Original subtitles

NARRATOR: Just minutes after takeoff from Jakarta, Indonesia...

CAPTAIN SUNEJA: Lion six-one-zero.

I have no reliable altitude information.

All instruments disagree.

NARRATOR: ...pilots fight to control one of the world's newest airliners...

HARVINO: Fly up.

- NARRATOR: ...the Boeing Max 8. - HARVINO: Up! Up!

DAVID CARBAUGH: They never really figured out

what was going on.

NARRATOR: And end up crashing into the Java Sea.

RAY NURCAHYO: This was a very serious accident.

What does the tracking data show?

NARRATOR: Investigators follow an erratic flight path...

NURCAHYO: They're off course

and their altitude's all over the place.

NARRATOR: ...a history of maintenance issues...

CAPTAIN: Did we have problems? You bet we did.

NARRATOR: And learn about a treacherous piece of hidden software.

BOEING REP: It looks like the MCAS kicked in.

NURCAHYO: What's that?

NARRATOR: What they uncover shocks the world

and grounds an entire fleet.

JOHN COX: The 737 MAX story

will clearly be a watershed event in aviation history.

(lightning strikes)

MAN (on radio): Mayday, mayday!

(radio chatter)

NARRATOR: It's just after 5 am in Jakarta, Indonesia,

as 181 passengers settle in for a short domestic flight.

In the cockpit...

HARVINO: Fuel pumps.

NARRATOR: Harvino performs pre-flight procedures.

CAPTAIN SUNEJA: Fuel pumps are on.

NARRATOR: The Captain on this flight is Bhavye Suneja

who has more than 6,000 flying hours.

The passengers are onboard the latest version

of the renowned Boeing 737, known as the Max 8.

David Carbaugh is a former Boeing test pilot.

CARBAUGH: The Max is the fourth iteration

of the 737,

one of the most successful airliners ever.

And it was basically born out of a need

to improve efficiency and performance.

NARRATOR: The Max 8 has quickly become

Boeing's fastest-selling airplane,

with more than 300 already in the skies

and almost 5,000 in the order books.

The one being used on today's flight

was delivered to Lion Air two months ago.

TOWER CONTROLLER: Lion six-one-zero,

you are cleared to runway 2-5 left via Sierra Charlie One.

Contact tower when you are in position.

HARVINO: Lion six-one-zero,

cleared to runway 2-5 left via Sierra Charlie One.

CAPTAIN SUNEJA: All clear. No traffic.

Let's run before takeoff.

HARVINO: Flaps.

CAPTAIN SUNEJA: Flaps Five. Five indicated.

NARRATOR: Lion Air Flight 610 is a 90-minute journey

from Jakarta over the Java Sea to Bangka Island.

The low-cost airline operates hundreds of these short flights

every day.

CARBAUGH: Indonesia is the fourth

most populous country in the world.

And with 17,000 islands, you gotta have an easy way

to do short-range transportation to get to those places.

And the Max is the ideal airplane for that kind of operation.

TOWER CONTROLLER: Lion six-one-zero cleared

for take-off Runway 2-5.

Contact Terminal East when airborne.

HARVINO: Lion six-one-zero cleared for takeoff.

(engine roaring)

NARRATOR: At 6:20...

HARVINO: Rotate.

NARRATOR: ...the Max 8 lifts off the runway at Jakarta.

(control system beeps)

But immediately, there's trouble.

The Captain's control yoke starts shaking,

a warning that the plane is about to stall.

HARVINO: Takeoff config.

CAPTAIN SUNEJA: Okay... but what?

NARRATOR: The pilots can't identify the source of the problem.

They have no choice but to continue climbing.

The passengers are unaware that the pilots are dealing

with anything unusual.

(control system alerts)

TERMINAL CONTROLLER: Lion six-one-zero,

fly heading 2-4-8 and follow Standard Instrument Departure.

HARVINO: Lion Air 610.

NARRATOR: The air traffic controller has no idea

that there's an issue in the cockpit.

The pilots get a warning

that their airspeed indicators do not agree.

HARVINO: Airspeed disagree.

What's going on?

Should we request a return to Jakarta?

CAPTAIN SUNEJA: Landing gear up.

TERMINAL CONTROLLER: Lion six-one-zero,

climb to flight level two-seven-zero.

NARRATOR: Still unaware of any trouble, the controller instructs

the crew to continue climbing to 27,000 feet.

HARVINO: Altitude disagree.

NARRATOR: The First Officer now notices that the altimeters

also show conflicting readings.

CAPTAIN SUNEJA: Acknowledged. Altitude disagree.

HARVINO: Lion six-one-zero.

Confirm our current altitude, please.

TERMINAL CONTROLLER: Lion six-zero-one

your present altitude is... 900 feet?

NARRATOR: The pilots are getting conflicting data

about their altitude and their airspeed.

Captain Suneja expects his First Officer

to carry out the procedure for this situation.

CAPTAIN SUNEJA: Okay. Memory items. Airspeed unreliable.

HARVINO: Uh, what altitude should I request?

CAPTAIN SUNEJA: Yeah, uh, request, uh...

proceed.

NARRATOR: The situation is deteriorating quickly.

Climbing above 1,000 feet,

the pilots are still unsure of their airspeed.

If they fly too slowly,

the plane could stall and fall from the sky.

CAPTAIN SUNEJA: Request clearance

to any holding point.

NARRATOR: Captain Suneja wants to get the plane

to a point where he can circle and solve the problem.

HARVINO: Lion six-one-zero,

request clearance to some holding point

due to our current condition.

Terminal Controller: Lion six-one-zero,

what's the nature of your problem, please?

HARVINO: We are experiencing

a flight control problem, Lion six-one-zero.

Where's the... airspeed... airspeed.

There's no airspeed unreliable.

CAPTAIN SUNEJA: It's there.

HARVINO: Got it.

Auto pilot if engaged, disengage.

COX: Not every failure is a major emergency.

And checklists are designed to grade or evaluate

the severity of a system failure.

So pilots are trained to methodically go

through each step by step.

HARVINO: Auto throttle if engaged,

disengage.

CAPTAIN SUNEJA: Disengaged.

NARRATOR: But the checklist isn't helping.

CAPTAIN SUNEJA: Okay. Okay.

NARRATOR: Now flying 5,000 feet

above the sea, Captain Suneja struggles

to keep the plane's nose up.

HARVINO: The flight path vector may be unreliable.

TERMINAL CONTROLLER: Lion 6-1-0, turn right

heading zero-seven-zero to avoid traffic ahead.

HARVINO: Set the pitch attitude.

Roger, heading zero-seven-zero.

TERMINAL CONTROLLER: Lion six-one-zero,

are you now descending?

HARVINO: We're having flight control problems and are flying manually.

Terminal Controller: Six-one-zero,

maintain heading zero-five-zero.

COX: The cabin would have realized

that the airplane was not climbing as normal

and that it had leveled off,

and there was probably some up and down sensations.

NARRATOR: Captain Suneja has been fighting

to keep the plane's nose from pitching downwards.

CAPTAIN SUNEJA: Please take control for a moment.

NARRATOR: He now assigns that task to his First Officer.

HARVINO: I have control.

NARRATOR: So he can troubleshoot the problem himself.

HARVINO: Whoa. It's very...

NARRATOR: The First Officer is also having difficulty

keeping the aircraft level.

COX: There was a wide variety,

uh, of problems that they had to sort out,

and the first thing was,

what's common between all of these failures?

Because that's how you start to sort through the problems.

NARRATOR: Flight 610 is flying erratically over the Java Sea

and becoming increasingly more difficult to control.

The lives of everyone on board

now depend on the pilots figuring out the problem...

CAPTAIN SUNEJA: I don't know where we are.

NARRATOR: ...and getting the plane to the ground safely.

CAPTAIN SUNEJA: Lion six-one-zero.

I have no reliable altitude information.

All instruments disagree.

TERMINAL CONTROLLER: Roger, Lion six-one-zero.

No restrictions.

CARBAUGH: When an aircraft declares an emergency,

the controller's number one job

is to provide assistance to that airplane.

NARRATOR: The controller allows Flight 610

to fly at any altitude the pilots choose.

CAPTAIN SUNEJA: Uh please clear 3,000 above and below of traffic.

TERMINAL CONTROLLER: Okay, will do.

What altitude would you like?

CAPTAIN SUNEJA: Five... uh...

HARVINO: It's diving. It's diving.

CAPTAIN SUNEJA: It's okay. It's okay.

NARRATOR: Flight 610 is now speeding towards the sea.

And the pilots are out of options.

HARVINO: Fly up. Up! Up!

GPWS: Terrain. Terrain. Pull up.

TERMINAL CONTROLLER: Lion six-one-zero, control.

Lion Air six-one-zero, control.

Citylink 8-8-2, please hold on current position.

Do you have a visual on Lion six-one-zero,

a Boeing 737 Max 8?

PILOT: Negative. No other planes in sight.

♪ ♪

NARRATOR: Thirty minutes after crashing into the Java Sea,

the wreckage of Lion Air Flight 610 is located.

There are no survivors.

Relatives of the passengers are flown to Jakarta

for trauma counseling.

While they wait for the recovery of the bodies of their loved ones,

investigators from Indonesia's accident investigation branch, KNKT,

need to understand why one of the best-selling new aircrafts

in the world fell from the sky.

NURCAHYO: Okay. What does the tracking data show?

NARRATOR: Working with data from air traffic control,

KNKT investigators focus on the flight path of Lion Air 610.

NURCAHYO: They're off course

and their altitude is all over the place.

(speaking Indonesian)

NURCAHYO: From this data, we learned that this plane's altitude

was fluctuating. It kept going up and down.

We wanted to find out why the pilot

couldn't keep the plane at a constant altitude.

NARRATOR: Investigators need to know if the controller can shed

any light on the problems the crew was facing.

TERMINAL CONTROLLER: They reported

that they were having a control issue.

Lion six-one-zero,

what's the nature of your problem please?

HARVINO: We are experiencing

a flight control problem, Lion six-one-zero.

TERMINAL CONTROLLER: That's all he said,

a flight control problem.

Soon after that, they reported

that their instruments were unreliable.

CAPTAIN SUNEJA: Lion six-one-zero.

I have no reliable altitude information.

All instruments disagree.

CONTROLLER: Roger, Lion six-one-zero.

No restrictions.

That was about it.

(speaking Indonesian)

NURCAHYO: From the information we received

from the Air Traffic Controller, we didn't get the impression

that the pilot was under pressure.

The pilot's tone was normal.

It didn't seem that he was stressed.

(speaking Indonesian)

NARRATOR: Since the pilots of Flight 610 reported flight control problems

and unreliable instruments,

investigators wonder if recent maintenance records

could explain what brought down the Max 8

only 11 minutes after takeoff.

NURCAHYO: This flight had some problems with control.

At that point, we needed to learn more

about the plane's maintenance history.

The angle of attack sensor was replaced the day before?

NARRATOR: There are two angle of attack sensors on the 737 Max 8.

The sensors calculate the angle

between the plane's wing and the oncoming air.

Their data helps determine if the plane's wings

are providing sufficient lift.

CARBAUGH: It's a very important piece of information.

The pilots need to have some kind of warning

that they are approaching stall,

and so the angle of attack sensor is what gives that.

NARRATOR: For several days, the left-side sensor

had been giving faulty readings.

It was finally replaced before the plane

flew from Bali to Jakarta, one day before the accident.

Investigators interview the crew

who flew the same plane just hours before the crash

to determine if there were any problems

with the replacement sensor.

CAPTAIN: Did we have problems?

You bet we did.

NURCAHYO: We conducted an interview with the crew of flight 043.

We learned from them that after takeoff the crew was also having problems.

NARRATOR: What investigators hear next is chilling.

The Captain explains that when he lifted off from Bali,

there were simultaneous warnings

that his airspeed and altitude indicators had failed.

CAPTAIN: Airspeed disagree.

Altitude disagree.

NARRATOR: A few seconds later, the MAX 8's stick shaker activated,

indicating that a stall was imminent.

CAPTAIN: Keep climbing. Gear up.

COX: All the modern airliners have three sets

of independently powered essential flight instruments,

air speed and altitude, and also the attitude of the airplane.

If there is a discrepancy, you can determine

which is providing inaccurate data.

CAPTAIN: Your instruments are correct.

You have control.

The failure was on my side, so I handed off.

Flaps up.

NARRATOR: The Captain adjusts his faulty instruments,

so they display data from the First Officer's side.

- GPWS: Pull up. - CAPTAIN: We're diving.

Pitch up. Keep trimming.

That's when the plane started diving, over and over.

NARRATOR: The Captain reports that the plane

began a series of un-commanded dives.

CAPTAIN: Use your trim. That's it.

NARRATOR: In order to keep the plane climbing at a constant angle,

the pilots set the position

of their horizontal stabilizer at takeoff

and make minor adjustments during the flight.

That's called trim.

Trim can either be adjusted by the autopilot

or manually by the crew.

But every time the first officer tries to trim the nose up,

the automated system pushes it back down.

The First Officer is finding it almost impossible

to keep the plane climbing.

COX: The trim system on a modern jet

has to be very powerful.

The trim, in many cases,

is actually more powerful than the control column.

NARRATOR: For some reason, the MAX 8's stabilizer

continues to move independently, pushing the plane's nose down

despite the First Officer's commands.

CAPTAIN: Let's see what's in the book.

NARRATOR: When the automated system moves the stabilizer,

it also spins a large wheel

that's located between the two pilots.

This tells them that the system

is adjusting the trim on its own.

(speaking Indonesian)

ONY WIBOWO: When the captain bent down to look at the checklist manual

to solve the problem during this flight,

the third crew was the one notifying the pilot

that the trim was moving abnormally.

CAPTAIN: Runaway Stabilizer.

Moving switches to cutout.

NARRATOR: The crew realizes the stabilizer's automatic

trim system is malfunctioning.

It's continually pushing the nose down.

Disengaging the system resolves the issue.

CARBAUGH: When they cut out the trim switches,

the system stopped doing nose down trim.

CAPTAIN: Moving the switch to cutout pretty much solved it.

NARRATOR: The investigators learn that the previous crew

then did something astonishing.

CAPTAIN: So we kept going.

INVESTIGATOR: You kept going?

NURCAHYO: If they had decided to return and land in Denpasar,

it would have taken only 5 to 10 minutes

and they could've landed safely.

But they decided to continue flying to Jakarta.

CAPTAIN: Lion Air 43.

We'll continue on to Jakarta.

NARRATOR: Following a near catastrophe,

with unreliable instruments and the stick shaker blaring,

the crew elected to continue the 90-minute flight to Jakarta.

COX: It surprised all of us

that they continued the flight.

NARRATOR: The crew managed to make a safe landing at Jakarta

and reported the problem to maintenance personnel.

CAPTAIN: I reported the issue and filled out the flight maintenance log.

COX: If the airplane experiences

an abnormal or an unusual system failure,

it goes into the maintenance log.

NURCAHYO: Air Speed and Altitude disagree,

but not a word about the stabilizer problem?

NARRATOR: Investigators are surprised to learn

that the Captain of the previous flight

said nothing about the out-of-control stabilizer

or the action he took to correct it.

CAPTAIN: Runaway Stabilizer.

Moving switches to cutout.

CARBAUGH: The lives of the passengers

and the crew that follows you

is basically dependent on you

filling out the paperwork correctly.

CAPTAIN SUNEJA: Good morning.

HARVINO: Good morning.

CAPTAIN SUNEJA: They're done loading.

So we should be able to get out of here on time today.

NARRATOR: A few hours later, the passengers and crew

of Flight 610 boarded the aircraft

with no knowledge or warning of the potential problems

faced by the previous crew hours earlier.

HARVINO: Fuel pumps?

CAPTAIN SUNEJA: Fuel pumps are on.

NARRATOR: Did a repeat of the problem on this aircraft result

in the deaths of the 181 passengers and eight crew?

NARRATOR: It takes three days for search and rescue teams

to lock onto the signal coming from the Max 8's Flight Data Recorder.

Divers recover it from a depth of 115 feet.

The recorder has preserved data from the accident flight

and 18 previous flights covering almost 1800 different parameters.

NURCAHYO: Master Caution goes off as soon

as they leave the ground

probably because Air Speed and Altitude don't agree.

Stick shaker activates here.

NARRATOR: The data shows a repeat of the problem on the previous flight--

Faulty readings caused by a discrepancy

between the left and right angle of attack sensors.

(speaking Indonesian)

WIBOWO: From the FDR data we received,

we learned that this plane had faulty angle of attack readings

that affected both flights similarly.

NURCAHYO: Left and right angle of attack values

are off by 21 degrees for the entire flight.

NURCAHYO: We suspected the new angle of attack sensor installed in Bali

was either faulty or the installation process

was done incorrectly.

NARRATOR: The mechanic who replaced the sensor

before the flight from Bali to Jakarta

failed to ensure it was calibrated,

which resulted in faulty readings.

COX: There's a procedure that would have shown it was erroneous

and that it was bad.

They signed off that they did it.

They could not have done it.

NARRATOR: On the Max 8, the angle of attack sensor

doesn't just measure the airplane's angle.

HARVINO: Altitude disagree.

NARRATOR: It helps calculate precise airspeed and altitude.

NURCAHYO: That explains why airspeed and altitude

disagreed throughout the whole flight.

NARRATOR: The malfunctioning sensor on the captain's side

resulted in a difference between the left

and right side speed and altitude displays.

NURCAHYO: Then there's this.

NARRATOR: The data clearly shows that for every nose up trim input

there was a corresponding automatic nose-down trim input.

NURCAHYO: It sounds like what the crew of Flight 43 described.

NARRATOR: The data shows investigators

that for some reason, the plane's automated trim system

was repeatedly dropping the plane's nose

while the pilots fought to lift it.

NURCAHYO: Twenty-six separate nose-down commands.

This doesn't look like a runaway stabilizer to me.

NARRATOR: Runaway stabilizer is a common malfunction of the trim system,

usually resulting in one continuous

un-commanded movement of the stabilizer.

NURCAHYO: The NTSB brought a representative from Boeing

to help us in our investigation.

We asked them to explain why in both Flight 610 and 043,

the same plane continued to pitch down.

(speaking Indonesian)

NURCAHYO: We're trying to understand these automatic inputs.

BOEING REP: It looks like the MCAS kicked in.

NURCAHYO: What's that?

NARRATOR: Boeing points to an obscure automated system known as MCAS--

The Maneuvering Characteristics Augmentation System.

WIBOWO: That's when we first learned about the MCAS.

NARRATOR: To understand what could have caused the crash of Flight 610,

investigators need to go back seven years to 2011

when Boeing first announced the development of the MAX 8.

DAVID: The 737 MAX

was basically born out of a need

to improve the performance and sales of the 737.

NARRATOR: In 2010, Boeing's main competitor, Airbus,

unveiled the A320 neo,

a fuel-efficient short-haul airplane.

It was an immediate hit with airlines

at a time of rising fuel costs.

COX: Boeing was caught by surprise.

The A320 neo was significantly more fuel-efficient.

So all of a sudden, they were faced with a dilemma.

Do you design a new airplane, 4-or 5-year project,

or do you modify the existing 737?

NARRATOR: But there were problems with taking a plane

that was designed in the 1960s

and turning it into a fast and fuel-efficient aircraft.

CARBAUGH: To improve the performance of the MAX,

they decided to install more fuel efficient, larger engines.

NARRATOR: The only way to make those larger engines fit

was to slide them forward on the wings.

COX: The design engineers had a problem

with the ground clearance from the engines.

And on a 737, you can't increase the size of the main landing gear

because of the size of the wheel wells.

It has to fit there. So the only thing they could do

was to move the engines further forward and up.

NARRATOR: That solved one problem but created another.

It caused the 737 to pitch up at low speeds,

particularly when it was already in a nose up position

like during takeoffs.

COX: So they created software

that would recognize the airplane approaching stall

and artificially force the nose down,

and logically they turned to the trim system to do that.

NURCAHYO: And that's the problem

you solved with MCAS?

BOEING REP: Yes, it made the MAX handle like any other 737.

COX: MCAS was a design

for a very low probability event.

HARVINO: It's diving. It's diving!

CAPTAIN SUNEJA: It's okay.

NURCAHYO: How were they trained to respond?

BOEING REP: Well, they weren't. Not specifically.

HARVINO: Fly up. Up! Up!

NARRATOR: Could Boeing's high-tech solution to a design problem

have inadvertently put thousands of passengers

around the world at risk?

NARRATOR: In order to eliminate the need for costly pilot training,

Boeing had to convince authorities

that the Max 8 handled the same way

as all previous 737s.

CARBAUGH: Different handling characteristics will automatically require

time in the simulator and extra training.

NARRATOR: Boeing argued that since MCAS operated in the background

without the need for any pilot input,

it didn't affect the airplane's handling.

INVESTIGATOR: Not a word about MCAS here.

NARRATOR: Boeing never included mention of MCAS

in the flight control manuals.

They argued that since the system

was not under control of the crew,

it should not be included.

NURCAHYO: It's like the system doesn't even exist.

Boeing thinks that it's an automatic system

for safety purposes

and has nothing to do with pilot operation.

NARRATOR: According to Boeing, the MCAS software

would automatically move the plane's stabilizer

to push the plane's nose down

if it started to pitch up under very specific circumstances.

BOEING REP: It only kicks in when these three conditions are met.

NARRATOR: Boeing explains that MCAS only activates

when it senses that the angle of attack is excessive,

when the autopilot is off,

and when the flaps are retracted.

An extremely rare combination.

COX: Professional pilots don't typically stall airplanes.

So the likelihood of an MCAS activation

was thought to be extremely low.

INVESTIGATOR: This is the data from both flights.

NARRATOR: Tragically, the data shows that because of the faulty

maintenance on the angle of attack sensor,

Flight 610 ended up meeting all three conditions.

NURCAHYO: The series of problems occurred

when the left angle of attack sensor was replaced in Bali.

NARRATOR: Investigators dig deeper into the data

and discover the MCAS system had no failsafe.

NURCAHYO: The MCAS installed in the plane relied on only one sensor.

NARRATOR: MCAS only took data from one angle of attack sensor,

not both.

Most protection systems are designed with redundancies.

CAPTAIN: Your instruments are correct. You have control.

NARRATOR: So a single failure doesn't result in catastrophe.

CAPTAIN: Flaps up.

COX: What Boeing did not adequately do

was assess all of the other failures

that that single component would have.

NURCAHYO: The faulty angle of attack sensor

wrongly showed the plane pitching up steeply.

The autopilot was disengaged for the entire flight.

And then right here, they retract the flaps.

Exactly the same as the previous flight.

That's when MCAS kicks in and starts pushing the nose down.

NARRATOR: Up to this point, the crew only had a minor instrument problem.

By raising the flaps...

CAPTAIN SUNEJA: Okay. Okay.

NARRATOR: ...the pilots

unknowingly triggered a much more serious problem.

BOEING REP: We assumed that pilots would know how to respond.

NARRATOR: Boeing made the assumption

that pilots would respond to the un-commanded MCAS

inputs by disengaging the automatic trim.

COX: The Boeing assumptions were that the pilots

would instantly recognize the inadvertent MCAS activation

and treat it within three seconds.

NARRATOR: Investigators examine the flight data

of the previous Lion Air flight

to see how that crew reacted to the MCAS activation.

NURCAHYO: The first MCAS input

on Flight 43 is here.

The Captain pulls back on his control column

and applies manual trim,

then fights against the MCAS for 3 minutes and 40 seconds

before hitting the cutout switch.

COX: I think the assumption

that they were going to recognize and act

within three seconds was very optimistic, if not unrealistic.

CAPTAIN SUNEJA: Lion six-one-zero.

I have no reliable altitude information.

All instruments disagree.

NARRATOR: Unlike the previous crew, the pilots of Flight 610

struggled with the problem for more than 10 minutes...

HARVINO: Fly up. Up. Up!

NARRATOR: ...and never made the connection to a runaway stabilizer.

Investigators need to understand why two crews,

facing an identical problem, reacted so differently.

NARRATOR: Investigators struggle to understand

why the pilots of Lion Air Flight 610 lost control of the aircraft.

After nearly three months of searching the ocean floor,

the cockpit voice recorder is finally recovered

and taken for analysis.

WIBOWO: The CVR was the key to our investigation.

Together with the FDR data,

the CVR could reveal all the mystery in our investigation.

AIR TRAFFIC CONTROLLER: Lion 6-1-0

cleared for takeoff.

NARRATOR: Investigators hope the recording will help to explain

why the crew of Flight 610 couldn't identify the problem

and take corrective action to fix it.

HARVINO: Rotate.

(beeping)

Takeoff config.

CAPTAIN SUNEJA: Okay, but what?

NARRATOR: The faulty angle of attack sensor

triggers a series of warnings as soon as the plane lifts off.

HARVINO: Airspeed disagree.

What's going on?

Should we request a return to Jakarta?

CAPTAIN SUNEJA: Landing gear up.

NURCAHYO: After takeoff, the MCAS system was activated

and their plane started to pitch down.

NARRATOR: The captain has noticed that the plane's stabilizer

is now automatically trimming the nose down

and does what Boeing assumed he would.

He pulls back on the control column and uses manual trim

to counteract the computerized inputs.

NURCAHYO: Okay.

Boeing was right about that.

NARRATOR: But the captain never mentions the trim problem.

He and his first officer are focused entirely

on their faulty airspeed and altitude readings.

HARVINO: Where is the... airspeed...

airspeed. There's no airspeed unreliable.

CAPTAIN SUNEJA: It's there.

HARVINO: Got it.

NURCAHYO: This is where we found significant differences

between flight 043 and 610.

NARRATOR: It takes Harvino nearly two minutes

to locate the appropriate checklist for mismatched airspeed.

COX: I think the first officer was pretty well task saturated,

and one of the things that task saturation does in humans,

it limits our ability to communicate.

We don't hear well, and we don't verbalize things very well.

HARVINO: Flaps up four degrees

and seventy-five percent N1.

CAPTAIN SUNEJA: There it is.

NARRATOR: When the automated trim system pushes the nose down,

the large wheel makes a characteristic sound.

CARBAUGH: When the trim wheel moves,

it makes a sound like a freight train.

(engine hissing)

It's meant to be noticeable.

HARVINO: The following are reliable:

Attitude, N1, ground speed.

CAPTAIN SUNEJA: Check.

NURCAHYO: They still don't notice it.

Wrong about that.

COX: He didn't put it together that every time he trimmed up,

the MCAS system was trimming it back down.

NURCAHYO: Thirty-four times.

He applies nose up trim 34 times and doesn't think to wonder why.

Did not recognize the problem and take the corrective action

Boeing predicted they would.

CARBAUGH: In this particular case,

Boeing made assumptions about design, and pilot experience,

and training that didn't add up.

CAPTAIN SUNEJA: Please take control for a moment.

HARVINO: I have control.

NARRATOR: Investigators now hear another crucial difference

between Flight 610 and the previous flight.

NURCAHYO: That's it? Please take control?

Not a word about the fact

that he's had to make more than 30 trim inputs.

CARBAUGH: I think the captain

was very frustrated with the first officer.

HARVINO: Whoa. It's very...

CARBAUGH: And I am sure he didn't

really wanna hand it over to the first officer,

but he felt that he needed to in order to figure out

what was going on with the checklist.

NARRATOR: But because there's no mention of MCAS in the manual,

there isn't a checklist for the crew to follow.

- HARVINO: It's diving! It's diving! - CAPTAIN SUNEJA: Okay.

NARRATOR: With no warning from the Captain about the need

for repeated nose up trim,

the First Officer quickly becomes overwhelmed.

COX: Sadly, this first officer was pretty well overwhelmed

and as the system trimmed the nose down,

he was not nearly aggressive enough in responding to that.

NURCAHYO: In flight 610, the pilot didn't deactivate the automatic trim

and the plane's nose kept coming down because of the MCAS.

And it didn't stop until the plane crashed.

NARRATOR: One minute after taking control,

the first officer watches helplessly

as the plane plunges towards the Java Sea.

HARVINO: Fly up. Up. Up!

NARRATOR: KNKT Investigators discover that Boeing's assumptions

of how pilots would recognize

and overcome an un-commanded nose down trim

on the Max 8 were fatally flawed.

NURCAHYO: They sure didn't act the way Boeing said they would.

INVESTIGATOR: Here it is.

Without requiring exceptional skill or strength.

NARRATOR: Investigators soon learn why Boeing's assumptions

about how pilots would react were so wrong.

To certify the MAX 8,

Boeing assured the FAA that an "average" flight crew

would be able to override the MCAS system.

NURCAHYO: So were these guys average?

Captain passed all his checks.

Looks like a competent pilot.

This guy is a whole different story.

NARRATOR: Investigators are surprised by the First Officer's background.

COX: The first officer on Lion Air Flight 610

had had challenges in training.

He had trouble staying up with the airplane,

understanding the complexities.

His manual flying skills were not optimum,

and he required additional training.

- HARVINO: It's diving! It's diving! - CAPTAIN SUNEJA: It's okay. It's okay.

NARRATOR: Flight 610 proved that Boeing was wrong

about how pilots would react to an MCAS failure.

HARVINO: Fly up. Up. Up!

CARBAUGH: They never really figured it out,

and then the captain gave control to someone

whose manual flying skills were not gonna save the day.

NARRATOR: As a result of the accident,

Boeing issues new guidelines for MAX 8 pilots

informing them about MCAS

and detailing the procedures to follow in the event

it triggers an un-commanded nose down.

The bulletin advises pilots to apply manual trim

and to move the Stabilizer Trim switches to CUTOUT.

COX: This was a reinforcement to the pilots that says:

There is a system on the airplane that can move the trim.

If it does so, treat it as a runaway stabilizer.

NURCAHYO: Hey, turn the TV on.

NEWS ANCHOR: Our breaking news.

An Ethiopian Airlines has crashed shortly after takeoff

from Addis Ababa, killing all one hundred...

NARRATOR: The belief that Boeing's advisory

would prevent another similar accident

is shattered four months later when another MAX 8 crashes.

Flight tracking data shows that Ethiopian Airlines

Flight 302's altitude fluctuated throughout the flight.

There's immediate speculation that, once again,

Boeing's MCAS software is to blame.

COX: In both accidents, the MCAS activated,

causing this nose down trim situation to occur repeatedly.

And in both cases, the crews let the airplane accelerate far,

far greater speed than it should have been.

Put those two together

and the controllability of the airplane was lost.

NARRATOR: This time the pilots knew about MCAS

and what to do in case it activated.

Yet, they still couldn't control the airplane.

CARBAUGH: Boeing realized, well,

if this crew can't handle it then other crews won't.

NARRATOR: In spite of the FAA's assurance that the MAX 8 is airworthy,

regulators around the world ground the global MAX 8 fleet

until the problem with MCAS is fixed.

WIBOWO: The main thing in our mind was we worried

that all of the Boeing 737 Max 8s

that are currently flying all over the world

might have the potential to suffer the same catastrophe.

NARRATOR: The FAA eventually follows suit.

CONGRESSMAN: And our concern isn't with the mistakes that were made...

NARRATOR: A US Congressional investigation determines

that Boeing made faulty technical assumptions

and errors in judgment, which led to these accidents.

CONGRESSMAN: That pilots didn't know about this is unacceptable.

NARRATOR: Boeing insists it's learned from these incidents

and is determined to make the MAX 8 safe

and regain public trust.

NURCAHYO: Boeing has committed

to making it easier for pilots to override the MCAS system.

Once that override is activated,

the system will not continue to re-engage.

And they're developing a training program

to familiarize pilots with MCAS.

COX: The 737 MAX story will change

forever how airplanes are certified,

and the 737 MAX will clearly be a watershed event

in aviation history.

Captioned by Point.360