calls
for the airplane

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

over to a new air
traffic controller.

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

NARRATOR: 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

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.

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

NARRATOR: There's only radio
silence from the Learjet.

What's up?

Is that Learjet.

It's not answering.

Maybe he's off frequency.

[suspenseful music]

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

NARRATOR: But when the aircraft
reaches its cruising altitude

of 39,000 feet--

They're still climbing.

Let me see their flight plan.

They've got a turn
coming at Cross City.

Let's hope they
make that turn.

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

[suspenseful music]

Damn it.

WESLEY KUTCH: It's not
making the course correction.

There was something
terribly wrong.

[suspenseful music]

This is Jacksonville Center.

I'm declaring an emergency.

[phone ringing]

Benzon here.

NARRATOR: Experts
at the National

Transportation Safety
Board are notified

of the escalating emergency.

Once the aircraft had
gone rogue, so to speak,

the next step is to
try to figure out why.

[radio chatter]

NARRATOR: To track down
the wayward Learjet,

controllers call
in F-16 fighters,

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

with air traffic control.

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

NARRATOR: Meanwhile, the NTSB
recruits Learjet investigator

Jim Tidball to the team.

Where is it right now?

NARRATOR: His first
task is to determine

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.

And after Memphis it was
headed towards Saint Louis.

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

[suspenseful music]

NARRATOR: 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

as to where the airplane was.

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.

NARRATOR: In the
air, the F-16 pilots

catch up with the rogue plane.

Can he see anything
in the cockpit?

NARRATOR: The windows
of the aircraft

provide an ominous clue.

ACTOR AS KENT OLSEN: No
movement, and the window

is covered in frost.

KENT OLSEN: If the
people are conscious,

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

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

The frosted over windscreen
and the darkened cockpit

and cabin indicated
that the crew

was probably no longer with us.

NARRATOR: 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.

NARRATOR: The plane is
spiraling toward the ground.

Investigators have no
idea where it will crash.

All they can do is wait.

They're going down.

NARRATOR: A Learjet
carrying pro golfer

Payne Stewart and
five other people

is falling from the
sky over South Dakota.

[suspenseful music]

ACTOR AS KENT OLSEN: Center,
I've got a crash site.

[somber music]

NARRATOR: The jet has
slammed into a hayfield

near Aberdeen, South Dakota.

There are no survivors.

[ominous music]

When NTSB investigators
arrive at the crash site,

they discover the aircraft
has completely disintegrated.

JOHN NANCE: When you've had a
vertical impact at high speed

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.

NARRATOR: Remarkably,
the Learjet's

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

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

JIM TIDBALL: 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.

OK.

Let's hear it.

[beeping]

NARRATOR: As they
listen, investigators

make a disturbing discovery.

[beeping]

It was eerie.

Because the airplane
is flying, and there

is no voice whatsoever.

NARRATOR: But one sound
provides a vital clue.

[beeping]

That's the cabin
altitude warning.

We are definitely looking at
a loss of pressure accident.

NARRATOR: The cabin
altitude alarm sounds when

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

lose vital cabin pressure.

Unfortunately,
investigators have

limited evidence to work with.

The disintegrated
wreckage is a dead end,

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

BOB BENZON: Because
of the chaotic nature

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.

NARRATOR: The team hopes
a flight simulation will

help determine what
happened on board

after the cabin lost pressure.

[beeping]

There goes the cabin
altitude warning.

Start the clock.

Emergency checklist.

Got it?

MITCHELL GARBER:
I think all of us

sort of had in our
heads the checklist

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.

NARRATOR: Benzon scans the
same emergency checklist that

was used by the Learjet pilots.

At 10,000 plus
or minus 500 feet,

cabin altitude control
pressure to the outflow valve

is trapped.

NARRATOR: It leads him to
an astonishing discovery.

BOB BENZON: We were surprised.

Because it implied
pretty strongly

that you need to troubleshoot
a pressurization problem.

First step should have
been don oxygen masks.

NARRATOR: The oxygen
mask instruction

is much further down the list.

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

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

NARRATOR: Investigators
finally have

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

Everything is fine,
then something causes

the plane to lose pressure.

[suspenseful music]

[beeping]

We've got a cabin
altitude warning.

Emergency checklist.

Uh--

They reach for their checklist
and start to troubleshoot.

[beeping]

What does the checklist say?

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,

and the oxygen mask were
sitting there unused.

[beeping]

NARRATOR: After 15
seconds without oxygen,

the crew would be
confused and disoriented.

Uh, read that again.

Before they can
solve the problem,

the crew loses consciousness.

BOB BENZON: The Lear
checklist, in a sense,

could lead a crew astray.

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

NARRATOR:
Investigators are never

able to determine
conclusively what caused

the plane to lose pressure.

[beeping]

BOB BENZON: The decompression
could have been caused

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.

So we don't know.

NARRATOR: But
whatever the reason,

the crew would
likely have recovered

if they had put their masks on.

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

today.

We've got a cabin
altitude warning.

Emergency checklist.

NARRATOR: Following
the investigation,

the NTSB recommends important
changes to aviation checklists.

We asked very strongly
that that checklist that we

suspected got the
crew in trouble

be changed to make
it clearer and more

useful in an emergency.

NARRATOR: The Federal
Aviation Administration

is quick to respond.

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

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.

Radio silence between pilots
and air traffic controllers

can mean many different things.

But only the physical evidence
can tell the real story.