Original subtitles

Pilot: Better buckle up.

Narrator: An expert crew...

Pilot: No worries.

Man: The team was very experienced.

Narrator: Pushes a commercial airliner to the limit.

Pilot: We need to overspeed.

Man: It's a very challenging environment.

Pilot: Hands off now.

Narrator: Did they go too far...

Controller: They wanted to do some 360s.

Pilot: It's pitching up all the time.

Man: Does that seem right to you guys?

Narrator: ...and put their plane on a deadly flight path?

Pilot: Damn it!

Narrator: Investigators face a terrifying mystery.

Man: Why didn't the stall protection kick in?

Narrator: Why did one of the world's most advanced aircraft

fall from the sky?

And how can they stop it from happening again?

Flight Attendant: Ladies and gentlemen, we are starting our approach.

Pilot: We lost both engines!

Flight Attendant: Put the mask over your nose.

Emergency descent.

Pilot: Mayday, mayday.

Flight Attendant: Brace for impact!

Controller: I think I lost one.

Man: Investigation starting...

Man: He's gonna crash!

Narrator: Perinea Airport in southern France.

Air New Zealand engineers

are getting ready for an unusual flight.

Pilot: Gentlemen, good afternoon.

Find any problems under the hood?

Narrator: They've spent the last three weeks

giving the A320 a complete maintenance check.

Man: Everything looks good. You won't have any problems.

Narrator: Now Captain Norbert Kaeppel

is going to put its automated systems

to the test in the air.

Norbert Kaeppel: Looks like it's my turn.

Narrator: XL Airways Germany

has been leasing the A320 from Air New Zealand,

but a fresh coat of paint now displays its owner's colors.

There's just one more step

before XL can give the plane back.

Kaeppel: Better buckle up.

The cabin is clear.

Narrator: Before XL Airways

returns the plane to Air New Zealand,

it must demonstrate that the plane

is in perfect working order.

John cox: It's very similar to returning a car off lease

where the dealership will take the car,

they'll let maintenance look at it,

make sure that it hasn't been in an accident,

that it hasn't been abused in some way,

and that the systems actually work as designed.

Controller: Triple 8 tango, how many minutes do you need?

Narrator: Captain Kaeppel from XL Airways Germany

will be flying the plane.

Kaeppel: Two minutes.

Narrator: His colleague, First Officer Theodore Ketzer,

will help monitor the instruments.

Theodore Ketzer: Two minutes we'll be ready.

Narrator: Also on board,

Captain Brian Horrell of Air New Zealand.

He'll be guiding the German pilots

through a series of 35 in-flight tests

that make up what's known as an acceptance flight.

Cox: An acceptance flight

is a flight where a crew, a specially trained crew,

will take the airplane out and exercise all the systems,

including the alternate systems.

Controller: Ok, triple 8 tango, departure is three-November.

Kaeppel: Three-November. Do you have that?

Cox: The test director and the pilots

go through the test plan

and agree, step by step, what they're going to do.

It is a very intense period of time

because you have a lot to do in a short period of time.

Controller: Triple 8 tango,

cleared for takeoff, runway 3-3.

Narrator: There are no regular passengers

on this kind of flight,

but three engineers

and an aviation official from New Zealand

are along for the ride.

When the test is complete,

they'll stay on board for the flight home to New Zealand.

Cox: They are about to inherit

the maintenance responsibility for this aircraft.

So having engineers very close to the airplane

for an extended period of time

is good business, it's good safety.

It's the way it should be done.

Narrator: For Air New Zealand, a successful acceptance flight

is the key to getting this A320 back into commercial service

as soon as possible.

Ketzer: V-1.

Rotate.

Narrator: The Airbus A320

is one of the most automated passenger planes in the world.

Its advanced computer systems handle most of the flying,

reducing the possibility of pilot error.

Cox: It is different than a lot of conventional airplanes

in that you fly it through a computer.

But the handling characteristics of the airplane

are very, very good.

Narrator: The first test...

Ketzer: Gear up.

Narrator: Checks the system that stows the landing gear.

Horrell: Time.

Narrator: They need to make sure the gear locks into place

within a specific length of time.

Horrell: 14 seconds is good.

Controller: Triple 8 tango, bonjour.

Climb level 1-8-0.

Narrator: A new controller in Bordeaux takes over

as flight 888 leaves Perpignan airspace.

Ketzer: Climbing flight level 1-8-0.

Narrator: The flight plan calls for a 2 1/2-hour trip

that reaches the west coast of France

before looping back to Perpignan.

The route should provide an opportunity

to test nearly every system.

Kaeppel: Do you need anything from us while we climb?

Horrell: It just says to climb to flight level 3-1-0.

And bank angle to 33.

Check that it holds the bank angle.

And beyond 33 that it rolls back.

Narrator: Horrell asks the pilots

to bank the plane into a steep turn.

Kaeppel: Ok.

Narrator: The captain needs permission to turn so dramatically off course.

Kaeppel: I'll talk to them.

Triple 8 tango, just be advised, could we do one or two 360s?

We're an acceptance flight

so it would be nice if you could give us some airspace

to do a few procedures.

Narrator: The controller doesn't think it's safe.

Controller: We cannot allow test flights in general air traffic.

We are not doing this kind of flight, sir.

Kaeppel: Ok. Um...

So, the flight was actually requested like that.

Cox: European airspace has got a lot of airplanes

moving in a variety of directions.

If there is conflicting traffic around them,

then the air traffic controller

has no choice but to deny the request.

Narrator: Captain Kaeppel doesn't argue.

Kaeppel: So, no worries.

We'll just go back to Perpignan.

Cox: There is probably a very minor annoyance level,

but professional airmen are adaptive people by nature,

and so we'll adapt to it and we'll pick this up later.

Controller: Triple 8 tango,

descend flight level 3-1-0 and turn right.

Kaeppel: Turning right inbound, triple 8 tango.

Narrator: The Airbus will now loop back east of Bordeaux

and return to Perpignan.

Twenty minutes later,

Perpignan air traffic control has flight 888 back on radar.

But as the plane descends...

The captain begins to lose control.

Kaeppel: It's pitching up all the time.

It's pitching up.

Narrator: The plane tips up steeply.

Man: Does that seem right to you guys?

Horrell: Stick forward.

Narrator: The captain throttles up

and pushes his stick forward to bring the nose down.

But it doesn't work.

Cox: The captain's side stick goes forward.

It's clearly an effort to try to lower the nose.

And I believe he does not understand

why the airplane doesn't respond

as he's applying pretty well full power.

Kaeppel: Flaps up. Flaps up!

Narrator: Pulling in the flaps reduces drag

and should help them regain control.

But it's no use.

The plane is diving towards the sea.

Man: Oh, god!

Oh, god!

Computer: Pull up.

Kaeppel: Damn it!

Computer: Pull up.

Controller: Triple 8 tango, contact tower.

Triple 8 tango, contact tower.

I've got an emergency.

Narrator: Search and rescue teams

race to flight 888's last known location,

but there's no sign of any survivors.

Man: This is clearly difficult and devastating news

for the families of all concerned worldwide.

Narrator: The search goes on into the night.

Investigators question witnesses along the coast

about the last moments of the flight.

Man, translated: I saw the plane flying over me.

All of a sudden, it went into a dive.

Man: This is the map we're working with.

Narrator: French Air crash investigators from the BEA

are responsible for figuring out what went wrong.

Man: It went down right...here.

Narrator: Sebastien David leads the investigation.

Sebastien David: The first phase of the sea search operation

was finding precisely where the wreckage was.

Narrator: David and his team are under enormous pressure.

David: I want you to mobilize all the resources.

Narrator: The A320

is one of the industry's most popular passenger planes.

David: A large number of this kind of aircraft

is being flown all over the world.

Narrator: It's also the first airliner

to use advanced computerized controls.

Cox: With the A320,

automation flies the airplane the majority of the time.

Narrator: If there's a problem

with the plane's high-tech flight computers,

many more lives could be at risk.

Investigators need to find the cause of the crash quickly,

before it happens again.

No one has survived the crash of XL Airways flight 888.

Grieving families arrive in France

to recover the bodies of their loved ones.

Woman: I didn't expect to be on my own at 34,

um, like this.

Narrator: Air New Zealand executives

are also on the scene.

Man: My commitment to the families was

I want to stay here until we can bring our boys home,

or we're in a position to determine

that that's not possible.

David: What on earth is an acceptance flight?

Narrator: The unusual nature of the flight

presents an extra challenge for investigators.

David: We did not have any reference

for that kind of flight.

There was no defined framework.

Narrator: No one may ever know what the crew was doing

unless they can find the plane's flight recorders.

Man: We have to send the divers into the sea

to find the plane.

Narrator: But the bad weather is making it nearly impossible

for divers to locate the wreckage.

Man: With the worsening forecast,

the search and rescue teams have re-emphasized personally to me

that there is real urgency behind their efforts

to locate the two flight recorders.

Narrator: Yann Torres leads the recovery effort.

Yann Torres, translated: Most of the time

there was severe wind and swells on the surface,

which made visibility on the bottom deplorable--

that is, only 50 centimeters to a meter.

Narrator: Searchers turn to sonar

to hunt for debris from the plane on the sea floor.

Torres: This was possible,

thanks to a minesweeper from the navy.

By using sonar,

we were able to identify the larger pieces of wreckage.

Narrator: But finding the wreckage

is only half the battle.

Bringing it to the surface will take more time.

David: It was climbing like this when you saw it?

Narrator: Investigators ask witnesses

to describe the motion of the plane.

David: Some of them related an unusual flight path.

Witnesses say it was climbing here.

And they were descending here.

Right here it looks like they lost control of the plane.

Those testimonies were very important

for the beginning of the investigation.

Narrator: Investigators wonder if the pilots lost control

attempting a risky flight test.

They ask controllers what they know.

Controller: They wanted to do some 360s.

Kaeppel: We're an acceptance flight,

so it would be nice if you could give us some airspace

to do a few procedures.

Controller: I told them, "No way."

Narrator: They learn the pilots asked permission

to perform some tests,

but that the controller turned them down.

Controller: We are not doing this kind of flight, sir.

Kaeppel: So, no worries.

We'll just head back to Perpignan.

Narrator: If the flight test was called off,

there must be another explanation

for the plane's unusual flight path.

Three days after the crash, a major breakthrough.

The recovery team finds the black boxes.

The flight data recorder and cockpit voice recorder

may hold the clues investigators need.

Man: Nice and easy.

Narrator: Johan Condette is a BEA Investigator.

Johan Condette, translated: The recorders were recovered

very quickly,

which made us think that we would be able

to recover the data on the recorders just as quickly.

Narrator: The boxes are drenched in seawater.

The memory cards need to be dried out

before the data can be recovered.

Condette: We open it.

We remove the various layers of protection

that the memory card is wrapped in.

And once the card has been extracted, we dry it,

and then we read it out.

Narrator: But this time, it doesn't work.

Condette: Damn it!

There must still be some moisture in there.

We weren't able to recover the data.

And we have a laboratory designed just for that job,

so it was very frustrating.

Narrator: Investigators suspect moisture could be trapped

deep in the electronics.

Desperate to know what the pilots of flight 888 were doing,

they take the boxes to their U.S. Manufacturer.

Condette: Honeywell has special equipment

for reading the cards individually.

It seemed to us the quickest way to recover the data.

Narrator: While they wait for word on the data,

investigators turn to the wreckage

recovered from the sea floor.

They focus on pieces from the engines.

Horrell: Stick forward.

Narrator: If the engines failed,

it could explain why the plane fell into a fatal dive.

Bent blades from the engine turbines

provide an important clue.

Torres: We could see significant damage

inside the turbines.

And this suggests the engines

were at significant speed of rotation at impact.

Narrator: The type of damage tells investigators

that the engines were working properly

when the plane hit the water.

David: No sign of any problems here.

The engineers worked on these for three weeks.

Narrator: Investigators study the A320's maintenance records.

David: See if we can find something, ok?

Narrator: They know that engineers spent three weeks

preparing the plane

for its return to the Air New Zealand fleet.

Cox: It's a good thing for both parties to recognize

exactly the state of the airplane

when the operational control of the airplane

reverts from one party to another.

Narrator: If the aircraft had a mechanical problem

or defect,

there should be a record of it in the file.

But there's nothing that even hints

at a problem with the plane.

David: Anyone? Anything?

Nothing?

Cox: They were comfortable

that the airplane was not only safe to fly,

but in condition that matched the contractual obligations.

Narrator: Investigators still have no idea what brought down flight 888,

so getting the black box data is more important than ever.

David: It was a big frustration.

We were sure that the flight recorder's data

would help us to understand what happened.

Narrator: Six weeks after the crash of XL Airways flight 888,

the water-soaked flight recorders are repaired,

and investigators can finally listen to the conversations

captured in the cockpit.

David: Let's hear this.

Kaeppel: We're an acceptance flight,

so it would be nice if you could give us some airspace

to do a few procedures.

Narrator: What they hear confirms that the controller

didn't give the crew permission to fly any tests.

Controller: We cannot allow test flights

in general air traffic.

We cannot do this kind of flight, sir.

Narrator: Then they hear something disturbing.

Horrell: We haven't done a VHF-3 yet, have we?

We've got to do a call on that.

Narrator: Despite the controller's refusal,

the crew continues testing the plane.

Kaeppel: Ok, we can do the VHF-3.

David: Stop.

Play that back.

Narrator: Investigators listen

and take note of the tests the crew performed.

Kaeppel: Ok, we can do the VHF-3.

David: Navigation systems, 2.

The fact that the ATC controller

did not allow the crew to perform the 360

led to a situation where the crew had to improvise

to be able to follow the flight program.

Controller: Triple 8 tango,

descend flight level 3-1-0 and turn right.

Kaeppel: Turning right inbound, triple 8 tango.

Narrator: The crew finds a way to fit some tests in

while they fly back to Perpignan.

Horrell: Ok, that's good.

During the turn, let's roll to 33, then to 45.

Narrator: A right turn

gives the captain a chance to test the system

that prevents the plane from banking too steeply.

Horrell: Hands off now.

Narrator: Then he waits for the flight computer

to level the plane.

Horrell: Yup, yes, voila. It's all good.

David: Bank angle test, 7.

The tests are out of order.

They're improvising now.

Cox: They recognized at that moment

they were not going to finish the entire test plan.

So, what can we do to maximize the time we have left?

Horrell: We need to overspeed.

David: They followed the flight program,

taking into account

opportunities that were presented to them.

Kaeppel: You just want to hear the overspeed warning?

Narrator: Many of the tests

activate the plane's safety systems

and set off alarms in the cockpit.

Horrell: There it is.

You can cancel the warning if you like.

David: Overspeed, 8.

Narrator: The crew manages to complete twelve tests

in just half an hour.

David: That's a busy crew.

Cox: An acceptance flight

is very enjoyable from a pilot's standpoint.

But it is a very challenging environment

because you're doing a lot of things with the airplane.

David: We had the impression

that everything went very fast for the crew.

Narrator: As the plane descends below the clouds,

the crew sees an opportunity to do another test.

Kaeppel: So, you want what?

Horrell: Yeah, we need to go slow with recovery.

Cox: This test requires

that the airplane be slowed well below normal speed

to let the automated protections activate

and then record what they do.

Narrator: When the Airbus slows down too much,

the flight control computer should automatically boost speed

to prevent the plane from losing lift.

Kaeppel: Down below the clouds.

Cox: You would not want to do slow flight conditions

at very low altitudes.

Those would be items that you'd want to do at 10,000 feet,

because if something does go wrong,

you want to have room to maneuver and sort it out.

Horrell: Get your power at idle.

Adjust pitch.

Flaps full.

Narrator: The captain reduces speed

and waits for the automatic protections to kick in.

But this time, nothing happens.

Suddenly, this test is going horribly wrong.

Kaeppel: It's pitching up all the time.

David: Why didn't the stall protection kick in?

Cox: Why isn't the airplane responding?

What do we need to do?

Is there something else wrong?

It's a diagnostic process

that you don't have a lot of time with.

So, the big question that keeps coming back up is,

why isn't the airplane responding

as it has always done for me before?

Narrator: Airbus' automated protection system

has proved invaluable on other flights.

In 2009, just after takeoff from New York...

A flock of geese disables both engines

on a U.S. Airways A320.

As Pilot Sully Sullenberger

prepares to ditch the plane in the Hudson River,

the computer automatically adjusts the plane's angle

into the wind,

the angle of attack.

It keeps him from stalling,

saving the lives of everyone onboard.

Investigators wonder if the crash of flight 888

has revealed a hidden flaw

in one of aviation's most famous electronic safety nets--

a flaw that is putting thousands of passengers at risk every day.

David: We had to understand the conditions

which could have led to this situation.

Narrator: As the investigation

into the crash of flight 888 continues,

the BEA learns of another aviation tragedy.

An Air France Airbus A330 has crashed off the coast of brazil,

killing all 228 people on board.

Sebastien David is losing some of his best investigators

as they are reassigned to deal with the Air France crash.

David: The team we had at the beginning of the investigation

had to split into both investigations.

So that makes it more difficult to conduct the investigation.

Narrator: David and his smaller team

now face even more pressure to solve the mystery of flight 888.

Condette: Monsieur David,

I have the angle of attack sensor data.

Narrator: Investigators hope

the flight data recorder from XL Airways flight 888

will finally explain what went wrong

in the skies over Perpignan, France.

Information from a key set of sensors stands out.

David: That's odd.

Narrator: Partway through the flight,

two critical sensors failed at exactly the same time.

David: We know they were descending here,

but the sensors still show a climb.

Narrator: Angle of attack sensors

act like small weather vanes on the outside of the plane.

During flight, they pivot.

Their movement helps the flight computer

monitor the position of the plane

so it can automatically adjust the flight systems

to maintain lift.

Cox: It is something

that airplanes calculate continuously,

and it is most critical

as far as advising the pilots of an impending stall.

Narrator: If the sensors got stuck in one position

when they malfunctioned,

it would explain why the computer didn't detect

the dangerous angle of the plane.

David: We need to get a look at those sensors.

Narrator: But the sensors are still missing

at the bottom of the sea.

Torres: The entire gendarmerie

was mobilized for the search.

We made it understood

that it was absolutely critical for our investigation.

Narrator: The wreckage is so deep

that divers must work in shifts

to avoid decompression sickness,

or the bends.

Torres: Diving at 40 meters starts to become

what we call a deep dive.

And so a diver can only be exposed for a short time

because we're dealing with compressed air.

Narrator: Investigators catch a lucky break.

After two days of searching,

divers manage to recover both sensors.

Torres: One was still attached to a part of the fuselage.

A second was sitting by itself on the bottom.

Narrator: Investigators test the mechanism

that allows the sensors to move.

David: Anything?

Narrator: It's working perfectly.

David: It was very difficult to imagine

a common technical problem

that led to the blockage of two angle of attack sensors

at the same time, at the same values.

Narrator: There seems to be no way to explain

why the sensors failed.

David: Well, something jammed them.

I want to see the FDR data again.

Narrator: David returns to the flight data

and searches for anything that might explain

why both sensors failed at exactly the same time.

Cox: I have never heard of

angle of attack simultaneous failures.

Narrator: David graphs altitudes

and corresponding air temperatures

throughout the flight.

David: Minus 50 at 32,000 feet.

Narrator: At high altitudes,

the air outside the plane is extremely cold.

This gives him an idea.

David: Can the sensors freeze?

Narrator: If there was ice in the sensor mechanism,

it might have frozen them in place.

The theory would explain

why they both jammed at the same time...

Kaeppel: It's pitching up all the time.

Narrator: Sending the plane's computer faulty data

about the angle of attack for the rest of the flight.

Kaeppel: It's pitching up.

Cox: With the two angle of attack vanes frozen,

the flight control computers were not going to get the input

that said you are reaching critical angle of attack.

Narrator: Investigators wonder if rainwater from a severe storm

flooded the sensors and then froze.

David: We investigated meteorological conditions

during the cruise

in order to find if those conditions

could have led to the jamming of the angle of attack sensors.

Narrator: It's a dead end.

David: The weather was nice that day.

Narrator: The plane didn't encounter any bad weather.

If water got inside the sensors,

it happened on the ground, not in the air.

But the advanced sensor is designed to keep rainwater out.

David: So, water would have to get all the way in here.

Narrator: To get inside and freeze,

the water would first have to travel

through a long, winding channel.

It seems like water had nothing to do with the failure.

The edge of one of the sensors

provides another intriguing lead.

It's coated with several layers of paint.

David: This should all be sanded off.

What else did those painters do?

We wanted to focus on all the maintenance operations

that could have had an influence on the sensors.

Narrator: Investigators visit the hangar

where the plane spent three weeks being serviced.

They learn the work included painting the plane,

replacing XL Airways' colors

with those of the Air New Zealand fleet.

David: This led to investigate the painting operations

because the angle of attack sensors

need some specific protections.

Narrator: The procedure directs painters

to cover the sensors first,

so they don't get clogged with paint.

Cox: When airplanes are painted, it's the same with your car--

very special protections have to be made for certain items.

With your car, you cover the headlights

because you don't want paint over the headlights.

That's a very simple analogy.

But to a much more complex way,

the same thing is true with airplanes.

Narrator: Investigators consider the possibility

that the sensors malfunctioned

because of a sloppy coat of paint.

Torres: At this point,

the investigation focused on finding out

if there was any possibility

that paint might have adhered there

and created a blockage

that prevented the rotation of the vane.

Narrator: They re-examine the angle of attack sensor data

from the flight recorder.

If paint was jamming the sensors,

it would have caused problems throughout the entire flight.

Ketzer: Climbing flight level 1-8-0.

Narrator: But the data clearly shows the sensors didn't fail

until 22 minutes after takeoff.

Kaeppel: Do you need anything from us while we climb?

Torres: The recorders showed

that the sensor was working at the beginning of the flight.

David: We need to get a look at those sensors.

Narrator: Investigators conclude paint wasn't the problem.

There must be another explanation for the failure.

They notice something else in the maintenance records.

The plane needed extra cleaning after the paint job was done.

David: Some dust was covering the top of the aircraft.

The maintenance people had to remove this dust.

Tell me exactly how you cleaned this plane.

Narrator: Normally, maintenance workers use a clean cloth

to remove any dust.

But this time, they rinse the plane with a hose.

David: The painting operations had taken a little bit of delay.

To rinse the aircraft was faster

than to use a clean cloth to remove the dust.

Narrator: Spraying uncovered sensors

with a high-pressure hose

might explain how water got so deep inside.

But the investigators need proof.

They mount a sensor in a test rig

and recreate the cleaning procedure.

Torres: Ok, hit it.

We knew the plane had been rinsed

with a fire hose plugged into the water main.

So we got hold of the details

regarding water pressure and flow.

Ok! Cut it.

Ok. Let's get it to the lab.

Narrator: Next, they place the sensor in a freezer...

And duplicate the cold air temperatures

found at 32,000 feet.

Torres: It was a massive ingestion of water

that solidified into ice.

I think we definitely got some ice in there.

It won't budge.

Narrator: The lab results seem to confirm

the investigators' hunch.

Ice inside the sensors could have frozen them in place.

But there's one final test they need to do

to be absolutely sure.

David: We performed a test flight

to check what could be the temperature

inside the angle of attack sensors.

That was the first time such a test was conducted

because nobody knew what could be the temperature

inside an angle of attack sensor.

Narrator: They flood the sensors of an A320 with water,

and recreate flight 888.

At low altitudes, the sensors work perfectly.

David: So far, so good.

Narrator: When the plane reaches 32,000 feet,

the temperature inside the sensor drops below freezing.

David: Here they go.

The sensors aren't moving.

Narrator: The water inside freezes,

and the sensors stop working.

David: The temperature was below zero degrees Celsius

when the aircraft reached a cruise altitude.

So this fact was coherent

with the freezing of some water inside the housing.

Ok, you can bring them home.

Narrator: The result explains why the flight computer

didn't prevent the plane from stalling

during the low speed test.

Horrell: Get your power at idle.

Adjust pitch.

Flaps full.

Narrator: With the sensors frozen,

the computer can't calculate the plane's true angle of attack.

Cox: The flight control computers

can only respond to data and inputs that they get.

In this case, the two angle of attack inputs

were simultaneously bad.

And the flight control computer has no way to know that.

Kaeppel: It's pitching up all the time.

It's pitching up.

Cox: Because the angle of attack vanes couldn't move,

they could not then activate the low speed protections

that the crew was expecting.

Narrator: The plane's automated safety systems

are effectively crippled.

But there's another mystery.

Horrell: Stick forward.

Narrator: Before the crash, the captain tries to fly out of trouble.

He increases power while pushing his side stick forward

to bring the nose down.

It's a textbook maneuver to prevent stalling.

But it doesn't work.

The plane continues to pitch up

until it loses lift and falls from the sky.

David: They tried to apply the nose-down input

on the side stick,

but their efforts were not sufficient.

Kaeppel: Damn it!

Narrator: Investigators need to know why.

A computer simulation

helps investigators analyze flight 888's final flight check,

the low speed test.

Horrell: Ok, get your power at idle.

Adjust pitch.

Flaps full.

Kaeppel: Ok. Here we go.

Narrator: Captain Kaeppel

deliberately slows his plane down for the test.

But the computer lets the speed drop too far--

below the minimum needed to keep the plane in flight.

David: They let their airspeed drop to 100 knots.

Condette: We noticed just how dramatically

their airspeed was falling.

Narrator: Investigators notice a warning

on the cockpit flight display

moments before the crash.

David: There. What is that?

Narrator: They learn that the warning

is supposed to alert the pilots

the flight computer is no longer helping to fly the plane.

It has switched to full manual mode.

Condette: You get a message in red

that appears in the middle of your primary flight display

telling you to use the manual elevator trim.

The message in English is "Use man pitch trim."

Narrator: The warning comes on

when the plane's computer gets conflicting information.

The frozen sensors are telling the computer

the plane is flying level,

while other onboard sensors

are relaying its extreme nose-up attitude.

One must be wrong.

Cox: The airplane by design,

when it starts getting data

that it cannot figure out what to do with,

reverted and said, "Alright, something is wrong.

We don't know what.

This is up to the pilots to sort out."

David: The plane gave the pilots control right here.

Narrator: It seems the crew of flight 888

either didn't see or didn't understand

the warning being sent by the computer.

Horrell: Stick forward.

Narrator: The pilot uses his side stick

to try to lower the nose.

Horrell: Stick forward.

Narrator: In manual mode, that's just not enough.

The crew also needs to adjust the trim wheel

for a more dramatic change of pitch.

Cox: The auto trim system is disabled,

and the pilots were required to do that manually.

Narrator: But they never do.

Cox: Now the pilots find themselves

in a very, very difficult situation.

The airplane's not accelerating,

the nose is coming up,

it's very hard to get it to come down,

and they're at low altitude.

David: The two crew members tried everything to recover

and to take the control of the aircraft.

But they did not fully understand the situation.

Narrator: Investigators check the pilots' qualifications.

Perhaps poor training accounts for their failure

to respond properly to cockpit warnings.

David: The captain who was the pilot flying

was the head of the operations divisions in the airline.

The co-pilot was also very experienced as a co-pilot.

And the captain that was sitting on the observer seat

was also a very experienced captain.

Everything looks fine.

Narrator: Their records are spotless.

David: And so the team was very experienced.

Narrator: Investigators need to know

why such an experienced crew failed to act quickly

when their plane was in danger.

They suspect one reason may be

the unusual nature of this flight--

an acceptance flight designed to test the plane's limits.

Horrell: Ok, that's good.

During the turn, let's roll to 33, then to 45.

Kaeppel: Ok.

Narrator: Every time they test the plane...

Horrell: Hands off now.

Narrator: The automation fixes the problem.

Horrell: Yup. Yes. Voila. It's all good.

Narrator: Even when they hear alarms,

they don't worry.

Horrell: We need to overspeed.

Kaeppel: You just want to hear the overspeed warning?

Narrator: They're expecting the plane

to correct the problem.

Horrell: There it is.

You can cancel the warning if you like.

Condette: They trusted their plane too much.

David: The crew allowed the speed to get so low

because they were very confident

in the good functioning of the aircraft.

Cox: Unfortunately in this case

they allowed it to go all the way to the point

that the airplane actually began to stall.

Horrell: Stick forward.

Cox: Then they were in a stall-recovery situation

without a lot of altitude to work with.

Kaeppel: Flaps up. Flaps up!

Narrator: With their plane in a catastrophic stall,

the seven men aboard flight 888 were doomed.

Man: Oh, god!

Oh, god!

Kaeppel: Damn it!

Cox: Our march toward automation

has nowhere come close to stopping.

And it's appropriate.

In previous generation airplanes,

you first learned to fly the airplane,

and then you learned to manage the automation.

In later generation airplanes,

you learn the automation as an integral part.

But we have to have the interface

between the pilots and the automation

improve and mature.

Narrator: The official accident report

highlights several contributing factors,

including the aircraft washing procedures

and the decision to perform flight checks at low altitude.

Horrell: Yeah, we need to go slow with recovery.

Narrator: The report also calls for clearer rules

governing acceptance flights

and more training for stall recovery.

David: This led the BEA to recommend training

for the pilots to be able to recover from stall conditions.

Cox: Improved training for loss-of-control events

is something that all pilots need.

Loss of control is the leading cause of fatalities

in all aspects of aviation.

So it is an area that we need to focus on as an industry

to keep our safety record improving.

Kaeppel: Gentlemen, good afternoon.

Cox: Acceptance test flying's gonna be with us.

Maintenance check flights are a necessary part of aviation.

Kaeppel: Better buckle up.

Cox: And so we need to take these lessons

and learn them well

because we're gonna be doing these flights again.