All language subtitles for Mayday - S02E02 - A Wounded Bird (One Wing Flight) WEBDL-1080p_track3_[eng]

(narrator): A botched takeoff
in Buenos Aires...

...stuns investigators.

- To me, that was unprecedented.
- Get out of it! Get out of it!

(narrator): A shocking error...

- We're stuck in it!

(narrator): ...lies behind
the deadly free-fall
of American Airlines Flight 587.

(people screaming)

And when Continental
Connection 3407 stalls,

the flight crew's reaction
is baffling.

- Not only did they not respond
correctly,

they responded
in the exactly opposite way.

(narrator): Commercial pilots
undergo hundreds of hours
of training and testing.

Still, experienced pilots
make rookie mistakes.
(screaming)

- Rookie errors
don't necessarily occur
to just rookie pilots.

It can happen
to the most experienced pilot.

- Mayday, mayday.

- It's going up!

(indistinct radio chatter)

(narrator): It's 8:30 p.m.
at Jorge Newbery Airfield
in Buenos Aires, Argentina.

(ATC): Wind: 020 at 5.

Altimeter: 30.10.

(narrator):
A Boeing 737 flight crew
prepares for takeoff.

Their plane is operated
by the Argentinean airline LAPA.

- D'you make it?
- No.

- Hey, Captain.
- Hey.

(narrator):
The captain of LAPA Flight 3142
is Gustavo Weigel.

He's an experienced pilot
who's been flying
for more than 20 years.

- Everything okay?

- Fine. Everything's fine.

- We're just waiting
on our fuel.

(narrator):
First Officer Luis Etcheverry

has logged more than 500 hours
in the 737.

- Total fuel required:
8,500 kilograms to be
transferred to the wings.

(narrator): Tonight's flight
is a little over an hour.

Its destination:
the city of Cordoba,

400 miles west of Buenos Aires.

Along with the pilots,
three flight attendants
and 95 passengers are on board.

- Before-start checklist.
- Before-start checklist.

(narrator): The crew is making
last-minute preparations
for takeoff.

- Cockpit preparations?
- Completed.

(in Spanish):

The relationship
between the crew
seemed to be very close.

It appeared
that they were friends.

- You guys should come
for dinner in Córdoba.

- That sounds good.
What should we bring?

- You can bring the ice cream.
- You know, we're seconds away.

You should probably
get back there and strap in.

- Alright, guys,
it's been a pleasure.
See you soon.

- Cleared for takeoff,
LAPA 3142.

(engines revving)
- Taking off.

(narrator): Flight 3142 speeds
down the runway.

As the aircraft lifts off,
it's immediately apparent
that something is wrong.

(in Spanish):

The plane begins to take off,
but instantly it starts shaking,
like it was going to fall apart.

We all knew
something was going wrong.

- What the hell?

(narrator): Hurtling forward
at 160 knots...

...the 737 slams violently
back to the ground.

They're now headed straight
for a busy highway
and an industrial gas plant.

- Stop, stop, stop, stop.

(in Spanish):
It was very quick.

I just looked at my friends
and I braced my head.

- No, no, no, no, no!
- The airplane crossed
a busy highway without warning.

It killed people
who were commuting
at that time in their cars.

- Stop! Stop!

(narrator): Flight 3142 slams
into the gas plant.

(Spanish): I could feel
extreme heat all around me.

I was suffocating.

And I needed to get out,
but I couldn't release
my seatbelt.

(narrator): Rescuers race
to the site of the crash,

but survivors on board
don't have much time.

Fire threatens to consume
the entire plane.

(Spanish):
I felt like I was dying.

(coughing)
And someone said to me,
"Get out!"

(narrator):
Though badly injured,

Marisa Beiro is lucky
to survive.

The crash has killed
60 passengers,

three crew members,
including both pilots,

and two motorists.

It's a disaster
unlike anything Buenos Aires
has ever seen before.

- It was a major calamity.

It involved automobiles,
it involved a natural-gas
regulating plant.

- It's a lot of smoke.
Hard to see anything.

(narrator): Horacio Larrosa
is a senior investigator

for Argentina's
Accident Investigation Unit.

(in Spanish):
You try to focus on the job,

and look for details
that later on
could be harder to find,

once the rescue teams
have finished their work.

- Neither pilot survived.
- Okay.

(narrator): Any hope
of finding out what went wrong
lies in the wreckage.

Because the 737
is American-made,

the U.S. National
Transportation Safety Board
joins the investigation.

- Whatever you need,
we're here to help.

- There was just a tremendous
amount of public concern,

and a great deal
of encouragement to try to solve
this definitively and quickly.

- One of the big questions was:

How did this aircraft
go off the end of the runway,
especially on takeoff?

- Look here.

(narrator): The wings
of the downed plane reveal the
first clue for investigators.

(in Spanish):
I was able to observe,
with some of my colleagues,

that the aircraft's flaps
were apparently not extended.

- Let's get this wing piece
outta here.

(narrator): For takeoff,
737 pilots must always extend
the plane's wing flaps.

The flaps increase
the area of the wing
and give it extra lift.

Without them, a fully loaded 737
cannot get off the ground.

Did the flaps retract
during the crash,

or were they never deployed
in the first place?

- When you see something
that's out of place,

you begin to wonder:
What has happened?

Has someone raised the flaps,

or has some electronic
or hydraulic intervention
made the flaps come up?

- We need to study
the entire system.

(narrator): In the meantime...

- Oh, oh. Yep.

(narrator):
...the team on site retrieves
the plane's black boxes.

- The importance
of flight recorders
in accident investigation

cannot be overemphasized.

(narrator):
But they're badly damaged,

and immediately sent
to Washington for repair.

- There was a good deal
of pressure to get back
the cockpit voice recorder

and the flight-recorder
information in a timely way.

(narrator): In a nearby hangar,

investigators carefully examine
every wire, gear and screw
of the wing flaps.

- Actuators seem fine.

(narrator): They focus on a part
that controls
the flaps' movement:

the jackscrew, which acts much
like a jack used to lift a car.

As it turns,
it moves a nut that extends
or retracts the flaps.

- That nut travels
along the shaft.

It stops at various places
to indicate various degrees
of flap extension.

We had discovered
the nuts on the screw
were in the retracted position.

(narrator):
The flap lever from the cockpit
confirms the finding.

- The lever's pretty banged up,
but it sure looks like
it's in the flaps-up position.

(in Spanish):

It had left a mark
with the flap lever
in the up position.

So there was no chance
that it had moved
during the accident.

(narrator): The astonishing
discovery reveals the flaps
were never extended.

Flight 3142's configuration
for takeoff was all wrong.

Baffled investigators wrestle
with a difficult question.

- How could an attempted takeoff
be made with the flaps
in this position?

(passengers screaming)

(narrator): Investigators want
to know how the experienced crew
on board Flight 3142

took off
without their flaps extended.

- No, no, no, no, no, no!

(in Spanish):
You find yourself wondering:

Why did this action
not take place

when it is indispensable
for flight?

- Can we get the FDR data
on the screen?

(narrator):
The crucial black-box data
finally arrives from Washington.

Investigators hope
this will help explain
what happened.

(sighing)
- Great.

Let's go to the flap positions
and engine performance.

(narrator):
The flight data recorder
confirms suspicions.

- With no flaps... they stall.

They get the plane
back down here...

...50 metres from the end
of the runway.

There's no way
they could stop in time.

(narrator): It verifies
the flaps were not extended,
but not why.

Investigators turn
to the cockpit voice recorder
for clues.

(Spanish): The only possibility
was in the voice recorder.

- Everything okay?
- Fine. Everything's fine.

(narrator): Investigators begin
by listening to what was
happening just before takeoff.

- Waiting on our fuel?
- So besides him,

any other guys
you're interested in?

- Yes, but you don't know him.

I haven't seen him in a while.

(narrator): What they hear
from the crew is astounding.

(flight attendant):
The whole thing's
getting complicated.

- You're breaking my heart.

(narrator): Not only unexpected,
but entirely unprofessional.

- They should be running
checklists.
What's going on?

- They're required to have
a sterile cockpit.

Once you start the engines
up to 10,000 feet,

you talk only
about operational procedures.

And this is to prevent
distraction.

- You guys should come
for dinner in Córdoba.

- That sounds good.
What should we bring?
- You can bring the ice cream.

- Okay.
(scoffing)

- Before-start checklist.

- Before-start checklist.

- They're talking
about planning a meal together,

they're talking
about their romantic lives.

And this is interspersed
with the checklist.

- Hey, you know I'm with you
in the good times and the bad,
moron.

It's a good thing
I'm nothing like you.

- You're full of it.
You're only with me
for the good times.

- Cockpit preparations?
- Completed.

- The checklists
were interrupted
and were performed incorrectly.

- Flaps are part
of the before-takeoff checklist.
Do they even do that?

- Anti-ice?
- Off.

- Start levers?

- Idle stop.

- Ready to taxi, 3142.

(ATC): 3142, ready to taxi,
Charlie-5 to runway 1-3.

- Charlie-5 to 1-3.
- Don't smoke all of it.
Give me a puff at least.

- Even a puff
can make you old and grey.

- Thanks.
- They're actually smoking
in the cockpit.

- The three were passing
a cigarette, which is prohibited
by the company.

They're not supposed
to be smoking
in the cockpit at all.

- No mention of flaps.

They're starting to taxi.

- You should probably head
back there and strap in.
- Alright, guys.

(narrator): The reason the crew
failed to extend the flaps
is now clear.

- Hurry, hurry.

(narrator):
They were simply too distracted
by their own careless behaviour.

(ATC): Cleared for takeoff,
LAPA 3142.

(narrator):
But what investigators hear next
is even more shocking.

(alarm sounding)
- There it is.

(narrator):
It's an alarm warning the crew
of their mistake.

(in Spanish):
The sound of the alarm was loud.

It could be heard perfectly
in the voice recorder
many times.

(alarm sounding)

- I don't know
what the alarm is, my friend.
Everything seems fine.

- Okay, pause.
How can they ignore that?

(narrator): How could a crew
forget to perform

one of the most basic
takeoff procedures,

and then go on to ignore
the loud, persistent warning

designed to alert them
to their serious mistake?

(in Spanish):

I believe they didn't understand
the importance of this alarm,

which was absolutely critical
for takeoff.

(narrator): Sixty-five people
lost their lives

because the crew
wasn't paying attention
to what they were doing.

(alarm sounding)

- If the alarm went off
and it warned that the flaps
weren't configured,

why didn't they do something?

(narrator):
In their final report,

investigators stress the need
for pilots to always comply
with the sterile cockpit rule.

It restricts crew conversation
and helps minimize distractions
during key parts of the flight.

- By not maintaining
a sterile cockpit
and following every checklist

and doing exactly
what you're supposed to do...
people die.

(narrator): But sometimes,

following strict operational
discipline can still lead
to catastrophe.

- Even when pilots are following
the procedures correctly,

you can still have
a rookie error.

- Get out of it! Get out of it!

(narrator): Just nine weeks
after the 9/11 attacks,

New York's John F. Kennedy
Airport is busy again.

American Airlines Flight 587
is carrying 251 passengers
enroute to the Caribbean.

(groaning)

- Your leg.
You check the rudders.

(narrator):
The crew is preparing the plane
for takeoff.

- Rudders, check.
Taxi checklist is complete.

- Okay.

(narrator): Captain Ed States
is a former military pilot

who joined American Airlines
16 years ago.

First Officer Sten Molin
has racked up more
than 4,000 hours of flying time

and is the pilot flying today.

- Winds checked.

- American 587,
follow Japan Air Boeing 747
ahead.

- Follow Japan Air,
American 587.

(narrator): Flight 587's
flight plan takes it out
over New York's Jamaica Bay

before heading south
to the Dominican Republic.

- You have the airplane.

- The captain indicated
the first officer would be
the flying pilot on this leg.

The captain designated him
to fly the flight.

That's routine.
Uh, it's the captain's choice.

- American 587, Kennedy Tower.
Caution:

Wake turbulence,
runway 3-1 left.
Taxi into position and hold.

- You happy with that distance?

- Ah, we'll be alright
once we get rolling.

He's supposed to be five miles
by the time we're airborne.
That's the idea.

- So you're happy.

I'm on the roll.

Thank you, sir.

- V1. Rotate.

(narrator): Flight 587 lifts off
at 9:14 a.m.

(banging)
- American 587, heavy.

Climb and maintain 1-3,000.

(rumbling)

(narrator): Residents of Queens,
New York, hear the familiar
sound of jets overhead.

- Planes, you know,
take off and land.

They fly
right over the peninsula
every 45 seconds.

It was just a normal thing.

(narrator): High above,
a patch of turbulence
rocks Flight 587.

- Ooh, boy.
(indistinct chatter)

- Max power.

(alarm sounding)
- You alright?

- Yeah. I'm fine.
- Hang onto it. Hang onto it.

- Let's go for power, please!

(narrator):
2,300 feet above the ground,
disaster strikes.

- Holy crap!
(passengers screaming)

(narrator):
The plane is losing altitude
and falling out of the sky.

- What the hell are we into?

(narrator): There are more
than 68,000 pounds
of flammable jet fuel on board.

(screaming)
- Oh, my god!

(alarm sounding)
(narrator): Flight 587 plummets
towards Queens, New York.

- We're stuck in it!
- Get out of it!
Get out of it! Get out of it!

- The house started vibrating
very heavily. You know,
this all happened really quick.

(sirens wailing)
(people shouting)

(narrator): At impact, the fuel
ignites a massive fireball,

engulfing several homes.

- The plane crashed
pretty much in the backyard,
in the street, uh, exploded.

(sirens wailing)

- God, it's a plane!
- It looks like a war zone.

(narrator): All 260 people
on board are dead,

as well as five people
on the ground.

Many wonder:
Was this an accident?

(sirens wailing)

- We were still heavily involved
in the investigation of 9/11.

I immediately got concerned
as to:

Was this another
terrorist attack?

(narrator): That means the FBI
and the NTSB

will be investigating
this air crash together.

- This accident occurred
so close to the tragedy of 9/11

that we naturally jumped
to conclusions,

and we had to force ourselves
to back up

and carefully study
the evidence.

They came in fast and steep.
Let's hope
it's not what we think.

(narrator): Their mission
is to answer a vital question:

Was this terrorism,
or an accident?

Any evidence of a bomb
would be in the debris.

- Everything else stays here
for now.

- Experts would be physically
examining all of the parts
of the plane

to see if there was any
indentations...

indicating that the explosion
was inside
and pushed everything out.

(narrator): But the crash site
and tests for explosive residue

reveal no evidence that a bomb
took down the plane.

- We learned very quickly that,
in fact,

it was not a terrorist event.

(narrator): Then a discovery,
three quarters of a mile
from the crash,

provides investigators
with a massive clue.

- We found
the vertical stabilizer
miles and miles away.

(narrator):
The vertical stabilizer is found
in Jamaica Bay,

between the airport
and the crash site.

The location tells investigators
it broke off while the plane
was still in the air.

(beeping)

- That was a good first...
first step for us.

(narrator):
The vertical stabilizer
is part of the tail.

Along with the horizontal
stabilizer,

it's critical for stable flight.

- You can't fly without a tail.
I mean, you can't.

The airplane's gonna go down.
There's nothing you can do
about it.

(narrator): NTSB investigators
are under pressure to find out
what happened to the A300,

one of the world's
most popular aircraft.

- How does a vertical stabilizer
just fall off?

- I'd been
Investigator-in-Charge
of the NTSB for, at that time,

oh, gosh, 20 years or so,

and I had never seen anything
quite like this.

(narrator): Investigators turn
to the plane's
cockpit voice recorder,

hoping to discover
what went wrong
with the stabilizer.

- American 587, Kennedy Tower.
Caution:

Wake turbulence,
runway 3-1 left.

Taxi into position and hold.

(narrator): After the controller
issues a warning
about wake turbulence,

the first officer
sounds concerned.

- You happy with that distance?

- Ah, we'll be okay
once we get rolling.

He's supposed to be five miles
by the time we're airborne.

(narrator): Wake turbulence
is caused by the movement of air
over and under the wing.

When the two streams of air
meet at the wing tips,

they combine to create
a powerful vortex
that trails behind the plane.

- Max power!
(alarm sounding)

- You alright?
- Holy crap!

(narrator): Did the pilots
get too close to the plane
in front of them?

- Holy crap!
(narrator): Investigators listen
as First Officer Molin

wants more speed to help them
fly through the turbulence.

- Hang onto it. Hang onto it.

(narrator): Moments later,
catastrophe strikes.
(crash)

- 15:58.
That's the tail coming off.

(narrator): Was the aircraft
upset by the wake of a plane
taking off ahead of it?

- We knew, of course,
from listening to the, uh,
Air Traffic Control tapes,

that the accident aircraft
took off a 1.5 minutes
or two minutes after a JAL,

Japanese Airline Boeing 747.

(narrator): Radar data shows
that Flight 587 was flying
at a safe distance.

The wake was too weak
to be dangerous.

- Not even close
to what it would take
to rip the tail off an Airbus.

(narrator):
But another piece of data
provides a vital clue:

frantic rudder movements.

(alarm sounding)
(beep)

- Eleven degrees left.

Eleven degrees right.

We saw the rudder go back
and forth to its maximum...

deflection several times
very, very rapidly.

Could he have ripped
the tail off his own plane?

(narrator): NTSB investigators
wonder if extreme rudder
movements on Flight 587

created an aerodynamic force
strong enough to rip
the vertical stabilizer off.

- We needed to determine
whether that particular motion,

uh, would be violent enough
to snap the vertical stabilizer
off.

(narrator): Normally,
pilots only move the rudder

a couple of degrees
in either direction
to steer the plane.

But First Officer Sten Molin
was moving his plane's rudder
much more than that.

- You ready?

(narrator): To learn more,
they create a computer
simulation of an A300,

and fly it the same way
as First Officer Molin,

moving the rudder 11 degrees
back and forth three times.

- With each rudder deflection,

the aerodynamic loads
on the tail increase.

(alarm sounding)

(alarm ringing)
- There.

(alarm ringing)
That would've done it.

- And it was those increasing
loads that caused this.

(beeping)

- Well,
he's doing it to himself!

(narrator):
The discovery finally explains
what happened

to American Airlines Flight 587.

But it doesn't explain why.

- So now we've eliminated
several items,

and we're starting to look
at the actions of the flight
crew very carefully.

(narrator):
Why would an experienced pilot
move his rudder so violently

to fly out of the wake?

When they talk to pilots
who flew with Molin,

investigators make
a surprising discovery.

- Take a seat.

We began to suspect that the...
first officer overreacted.

Tell me what happened.

- He had a history
of responding...

very aggressively
to wake turbulence.

- He did the same thing
seven years ago.

- He moved the rudder pedal
quickly back and forth.

The captain said
he was shocked by this.

- He was overworking
the rudders.

- He said,
"Why did you do that?
Why did you respond like that?"

And according to the statement,
the first officer said,

"They taught us to respond
like that in the, uh, training."

(narrator): When investigators
turn their attention
to American Airlines training,

they're shocked
by what they learn.

Pilots are taught
that minor wake turbulence
can induce a sudden steep roll.

- We determined that they were
actually providing...

inadvertently providing
some negative training
to their pilots.

That led us to the conclusion
that he overreacted.

(narrator): First Officer Molin
was trained to believe

that severe wake turbulence
could cause
a catastrophic upset.

- Max power!
- You alright?

(alarm sounding)
- The captain asks him:
"Are you alright?"

And it's noteworthy
that the captain
does not add max power.

In the captain's opinion,
max power is not appropriate
in this situation.

The First Officer
began responding with...

wheel back-and-forth
and accompanied
by back-and-forth rudder.

- Hang on. Hang onto it.

(alarm sounding)
- The first officer overreacted
on the rudders.

He didn't let the aircraft
stabilize in one position
or the other,

so it... it hits a stop
and then whips itself back.

Back and forth,
back and forth,

and this creates huge loads
on the vertical part of the fin.

(narrator):
The first officer's actions
stress the vertical stabilizer

until it breaks
under the strain.

- What the hell are we into?!
(alarm sounding)

- Get out of it!
Get out of it! Get out of it!

(all screaming)

(alarm sounding)
(automation): Stall. Stall.

(sirens wailing)
(people shouting)

(narrator): After the accident,
American Airlines changes
its training procedures

for wake turbulence.

- Once it became clear
that some negative training
was going on,

American Airlines,
to their credit, uh...

revamped the program to prevent
this type of activity.

(narrator): American Airlines
modifies their training
simulator to be more realistic.

Pilots are now taught
not to use the rudder
at high speed.

A new warning light
is also installed in the cockpit

to help prevent pilots from
deflecting the rudder too far.

- I think
587 brought an awareness
to the aviation industry.

Pilots, they push that rudder
in full deflection,

it could have
disastrous effects.

(narrator):
But despite the lessons learned
from the crash

of American Airlines 587,

a rookie mistake causes disaster
seven years later.

- Gear down. LOC's alive.
- Gear's down.

Ah! Ah!
(alarm sounding)

- Jesus Christ!

(screaming)

- It was one of the grisliest,
nastiest scenes
that I think I've seen.

(sirens wailing)

(narrator):
Continental Connection
Flight 3407,

operated by Colgan Air,

is enroute from Newark,
New Jersey,
to Buffalo, New York.

It's been a busy flight
for Captain Marvin Renslow.

He's providing guidance
to a new first officer.

- Ah...

(sneezing)
Ah!

(narrator): Twenty-four-year-old
Rebecca Shaw

has been with the airline
for just over a year.

She must decide now if she wants
to become a captain.

- I don't know what I wanna do
with the upgrade.

- If you stayed on the Q,
obviously you're not making
the captain rate.

- Right.
- But you may have
a better quality of life

with regards to buying a house
and having a schedule.

(narrator): Shaw trained
on the plane they're flying now,

a Canadian-made Bombardier Q400.

There are 45 passengers
on board.

Flight 3407 is heading northwest
over Upstate New York.

The trip is only 53 minutes.

Visibility is poor,

and there's a forecast of snow
and moderate winds in Buffalo.

- Folks, from the flight deck,
your first officer speaking.

At this time,
we're about 15 minutes
outside of Buffalo.

Weather in Buffalo
is pretty foggy.

Snowing a bit there.
I'd like to make sure

everyone remains in their seat
so the flight attendants can
prepare the cabin for arrival.

(narrator): As the flight
makes its approach,

the pilots prepare the aircraft
for landing.

- Gear down. LOC's alive.
- Gear's down.

- Alright. Flaps, 15.

(narrator): Extending the flaps
provides more lift,

allowing the plane to slow
to its final-approach speed.

(alarm sounding)
- Uh...

Oh! Ah!

(alarm sounding)

(narrator): Suddenly,
the Q400 slips out of control.

Captain Renslow struggles
to contain his aircraft.

(alarm sounding)
- Ah!

(Renslow groaning)
- Mother...
(exclamations)

(panting)

(narrator): But it seems to have
a mind of its own.

(all screaming)

- Mother bear!

- Should the gear be up?!
- Gear... up!
(narrator): It's too late.

The plane is now in a stall,
and Renslow can't recover.

- Ah, we're down.

(screaming)

(all screaming)

(narrator): The plane crashes
into a suburban home
in Clarence Center,

a town five miles short
of Buffalo Airport.

All 49 passengers and crew
are killed on impact.

One person on the ground
also dies.

The devastated house
and downed plane
are a blazing inferno.

(sirens wailing)

- The height of it
was just unbelievable.
(siren wailing)

Obviously because of the fuel
that was probably added to it,
and, uh,

and the debris area
was very large.

It was a horrific sight.

(narrator):
Firefighters work tirelessly
through the night.

The scene in the morning
is one of utter devastation.

- Clint Crookshanks
from the NTSB.
Can I start poking around?

(narrator): Clint Crookshanks
is one of the first
investigators on the case.

- When we arrived on scene,
there was a fire still burning.

Turns out it was from a gas line
that had been broken
in the house.

The firemen would put the fire
out and it would reignite
every couple of minutes.

(narrator): Investigators hope
the flight's black boxes
will provide answers.

- We were able to cut a hole
in the side of the fuselage.

Once we took the recorders
out of the airplane,

we put them on the jet
and they were flown back
to Washington, DC,

to our headquarters.

(narrator): At the NTSB labs
in Washington,

Systems Investigator
Scott Warren analyzes

the aircraft's cockpit
voice recorder, or CVR,

to determine if there are any
indications of a problem
in the cockpit.

- Is that ice on the windshield?

(narrator):
He discovers that six minutes
before the crash,

the crew of Flight 3407 notices
a build-up of ice
on the aircraft.

(Renslow): I got it on my side.

You don't have yours?

- Oh, yeah.
Oh, it's lots of ice.

(narrator):
Ice can be a deadly threat
to any airplane.

- If an aircraft has ice on it,
it will have more drag on it,

so it will require more power
to maintain a given airspeed.

- When ice accretes on a wing,
it adds weight to the airplane,

but most importantly,
it changes the shape
of the wing.

And it's the curved shape
of the wing that actually
creates the lift.

So by changing
the lift characteristics
of the airplane,

it makes it less able to fly.

- Flaps, 15 before...

(narrator): The CVR reveals
that only minutes
after the crew detects ice,

a device called the stick shaker
goes off.

(Shaw): Ah!
(beeping)

(narrator): It's a warning
to pilots that the plane
is losing airspeed.

If they don't go faster,
the plane will stall
and fall out of the sky.

(Shaw screaming)

Scott Warren knows
the Q400 has a sophisticated
de-icing system.

To prevent ice accumulating,
the plane has rubber bladders
along the front of the wings

called de-icing boots.

A series of valves uses air
from the engines

to inflate the boots
and crack the ice off the wing.

Studying the flight data
recorder, or FDR,

will reveal whether the de-icing
system was switched on.

(Warren):
We know from the FDR data
that the de-icing system

had been selected on
by the crew,

and it was on during
the majority of the flight.

(narrator):
The pilots had switched
the de-icing mechanisms on.

But were they working properly?
To answer that question,

investigators sift through
piles of charred wreckage

until they find
the de-icing valves.

- We took those valves and,
as far as we could tell,

all those valves
were working properly.

(narrator):
If ice didn't bring down
Flight 3407...

...what else caused the plane
to stall,

crash, and kill 50 people?

(narrator): Investigators know
icing conditions
were not bad enough

to take down Continental
Connection Flight 3407.

Something else must've caused it
to suddenly lose airspeed.

NTSB investigator Scott Warren
knows the plane was flying
at 131 knots

when the stick shaker went off,

more than enough speed
to stay airborne.

- Alright. Flaps, 15.

- When the stick shaker
went off...
- Uh...

Oh!
(alarm sounding)

- ...they were not necessarily
at the edge of a stall.

They were still 20 knots or so
away from the stall.

(narrator): This new revelation
deepens the mystery
of Flight 3407.

The stall warning was triggered
when the plane was in no danger
of slowing to a stall speed.

Investigators work
with the plane's manufacturer to
learn more about the aircraft.

They discover
the Bombardier Q400
has a unique safety feature

known as a Reference
Speed Switch.

The switch changes the airspeed
at which the plane's
stall warning is activated.

- - Some kind
of variable Ref Speed?

(narrator): Captain Renslow
should have activated the switch

before flying
through the icy weather.

- When you are
in icing conditions,

and ice does accrue on the wing,

it can cause the stall speed
to go up,

and so this Ref Speed Switch
correspondingly causes

the warning to come on sooner
or at a higher speed.

- What that switch does,
is it basically, uh,

changes the trigger settings
for the stick shaker.

(narrator):
If ice was slowing the plane,

Captain Renslow would be alerted
sooner than usual
to pick up speed

and avoid a stall situation.

Investigators eventually find
the Reference Speed Switch panel

buried in layers
of crash debris.

- Bingo.

(narrator): And it's in
the activated position.

- And we'll probably be
picking up some ice.

(narrator):
If Renslow and Shaw remembered
to configure the plane properly

by turning
on the Reference Speed Switch,

why didn't they notice
their airspeed was too slow
for the icy conditions?

- Obviously you're not making
the captain rate.
- Right.

(narrator): The CVR reveals
a chilling answer.

The flight crew had been talking
throughout the flight,

continuing
into the landing approach,

a violation
of the "sterile cockpit rule."

(Shaw): Yeah,
and that's another thing.

And he said, "Yeah,
you're gonna be upgraded
in six months."

Blah, blah, blah.
(Renslow laughing)

(narrator):
When the stick shaker goes off,

the distracted crew
is caught off-guard.
(exclamations)

- Once the stick shaker
activated,
they could have, uh,

turned the switch off,
or put the nose down
and increased their airspeed.

(narrator): Using data
from the flight recorders,

investigators create
a computer simulation

to give them a better
understanding of the crash.

- Watch what happens
just after the stick shaker
goes off.

(narrator): It illustrates
that just after the stick shaker
was triggered,

the plane suddenly pulled up.

This action dramatically slowed
the aircraft.

And at this point, it did stall.

- Essentially, the airplane
entered an aerodynamic stall
from which it did not recover.

It pitched over
and hit the ground.

(narrator):
Investigators are dumbfounded.

Both pilots should have known
how to respond

to one of flight's
most basic tasks.

The crew's every action
during the critical seconds
after the stall warning sounded

now demand careful scrutiny.

- We wanted to see if the way
they flew the airplane
was the way they were trained.

(narrator): Investigators dig
deeper into the FDR data

to examine how the pilot
manoeuvred the plane after
the stick shaker was triggered.

They focus in
on the control column.

What Scott Warren finds
is stunning.

In response to the stick shaker,
Captain Renslow should have
pushed the column forward

to bring the nose down
and gain speed.

But the distracted captain
did the exact opposite.

- Ah!
- We found that the crew,
instead of pushing forward,

which is the normal response
to a stick shaker triggering,

the crew was actually
pulling back on the control.

(narrator): This had the effect
of pulling the nose up,

causing the airspeed to drop
and tipping the aircraft
into an actual stall.

Captain Renslow
apparently mishandled

one of the most elemental
piloting manoeuvres:

How to recover from a stall.
(Shaw exclaiming)

- Had the first officer simply
called out, "You're stalled,
advance the power,

push the nose over,"
the airplane would've been able
to recover.

- From a human point of view,
it's sad to recognize that
those sorts of things happened,

and the tragedy
that came from that.

(narrator): It's concluded
that Captain Renslow's failure
to properly respond

to the stall warning
is the primary cause
of the crash of Flight 3407.

He reacted
in the worst possible way

and sealed the fate
of the plane.

- You get a stall warning
and you have to take
corrective action,

and you know the altitude
is very low,

you don't have a lot of options;

you just have to be able
to react.

(screaming)
- No, no, no, no, no! Ah!

(narrator): At the heart of some
of the worst airline accidents

lie mistakes
of staggering simplicity.

- What the hell are we into?!

- Rookie errors
don't necessarily occur
to just rookie pilots.

It can happen
to the most experienced pilot.

(sirens wailing)

Subtitling: difuze