All language subtitles for Air.Disasters.S11E07.Caught.on.Tape.1080p.PMTP.WEB-DL.AAC2.0.H.264-maldini_track3_[eng]

DR. LIU (English Dub): The plane
was sinking deeper and deeper.

NARRATOR: In the heart of
one of Asia's busiest cities,

rescuers rush to pull air
crash survivors to safety.

INVESTIGATOR 2: Nothing
wrong with this actuator.

NARRATOR: Taiwan's
Aviation Safety Council

confronts some urgent questions
about TransAsia Flight 235.

PETER: What were
the flight crew doing?

Were there engineering
issues involved in this event?

How on earth did it
end up in this situation?

INVESTIGATOR 1:
Take a look at this.

NARRATOR: A video surfaces that
makes the disaster in Taipei

notorious worldwide.

PETER: It's quite harrowing
because you're seeing the

final moments of a tragic event
unfolding before your eyes.

INVESTIGATOR 2: What was
happening on that plane?

♪ ♪

NARRATOR: Taipei,
capital city of Taiwan.

Near its center, amidst soaring
towers, lies Songshan Airport.

The next plane scheduled
for departure this morning

is TransAsia Flight 235.

The TransAsia cabin
crew is waiting for a

last-minute addition
to the passenger list.

FLIGHT ATTENDANT:
Welcome aboard. Row 19D
midway down, aisle seat.

NARRATOR: Dr. Liu
Chau-Hui has made it.

DR. LIU (English Dub):
It just so happened
that particular flight

had a few open seats.

I was supposed to be
on the later flight,

but I decided to
get on the earlier one.

DR. LIU: Yeah. Is this me?

ANNOUNCEMENT:
Ladies and gentlemen,
make sure your seat backs

and tray tables are in
their full upright positions.

Ensure your seat belt
is securely fastened.

NARRATOR:
There are three highly-trained
pilots in the cockpit.

The first officer
is Liu Tzu-Chung.

He has almost 7,000
hours of flight time.

FO. LIU: Oil pressure.

CAPT. LIAO: Check.

NARRATOR:
Captain Liao Chien-Tsung
is a former military pilot.

There's also a third pilot who's
an observer on today's flight.

FO. LIU: Forty-five starter off.

CAPT. LIAO: Start lights off.

NARRATOR: TransAsia 235 is
a commuter flight from Taipei

to the Taiwanese
island of Kinmen,

just off the coast
of mainland China.

Scheduled flight time
is approximately one hour.

FLIGHT ATTENDANT:
Would you like a paper?

DR. LIU: Oh, thank you.

NARRATOR: Dr. Liu Chau-Hui
is returning home to Kinmen,

where he runs a
medical practice.

DR. LIU (English Dub):
I usually took TransAsia

because their
service was quite good.

When I'd get on the
plane, I'd like to grab a paper

and catch up on
the day's events.

FLIGHT ATTENDANT:
The cabin's ready, sir.

CAPT. LIAO: Okay. Roger, thanks.

FO. LIU: Songshan ground,
TransAsia 235 request taxi.

AIR TRAFFIC CONTROLLER:
TransAsia 235, runway one-zero,

taxi via whiskey.

FO. LIU: Okay.
Whiskey to one-zero.

NARRATOR: The ATR 72-600 is the
latest, most advanced version

of the European commuter plane.

Its Pratt &
Whitney turboprop engines

are extremely
powerful and fuel-efficient.

PETER: It's a very popular
aircraft, particularly because

it has attractive
operating economics.

It's commonly used in short-haul
regional airline operations.

NARRATOR: The pilots'
digital displays create

what's known as a glass cockpit.

PETER: When people refer
to a glass cockpit aircraft,

they're referring to
not only the displays

but what often
we're talking about is

an advanced-technology aircraft

with sophisticated
automation capabilities.

FO. LIU: The electronic
checklists switch automatically.

Once you complete certain
parts it'll switch forward.

NARRATOR: The first
officer briefs his colleague

on the cockpit's technology.

Hung Ping-Chung is
an experienced pilot

who's learning this
computerized system.

SO. HUNG: Can
you do it manually?

FO. LIU: Well, you can,
but when starting the engine,

for example, it'll
go to the next page

once you close the bleed valves.

♪ ♪

NARRATOR: Songshan Airport sees
six million passengers a year.

For air traffic
controllers, that means

handling about
100 flights a day.

AIR TRAFFIC CONTROLLER:
TransAsia 235, runway one-zero,

wind one-zero-zero degree niner
knots, cleared for takeoff.

FO. LIU: Okay.
Cleared for takeoff.

Cabin crew, prepare for takeoff.

DR. LIU: Have a great flight.

FLIGHT ATTENDANT: Thank
you. Enjoy your flight.

NARRATOR:
Just before 11 in the morning,
Flight 235 gets rolling.

FO. LIU: Engine
instrument check normal.

CAPT. LIAO: V-1.
FO. LIU: V-1.

CAPT. LIAO: Rotate.

♪ ♪

NARRATOR: The captain
engages the autopilot

and sets his desired
airspeed and altitude.

PETER: As soon as the
aircraft has taken off,

they're going through a
series of checklist items.

CAPT. LIAO: Gear up.

FO. LIU: Gear up.

PETER: I know they've got
a particular climb profile,

and they're executing
the after takeoff checks

and the initial
climb checks to make sure

that all the systems
are performing as required.

NARRATOR: Flight 235 climbs
out over Metropolitan Taipei,

a densely packed city of
more than seven million people.

Seconds later... the
Master Warning sounds.

PETER: The Master
Warning is indicative of

an emergency situation requiring
an immediate response.

NARRATOR: TransAsia
235 has lost an engine.

The captain
disengages the autopilot.

CAPT. LIAO: I have control.
FO. LIU: You have control.

NARRATOR: In the cabin,
engine noise suddenly drops.

The pilots need to get
their plane back on the ground.

CAPT. LIAO: Heading mode.

NARRATOR: The captain wants
a heading back to the airport.

FO. LIU: We're below 2500 feet.
Turn to heading... it's...

CAPT. LIAO: Come on.

FO. LIU: Zero, zero-niner-five.

CAPT. LIAO: Check.

PETER: When you lose an engine
in a twin-engine aircraft,

you need to be able to
maintain your climb performance

and you need to be very
careful that your airspeed

does not decay or reduce
too much during that climb.

FO. LIU: Okay,
engine flameout check.

CAPT. LIAO: Check.

NARRATOR: Speed and
climb-rate are dropping fast.

FO. LIU: Watch the speed.

AUTOMATION: Stall. Stall.

NARRATOR: The stall warning
means the plane is flying

too slowly to maintain lift.

PETER: The stall
warning at low altitude is

a critical situation that no
pilot ever wants to end up in.

NARRATOR: Flight 235 is less
than a mile from the runway.

♪ ♪

NARRATOR:
Passengers can now see that
they're no longer climbing.

CAPT. LIAO: Terrain ahead.

SO. HUNG: You are low!

PETER: The stick shaker
is a tactile alerting system

where the control column shakes
or vibrates very noticeably.

It's a very
salient cue to pilots

to indicate that
you must intervene

to prevent the
aircraft from entering a stall.

♪ ♪

NARRATOR: The
situation is critical.

PETER: It's a
highly stressful event.

FO. LIU: Tower, TransAsia
2-3-5, Mayday. Mayday.

Engine flameout.

NARRATOR: Songshan
controllers fear the worst,

a crash in the
middle of the city.

♪ ♪

FO. LIU: Engine
flameout both sides.

SO. HUNG: How is this possible?

♪ ♪

NARRATOR: Flight 235
is now only 500 feet

above the streets of Taipei.

PETER: The crew were surrounded
by high-density housing,

highrise apartment blocks,
a heavily populated area.

You're really between
a rock and hard place.

SO. HUNG: Impact!
Brace for impact!

CAPT. LIAO: Oh no! Pull up!

AUTOMATION: Terrain. Terrain.
CAPT. LIAO: Oh no!

♪ ♪

NARRATOR: All controllers
can see is that Flight 235

has dropped off the radar.

They have no idea if
anyone has survived.

AIR TRAFFIC CONTROLLER:
Suspend all takeoff
and landing operations.

Begin emergency procedures.

NARRATOR:
After hitting an elevated
highway in downtown Taipei,

TransAsia Flight 235 is
sinking in the Keelung River.

DR. LIU (English Dub): I
could feel something was off.

I thought to myself: Why is
there water where my shoes are?

♪ ♪

NARRATOR: Those lucky
enough to survive the crash

are now at risk of drowning.

DR. LIU (English Dub):
I remember very
clearly, I saw a woman who

I thought was an air hostess.
I told her not to be afraid.

DR. LIU: It will be okay.

NARRATOR: The water
level starts to rise.

DR. LIU (English Dub): The plane
was sinking deeper and deeper.

The temperature was very
cold. I couldn't hear anything.

The water had
drowned out all sounds.

NARRATOR: Then,
passengers are relieved to hear

a welcome sound.

Rescuers are on the way.

First responders
climb onto the fuselage

and start pulling
people from the wreckage.

DR. LIU (English Dub): I just
wanted the doors to open quickly

so that I could escape.

NARRATOR: The swift current
of the Keelung River means

that shocked
survivors won't be safe

until rescuers can get
them to the riverbank.

The city of
Taipei has never seen

an aviation accident like it.

Of the 58 people on Flight
235, only 15 make it out alive.

All three pilots are dead.

♪ ♪

Investigators from Taiwan's
Aviation Safety Council

are anxious to start collecting
evidence at the scene.

STEVEN (English Dub): The
most important thing for us

is to retrieve the black boxes.

However, we have to wait for
the search and rescue to finish

before we can go in.

NARRATOR: For now,
they have to be patient.

But a stunning piece of
evidence has already surfaced.

INVESTIGATOR 1: Take a
look at this. It just came in.

INVESTIGATOR 2: Can
you put it up here for me?

What?

What was happening on
that plane? Play it again.

PETER: It was quite
extraordinary that the final

sequence of
events was captured by

the dash cam footage
in the motor vehicle.

It's quite harrowing because
you're seeing the final moments

of a tragic event
unfolding before your eyes.

INVESTIGATOR 2:
Freeze it. Freeze it.

STEVEN (English Dub): We
were obviously really shocked,

wondering why the plane
was flying in this way.

INVESTIGATOR 1:
What do you think? Left
engine? Control surfaces?

THOMAS: When you
watch the video clip,

you know there's something
wrong about the engine.

The prop seems very slow.

INVESTIGATOR 2: You can
see the propeller blades.

They couldn't have
been going at full speed.

THOMAS: I thought either
the aircraft lost one engine

or either the flap or the
aileron jammed during takeoff.

INVESTIGATOR 2: We need
to study that wreckage.

♪ ♪

NARRATOR: Salvage crews
pull what remains of Flight 235

from the Keelung River.

THOMAS: We recovered everything.

I think we finished
the wreckage recovery

around noon-time the second day.

NARRATOR: There's no
telling which piece of wreckage

might hold an important clue.

Investigators wonder if
the flight control system

shows any sign of a malfunction.

THOMAS: So we have to examine
that part of the wreckage.

INVESTIGATOR 2: Nothing
wrong with this actuator.

THOMAS: We cannot find anything
wrong with the actuator,

the linkage of the control.

We cannot find any
abnormal situation

for the flight control system.

INVESTIGATOR 1:
Control system seems fine.

NARRATOR: A search for
any pre-impact failures

in the plane's hydraulic
system also comes up empty.

INVESTIGATOR 2: Nothing
wrong with the hydraulics.

Is this the left engine?

INVESTIGATOR 1: Yes.

NARRATOR: Investigators
know from the dash cam video

that the plane was
banked steeply to the left.

A mechanical fault
with the left engine

seems like the next
most obvious suspect.

INVESTIGATOR 2:
We need to take a look
inside. Get the borescope.

STEVEN (English Dub):
From a borescope examination,

we can see whether or not
the compressor and turbine

are damaged on the inside.

Since the turbine rotates
with extremely high speed,

if it is even slightly damaged

it will be completely destroyed.

NARRATOR: But the borescope
examination yields no new clues.

STEVEN (English Dub):
The examination showed that

everything was in place,
and all the moving parts

were still capable of moving.

INVESTIGATOR 2:
Left engine completely
operational. Ah. Strange.

NARRATOR: They need to
explore other possibilities.

INVESTIGATOR 2: What
about the right engine?

Let's go take a look.

NARRATOR: They
study the right engine,

and what they
find is mystifying.

INVESTIGATOR 2: Look at
the blades. They're feathered.

NARRATOR: Feathered is a
propeller's failsafe position.

When a propeller
engine loses power in flight,

the blades automatically rotate
parallel to the air stream

to reduce drag.

PETER: What an
auto-feather does,

it changes the
pitch of the blades

to reduce the drag on the blades

to make sure that the
airplane's flying performance

is not degraded.

NARRATOR: The discovery
only deepens the mystery.

INVESTIGATOR 2: Why would
the right engine be feathered

when the dash cam video
clearly shows the plane

banking to the left?

INVESTIGATOR 1: It
doesn't make any sense.

INVESTIGATOR 2:
Let's have a look.

THOMAS: When we discovered a
feather of the propeller, we

know there should be something
wrong about the engine.

INVESTIGATOR 2: Anything?

INVESTIGATOR 1: Nothing at all.

STEVEN (English Dub):
Both engines yielded normal
results after examination.

They were both fine.

INVESTIGATOR 1: There's nothing
wrong with this engine either.

INVESTIGATOR 2: If both
engines were operational,

why did this plane crash?

NARRATOR:
Investigators now have two
related questions to answer.

What caused the right
engine's propeller to feather?

CAPT. LIAO: Terrain ahead!

NARRATOR: And why did the plane
bank violently to the left

just before impact?

NARRATOR: At a Songshan Airport
hangar, Taiwanese investigators

still have no explanation

for the crash of
TransAsia Flight 235.

Video of the turboprop's fatal
plunge into the Keelung River

has spread worldwide.

But clues to what caused
the crash are in short supply.

INVESTIGATOR 1:
Hello? Okay. Thank you.
Sir, the FDR data's in.

INVESTIGATOR 2: All
right. Let's have a look.

NARRATOR: Investigators hope the
plane's flight data recorder

can tell them more.

♪ ♪

The FDR records dozens
of performance parameters,

including fuel flow, engine
temperature and propeller speed.

FO. LIU: Okay,
engine flameout check.

CAPT. LIAO: Check.

NARRATOR:
Investigators already know that

the right side propeller
feathered before impact.

FO. LIU: Watch the speed.

♪ ♪

INVESTIGATOR 2: Let's see the
operating systems of engine two.

NARRATOR: Perhaps the
flight data can tell them why.

THOMAS: When we go through
the data, for engine number two

we find some parameters
were normal like oil pressure,

engine temperature, fuel flow.

INVESTIGATOR 2: The
engine's completely fine.

NARRATOR: But one
other piece of data

seems to tell a different story.

INVESTIGATOR 2:
Take a look at this.

The torque is
all over the place.

THOMAS: One parameter,
the torque value, fluctuated.

NARRATOR: Torque is a
measure of an engine's power

to spin the propeller.

It increases and
decreases during flight,

but it's not
supposed to fluctuate.

INVESTIGATOR 2: Why is it doing
that? Pass me the schematic.

NARRATOR: They dig
deeper, studying how

the Pratt & Whitney
engine measures torque.

THOMAS: So we tried to
find out the design logic

for the system.

INVESTIGATOR 2: What's the
connection between the torque

and the feathered propellers?

NARRATOR: They learn that the
engine's auto-feathering system

includes an
electronic torque sensor.

It measures how much twisting
force the engine is producing.

Extremely low torque indicates
that the engine has failed.

So a low reading triggers the
system to feather the propeller.

But they know the
engine did not fail.

There seems to be only one way

to explain the
unusual torque data.

INVESTIGATOR 2: Maybe the sensor
is sending a faulty reading,

triggering the
auto-feathering unit.

NARRATOR: They
suspect the problem was not

with the engine itself but with
the sensor measuring torque.

THOMAS: We figured out
that that probably will be

the signal problem between the
torque sensor and the receiver.

INVESTIGATOR 2: Send the sensor
to the lab so we can analyze it.

NARRATOR: If they're right about
the torque sensor failing,

then they'll finally have solved

the mystery of the
feathered propeller.

But investigators are
no closer to understanding

another mysterious
aspect of this crash.

Why did a two-engine plane

with a feathered
propeller on the right side

end up banking to the left?

Searching for an answer,
they return to the flight data.

INVESTIGATOR 2:
What do the parameters
of the left engine say?

Can you show me
the fuel flow, please?

INVESTIGATOR 1:
That all seems fine.

INVESTIGATOR 2:
The propeller speed.

NARRATOR: According to
the data, the left engine

was in perfect working order.

STEVEN (English Dub):
Engine number one's
performance was always good.

All its statistics were normal.

INVESTIGATOR 2:
The power lever angle.

NARRATOR: But when they
check the throttle settings,

they make a stunning discovery.

INVESTIGATOR 2: Unbelievable.

THOMAS: When we go through
the FDR data, we find that the

power of the number one engine
was gradually being reduced,

reduced and
eventually being shut off.

INVESTIGATOR 2: The left
engine was manually shut down.

NARRATOR:
Investigators know the ATR 72

is not equipped with
an auto-throttle system.

The throttles can
only be moved by hand.

INVESTIGATOR 2:
It had to have been shut
down by one of the pilots.

THOMAS: So we start to
wondering why the pilot

would shut down the good engine.

STEVEN (English Dub):
Honestly, at the beginning,

we did not understand
how this could happen.

INVESTIGATOR 1: That's crazy.

♪ ♪

INVESTIGATOR 1: Let's take
a look at the circuit board.

NARRATOR: Investigators
examine the torque sensor

from the right engine
of TransAsia Flight 235.

They're looking for any
defect that could have caused

the propeller to
feather in flight.

STEVEN (English Dub): The lab
used precise testing methods.

They made a cross-section
of the circuit board

and looked at its image.

♪ ♪

INVESTIGATOR 1: Take a look
at this. It's a broken solder.

NARRATOR:
They discover microscopic
faults in the circuit board.

PETER: And that was
related to the soldering joints

in a particular circuit
board being compromised

for reasons that were
difficult to establish.

It was possibly related to some
form of manufacturing defect

or something of that nature.

THOMAS: And that
would be enough to stop

the transmission of the signal.

NARRATOR: With a
broken circuit board,

the torque sensor
couldn't do its job.

Even though the
engine was turning,

the sensor
couldn't detect any torque.

So the system automatically
feathered the propeller.

PETER: The brain of the
system thought that torque

had reduced below a
pre-determined value,

which I think is about 18%,

and that is what
triggered the auto-feather.

FO. LIU: Okay,
engine flameout check.

CAPT. LIAO: Check.

NARRATOR:
Finally, they understand

why the right side
propeller feathered.

But they still
haven't explained the crash.

The ATR 72 has two engines.

Losing propeller
thrust in one of them

should not have been
a catastrophic event.

THOMAS: They are designed
to fly only with one engine.

CAPT. LIAO: Terrain ahead.

AUTOMATION:
Terrain. Terrain. Pull up.

PETER: Pilots train for engine
out operations regularly.

Typically, it's bread and
butter for an airline pilot

to deal with an engine failure
on a multi-engine aircraft.

NARRATOR: To figure
out why 43 people died,

investigators must now answer
a much more difficult question.

THOMAS: We still have number one
engine produce power normally,

but for some
reason the pilot decided

to shut down the good engine.

FO. LIU: Watch the speed.

THOMAS: We had to find out why.

NARRATOR: Investigators turn
to the cockpit voice recording.

INVESTIGATOR 1: Okay.
Ready? Let's hear what we got.

FO. LIU: Oil pressure?

CAPT. LIAO: Check.

THOMAS: The accident
flight is very short,

less than three minutes.

So we listened to
the CVR starting from

the takeoff roll to
the end of the flight.

FO. LIU: Before taxi
Checklist. Propeller brake?

CAPT. LIAO: Off.

FO. LIU: Nose wheel steering?

CAPT. LIAO: On.

FO. LIU: Procedure complete.

INVESTIGATOR 1:
Checklist complete.

So far they're
following procedure to a T.

THOMAS: You have to make
your procedure very clear.

INVESTIGATOR 2: Let's see
what happens closer to takeoff.

FO. LIU: Engine
instrument check normal.

CAPT. LIAO: V-1.
FO. LIU: V-1.

CAPT. LIAO: Rotate.

AIR TRAFFIC CONTROLLER:
TransAsia 235, contact approach

on one-one-niner-decimal
seven. Good day.

INVESTIGATOR 2:
What's that sound?

INVESTIGATOR 1: It must be
the engine two fault warning.

PETER: When the Master
Warning first activated,

they were approximately about
1200 feet above ground level.

INVESTIGATOR 2:
They're flying an ATR 72/600.

It shouldn't be a huge problem.

THOMAS:
If they followed procedure,
do everything correctly,

they should be able to fly back
to land without any problem.

INVESTIGATOR 1: This
is a crucial moment.

Let's hear what
they're gonna do next.

CAPT. LIAO: I have control.

NARRATOR:
Investigators hear the sound
of the autopilot turning off.

INVESTIGATOR 1: He's
disengaging the autopilot.

He shouldn't be doing that.

PETER: It's hard to
understand why the pilot flying

disconnected the autopilot
during an emergency situation.

He just made a
difficult situation worse.

INVESTIGATOR 2: Keep playing.

FO. LIU: Okay,
engine flameout check.

CAPT. LIAO: Check.

PETER: Their
attention will be directed to

the engine warning
display, which in the ATR 72

clearly indicates
which engine has failed.

THOMAS: There's a checklist
procedure on the screen.

You follow it step by step.

NARRATOR:
But instead of following
the emergency checklist...

FO. LIU: Watch the speed.

NARRATOR: ... the captain
does something inexplicable.

CAPT. LIAO: Pull
back number one.

INVESTIGATOR 2: The captain is
starting to shut down engine one

without fully understanding

what the computer
system is telling him.

NARRATOR: Both engines are
capable of producing power.

But because the right engine has
feathered, it has lost thrust,

behaving like a
car in neutral.

When the captain pulls
back the left throttle,

he leaves himself with no
thrust from either engine.

PETER: He didn't
seem to fully appreciate

that that had
ultimately resulted

in number one
engine being shut down.

INVESTIGATOR 2: How
could he do such a thing?

NARRATOR:
Investigators have discovered

from the cockpit voice recorder

that the captain of Flight 235

shut down the
plane's only working engine.

INVESTIGATOR 2: Why didn't
the first officer stop him?

NARRATOR: They continue
listening to the recording,

trying to understand
why the captain's mistake

wasn't corrected in time.

CAPT. LIAO: I will pull
back on engine one throttle.

INVESTIGATOR 2:
He can't just say he's
gonna shut down the engine.

NARRATOR: Pilots are
supposed to run a cross-check,

where one pilot verifies
the actions of the other.

PETER: When the pilot flying
shut down the operative engine,

he did so very quickly

without discussing it
with the pilot monitoring.

INVESTIGATOR 1:
He's acting before even

confirming what
the emergency is.

THOMAS: When there
is a warning come up,

the procedure says you identify
the problem before you act.

FO. LIU: No, wait a
second. Cross-check.

PETER: The pilot
monitoring, to his credit,

did try to stop the pilot flying

from manipulating the
engine number one power lever,

and he announced he
wanted a cross-check.

But there was no
definitive confirmation from

the pilot flying that the
problem was engine number two.

CAPT. LIAO: Heading mode.

NARRATOR: Instead, the captain
interrupts the first officer

to ask for a new heading.

FO. LIU: We're below 2500 feet.

CAPT. LIAO: Come on!

FO. LIU: Zero. Zero-niner-five.

CAPT. LIAO: Check.

INVESTIGATOR 2:
The first officer did
tell the captain to wait.

He knows that the captain

was pulling back
on the wrong engine,

and when he did
try to question it

the captain just
confirmed what he was doing.

PETER: All of a sudden they've
got a dual engine failure,

and the pilot monitoring I think
has been caught off guard,

and he's not really
sure what's gone on.

CAPT. LIAO: Restart the engine.

FO. LIU: I can't
restart the engine!

CAPT. LIAO: Oh, wow. I
shut off the wrong engine.

PETER: The pilot flying
clearly has an epiphany

that they're in
very dire trouble.

CAPT. LIAO: Restart the engine.

FO. LIU: I can't
restart the engine!

CAPT. LIAO: I shut
off the wrong engine.

STEVEN (English Dub):
It's very sad.

When I heard him say, "I
shut off the wrong engine,"

I was completely devastated.

NARRATOR: By the time the
captain realizes his mistake,

it's too late.

SO. HUNG: Impact!
Brace for impact!

FO. LIU: Pull up!
CAPT. LIAO: Noooo!

PETER: Unfortunately,
neither crew member

actually followed the
standard set of procedures

for dealing with an
engine flameout after takeoff.

NARRATOR: Investigators now have

an even more
puzzling question to answer.

INVESTIGATOR 2:
Why didn't the captain
understand what he was doing?

NARRATOR: The captain's failure
to recognize the situation

and react properly
ended up costing 43 lives.

He thought that the
left engine had failed

when the aircraft was
clearly telling him it was

the right engine
that had a problem.

How could the captain
have gotten things so wrong?

INVESTIGATOR 2: What was
this captain's background?

NARRATOR: When they dig
into the captain's history,

they make a
disturbing discovery.

INVESTIGATOR 1:
The captain failed one of
his key training components.

PETER: The pilot flying's
training records had indicated

that he was prone to
being a bit anxious.

CAPT. LIAO: I have control.

FO. LIU: You have control.

PETER:
Feeling a little bit overwhelmed
in emergency situations

and had a tendency
to prematurely respond

or act in that situation.

CAPT. LIAO: Pull
back number one.

♪ ♪

INVESTIGATOR 1: He was
also fired from his last job.

NARRATOR:
Although the captain was an
accomplished military pilot,

his civilian record
is raising questions.

INVESTIGATOR 2: Maybe he
wasn't used to the ATR 72/600.

NARRATOR: The records
soon confirm that hunch.

Liao Chien-Tsung had
logged relatively few hours

in TransAsia's
newest commuter plane.

PETER: The captain in
the left-hand seat had

approximately
5,000 hours total time,

and he had about 250
hours on the ATR 72/600.

FO. LIU: Wait a
second. Throttle!

CAPT. LIAO: Number
one feather shut-off.

NARRATOR:
The ATR 72-600 is known
for its advanced technology.

Investigators now
wonder if this aircraft,

with its computerized glass
cockpit, was too complicated

for a relatively inexperienced
pilot to manage in a crisis.

CAPT. LIAO: Restart the engine.

FO. LIU: I can't
restart the engine!

PETER: They can
often be overwhelmed

with the huge
volume of information.

They also have to consider
the nature of the automation

and the modes that
are presented to them.

So it's more challenging.

CAPT. LIAO: I shut
off the wrong engine.

NARRATOR: Did information
overload lead to the deaths

of 43 people in one of
Taiwan's worst air disasters?

NARRATOR: Investigators need to
know if the advanced technology

designed to help
pilots in the ATR 72/600

may instead have contributed
to the crash of Flight 235

by confusing the
TransAsia captain.

INVESTIGATOR 2: Okay.
Ready to fly out of Taipei?

INVESTIGATOR 1: Let's do it.

NARRATOR: To try to find out,
they program a flight simulator

using the flight data
from the downed plane.

THOMAS: We have weather
information. We have FDR data.

We have CVR data. So
we put those together

to duplicate the
condition of the accident.

NARRATOR:
The data lets investigators
fly the exact same flight:

the same speeds,
same climb rate,

and, 37 seconds into the
flight, the same cockpit alarm.

INVESTIGATOR 1: That's the
warning. Engine two flameout.

NARRATOR: The plane's
computer instantly identifies

which engine has lost thrust.

INVESTIGATOR 2: Check autopilot
armed. Run the checklist.

NARRATOR: The
automated checklist pops up.

Clear, concise
and easy to follow.

INVESTIGATOR 1: Up
trim on engine one.

Auto feather on number two.

INVESTIGATOR 2: Check.

INVESTIGATOR 1: Engine
two flameout confirmed.

INVESTIGATOR 2: Confirm.
Secure engine number two.

NARRATOR: The checklist
calls for the pilot monitoring

to reduce power in the
feathered engine to idle.

The other pilot
guards the working engine.

PETER: Then you would
bring a condition lever

into the fuel shut-off détente,

which removes
fuel from the engine.

INVESTIGATOR 1: Condition
lever to fuel shut-off.

INVESTIGATOR 2: Check.

PETER: And then the engine
will be secured and shut down.

INVESTIGATOR 2:
Engine number two secured.

NARRATOR: Now
powered by just one engine,

the plane keeps
climbing safely on autopilot.

The computerized
systems have helped

the pilots avoid
disaster, exactly as designed.

PETER:
It's quite manageable. The
crew can continue the flight,

climb to a safe altitude,
reconsider their options.

INVESTIGATOR 2: Now
we just have to fly

back to the airport
and land. I have an idea.

Let's see what happens if we
just let the plane fly itself.

Reset from the start.

INVESTIGATOR 1: Resetting.

THOMAS: When we do the simulator
test, we try to find out

what will happen if
the pilots do nothing.

NARRATOR: Incredibly,
the simulation shows that

even if there had been
no pilot input at all,

the plane would
not have crashed.

THOMAS: The
aircraft will continue climb

and then fly with no problem.

So I think the
aircraft was designed to handle

that situation, as long as
we don't do anything wrong.

NARRATOR:
Any doubts about the glass
cockpit have now been erased.

The advanced
systems of the ATR 72-600

did not lead to the
crash of Flight 235.

There must have
been some other factor.

Investigators study
reports from previous incidents

where similar
mistakes were made.

They suggest an
intriguing possibility.

INVESTIGATOR 2: Interruptions
and multi-tasking.

NARRATOR: Investigators know the
captain's workload was high.

Taking manual control of
the plane distracted him

from running a cross-check
with his first officer.

INVESTIGATOR 2:
He's multi-tasking.

FO. LIU: Watch the speed!

INVESTIGATOR 2:
He could have been suffering
from change blindness.

PETER: Change blindness, people
are focused or fixated on

another item or
area of interest,

and so they miss
what would be considered

a very distinguishable
change in the environment,

but they don't perceive it.

CAPT. LIAO: I will pull
back engine one throttle.

INVESTIGATOR 2: Even when all
the systems were telling him

it was engine two,
his perception told him

he was doing the right
thing. Change blindness.

NARRATOR: The first
officer even tried to warn him.

FO. LIU: No, wait a
second. Cross-check.

NARRATOR: It seems the captain
was blind to the clear warning

that his right
engine had feathered.

Investigators finally understand

what went wrong
aboard TransAsia Flight 235.

A microscopic
crack in a circuit board

disabled an engine sensor

that led the system
to wrongly determine

that the right
engine had failed.

But that in itself wouldn't
have caused the plane to crash.

INVESTIGATOR 2:
This was a series of mistakes
on the part of the captain.

When engine two
feathered, the captain reacted

before he had properly
assessed the situation.

NARRATOR: The captain should
have followed a checklist.

CAPT. LIAO: I have control.

NARRATOR: Instead, he
turned off the autopilot

and reduced power
in the wrong engine.

CAPT. LIAO: I will pull
back engine one throttle.

INVESTIGATOR 2: All we
know for sure is he shut down

their only working engine.

By the time he
realizes, it's too late.

CAPT. LIAO: Restart the engine.

FO. LIU: I can't
restart the engine!

CAPT. LIAO: Wow. I
shut off the wrong engine.

♪ ♪

INVESTIGATOR 2: Why did
TransAsia hire this pilot?

NARRATOR: Investigators dig into

TransAsia's
corporate background...

INVESTIGATOR 1: Check this out.

NARRATOR: ... trying
to understand how a pilot

with such a poor record
ever got through the door.

INVESTIGATOR 1: And this.

INVESTIGATOR 2: This company's
been expanding rapidly.

NARRATOR: What they
find paints a picture

of a growing company
struggling to compete

with bigger players in
the competitive Asian market.

PETER: A more regional
operator like TransAsia Airways

appears to have
struggled to certainly

recruit and retain the sort of
expertise that airlines seek.

NARRATOR: The crash
of Flight 235 would be

the last accident
for TransAsia Airlines.

In November 2016, the
company ceased operations

and went out of business.

PETER: There's a multitude
of reasons that the board

decided to shut
down the airline.

But there's an
inescapable conclusion that

the adverse or poor safety
performance of the airline

certainly had an
economic impact on the airline.

NARRATOR: Even though TransAsia
Airlines no longer flies,

air crash investigators hope
that the tragedy of Flight 235

will serve as an
important safety reminder

to pilots at other
airlines around the world.

THOMAS: We all understand
that pilots, they're human.

Humans make mistakes.

So that's why we design the
standard operating procedures.

And the basic
important thing is for people

just follow the procedure.