All language subtitles for Air Disasters S21E08 1080p PMTP WEB-DL DDP5 1 H 264-BLOOM_track3_[eng]

Halloween 1994, a commuter

Halloween 1994, a commuter

plane circles outside Chicago
waiting for clearance to land.

plane circles outside Chicago
waiting for clearance to land.

Eagle flight 184,
descend and maintain 8,000.

Eagle flight 184,
descend and maintain 8,000.

Done.

8,000 Eagle 184.

8,000 Eagle 184.

Without warning, the
controls snap to the right.

Without warning, the
controls snap to the right.

The plane plunges straight
toward the ground.

The plane plunges straight
toward the ground.

Pilots who had questioned
the safety of an airplane.

The airplane will have a nasty
tendency to go out of control.

The airplane will have a nasty
tendency to go out of control.

Investigators travel the world for answers.

The crash makes Roselawn one
of aviation's darkest words.

The crash makes Roselawn one
of aviation's darkest words.

Ladies and gentlemen, we
are starting our approach.

We lost both engines.

...the mask over your nose.

- Emergency...
- Mayday!

- Emergency...
- Mayday!

Mayday!

Brace for impact!

It's gonna crash!

It's mid-afternoon
on October 31, 1994.

It's mid-afternoon
on October 31, 1994.

American Eagle flight
4184 left Indianapolis,

American Eagle flight
4184 left Indianapolis,

Indiana, 15 minutes ago.

It's heading to Chicago.

There are 68 passengers
and crew on board.

There are 68 passengers
and crew on board.

Happy Halloween, cowboy.

Thank you.

Thank you.

Flying through
the clouds, the aircraft

Flying through
the clouds, the aircraft

begins to experience
some turbulence.

I'm going to keep them in
their seats in this chop.

No sense in taking chances.

No sense in taking chances.

Captain Orlando Aguilar is

in command of today's flight.

It's supposed to be his day off.

He volunteered for this
flight to make extra money.

He volunteered for this
flight to make extra money.

His wife is expecting
their second child.

His wife is expecting
their second child.

Let's see if we
can get above this.

Is there any chance flight
184 can climb to one 6,000?

Is there any chance flight
184 can climb to one 6,000?

Flight 184,
maintain one 6,000.

First officer Jeff Gagliano

First officer Jeff Gagliano

is handling the flight duties
on this leg of the flight.

He programs the
autopilot to climb

He programs the
autopilot to climb

to a less turbulent altitude.

Jeff actually was working on
his dad's ranch in Wisconsin

Jeff actually was working on
his dad's ranch in Wisconsin

just before he came in for that
trip on Halloween that day.

just before he came in for that
trip on Halloween that day.

Getting on a horse or
getting in an airplane,

those were two of the
things that Jeff loved most.

Flight 4184 is
an ATR 72, a groundbreaking

new aircraft built in France.

new aircraft built in France.

Cost efficient and
comfortable, the plane has

Cost efficient and
comfortable, the plane has

become popular on short runs.

This flight is just
one of five short hops

This flight is just
one of five short hops

the crew will be making today.

Aguilar and Gagliano have flown
this route countless times

and know it by heart.

and know it by heart.

When you're flying from
Indianapolis to Chicago,

you're flying through
some of the busiest

you're flying through
some of the busiest

airspace in the world.

As flight 4184
approaches Chicago O'Hare,

As flight 4184
approaches Chicago O'Hare,

the pilots begin the
descent to 10,000 feet.

Chicago center, we have
discretion down to one

Chicago center, we have
discretion down to one

zero thousand.

We're on our way down now.

We're on our way down now.

Zero 184, roger.

Zero 184, roger.

In Chicago,
controller Michelle Willman

is returning from a break.

She's told that
traffic into O'Hare

is facing potential
delays because of weather.

is facing potential
delays because of weather.

She will have to be prepared
to put some flights on hold.

Operations into
and out of O'Hare

Operations into
and out of O'Hare

are handled on a priority basis.

It's not necessarily a first
come, first serve basis.

It's not necessarily a first
come, first serve basis.

International flights
arriving to O'Hare,

because of their fuel
status, get priority.

And then the turboprops
come in at the end.

And then the turboprops
come in at the end.

Eagle 184, holds
southeast on victor seven.

Eagle 184, holds
southeast on victor seven.

Chicago center, roger.

Hold southeast on victor seven.

Eagle 184.

Eagle 184.

Flight 4184 must now fly

a racetrack-shaped
holding pattern

over northwestern Indiana.

over northwestern Indiana.

Chicago center, Eagle
184, entering the hold.

Chicago center, Eagle
184, entering the hold.

Eagle 184, roger.

Eagle 184, roger.

Aguilar programs the
autopilot to keep the plane

circling at 10,000 feet.

I'll go up front and
see if they want anything.

Can I get you boys anything?

I'm good.

Man, this thing gets a real
high tech angle in these turns.

Yeah.

We're just wallowing
in the air right now.

We're just wallowing
in the air right now.

You want flaps 15?

It'll bring the nose down.

Sure.

And I guess Sandy's
going "woo" now.

And I guess Sandy's
going "woo" now.

Well, see y'all.

All right.

The crew
needs to let the airline

The crew
needs to let the airline

know about their delay.

It could affect the rest
of the day's schedule.

Crews use text
messages to communicate

Crews use text
messages to communicate

with dispatchers so they don't
tie up radio frequencies.

Should I let them know
how much fuel we got?

Should I let them know
how much fuel we got?

Sure.

Space F-U-E-L, is that...

Space F-U-E-L, is that...

we got 3,600 pounds.

Well, folks, once again,
this is the captain.

Well, folks, once again,
this is the captain.

I do regret to inform you that
air traffic control has put us

into a holding pattern up here.

We're holding for approximately
20 minutes out of Chicago

We're holding for approximately
20 minutes out of Chicago

at this time.

I do apologize for
all the delays.

I do apologize for
all the delays.

That's much nicer
now, flaps 15.

Once they let us out of the
hold and forget they're down,

Once they let us out of the
hold and forget they're down,

we'll get the overspeed warning.

Eagle flight 184,
descend and maintain 8,000.

Danny, 1,000 Eagle 184.

Danny, 1,000 Eagle 184.

Eagle flight 184,
should be about 10

Eagle flight 184,
should be about 10

minutes till you're cleared in.

Thank you.

The flight
is allowed to descend.

The flight
is allowed to descend.

Are we out of the hold?

No.

Just going down to 8,000.

Just going down to 8,000.

Then a warning.

Ah, I knew we'd do that.

Ah, I knew we'd do that.

The plane
is going too fast

to fly with its flaps extended.

I was trying to
keep it at 180.

I was trying to
keep it at 180.

Gagliano retracts the flaps.

There's a strange sound
coming through the fuselage.

There's a strange sound
coming through the fuselage.

Suddenly, the control column
turns sharply to the right.

Suddenly, the control column
turns sharply to the right.

God damn it!

Uh!

The controls won't budge.

Looks like the plane
is starting to recover.

Looks like the plane
is starting to recover.

The plane is
falling from the sky.

The plane is
falling from the sky.

The pilots begin
to recover control,

The pilots begin
to recover control,

but then it happens again.

Mellow out!

Mellow out!

Tony, rolled up.

See, that's it.

Nice and easy.

Pull up... terrain.

Pull up.

Pull up.

It was coming down too
steep to even try to land.

It was coming down at an...

I mean, a sharp angle...
a real sharp angle.

Flight 4184
has crashed into a field

Flight 4184
has crashed into a field

just outside Roselawn, Indiana.

Both pilots, the two
flight attendants,

and all 64 passengers are dead.

and all 64 passengers are dead.

The Roselawn crash
would soon become

The Roselawn crash
would soon become

one of the most important
accidents in aviation history.

one of the most important
accidents in aviation history.

It will lead investigators to
new conclusions about a string

of older crashes.

of older crashes.

The morning after the crash
of American Eagle flight 4184,

a team from the National
Transportation Safety Board

a team from the National
Transportation Safety Board

is on the scene just
outside Roselawn, Indiana.

Greg Feith is the
lead investigator.

The morning that we arrived at
the accident site, it was cold.

The morning that we arrived at
the accident site, it was cold.

It was overcast.

It was one of those
drizzly, dank days.

It was one of those
drizzly, dank days.

All you could smell was the
jet air or the kerosene fuel.

And because it
was muddy and wet,

you had that odor, or
that aroma, of dirt.

you had that odor, or
that aroma, of dirt.

And so with all of
those smells, that...

I mean, that really
evokes some emotion there.

I mean, that really
evokes some emotion there.

And now you have to
walk through that field

and actually start
to do your job.

With 4184, it was
one of those types

With 4184, it was
one of those types

of accidents where
there was very

little left of the airplane.

Investigators know that the way

Investigators know that the way

the wreckage is spread
out can tell them

how the plane hit the ground.

Because there was a fan-shaped
debris pattern and it was

spread out over a
very large area,

spread out over a
very large area,

we knew that the
impact was very shallow

but at a very high speed.

The airplane's
two flight recorders

are found intact in the tail.

are found intact in the tail.

They're taken to the
NTSB's labs for analysis.

They're taken to the
NTSB's labs for analysis.

The data on the recorders
could provide the clues

investigators need
to solve the mystery

investigators need
to solve the mystery

of what caused this crash.

But extracting the
data takes time.

But extracting the
data takes time.

In the meantime, investigators
look for the location

of key pieces of wreckage.

The first things we
typically look for are the four

The first things we
typically look for are the four

corners of the airplane.

The NTSB's Bob
Swaim leads that search.

The NTSB's Bob
Swaim leads that search.

You're looking for
the nose and the tail

and the two wingtips.

Because if you can tell
where the four corners

Because if you can tell
where the four corners

of the airplane are,
you get an initial idea

of whether the pilot
was in control or not.

of whether the pilot
was in control or not.

The plane's four corners

are far away from each other.

are far away from each other.

The nose and cockpit are
completely destroyed.

This tells investigators
that the plane

hit the ground nose first in
a shallow but rapid descent.

hit the ground nose first in
a shallow but rapid descent.

- Oh my god!
- Mellow it out!

- Oh my god!
- Mellow it out!

Mellow out!

Uh.

The fact that the
plane wasn't in a steep descent

on impact indicates
that the pilots

on impact indicates
that the pilots

had some control in the final
seconds before the crash...

they just ran out
of room to pull up.

Investigator Bob Swaim,
meanwhile, has recovered some

of the plane's
instruments... including

of the plane's
instruments... including

its Attitude Director
Indicator, also known

as the "artificial horizon."

as the "artificial horizon."

It's a key instrument that tells
pilots if they're flying level.

If it malfunctioned, it
could have misled the crew

If it malfunctioned, it
could have misled the crew

and caused them
to make mistakes.

A lot of the cockpit pieces
use a fluorescent paint,

or something similar.

And when they
contact each other,

And when they
contact each other,

little, little bits
of the paint transfer.

If we look at those with a
black light, we can see things

If we look at those with a
black light, we can see things

that the naked eye cannot see.

that the naked eye cannot see.

The force of the impact

has left tiny scratches on
the shattered instrument.

Swaim discovers that
the attitude indicator

seems to have been working.

seems to have been working.

Its final readings show
the plane was leveling off.

The instrument coincides
with the plane's

The instrument coincides
with the plane's

actual position on impact.

The discovery means that
the pilots knew their plane

The discovery means that
the pilots knew their plane

was diving toward the ground.

Investigator Greg Feith is
getting a clearer picture

Investigator Greg Feith is
getting a clearer picture

of the flight's final seconds.

Now he wants to know about
the history of this flight

Now he wants to know about
the history of this flight

before it fell from the sky.

One of the elements of the
investigation, of course,

One of the elements of the
investigation, of course,

was to look at air
traffic control.

Eagle 184, hold
southeast on victor seven.

Eagle 184, hold
southeast on victor seven.

Feith learns
that flight 4184 had been

Feith learns
that flight 4184 had been

in a holding pattern
southeast of Chicago

for 39 minutes before the crash.

When we looked at the air
traffic control records,

When we looked at the air
traffic control records,

we found that the
flow rate... that is,

the number of airplanes
that were going into Chicago

the number of airplanes
that were going into Chicago

O'Hare at the time...

had to be reduced
because of the weather

moving through the area.

Well, folks, I do
regret to inform you

Well, folks, I do
regret to inform you

that air traffic control has
put us into a holding pattern

up here.

And because of
the reduced rate into Chicago,

And because of
the reduced rate into Chicago,

we knew that 4184 was
going to have to hold

for a very long period of time.

for a very long period of time.

Chief investigator Greg Feith

wants to know more about
the weather conditions

along the holding pattern.

along the holding pattern.

So I want weather
data, pilot reports,

So I want weather
data, pilot reports,

atmospheric conditions,
Doppler radar,

or anything you can find.

Flight 4184
wasn't the only plane

circling O'Hare that day.

circling O'Hare that day.

Several other planes
were also on hold.

They all landed safely.

They all landed safely.

Interviews with the pilots
of some of those planes

Interviews with the pilots
of some of those planes

give investigators
an important clue.

One after another, they
all experienced icing...

One after another, they
all experienced icing...

some as much as 3/4 of an inch.

Many of the pilots
report the same thing...

Many of the pilots
report the same thing...

ice.

Dr. Marcia Politovich works
at the National Center

for Atmospheric Research.

for Atmospheric Research.

She's one of the leading
experts on icing,

and the danger it
poses to aircraft.

and the danger it
poses to aircraft.

This essentially changes
the shape of the wing

while you're in flight.

It creates drag,
it reduces lift,

It creates drag,
it reduces lift,

it causes performance
and handling problems,

and it's just not a
good thing to have.

and it's just not a
good thing to have.

Investigators examine weather records

Investigators examine weather records

from the day of the crash.

They find a disturbing pattern
of reports of icing all

They find a disturbing pattern
of reports of icing all

along a cold front near Chicago,
but the reports describe

the icing as light to moderate.

the icing as light to moderate.

Perhaps the size of
the commuter plane

was a factor in this crash.

was a factor in this crash.

Yeah, different planes
respond to icing differently.

A large plane will respond
differently than a small plane.

A large plane will respond
differently than a small plane.

Reasons for that are
both environmental

and having to do with
the airframe itself.

and having to do with
the airframe itself.

Large jets generally fly

above the dangerous
conditions inside a cloud,

above the dangerous
conditions inside a cloud,

but the ATR 72 can't do that.

but the ATR 72 can't do that.

Smaller plane
can't fly as high,

they're stuck in the icing
environment for longer.

they're stuck in the icing
environment for longer.

They may not have
de-icing equipment.

And if they get in
trouble, they may not

have enough excess
power to get out of it.

have enough excess
power to get out of it.

Investigators discover that flight

4184's holding pattern took
it through layers of clouds

4184's holding pattern took
it through layers of clouds

repeatedly.

Each time, it would have been
exposed to icing conditions.

Each time, it would have been
exposed to icing conditions.

4184 we knew had been
holding in an icing event.

There were layers
of clouds that they

There were layers
of clouds that they

have been flying in and out of.

Steve Frederick
was flying out of Chicago

on the morning of the crash.

on the morning of the crash.

He flew through the same
treacherous weather.

Each time that I went
through that cold front

Each time that I went
through that cold front

during that day, the
weather was intensifying.

The ice was getting
worse, and I was getting

The ice was getting
worse, and I was getting

more and more concerned.

Frederick asked his captain

to pass on a warning
about the weather

to pass on a warning
about the weather

so that other pilots would
be alerted to the danger.

I found out a little bit later
on that my captain had never

I found out a little bit later
on that my captain had never

warned dispatch,
and these pilots

never got the
warning about the ice

that was out there that day.

that was out there that day.

And there's no feeling in the
world that can compare to how

badly I felt at that moment.

badly I felt at that moment.

Greg Feith knows
that, along with American Eagle

flight 4184, controllers had
put several other planes into

flight 4184, controllers had
put several other planes into

a holding pattern near Chicago.

But they all landed safely
after coming out of the hold.

But they all landed safely
after coming out of the hold.

One of the issues about
air traffic control is that

the controllers can't just
look at their radar screen

the controllers can't just
look at their radar screen

and identify areas
of... of precipitation

or icing conditions readily.

The controllers don't know that
an airplane is sitting in icing

The controllers don't know that
an airplane is sitting in icing

conditions unless
the pilot provides

them with what they call a
PIREP, or a pilot report.

them with what they call a
PIREP, or a pilot report.

So if the crew,
in this case 4184,

So if the crew,
in this case 4184,

doesn't provide that
information to the controller,

then the controller doesn't know
that an icing event actually

is occurring out there.

is occurring out there.

Feith and his
team wonder if the flight

crew simply didn't
realize they were

flying into icy conditions.

flying into icy conditions.

The plane's cockpit voice
recorder provides the answer.

The plane's cockpit voice
recorder provides the answer.

Oh, that's much
nicer now... flaps 15.

Oh, that's much
nicer now... flaps 15.

Yeah.

Showing some ice now.

Showing some ice now.

I say let us out of
the hold and forget...

But nine
minutes before the crash,

the crew had noticed their
plane was picking up ice.

the crew had noticed their
plane was picking up ice.

The pilots must have
been aware that they

were flying through an
area of aircraft icing.

were flying through an
area of aircraft icing.

You haven't heard any more
from this controller, huh?

Nope, not a word.

Nope, not a word.

Then, two minutes
before the accident,

another remark draws the
attention of investigators.

another remark draws the
attention of investigators.

We still got ice.

I see what you mean.

The crew
knew about the ice.

Now investigators need to
know what they did about it.

Now investigators need to
know what they did about it.

The ATR 72 is equipped with
sophisticated de-icing devices.

The ATR 72 is equipped with
sophisticated de-icing devices.

It's crucial to know what the
crew did about the ice buildup

on their wings.

This time, the flight data
recorder provides the answers.

This time, the flight data
recorder provides the answers.

Almost 17 minutes
before the crash,

Almost 17 minutes
before the crash,

something sets off the
Master Caution Warning.

It could signal a problem in
one of the plane's systems.

It could signal a problem in
one of the plane's systems.

It could also mean the
electronic ice detector is

picking up the presence of ice.

picking up the presence of ice.

The flight data recorder shows
investigators that, in response

The flight data recorder shows
investigators that, in response

to the alert, Captain Aguilar
turned the plane's de-icing

to the alert, Captain Aguilar
turned the plane's de-icing

system to its maximum setting.

The NTSB's Charley Pereira
looks into the performance

of the ATR 72.

of the ATR 72.

The icing alert system
had sounded orally,

and they heard it and
they activated protection

and they heard it and
they activated protection

systems on the airplane.

And at the time of the accident,
the de-ice systems were on.

And at the time of the accident,
the de-ice systems were on.

The complete ice protection
system on the ATR 72 airplane

The complete ice protection
system on the ATR 72 airplane

consists of a combination
of what we call

anti-icing, which
are hot surfaces that

anti-icing, which
are hot surfaces that

don't allow the ice to form.

Windshields and
the propellers are

also heated on this airplane.

also heated on this airplane.

And then they have
de-ice systems,

which are on the leading
edges of the wings...

what are called pneumatic boots.

what are called pneumatic boots.

They're like rubber
inflatable chambers

that you blow air into, and they
expand kind of like a balloon.

And that cracks the ice, then
the ice flies off the airplane.

The flight data recorder

shows that after he activated
his de-icing system,

shows that after he activated
his de-icing system,

Captain Aguilar also pushed
the throttle forward slightly,

increasing the plane's speed.

increasing the plane's speed.

This increased the
speed of the air moving

over the plane's
wings, making it

harder for ice to settle there.

harder for ice to settle there.

The pilots had done
everything they could to deal

with ice buildup on the plane.

with ice buildup on the plane.

But were the anti-icing
systems actually working?

But were the anti-icing
systems actually working?

The shattered remains
of that de-icing system

The shattered remains
of that de-icing system

are now the main focus
of the investigation.

The airplane was designed

in France by a group of
French and Italian companies.

in France by a group of
French and Italian companies.

The de-icing system was
part of that design.

The de-icing system was
part of that design.

So the components were made by
small French vendors who were

So the components were made by
small French vendors who were

located around the
countryside, and then

they were assembled
there in Toulouse

into the final airplane.

into the final airplane.

Bob Swaim arrives
in France with pieces

Bob Swaim arrives
in France with pieces

of the de-icing system.

I brought some pieces
from flight 4184 to look at.

The key component to
the de-icing system

The key component to
the de-icing system

is probably not the
black rubber boot

that you see on the airplane,
but the timer that's inside

that you see on the airplane,
but the timer that's inside

the airplane, or the
timers, and the valves

that control those boots.

The force of the
crash has left telltale markings

The force of the
crash has left telltale markings

called "index marks."

They show the position of the
valves at the time of impact.

They show the position of the
valves at the time of impact.

Swaim compares them to
the original blueprints.

Does anything seem
out of the ordinary?

Does anything seem
out of the ordinary?

The trip to France
has led to yet another dead end.

The trip to France
has led to yet another dead end.

There was nothing wrong with
the plane's de-icing system.

There was nothing wrong with
the plane's de-icing system.

Thanks a lot.

I appreciate it.

Thank you.

Investigators are puzzled.

Showing some ice now.

If the crew knew
they had ice on their wing

If the crew knew
they had ice on their wing

and their de-icing
system was working,

why did the plane crash?

Other pilots think
they know the answer,

and decide to speak out.

and decide to speak out.

Their decision will
dramatically change the course

of this investigation.

of this investigation.

Three weeks after the crash,
American Eagle pilot Steve

Three weeks after the crash,
American Eagle pilot Steve

Frederick distributes a warning.

It says, "The ATR 72 fleet
operated by American Eagle

is dangerous in
icing conditions."

is dangerous in
icing conditions."

It claims American
Eagle pilots have

pleaded with the
airline and regulators

pleaded with the
airline and regulators

to do something about it...

but to no effect.

I drafted and distributed
a brochure in Chicago O'Hare

I drafted and distributed
a brochure in Chicago O'Hare

airport which essentially
warned people about the problems

with the ATR aircraft, and
made an outreach to the public

with the ATR aircraft, and
made an outreach to the public

in order to try and
get something done

because nothing was happening.

because nothing was happening.

Steve Frederick has more

than a professional interest
in the crash of Flight 4184.

than a professional interest
in the crash of Flight 4184.

Co-pilot Jeff Gagliano
was his close friend.

They graduated from
flight school together.

They graduated from
flight school together.

Gagliano's death
has hit him hard.

He made the comment one
time that he would probably

He made the comment one
time that he would probably

wind up dying because
of ice in an ATR,

and it was eerily prophetic.

and it was eerily prophetic.

A month after the
crash of American Eagle flight

4184, pilot frustration over the
ATR's airworthiness boils over.

4184, pilot frustration over the
ATR's airworthiness boils over.

A group of a dozen
pilots refuses to fly,

A group of a dozen
pilots refuses to fly,

citing risky weather.

The airline is forced
to cancel flights.

And then Steve Frederick
goes one step further.

And then Steve Frederick
goes one step further.

He voices his concerns on
a network TV morning show.

He voices his concerns on
a network TV morning show.

We were told this airplane
will try and kill you.

If you get too slow in
ice, the... the airplane

will have a nasty tendency
to go out of control.

will have a nasty tendency
to go out of control.

When I came back to
flying after my appearance

on "Good Morning
America," I was summarily

on "Good Morning
America," I was summarily

suspended without pay.

The public protest leads

investigators to wonder
if the ATR 72 has

investigators to wonder
if the ATR 72 has

a deadly vulnerability to ice.

Merci.

Merci.

Investigator Charley Pereira

visits the ATR's French
manufacturer, Aerospatiale,

visits the ATR's French
manufacturer, Aerospatiale,

to learn more about
the plane's history.

We embarked on
a research effort

We embarked on
a research effort

to try to identify
all previous ATR 42

and 72 roll control incidents.

and 72 roll control incidents.

He finds a
disturbing pattern.

He finds a
disturbing pattern.

And about five...

five of those were found to
be similar, after the fact,

five of those were found to
be similar, after the fact,

in our review to
the Roselawn case.

One such incident
took place in December 1988

One such incident
took place in December 1988

in Mosinee, Wisconsin.

in Mosinee, Wisconsin.

An American Eagle
ATR 42 had been

preparing to land
in icy conditions

at Central Wisconsin Airport.

at Central Wisconsin Airport.

The airplane was on approach
in severe icing conditions...

The airplane was on approach
in severe icing conditions...

described as freezing
drizzle and freezing rain.

Captain Mike Bodak
was the pilot that day.

Captain Mike Bodak
was the pilot that day.

We were just on the
last two legs of our trip

before we'd be done with work,
and we were doing our descent.

before we'd be done with work,
and we were doing our descent.

Everything was
proceeding normally.

Everything was
proceeding normally.

Negative ice, just wet.

We'll call the flight
center and let them

know we're turning inbound.

know we're turning inbound.

I hear in the tail
a sound, "baa, baa,

baa, baa, baa, baa,"
like that, but it

baa, baa, baa, baa,"
like that, but it

just got louder and louder.

We have no idea
what is occurring.

We have no idea
what is occurring.

I thought initially a propeller
blade may have come off.

I thought initially a propeller
blade may have come off.

It was as if the steering wheel
wasn't connected to anything.

The plane stalls.

The plane stalls.

Its wings can't generate enough
lift to keep it in the air.

As I see I'm not getting
any of the airplane back,

I come up on the power levers...

I come up on the power levers...

all the way.

The engines are now
really trying to fly.

And at this point, I'm getting
some of the airplane back.

And at this point, I'm getting
some of the airplane back.

So I make a forward motion
to try and break the stall,

and it's still going
to "terrain, terrain"

and it's still going
to "terrain, terrain"

and I don't have the
airplane back yet.

And my first officer says...

Drop!

And I say, Max RPM.

And I say, Max RPM.

Terrain, terrain.

And he throws the
props from 86% to 100%,

And he throws the
props from 86% to 100%,

and instantaneously, boom,
we fly out of this stall.

and instantaneously, boom,
we fly out of this stall.

Woo!

The plane is less than
1,200 feet above the ground.

Captain Bodak has learned a
sobering lesson about the ATR.

Captain Bodak has learned a
sobering lesson about the ATR.

There was no warning.

There was no warning.

The plane stalled
without any warning.

Planes do have warnings for
stalls, but in this case

Planes do have warnings for
stalls, but in this case

there was no warning.

I got... the first warning
that I was in a stall

was I was in a stall.

But other
pilots weren't as lucky.

But other
pilots weren't as lucky.

An ATR 42 operated
by an Italian airline

was flying over the
Alps en route to Germany

was flying over the
Alps en route to Germany

in October 1987.

The plane lost control and
crashed in the mountains,

The plane lost control and
crashed in the mountains,

killing all 37 people on board.

Ice was the main factor,
but the final report

Ice was the main factor,
but the final report

blamed pilot procedures.

For investigators,
it's really important

For investigators,
it's really important

to look back at historical
information about any airplane.

You want to look for trends.

What they would
find is a troubling detail

What they would
find is a troubling detail

with this plane's history.

Did any of your studies
uncover a wing design flaw?

Did any of your studies
uncover a wing design flaw?

Charley Pereira wants
to know if the engineers who

Charley Pereira wants
to know if the engineers who

built the plane could
explain why an ATR 72 would

go so badly out of control.

go so badly out of control.

To his surprise, he
learns they knew that it

had a susceptibility to icing.

had a susceptibility to icing.

You've seen the flight data
from the accident flight.

Where will the ice have
formed to cause that?

Where will the ice have
formed to cause that?

When I asked one
of their oldest,

most senior aerodynamicists
who couldn't speak any English

at all what he thought would
be the shape and location

at all what he thought would
be the shape and location

of an ice accretion
that could cause

of an ice accretion
that could cause

the behavior that we saw
on the flight recorder

for the Roselawn airplane.

He drew up the airfoil section...

He drew up the airfoil section...

a little shape just
behind the de-ice boots...

and said "this was it."

and said "this was it."

And the translation
was that this is

what will cause this problem.

After the de-icing boot.

After the de-icing boot.

Investigator Charley Pereira

is beginning to understand
how ice can affect the wings

is beginning to understand
how ice can affect the wings

of the French-built plane.

If the ice built
up behind the boot,

If the ice built
up behind the boot,

the crew would have
no way to clear it.

We still got ice.

And even a
small amount of ice

And even a
small amount of ice

can have a devastating
effect on an airplane.

Ice can disrupt the smooth
movement of air over the wing.

But how could so much ice
build up behind the boot?

But how could so much ice
build up behind the boot?

Investigators contact Dr. Marcia
Politovich for assistance.

Investigators contact Dr. Marcia
Politovich for assistance.

The NTSB called us to
help them analyze weather

The NTSB called us to
help them analyze weather

conditions in this case.

Her research shows that
the pilots of flight 4184

Her research shows that
the pilots of flight 4184

likely flew into something
they'd never even heard of,

likely flew into something
they'd never even heard of,

something even more
dangerous than ordinary ice.

Yeah, based on the weather analysis,

Yeah, based on the weather analysis,

it looked to us like
the kind of icing

that the plane encountered was
from supercooled large drops.

that the plane encountered was
from supercooled large drops.

Now, "large" is relative.

What we're talking
about large here

is about the size
of a human hair.

is about the size
of a human hair.

Supercooled large
droplets are about 100

times smaller than a raindrop.

They form inside storm
clouds when the temperature

They form inside storm
clouds when the temperature

is near freezing.

But the drops don't freeze
until they come into contact

But the drops don't freeze
until they come into contact

with something solid...

like the wing of an airplane.

Conditions that day were
ideal for the formation of

these tiny, freezing droplets.

these tiny, freezing droplets.

On every lap of its
holding pattern,

flight 4184 flew through
layers of clouds that

flight 4184 flew through
layers of clouds that

hid a small but lethal element.

They just put that poor
guy in the wrong place

They just put that poor
guy in the wrong place

at the wrong time.

Investigators learn that

supercooled large
droplets, or SLDs,

supercooled large
droplets, or SLDs,

have a distinctive
way of accumulating

on an aircraft wing.

Ordinary ice accumulates
on the leading

edge of the wing where de-icing
boots can get rid of it easily.

edge of the wing where de-icing
boots can get rid of it easily.

But SLDs act differently.

These supercooled drops
hit the wing and slide

These supercooled drops
hit the wing and slide

back over it before freezing.

This forms a ridge
behind the boots,

This forms a ridge
behind the boots,

out of reach of the
de-icing system.

So as 4184 was flying in
that type of environment,

So as 4184 was flying in
that type of environment,

rather than the water droplet
freezing on the protected

surface, or the de-ice
boot, it actually

surface, or the de-ice
boot, it actually

ran behind the de-ice boot and
froze on the metal surface.

The pilots can't
get a good view of their wings

The pilots can't
get a good view of their wings

from the cockpit.

It's showing some ice now.

They would have been
utterly unaware of the danger

They would have been
utterly unaware of the danger

taking shape.

For Greg Feith,
the investigation

is coming to a head.

His investigators think they
know why flight 4184 crashed,

His investigators think they
know why flight 4184 crashed,

but they can't prove it.

but they can't prove it.

To make matters worse,
the plane's manufacturer

suggests that the Roselawn
crash wasn't caused by an ice

suggests that the Roselawn
crash wasn't caused by an ice

buildup, but by poor piloting.

The NTSB thought it
was an aircraft problem.

And the French
aircraft manufacturer

thought it was a
pilot problem, and not

thought it was a
pilot problem, and not

their particular product.

Feith wants
to know if there

had been problems with ice on
ATR-built planes in the past.

had been problems with ice on
ATR-built planes in the past.

He finds troubling similarities
between some incidents

He finds troubling similarities
between some incidents

dating back decades.

Using data from
flight data recorders,

Using data from
flight data recorders,

investigators look at ailleron
movements from flight 4184

and compare them to
the other incidents.

and compare them to
the other incidents.

They discover that
on all those flights,

They discover that
on all those flights,

the ailleron deflected
in exactly the same way.

the ailleron deflected
in exactly the same way.

There's no input at
all from the pilots.

We knew that all
of these aillerons

We knew that all
of these aillerons

were being commanded to move...

not by the pilot, but in
fact, the disrupted airflow

created by the icing event that
the airplane had encountered.

created by the icing event that
the airplane had encountered.

The physics of ice
buildup explains

The physics of ice
buildup explains

why the control column on flight
4184 snapped to the right.

why the control column on flight
4184 snapped to the right.

Air turbulence on the
wing was so powerful

that it lifted the ailleron,
which caused the plane to roll.

that it lifted the ailleron,
which caused the plane to roll.

Since the ailleron is
attached to the control column

by a cable, it jerked the
control yoke to the right.

by a cable, it jerked the
control yoke to the right.

The force of the turbulence
pulling on the ailleron

was so great, that even two
pilots trying to counter steer

was so great, that even two
pilots trying to counter steer

weren't able to bring
the ailleron back down.

The forces were determined
to be about 250 pounds.

The forces were determined
to be about 250 pounds.

So for the pilot, it would have
been trying to roll against 250

So for the pilot, it would have
been trying to roll against 250

pounds of aerodynamic force.

For chief
investigator Greg Feith,

For chief
investigator Greg Feith,

supercooled water droplets
that left a ridge of ice

on the wings are now
the prime suspect.

on the wings are now
the prime suspect.

But how to prove it?

We had to try and model
this icing event some way.

We had to try and model
this icing event some way.

At the
time of the crash,

NASA was just beginning to
study the effect of supercooled

NASA was just beginning to
study the effect of supercooled

large droplets on airplanes.

large droplets on airplanes.

Back in 1994,
pilots didn't know

what SLD, or supercooled
large droplets, were.

what SLD, or supercooled
large droplets, were.

There was very little
information in the pilot

community, and
there was actually

very little information in the
aviation industry about SLD.

very little information in the
aviation industry about SLD.

Investigators first turn to NASA for help.

Together, they launch
a daring experiment.

Together, they launch
a daring experiment.

They use an Air Force tanker
plane to create a cloud

They use an Air Force tanker
plane to create a cloud

of supercooled water droplets.

An ATR 72 flies
behind the tanker.

Yellow dye in the water
shows investigators how

Yellow dye in the water
shows investigators how

the droplets cover the plane.

The test should solve
the final mystery...

The test should solve
the final mystery...

how had ice caused flight 4184
to go so badly out of control?

how had ice caused flight 4184
to go so badly out of control?

One of the primary
purposes of flying the ATR 72

in behind the tanker was
to understand how the ice

in behind the tanker was
to understand how the ice

accumulated on the airplane.

But more importantly, the
effect of that ice in varying

But more importantly, the
effect of that ice in varying

configurations of the
airplane on the flight control

surfaces... that
is, the aillerons.

Investigators make a startling discovery.

Investigators make a startling discovery.

A seemingly harmless
action meant

to increase comfort on the
plane may have led to disaster.

to increase comfort on the
plane may have led to disaster.

I think it's a real high
deck angle in these terms.

Yeah.

Captain Aguilar knows
that the plane's high nose

angle is producing
an uncomfortable tilt

angle is producing
an uncomfortable tilt

in the passenger cabin.

You want flaps 15?

That'll bring the nose down.

Sure.

Extending the flaps would have

the effect of lowering
the plane's nose,

making the ride
more comfortable.

making the ride
more comfortable.

When investigators
duplicate this maneuver,

they find that it has a dramatic
effect on where the ice ridge

they find that it has a dramatic
effect on where the ice ridge

forms on the plane's wing.

The flaps make the icing
problem even worse.

The flaps make the icing
problem even worse.

By exposing more of the
upper surface of the wing

to the oncoming water droplets.

to the oncoming water droplets.

And that's one of the
reasons why we got...

the ridge of ice where
we got it was because

of the flaps' 15 configuration.

of the flaps' 15 configuration.

Oh, that's much
nicer now, flaps 15.

Yeah.

The crew
of flight 4184

The crew
of flight 4184

is unaware that a
ridge of ice more

than a centimeter
high has built up

than a centimeter
high has built up

on the surface of their wings.

Eagle flight 184,
descend and maintain 8,000.

Eagle flight 184,
descend and maintain 8,000.

Down to 8,000, Eagle 184.

The ice
buildup has no effect

on the flight until first
officer Gagliano begins

on the flight until first
officer Gagliano begins

his descent to 8,000 feet.

I knew we'd do that.

I knew we'd do that.

The descent
increases the plane's airspeed.

This triggers a warning
from the flight computer,

This triggers a warning
from the flight computer,

telling the crew
they're flying too

fast with the flaps extended.

I was trying to
keep it at 180.

I was trying to
keep it at 180.

Gagliano now
retracts the flaps,

but the routine gesture
has a dramatic effect

but the routine gesture
has a dramatic effect

on the plane's aerodynamics.

When they retracted the flaps
as they started their descent

When they retracted the flaps
as they started their descent

down to 8,000 feet, the
airplane pitched back up

into a very nose-high attitude.

into a very nose-high attitude.

Airflow over
the ice-laden wing

was disrupted when the
nose lifted back up.

was disrupted when the
nose lifted back up.

That created the turbulence
that pulled up the Aillerons,

That created the turbulence
that pulled up the Aillerons,

sending the plane into a roll.

The plane stalled, and
tumbled from the sky.

Damn!

Damn!

Uh!

Had this crew had about 2,000
to 3,000 more feet of altitude,

Had this crew had about 2,000
to 3,000 more feet of altitude,

there's a high probability
that they would have been

able to salvage or
recover the airplane

before it struck the ground.

before it struck the ground.

The NTSB has
uncovered a deadly flaw

The NTSB has
uncovered a deadly flaw

in a popular airplane.

There's a growing concern
that unless something is done,

There's a growing concern
that unless something is done,

this kind of accident
would soon happen again.

this kind of accident
would soon happen again.

Investigators conclude that problems

with the ATR's wing design make
it vulnerable to this menace.

with the ATR's wing design make
it vulnerable to this menace.

The Federal Aviation
Administration

takes drastic action.

takes drastic action.

We are going to issue
an airworthiness directive

this afternoon
that will preclude

this afternoon
that will preclude

the operation of these aircraft
into known icing conditions.

The FAA
takes swift action,

The FAA
takes swift action,

banning all models
of the aircraft

from flying in icy conditions.

from flying in icy conditions.

This throws regional airlines
like American Eagle into chaos.

Public concern over the
safety of ATR airplanes

Public concern over the
safety of ATR airplanes

grows in the aftermath
of the Roselawn crash.

The most controversial charge
is that the FAA had relied

The most controversial charge
is that the FAA had relied

on the French authorities to
test and certify the aircraft,

on the French authorities to
test and certify the aircraft,

and then just rubber-stamp
their results.

Therefore, the ATR 72 was
never really tested by the FAA

in any way, shape,
and form, as though it

in any way, shape,
and form, as though it

was manufactured here.

The plane's
French builder

proposes to fix the problem
by making the de-icing boots

proposes to fix the problem
by making the de-icing boots

wider so they cover a
larger part of the wing.

The company also rewrites
operating procedures,

The company also rewrites
operating procedures,

forbidding pilots
from using the flaps

or flying on autopilot
in icing conditions.

or flying on autopilot
in icing conditions.

In response, the FAA
issues an amendment

to their earlier directive,
loosening operating

restrictions on the ATRs.

Most airlines decide
not to take any chances.

Most airlines decide
not to take any chances.

They move their ATRs to the
south, where a warmer climate

They move their ATRs to the
south, where a warmer climate

would reduce the risk of ice.

The crash at Roselawn set
off a flurry of new research

The crash at Roselawn set
off a flurry of new research

into aircraft icing and the
conditions that produce it,

resulting in improved
aircraft anti-icing

resulting in improved
aircraft anti-icing

systems and pilot training.

Upgrades in air traffic
control technology,

as well as advances in
weather forecasting,

as well as advances in
weather forecasting,

satellites and radar, provide
improved and critical data.

satellites and radar, provide
improved and critical data.

The tragedy in the investigation
that followed the crash

of flight 4184 led to
industry-wide changes that made

of flight 4184 led to
industry-wide changes that made

cold weather flights safer.

There's a lot of
weather data out there...

There's a lot of
weather data out there...

satellites, radars, surface
ops... and it just keeps

satellites, radars, surface
ops... and it just keeps

getting bigger and bigger.